diff options
Diffstat (limited to 'source/blender/simulation')
| -rw-r--r-- | source/blender/simulation/BPH_mass_spring.h | 62 | ||||
| -rw-r--r-- | source/blender/simulation/CMakeLists.txt | 57 | ||||
| -rw-r--r-- | source/blender/simulation/intern/BPH_mass_spring.cpp | 1355 | ||||
| -rw-r--r-- | source/blender/simulation/intern/ConstrainedConjugateGradient.h | 335 | ||||
| -rw-r--r-- | source/blender/simulation/intern/eigen_utils.h | 236 | ||||
| -rw-r--r-- | source/blender/simulation/intern/hair_volume.cpp | 1274 | ||||
| -rw-r--r-- | source/blender/simulation/intern/implicit.h | 272 | ||||
| -rw-r--r-- | source/blender/simulation/intern/implicit_blender.c | 2360 | ||||
| -rw-r--r-- | source/blender/simulation/intern/implicit_eigen.cpp | 1509 |
9 files changed, 7460 insertions, 0 deletions
diff --git a/source/blender/simulation/BPH_mass_spring.h b/source/blender/simulation/BPH_mass_spring.h new file mode 100644 index 00000000000..5a8c78812a4 --- /dev/null +++ b/source/blender/simulation/BPH_mass_spring.h @@ -0,0 +1,62 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * The Original Code is Copyright (C) Blender Foundation + * All rights reserved. + */ + +/** \file + * \ingroup bph + */ + +#ifndef __BPH_MASS_SPRING_H__ +#define __BPH_MASS_SPRING_H__ + +#ifdef __cplusplus +extern "C" { +#endif + +struct ClothModifierData; +struct Depsgraph; +struct Implicit_Data; +struct ListBase; +struct Object; + +typedef enum eMassSpringSolverStatus { + BPH_SOLVER_SUCCESS = (1 << 0), + BPH_SOLVER_NUMERICAL_ISSUE = (1 << 1), + BPH_SOLVER_NO_CONVERGENCE = (1 << 2), + BPH_SOLVER_INVALID_INPUT = (1 << 3), +} eMassSpringSolverStatus; + +struct Implicit_Data *BPH_mass_spring_solver_create(int numverts, int numsprings); +void BPH_mass_spring_solver_free(struct Implicit_Data *id); +int BPH_mass_spring_solver_numvert(struct Implicit_Data *id); + +int BPH_cloth_solver_init(struct Object *ob, struct ClothModifierData *clmd); +void BPH_cloth_solver_free(struct ClothModifierData *clmd); +int BPH_cloth_solve(struct Depsgraph *depsgraph, + struct Object *ob, + float frame, + struct ClothModifierData *clmd, + struct ListBase *effectors); +void BKE_cloth_solver_set_positions(struct ClothModifierData *clmd); +void BKE_cloth_solver_set_volume(ClothModifierData *clmd); + +#ifdef __cplusplus +} +#endif + +#endif diff --git a/source/blender/simulation/CMakeLists.txt b/source/blender/simulation/CMakeLists.txt new file mode 100644 index 00000000000..10520a18513 --- /dev/null +++ b/source/blender/simulation/CMakeLists.txt @@ -0,0 +1,57 @@ +# ***** BEGIN GPL LICENSE BLOCK ***** +# +# This program is free software; you can redistribute it and/or +# modify it under the terms of the GNU General Public License +# as published by the Free Software Foundation; either version 2 +# of the License, or (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software Foundation, +# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. +# +# The Original Code is Copyright (C) 2014, Blender Foundation +# All rights reserved. +# ***** END GPL LICENSE BLOCK ***** + +set(INC + . + intern + ../blenkernel + ../blenlib + ../depsgraph + ../imbuf + ../makesdna + ../../../intern/guardedalloc +) + +set(INC_SYS + ${EIGEN3_INCLUDE_DIRS} +) + +set(SRC + intern/BPH_mass_spring.cpp + intern/ConstrainedConjugateGradient.h + intern/eigen_utils.h + intern/hair_volume.cpp + intern/implicit.h + intern/implicit_blender.c + intern/implicit_eigen.cpp + + BPH_mass_spring.h +) + +set(LIB +) + +if(WITH_OPENMP_STATIC) + list(APPEND LIB + ${OpenMP_LIBRARIES} + ) +endif() + +blender_add_lib(bf_physics "${SRC}" "${INC}" "${INC_SYS}" "${LIB}") diff --git a/source/blender/simulation/intern/BPH_mass_spring.cpp b/source/blender/simulation/intern/BPH_mass_spring.cpp new file mode 100644 index 00000000000..051f11aa1d9 --- /dev/null +++ b/source/blender/simulation/intern/BPH_mass_spring.cpp @@ -0,0 +1,1355 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * The Original Code is Copyright (C) Blender Foundation + * All rights reserved. + */ + +/** \file + * \ingroup bph + */ + +#include "MEM_guardedalloc.h" + +#include "DNA_cloth_types.h" +#include "DNA_meshdata_types.h" +#include "DNA_modifier_types.h" +#include "DNA_object_force_types.h" +#include "DNA_object_types.h" +#include "DNA_scene_types.h" + +#include "BLI_linklist.h" +#include "BLI_math.h" +#include "BLI_utildefines.h" + +#include "BKE_cloth.h" +#include "BKE_collision.h" +#include "BKE_effect.h" + +#include "BPH_mass_spring.h" +#include "implicit.h" + +#include "DEG_depsgraph.h" +#include "DEG_depsgraph_query.h" + +static float I3[3][3] = {{1.0, 0.0, 0.0}, {0.0, 1.0, 0.0}, {0.0, 0.0, 1.0}}; + +/* Number of off-diagonal non-zero matrix blocks. + * Basically there is one of these for each vertex-vertex interaction. + */ +static int cloth_count_nondiag_blocks(Cloth *cloth) +{ + LinkNode *link; + int nondiag = 0; + + for (link = cloth->springs; link; link = link->next) { + ClothSpring *spring = (ClothSpring *)link->link; + switch (spring->type) { + case CLOTH_SPRING_TYPE_BENDING_HAIR: + /* angular bending combines 3 vertices */ + nondiag += 3; + break; + + default: + /* all other springs depend on 2 vertices only */ + nondiag += 1; + break; + } + } + + return nondiag; +} + +static bool cloth_get_pressure_weights(ClothModifierData *clmd, + const MVertTri *vt, + float *r_weights) +{ + /* We have custom vertex weights for pressure. */ + if (clmd->sim_parms->vgroup_pressure > 0) { + Cloth *cloth = clmd->clothObject; + ClothVertex *verts = cloth->verts; + + for (unsigned int j = 0; j < 3; j++) { + r_weights[j] = verts[vt->tri[j]].pressure_factor; + + /* Skip the entire triangle if it has a zero weight. */ + if (r_weights[j] == 0.0f) { + return false; + } + } + } + + return true; +} + +static void cloth_calc_pressure_gradient(ClothModifierData *clmd, + const float gradient_vector[3], + float *r_vertex_pressure) +{ + Cloth *cloth = clmd->clothObject; + Implicit_Data *data = cloth->implicit; + unsigned int mvert_num = cloth->mvert_num; + float pt[3]; + + for (unsigned int i = 0; i < mvert_num; i++) { + BPH_mass_spring_get_position(data, i, pt); + r_vertex_pressure[i] = dot_v3v3(pt, gradient_vector); + } +} + +static float cloth_calc_volume(ClothModifierData *clmd) +{ + /* Calculate the (closed) cloth volume. */ + Cloth *cloth = clmd->clothObject; + const MVertTri *tri = cloth->tri; + Implicit_Data *data = cloth->implicit; + float weights[3] = {1.0f, 1.0f, 1.0f}; + float vol = 0; + + /* Early exit for hair, as it never has volume. */ + if (clmd->hairdata) { + return 0.0f; + } + + for (unsigned int i = 0; i < cloth->primitive_num; i++) { + const MVertTri *vt = &tri[i]; + + if (cloth_get_pressure_weights(clmd, vt, weights)) { + vol += BPH_tri_tetra_volume_signed_6x(data, vt->tri[0], vt->tri[1], vt->tri[2]); + } + } + + /* We need to divide by 6 to get the actual volume. */ + vol = vol / 6.0f; + + return vol; +} + +static float cloth_calc_rest_volume(ClothModifierData *clmd) +{ + /* Calculate the (closed) cloth volume. */ + Cloth *cloth = clmd->clothObject; + const MVertTri *tri = cloth->tri; + const ClothVertex *v = cloth->verts; + float weights[3] = {1.0f, 1.0f, 1.0f}; + float vol = 0; + + /* Early exit for hair, as it never has volume. */ + if (clmd->hairdata) { + return 0.0f; + } + + for (unsigned int i = 0; i < cloth->primitive_num; i++) { + const MVertTri *vt = &tri[i]; + + if (cloth_get_pressure_weights(clmd, vt, weights)) { + vol += volume_tri_tetrahedron_signed_v3_6x( + v[vt->tri[0]].xrest, v[vt->tri[1]].xrest, v[vt->tri[2]].xrest); + } + } + + /* We need to divide by 6 to get the actual volume. */ + vol = vol / 6.0f; + + return vol; +} + +static float cloth_calc_average_pressure(ClothModifierData *clmd, const float *vertex_pressure) +{ + Cloth *cloth = clmd->clothObject; + const MVertTri *tri = cloth->tri; + Implicit_Data *data = cloth->implicit; + float weights[3] = {1.0f, 1.0f, 1.0f}; + float total_force = 0; + float total_area = 0; + + for (unsigned int i = 0; i < cloth->primitive_num; i++) { + const MVertTri *vt = &tri[i]; + + if (cloth_get_pressure_weights(clmd, vt, weights)) { + float area = BPH_tri_area(data, vt->tri[0], vt->tri[1], vt->tri[2]); + + total_force += (vertex_pressure[vt->tri[0]] + vertex_pressure[vt->tri[1]] + + vertex_pressure[vt->tri[2]]) * + area / 3.0f; + total_area += area; + } + } + + return total_force / total_area; +} + +int BPH_cloth_solver_init(Object *UNUSED(ob), ClothModifierData *clmd) +{ + Cloth *cloth = clmd->clothObject; + ClothVertex *verts = cloth->verts; + const float ZERO[3] = {0.0f, 0.0f, 0.0f}; + Implicit_Data *id; + unsigned int i, nondiag; + + nondiag = cloth_count_nondiag_blocks(cloth); + cloth->implicit = id = BPH_mass_spring_solver_create(cloth->mvert_num, nondiag); + + for (i = 0; i < cloth->mvert_num; i++) { + BPH_mass_spring_set_vertex_mass(id, i, verts[i].mass); + } + + for (i = 0; i < cloth->mvert_num; i++) { + BPH_mass_spring_set_motion_state(id, i, verts[i].x, ZERO); + } + + return 1; +} + +void BPH_cloth_solver_free(ClothModifierData *clmd) +{ + Cloth *cloth = clmd->clothObject; + + if (cloth->implicit) { + BPH_mass_spring_solver_free(cloth->implicit); + cloth->implicit = NULL; + } +} + +void BKE_cloth_solver_set_positions(ClothModifierData *clmd) +{ + Cloth *cloth = clmd->clothObject; + ClothVertex *verts = cloth->verts; + unsigned int mvert_num = cloth->mvert_num, i; + ClothHairData *cloth_hairdata = clmd->hairdata; + Implicit_Data *id = cloth->implicit; + + for (i = 0; i < mvert_num; i++) { + if (cloth_hairdata) { + ClothHairData *root = &cloth_hairdata[i]; + BPH_mass_spring_set_rest_transform(id, i, root->rot); + } + else { + BPH_mass_spring_set_rest_transform(id, i, I3); + } + + BPH_mass_spring_set_motion_state(id, i, verts[i].x, verts[i].v); + } +} + +void BKE_cloth_solver_set_volume(ClothModifierData *clmd) +{ + Cloth *cloth = clmd->clothObject; + + cloth->initial_mesh_volume = cloth_calc_rest_volume(clmd); +} + +/* Init constraint matrix + * This is part of the modified CG method suggested by Baraff/Witkin in + * "Large Steps in Cloth Simulation" (Siggraph 1998) + */ +static void cloth_setup_constraints(ClothModifierData *clmd) +{ + Cloth *cloth = clmd->clothObject; + Implicit_Data *data = cloth->implicit; + ClothVertex *verts = cloth->verts; + int mvert_num = cloth->mvert_num; + int v; + + const float ZERO[3] = {0.0f, 0.0f, 0.0f}; + + BPH_mass_spring_clear_constraints(data); + + for (v = 0; v < mvert_num; v++) { + if (verts[v].flags & CLOTH_VERT_FLAG_PINNED) { + /* pinned vertex constraints */ + BPH_mass_spring_add_constraint_ndof0(data, v, ZERO); /* velocity is defined externally */ + } + + verts[v].impulse_count = 0; + } +} + +/* computes where the cloth would be if it were subject to perfectly stiff edges + * (edge distance constraints) in a lagrangian solver. then add forces to help + * guide the implicit solver to that state. this function is called after + * collisions*/ +static int UNUSED_FUNCTION(cloth_calc_helper_forces)(Object *UNUSED(ob), + ClothModifierData *clmd, + float (*initial_cos)[3], + float UNUSED(step), + float dt) +{ + Cloth *cloth = clmd->clothObject; + float(*cos)[3] = (float(*)[3])MEM_callocN(sizeof(float[3]) * cloth->mvert_num, + "cos cloth_calc_helper_forces"); + float *masses = (float *)MEM_callocN(sizeof(float) * cloth->mvert_num, + "cos cloth_calc_helper_forces"); + LinkNode *node; + ClothSpring *spring; + ClothVertex *cv; + int i, steps; + + cv = cloth->verts; + for (i = 0; i < cloth->mvert_num; i++, cv++) { + copy_v3_v3(cos[i], cv->tx); + + if (cv->goal == 1.0f || len_squared_v3v3(initial_cos[i], cv->tx) != 0.0f) { + masses[i] = 1e+10; + } + else { + masses[i] = cv->mass; + } + } + + steps = 55; + for (i = 0; i < steps; i++) { + for (node = cloth->springs; node; node = node->next) { + /* ClothVertex *cv1, *cv2; */ /* UNUSED */ + int v1, v2; + float len, c, l, vec[3]; + + spring = (ClothSpring *)node->link; + if (spring->type != CLOTH_SPRING_TYPE_STRUCTURAL && + spring->type != CLOTH_SPRING_TYPE_SHEAR) { + continue; + } + + v1 = spring->ij; + v2 = spring->kl; + /* cv1 = cloth->verts + v1; */ /* UNUSED */ + /* cv2 = cloth->verts + v2; */ /* UNUSED */ + len = len_v3v3(cos[v1], cos[v2]); + + sub_v3_v3v3(vec, cos[v1], cos[v2]); + normalize_v3(vec); + + c = (len - spring->restlen); + if (c == 0.0f) { + continue; + } + + l = c / ((1.0f / masses[v1]) + (1.0f / masses[v2])); + + mul_v3_fl(vec, -(1.0f / masses[v1]) * l); + add_v3_v3(cos[v1], vec); + + sub_v3_v3v3(vec, cos[v2], cos[v1]); + normalize_v3(vec); + + mul_v3_fl(vec, -(1.0f / masses[v2]) * l); + add_v3_v3(cos[v2], vec); + } + } + + cv = cloth->verts; + for (i = 0; i < cloth->mvert_num; i++, cv++) { + float vec[3]; + + /*compute forces*/ + sub_v3_v3v3(vec, cos[i], cv->tx); + mul_v3_fl(vec, cv->mass * dt * 20.0f); + add_v3_v3(cv->tv, vec); + // copy_v3_v3(cv->tx, cos[i]); + } + + MEM_freeN(cos); + MEM_freeN(masses); + + return 1; +} + +BLI_INLINE void cloth_calc_spring_force(ClothModifierData *clmd, ClothSpring *s) +{ + Cloth *cloth = clmd->clothObject; + ClothSimSettings *parms = clmd->sim_parms; + Implicit_Data *data = cloth->implicit; + bool using_angular = parms->bending_model == CLOTH_BENDING_ANGULAR; + bool resist_compress = (parms->flags & CLOTH_SIMSETTINGS_FLAG_RESIST_SPRING_COMPRESS) && + !using_angular; + + s->flags &= ~CLOTH_SPRING_FLAG_NEEDED; + + /* Calculate force of bending springs. */ + if ((s->type & CLOTH_SPRING_TYPE_BENDING) && using_angular) { +#ifdef CLOTH_FORCE_SPRING_BEND + float k, scaling; + + s->flags |= CLOTH_SPRING_FLAG_NEEDED; + + scaling = parms->bending + s->ang_stiffness * fabsf(parms->max_bend - parms->bending); + k = scaling * s->restlen * + 0.1f; /* Multiplying by 0.1, just to scale the forces to more reasonable values. */ + + BPH_mass_spring_force_spring_angular( + data, s->ij, s->kl, s->pa, s->pb, s->la, s->lb, s->restang, k, parms->bending_damping); +#endif + } + + /* Calculate force of structural + shear springs. */ + if (s->type & + (CLOTH_SPRING_TYPE_STRUCTURAL | CLOTH_SPRING_TYPE_SEWING | CLOTH_SPRING_TYPE_INTERNAL)) { +#ifdef CLOTH_FORCE_SPRING_STRUCTURAL + float k_tension, scaling_tension; + + s->flags |= CLOTH_SPRING_FLAG_NEEDED; + + scaling_tension = parms->tension + + s->lin_stiffness * fabsf(parms->max_tension - parms->tension); + k_tension = scaling_tension / (parms->avg_spring_len + FLT_EPSILON); + + if (s->type & CLOTH_SPRING_TYPE_SEWING) { + /* TODO: verify, half verified (couldn't see error) + * sewing springs usually have a large distance at first so clamp the force so we don't get + * tunneling through collision objects. */ + BPH_mass_spring_force_spring_linear(data, + s->ij, + s->kl, + s->restlen, + k_tension, + parms->tension_damp, + 0.0f, + 0.0f, + false, + false, + parms->max_sewing); + } + else if (s->type & CLOTH_SPRING_TYPE_STRUCTURAL) { + float k_compression, scaling_compression; + scaling_compression = parms->compression + + s->lin_stiffness * fabsf(parms->max_compression - parms->compression); + k_compression = scaling_compression / (parms->avg_spring_len + FLT_EPSILON); + + BPH_mass_spring_force_spring_linear(data, + s->ij, + s->kl, + s->restlen, + k_tension, + parms->tension_damp, + k_compression, + parms->compression_damp, + resist_compress, + using_angular, + 0.0f); + } + else { + /* CLOTH_SPRING_TYPE_INTERNAL */ + BLI_assert(s->type & CLOTH_SPRING_TYPE_INTERNAL); + + scaling_tension = parms->internal_tension + + s->lin_stiffness * + fabsf(parms->max_internal_tension - parms->internal_tension); + k_tension = scaling_tension / (parms->avg_spring_len + FLT_EPSILON); + float scaling_compression = parms->internal_compression + + s->lin_stiffness * fabsf(parms->max_internal_compression - + parms->internal_compression); + float k_compression = scaling_compression / (parms->avg_spring_len + FLT_EPSILON); + + float k_tension_damp = parms->tension_damp; + float k_compression_damp = parms->compression_damp; + + if (k_tension == 0.0f) { + /* No damping so it behaves as if no tension spring was there at all. */ + k_tension_damp = 0.0f; + } + + if (k_compression == 0.0f) { + /* No damping so it behaves as if no compression spring was there at all. */ + k_compression_damp = 0.0f; + } + + BPH_mass_spring_force_spring_linear(data, + s->ij, + s->kl, + s->restlen, + k_tension, + k_tension_damp, + k_compression, + k_compression_damp, + resist_compress, + using_angular, + 0.0f); + } +#endif + } + else if (s->type & CLOTH_SPRING_TYPE_SHEAR) { +#ifdef CLOTH_FORCE_SPRING_SHEAR + float k, scaling; + + s->flags |= CLOTH_SPRING_FLAG_NEEDED; + + scaling = parms->shear + s->lin_stiffness * fabsf(parms->max_shear - parms->shear); + k = scaling / (parms->avg_spring_len + FLT_EPSILON); + + BPH_mass_spring_force_spring_linear(data, + s->ij, + s->kl, + s->restlen, + k, + parms->shear_damp, + 0.0f, + 0.0f, + resist_compress, + false, + 0.0f); +#endif + } + else if (s->type & CLOTH_SPRING_TYPE_BENDING) { /* calculate force of bending springs */ +#ifdef CLOTH_FORCE_SPRING_BEND + float kb, cb, scaling; + + s->flags |= CLOTH_SPRING_FLAG_NEEDED; + + scaling = parms->bending + s->lin_stiffness * fabsf(parms->max_bend - parms->bending); + kb = scaling / (20.0f * (parms->avg_spring_len + FLT_EPSILON)); + + // Fix for [#45084] for cloth stiffness must have cb proportional to kb + cb = kb * parms->bending_damping; + + BPH_mass_spring_force_spring_bending(data, s->ij, s->kl, s->restlen, kb, cb); +#endif + } + else if (s->type & CLOTH_SPRING_TYPE_BENDING_HAIR) { +#ifdef CLOTH_FORCE_SPRING_BEND + float kb, cb, scaling; + + s->flags |= CLOTH_SPRING_FLAG_NEEDED; + + /* XXX WARNING: angular bending springs for hair apply stiffness factor as an overall factor, + * unlike cloth springs! this is crap, but needed due to cloth/hair mixing ... max_bend factor + * is not even used for hair, so ... + */ + scaling = s->lin_stiffness * parms->bending; + kb = scaling / (20.0f * (parms->avg_spring_len + FLT_EPSILON)); + + // Fix for [#45084] for cloth stiffness must have cb proportional to kb + cb = kb * parms->bending_damping; + + /* XXX assuming same restlen for ij and jk segments here, + * this can be done correctly for hair later. */ + BPH_mass_spring_force_spring_bending_hair(data, s->ij, s->kl, s->mn, s->target, kb, cb); + +# if 0 + { + float x_kl[3], x_mn[3], v[3], d[3]; + + BPH_mass_spring_get_motion_state(data, s->kl, x_kl, v); + BPH_mass_spring_get_motion_state(data, s->mn, x_mn, v); + + BKE_sim_debug_data_add_dot(clmd->debug_data, x_kl, 0.9, 0.9, 0.9, "target", 7980, s->kl); + BKE_sim_debug_data_add_line( + clmd->debug_data, x_kl, x_mn, 0.8, 0.8, 0.8, "target", 7981, s->kl); + + copy_v3_v3(d, s->target); + BKE_sim_debug_data_add_vector( + clmd->debug_data, x_kl, d, 0.8, 0.8, 0.2, "target", 7982, s->kl); + + // copy_v3_v3(d, s->target_ij); + // BKE_sim_debug_data_add_vector(clmd->debug_data, x, d, 1, 0.4, 0.4, "target", 7983, s->kl); + } +# endif +#endif + } +} + +static void hair_get_boundbox(ClothModifierData *clmd, float gmin[3], float gmax[3]) +{ + Cloth *cloth = clmd->clothObject; + Implicit_Data *data = cloth->implicit; + unsigned int mvert_num = cloth->mvert_num; + int i; + + INIT_MINMAX(gmin, gmax); + for (i = 0; i < mvert_num; i++) { + float x[3]; + BPH_mass_spring_get_motion_state(data, i, x, NULL); + DO_MINMAX(x, gmin, gmax); + } +} + +static void cloth_calc_force( + Scene *scene, ClothModifierData *clmd, float UNUSED(frame), ListBase *effectors, float time) +{ + /* Collect forces and derivatives: F, dFdX, dFdV */ + Cloth *cloth = clmd->clothObject; + ClothSimSettings *parms = clmd->sim_parms; + Implicit_Data *data = cloth->implicit; + unsigned int i = 0; + float drag = clmd->sim_parms->Cvi * 0.01f; /* viscosity of air scaled in percent */ + float gravity[3] = {0.0f, 0.0f, 0.0f}; + const MVertTri *tri = cloth->tri; + unsigned int mvert_num = cloth->mvert_num; + ClothVertex *vert; + +#ifdef CLOTH_FORCE_GRAVITY + /* global acceleration (gravitation) */ + if (scene->physics_settings.flag & PHYS_GLOBAL_GRAVITY) { + /* scale gravity force */ + mul_v3_v3fl(gravity, + scene->physics_settings.gravity, + 0.001f * clmd->sim_parms->effector_weights->global_gravity); + } + + vert = cloth->verts; + for (i = 0; i < cloth->mvert_num; i++, vert++) { + BPH_mass_spring_force_gravity(data, i, vert->mass, gravity); + + /* Vertex goal springs */ + if ((!(vert->flags & CLOTH_VERT_FLAG_PINNED)) && (vert->goal > FLT_EPSILON)) { + float goal_x[3], goal_v[3]; + float k; + + /* divide by time_scale to prevent goal vertices' delta locations from being multiplied */ + interp_v3_v3v3(goal_x, vert->xold, vert->xconst, time / clmd->sim_parms->time_scale); + sub_v3_v3v3(goal_v, vert->xconst, vert->xold); /* distance covered over dt==1 */ + + k = vert->goal * clmd->sim_parms->goalspring / + (clmd->sim_parms->avg_spring_len + FLT_EPSILON); + + BPH_mass_spring_force_spring_goal( + data, i, goal_x, goal_v, k, clmd->sim_parms->goalfrict * 0.01f); + } + } +#endif + + /* cloth_calc_volume_force(clmd); */ + +#ifdef CLOTH_FORCE_DRAG + BPH_mass_spring_force_drag(data, drag); +#endif + /* handle pressure forces (making sure that this never gets computed for hair). */ + if ((parms->flags & CLOTH_SIMSETTINGS_FLAG_PRESSURE) && (clmd->hairdata == NULL)) { + /* The difference in pressure between the inside and outside of the mesh.*/ + float pressure_difference = 0.0f; + float volume_factor = 1.0f; + + float init_vol; + if (parms->flags & CLOTH_SIMSETTINGS_FLAG_PRESSURE_VOL) { + init_vol = clmd->sim_parms->target_volume; + } + else { + init_vol = cloth->initial_mesh_volume; + } + + /* Check if we need to calculate the volume of the mesh. */ + if (init_vol > 1E-6f) { + float f; + float vol = cloth_calc_volume(clmd); + + /* If the volume is the same don't apply any pressure. */ + volume_factor = init_vol / vol; + pressure_difference = volume_factor - 1; + + /* Calculate an artificial maximum value for cloth pressure. */ + f = fabs(clmd->sim_parms->uniform_pressure_force) + 200.0f; + + /* Clamp the cloth pressure to the calculated maximum value. */ + CLAMP_MAX(pressure_difference, f); + } + + pressure_difference += clmd->sim_parms->uniform_pressure_force; + pressure_difference *= clmd->sim_parms->pressure_factor; + + /* Compute the hydrostatic pressure gradient if enabled. */ + float fluid_density = clmd->sim_parms->fluid_density * 1000; /* kg/l -> kg/m3 */ + float *hydrostatic_pressure = NULL; + + if (fabs(fluid_density) > 1e-6f) { + float hydrostatic_vector[3]; + copy_v3_v3(hydrostatic_vector, gravity); + + /* When the fluid is inside the object, factor in the acceleration of + * the object into the pressure field, as gravity is indistinguishable + * from acceleration from the inside. */ + if (fluid_density > 0) { + sub_v3_v3(hydrostatic_vector, cloth->average_acceleration); + + /* Preserve the total mass by scaling density to match the change in volume. */ + fluid_density *= volume_factor; + } + + mul_v3_fl(hydrostatic_vector, fluid_density); + + /* Compute an array of per-vertex hydrostatic pressure, and subtract the average. */ + hydrostatic_pressure = (float *)MEM_mallocN(sizeof(float) * mvert_num, + "hydrostatic pressure gradient"); + + cloth_calc_pressure_gradient(clmd, hydrostatic_vector, hydrostatic_pressure); + + pressure_difference -= cloth_calc_average_pressure(clmd, hydrostatic_pressure); + } + + /* Apply pressure. */ + if (hydrostatic_pressure || fabs(pressure_difference) > 1E-6f) { + float weights[3] = {1.0f, 1.0f, 1.0f}; + + for (i = 0; i < cloth->primitive_num; i++) { + const MVertTri *vt = &tri[i]; + + if (cloth_get_pressure_weights(clmd, vt, weights)) { + BPH_mass_spring_force_pressure(data, + vt->tri[0], + vt->tri[1], + vt->tri[2], + pressure_difference, + hydrostatic_pressure, + weights); + } + } + } + + if (hydrostatic_pressure) { + MEM_freeN(hydrostatic_pressure); + } + } + + /* handle external forces like wind */ + if (effectors) { + bool is_not_hair = (clmd->hairdata == NULL) && (cloth->primitive_num > 0); + bool has_wind = false, has_force = false; + + /* cache per-vertex forces to avoid redundant calculation */ + float(*winvec)[3] = (float(*)[3])MEM_callocN(sizeof(float[3]) * mvert_num * 2, + "effector forces"); + float(*forcevec)[3] = is_not_hair ? winvec + mvert_num : winvec; + + for (i = 0; i < cloth->mvert_num; i++) { + float x[3], v[3]; + EffectedPoint epoint; + + BPH_mass_spring_get_motion_state(data, i, x, v); + pd_point_from_loc(scene, x, v, i, &epoint); + BKE_effectors_apply(effectors, + NULL, + clmd->sim_parms->effector_weights, + &epoint, + forcevec[i], + winvec[i], + NULL); + + has_wind = has_wind || !is_zero_v3(winvec[i]); + has_force = has_force || !is_zero_v3(forcevec[i]); + } + + /* Hair has only edges. */ + if (is_not_hair) { + for (i = 0; i < cloth->primitive_num; i++) { + const MVertTri *vt = &tri[i]; + if (has_wind) { + BPH_mass_spring_force_face_wind(data, vt->tri[0], vt->tri[1], vt->tri[2], winvec); + } + if (has_force) { + BPH_mass_spring_force_face_extern(data, vt->tri[0], vt->tri[1], vt->tri[2], forcevec); + } + } + } + else { +#if 0 + ClothHairData *hairdata = clmd->hairdata; + ClothHairData *hair_ij, *hair_kl; + + for (LinkNode *link = cloth->springs; link; link = link->next) { + ClothSpring *spring = (ClothSpring *)link->link; + if (spring->type == CLOTH_SPRING_TYPE_STRUCTURAL) { + if (hairdata) { + hair_ij = &hairdata[spring->ij]; + hair_kl = &hairdata[spring->kl]; + BPH_mass_spring_force_edge_wind( + data, spring->ij, spring->kl, hair_ij->radius, hair_kl->radius, winvec); + } + else { + BPH_mass_spring_force_edge_wind(data, spring->ij, spring->kl, 1.0f, 1.0f, winvec); + } + } + } +#else + ClothHairData *hairdata = clmd->hairdata; + + vert = cloth->verts; + for (i = 0; i < cloth->mvert_num; i++, vert++) { + if (hairdata) { + ClothHairData *hair = &hairdata[i]; + BPH_mass_spring_force_vertex_wind(data, i, hair->radius, winvec); + } + else { + BPH_mass_spring_force_vertex_wind(data, i, 1.0f, winvec); + } + } +#endif + } + + MEM_freeN(winvec); + } + + // calculate spring forces + for (LinkNode *link = cloth->springs; link; link = link->next) { + ClothSpring *spring = (ClothSpring *)link->link; + // only handle active springs + if (!(spring->flags & CLOTH_SPRING_FLAG_DEACTIVATE)) { + cloth_calc_spring_force(clmd, spring); + } + } +} + +/* returns vertexes' motion state */ +BLI_INLINE void cloth_get_grid_location(Implicit_Data *data, + float cell_scale, + const float cell_offset[3], + int index, + float x[3], + float v[3]) +{ + BPH_mass_spring_get_position(data, index, x); + BPH_mass_spring_get_new_velocity(data, index, v); + + mul_v3_fl(x, cell_scale); + add_v3_v3(x, cell_offset); +} + +/* returns next spring forming a continuous hair sequence */ +BLI_INLINE LinkNode *hair_spring_next(LinkNode *spring_link) +{ + ClothSpring *spring = (ClothSpring *)spring_link->link; + LinkNode *next = spring_link->next; + if (next) { + ClothSpring *next_spring = (ClothSpring *)next->link; + if (next_spring->type == CLOTH_SPRING_TYPE_STRUCTURAL && next_spring->kl == spring->ij) { + return next; + } + } + return NULL; +} + +/* XXX this is nasty: cloth meshes do not explicitly store + * the order of hair segments! + * We have to rely on the spring build function for now, + * which adds structural springs in reverse order: + * (3,4), (2,3), (1,2) + * This is currently the only way to figure out hair geometry inside this code ... + */ +static LinkNode *cloth_continuum_add_hair_segments(HairGrid *grid, + const float cell_scale, + const float cell_offset[3], + Cloth *cloth, + LinkNode *spring_link) +{ + Implicit_Data *data = cloth->implicit; + LinkNode *next_spring_link = NULL; /* return value */ + ClothSpring *spring1, *spring2, *spring3; + // ClothVertex *verts = cloth->verts; + // ClothVertex *vert3, *vert4; + float x1[3], v1[3], x2[3], v2[3], x3[3], v3[3], x4[3], v4[3]; + float dir1[3], dir2[3], dir3[3]; + + spring1 = NULL; + spring2 = NULL; + spring3 = (ClothSpring *)spring_link->link; + + zero_v3(x1); + zero_v3(v1); + zero_v3(dir1); + zero_v3(x2); + zero_v3(v2); + zero_v3(dir2); + + // vert3 = &verts[spring3->kl]; + cloth_get_grid_location(data, cell_scale, cell_offset, spring3->kl, x3, v3); + // vert4 = &verts[spring3->ij]; + cloth_get_grid_location(data, cell_scale, cell_offset, spring3->ij, x4, v4); + sub_v3_v3v3(dir3, x4, x3); + normalize_v3(dir3); + + while (spring_link) { + /* move on */ + spring1 = spring2; + spring2 = spring3; + + // vert3 = vert4; + + copy_v3_v3(x1, x2); + copy_v3_v3(v1, v2); + copy_v3_v3(x2, x3); + copy_v3_v3(v2, v3); + copy_v3_v3(x3, x4); + copy_v3_v3(v3, v4); + + copy_v3_v3(dir1, dir2); + copy_v3_v3(dir2, dir3); + + /* read next segment */ + next_spring_link = spring_link->next; + spring_link = hair_spring_next(spring_link); + + if (spring_link) { + spring3 = (ClothSpring *)spring_link->link; + // vert4 = &verts[spring3->ij]; + cloth_get_grid_location(data, cell_scale, cell_offset, spring3->ij, x4, v4); + sub_v3_v3v3(dir3, x4, x3); + normalize_v3(dir3); + } + else { + spring3 = NULL; + // vert4 = NULL; + zero_v3(x4); + zero_v3(v4); + zero_v3(dir3); + } + + BPH_hair_volume_add_segment( + grid, x1, v1, x2, v2, x3, v3, x4, v4, spring1 ? dir1 : NULL, dir2, spring3 ? dir3 : NULL); + } + + return next_spring_link; +} + +static void cloth_continuum_fill_grid(HairGrid *grid, Cloth *cloth) +{ +#if 0 + Implicit_Data *data = cloth->implicit; + int mvert_num = cloth->mvert_num; + ClothVertex *vert; + int i; + + for (i = 0, vert = cloth->verts; i < mvert_num; i++, vert++) { + float x[3], v[3]; + + cloth_get_vertex_motion_state(data, vert, x, v); + BPH_hair_volume_add_vertex(grid, x, v); + } +#else + LinkNode *link; + float cellsize, gmin[3], cell_scale, cell_offset[3]; + + /* scale and offset for transforming vertex locations into grid space + * (cell size is 0..1, gmin becomes origin) + */ + BPH_hair_volume_grid_geometry(grid, &cellsize, NULL, gmin, NULL); + cell_scale = cellsize > 0.0f ? 1.0f / cellsize : 0.0f; + mul_v3_v3fl(cell_offset, gmin, cell_scale); + negate_v3(cell_offset); + + link = cloth->springs; + while (link) { + ClothSpring *spring = (ClothSpring *)link->link; + if (spring->type == CLOTH_SPRING_TYPE_STRUCTURAL) { + link = cloth_continuum_add_hair_segments(grid, cell_scale, cell_offset, cloth, link); + } + else { + link = link->next; + } + } +#endif + BPH_hair_volume_normalize_vertex_grid(grid); +} + +static void cloth_continuum_step(ClothModifierData *clmd, float dt) +{ + ClothSimSettings *parms = clmd->sim_parms; + Cloth *cloth = clmd->clothObject; + Implicit_Data *data = cloth->implicit; + int mvert_num = cloth->mvert_num; + ClothVertex *vert; + + const float fluid_factor = 0.95f; /* blend between PIC and FLIP methods */ + float smoothfac = parms->velocity_smooth; + /* XXX FIXME arbitrary factor!!! this should be based on some intuitive value instead, + * like number of hairs per cell and time decay instead of "strength" + */ + float density_target = parms->density_target; + float density_strength = parms->density_strength; + float gmin[3], gmax[3]; + int i; + + /* clear grid info */ + zero_v3_int(clmd->hair_grid_res); + zero_v3(clmd->hair_grid_min); + zero_v3(clmd->hair_grid_max); + clmd->hair_grid_cellsize = 0.0f; + + hair_get_boundbox(clmd, gmin, gmax); + + /* gather velocities & density */ + if (smoothfac > 0.0f || density_strength > 0.0f) { + HairGrid *grid = BPH_hair_volume_create_vertex_grid( + clmd->sim_parms->voxel_cell_size, gmin, gmax); + + cloth_continuum_fill_grid(grid, cloth); + + /* main hair continuum solver */ + BPH_hair_volume_solve_divergence(grid, dt, density_target, density_strength); + + for (i = 0, vert = cloth->verts; i < mvert_num; i++, vert++) { + float x[3], v[3], nv[3]; + + /* calculate volumetric velocity influence */ + BPH_mass_spring_get_position(data, i, x); + BPH_mass_spring_get_new_velocity(data, i, v); + + BPH_hair_volume_grid_velocity(grid, x, v, fluid_factor, nv); + + interp_v3_v3v3(nv, v, nv, smoothfac); + + /* apply on hair data */ + BPH_mass_spring_set_new_velocity(data, i, nv); + } + + /* store basic grid info in the modifier data */ + BPH_hair_volume_grid_geometry(grid, + &clmd->hair_grid_cellsize, + clmd->hair_grid_res, + clmd->hair_grid_min, + clmd->hair_grid_max); + +#if 0 /* DEBUG hair velocity vector field */ + { + const int size = 64; + int i, j; + float offset[3], a[3], b[3]; + const int axis = 0; + const float shift = 0.0f; + + copy_v3_v3(offset, clmd->hair_grid_min); + zero_v3(a); + zero_v3(b); + + offset[axis] = shift * clmd->hair_grid_cellsize; + a[(axis + 1) % 3] = clmd->hair_grid_max[(axis + 1) % 3] - + clmd->hair_grid_min[(axis + 1) % 3]; + b[(axis + 2) % 3] = clmd->hair_grid_max[(axis + 2) % 3] - + clmd->hair_grid_min[(axis + 2) % 3]; + + BKE_sim_debug_data_clear_category(clmd->debug_data, "grid velocity"); + for (j = 0; j < size; j++) { + for (i = 0; i < size; i++) { + float x[3], v[3], gvel[3], gvel_smooth[3], gdensity; + + madd_v3_v3v3fl(x, offset, a, (float)i / (float)(size - 1)); + madd_v3_v3fl(x, b, (float)j / (float)(size - 1)); + zero_v3(v); + + BPH_hair_volume_grid_interpolate(grid, x, &gdensity, gvel, gvel_smooth, NULL, NULL); + + // BKE_sim_debug_data_add_circle( + // clmd->debug_data, x, gdensity, 0.7, 0.3, 1, + // "grid density", i, j, 3111); + if (!is_zero_v3(gvel) || !is_zero_v3(gvel_smooth)) { + float dvel[3]; + sub_v3_v3v3(dvel, gvel_smooth, gvel); + // BKE_sim_debug_data_add_vector( + // clmd->debug_data, x, gvel, 0.4, 0, 1, + // "grid velocity", i, j, 3112); + // BKE_sim_debug_data_add_vector( + // clmd->debug_data, x, gvel_smooth, 0.6, 1, 1, + // "grid velocity", i, j, 3113); + BKE_sim_debug_data_add_vector( + clmd->debug_data, x, dvel, 0.4, 1, 0.7, "grid velocity", i, j, 3114); +# if 0 + if (gdensity > 0.0f) { + float col0[3] = {0.0, 0.0, 0.0}; + float col1[3] = {0.0, 1.0, 0.0}; + float col[3]; + + interp_v3_v3v3(col, col0, col1, + CLAMPIS(gdensity * clmd->sim_parms->density_strength, 0.0, 1.0)); + // BKE_sim_debug_data_add_circle( + // clmd->debug_data, x, gdensity * clmd->sim_parms->density_strength, 0, 1, 0.4, + // "grid velocity", i, j, 3115); + // BKE_sim_debug_data_add_dot( + // clmd->debug_data, x, col[0], col[1], col[2], + // "grid velocity", i, j, 3115); + BKE_sim_debug_data_add_circle( + clmd->debug_data, x, 0.01f, col[0], col[1], col[2], "grid velocity", i, j, 3115); + } +# endif + } + } + } + } +#endif + + BPH_hair_volume_free_vertex_grid(grid); + } +} + +#if 0 +static void cloth_calc_volume_force(ClothModifierData *clmd) +{ + ClothSimSettings *parms = clmd->sim_parms; + Cloth *cloth = clmd->clothObject; + Implicit_Data *data = cloth->implicit; + int mvert_num = cloth->mvert_num; + ClothVertex *vert; + + /* 2.0f is an experimental value that seems to give good results */ + float smoothfac = 2.0f * parms->velocity_smooth; + float collfac = 2.0f * parms->collider_friction; + float pressfac = parms->pressure; + float minpress = parms->pressure_threshold; + float gmin[3], gmax[3]; + int i; + + hair_get_boundbox(clmd, gmin, gmax); + + /* gather velocities & density */ + if (smoothfac > 0.0f || pressfac > 0.0f) { + HairVertexGrid *vertex_grid = BPH_hair_volume_create_vertex_grid( + clmd->sim_parms->voxel_res, gmin, gmax); + + vert = cloth->verts; + for (i = 0; i < mvert_num; i++, vert++) { + float x[3], v[3]; + + if (vert->solver_index < 0) { + copy_v3_v3(x, vert->x); + copy_v3_v3(v, vert->v); + } + else { + BPH_mass_spring_get_motion_state(data, vert->solver_index, x, v); + } + BPH_hair_volume_add_vertex(vertex_grid, x, v); + } + BPH_hair_volume_normalize_vertex_grid(vertex_grid); + + vert = cloth->verts; + for (i = 0; i < mvert_num; i++, vert++) { + float x[3], v[3], f[3], dfdx[3][3], dfdv[3][3]; + + if (vert->solver_index < 0) { + continue; + } + + /* calculate volumetric forces */ + BPH_mass_spring_get_motion_state(data, vert->solver_index, x, v); + BPH_hair_volume_vertex_grid_forces( + vertex_grid, x, v, smoothfac, pressfac, minpress, f, dfdx, dfdv); + /* apply on hair data */ + BPH_mass_spring_force_extern(data, vert->solver_index, f, dfdx, dfdv); + } + + BPH_hair_volume_free_vertex_grid(vertex_grid); + } +} +#endif + +static void cloth_calc_average_acceleration(ClothModifierData *clmd, float dt) +{ + Cloth *cloth = clmd->clothObject; + Implicit_Data *data = cloth->implicit; + int i, mvert_num = cloth->mvert_num; + float total[3] = {0.0f, 0.0f, 0.0f}; + + for (i = 0; i < mvert_num; i++) { + float v[3], nv[3]; + + BPH_mass_spring_get_velocity(data, i, v); + BPH_mass_spring_get_new_velocity(data, i, nv); + + sub_v3_v3(nv, v); + add_v3_v3(total, nv); + } + + mul_v3_fl(total, 1.0f / dt / mvert_num); + + /* Smooth the data using a running average to prevent instability. + * This is effectively an abstraction of the wave propagation speed in fluid. */ + interp_v3_v3v3(cloth->average_acceleration, total, cloth->average_acceleration, powf(0.25f, dt)); +} + +static void cloth_solve_collisions( + Depsgraph *depsgraph, Object *ob, ClothModifierData *clmd, float step, float dt) +{ + Cloth *cloth = clmd->clothObject; + Implicit_Data *id = cloth->implicit; + ClothVertex *verts = cloth->verts; + int mvert_num = cloth->mvert_num; + const float time_multiplier = 1.0f / (clmd->sim_parms->dt * clmd->sim_parms->timescale); + int i; + + if (!(clmd->coll_parms->flags & + (CLOTH_COLLSETTINGS_FLAG_ENABLED | CLOTH_COLLSETTINGS_FLAG_SELF))) { + return; + } + + if (!clmd->clothObject->bvhtree) { + return; + } + + BPH_mass_spring_solve_positions(id, dt); + + /* Update verts to current positions. */ + for (i = 0; i < mvert_num; i++) { + BPH_mass_spring_get_new_position(id, i, verts[i].tx); + + sub_v3_v3v3(verts[i].tv, verts[i].tx, verts[i].txold); + zero_v3(verts[i].dcvel); + } + + if (cloth_bvh_collision(depsgraph, + ob, + clmd, + step / clmd->sim_parms->timescale, + dt / clmd->sim_parms->timescale)) { + for (i = 0; i < mvert_num; i++) { + if ((clmd->sim_parms->vgroup_mass > 0) && (verts[i].flags & CLOTH_VERT_FLAG_PINNED)) { + continue; + } + + BPH_mass_spring_get_new_velocity(id, i, verts[i].tv); + madd_v3_v3fl(verts[i].tv, verts[i].dcvel, time_multiplier); + BPH_mass_spring_set_new_velocity(id, i, verts[i].tv); + } + } +} + +static void cloth_clear_result(ClothModifierData *clmd) +{ + ClothSolverResult *sres = clmd->solver_result; + + sres->status = 0; + sres->max_error = sres->min_error = sres->avg_error = 0.0f; + sres->max_iterations = sres->min_iterations = 0; + sres->avg_iterations = 0.0f; +} + +static void cloth_record_result(ClothModifierData *clmd, ImplicitSolverResult *result, float dt) +{ + ClothSolverResult *sres = clmd->solver_result; + + if (sres->status) { /* already initialized ? */ + /* error only makes sense for successful iterations */ + if (result->status == BPH_SOLVER_SUCCESS) { + sres->min_error = min_ff(sres->min_error, result->error); + sres->max_error = max_ff(sres->max_error, result->error); + sres->avg_error += result->error * dt; + } + + sres->min_iterations = min_ii(sres->min_iterations, result->iterations); + sres->max_iterations = max_ii(sres->max_iterations, result->iterations); + sres->avg_iterations += (float)result->iterations * dt; + } + else { + /* error only makes sense for successful iterations */ + if (result->status == BPH_SOLVER_SUCCESS) { + sres->min_error = sres->max_error = result->error; + sres->avg_error += result->error * dt; + } + + sres->min_iterations = sres->max_iterations = result->iterations; + sres->avg_iterations += (float)result->iterations * dt; + } + + sres->status |= result->status; +} + +int BPH_cloth_solve( + Depsgraph *depsgraph, Object *ob, float frame, ClothModifierData *clmd, ListBase *effectors) +{ + /* Hair currently is a cloth sim in disguise ... + * Collision detection and volumetrics work differently then. + * Bad design, TODO + */ + Scene *scene = DEG_get_evaluated_scene(depsgraph); + const bool is_hair = (clmd->hairdata != NULL); + + unsigned int i = 0; + float step = 0.0f, tf = clmd->sim_parms->timescale; + Cloth *cloth = clmd->clothObject; + ClothVertex *verts = cloth->verts /*, *cv*/; + unsigned int mvert_num = cloth->mvert_num; + float dt = clmd->sim_parms->dt * clmd->sim_parms->timescale; + Implicit_Data *id = cloth->implicit; + + /* Hydrostatic pressure gradient of the fluid inside the object is affected by acceleration. */ + bool use_acceleration = (clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_PRESSURE) && + (clmd->sim_parms->fluid_density > 0); + + BKE_sim_debug_data_clear_category("collision"); + + if (!clmd->solver_result) { + clmd->solver_result = (ClothSolverResult *)MEM_callocN(sizeof(ClothSolverResult), + "cloth solver result"); + } + cloth_clear_result(clmd); + + if (clmd->sim_parms->vgroup_mass > 0) { /* Do goal stuff. */ + for (i = 0; i < mvert_num; i++) { + // update velocities with constrained velocities from pinned verts + if (verts[i].flags & CLOTH_VERT_FLAG_PINNED) { + float v[3]; + sub_v3_v3v3(v, verts[i].xconst, verts[i].xold); + // mul_v3_fl(v, clmd->sim_parms->stepsPerFrame); + /* divide by time_scale to prevent constrained velocities from being multiplied */ + mul_v3_fl(v, 1.0f / clmd->sim_parms->time_scale); + BPH_mass_spring_set_velocity(id, i, v); + } + } + } + + if (!use_acceleration) { + zero_v3(cloth->average_acceleration); + } + + while (step < tf) { + ImplicitSolverResult result; + + /* setup vertex constraints for pinned vertices */ + cloth_setup_constraints(clmd); + + /* initialize forces to zero */ + BPH_mass_spring_clear_forces(id); + + // calculate forces + cloth_calc_force(scene, clmd, frame, effectors, step); + + // calculate new velocity and position + BPH_mass_spring_solve_velocities(id, dt, &result); + cloth_record_result(clmd, &result, dt); + + /* Calculate collision impulses. */ + cloth_solve_collisions(depsgraph, ob, clmd, step, dt); + + if (is_hair) { + cloth_continuum_step(clmd, dt); + } + + if (use_acceleration) { + cloth_calc_average_acceleration(clmd, dt); + } + + BPH_mass_spring_solve_positions(id, dt); + BPH_mass_spring_apply_result(id); + + /* move pinned verts to correct position */ + for (i = 0; i < mvert_num; i++) { + if (clmd->sim_parms->vgroup_mass > 0) { + if (verts[i].flags & CLOTH_VERT_FLAG_PINNED) { + float x[3]; + /* divide by time_scale to prevent pinned vertices' + * delta locations from being multiplied */ + interp_v3_v3v3( + x, verts[i].xold, verts[i].xconst, (step + dt) / clmd->sim_parms->time_scale); + BPH_mass_spring_set_position(id, i, x); + } + } + + BPH_mass_spring_get_motion_state(id, i, verts[i].txold, NULL); + } + + step += dt; + } + + /* copy results back to cloth data */ + for (i = 0; i < mvert_num; i++) { + BPH_mass_spring_get_motion_state(id, i, verts[i].x, verts[i].v); + copy_v3_v3(verts[i].txold, verts[i].x); + } + + return 1; +} diff --git a/source/blender/simulation/intern/ConstrainedConjugateGradient.h b/source/blender/simulation/intern/ConstrainedConjugateGradient.h new file mode 100644 index 00000000000..c924490f97d --- /dev/null +++ b/source/blender/simulation/intern/ConstrainedConjugateGradient.h @@ -0,0 +1,335 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * The Original Code is Copyright (C) Blender Foundation + * All rights reserved. + */ + +#ifndef __CONSTRAINEDCONJUGATEGRADIENT_H__ +#define __CONSTRAINEDCONJUGATEGRADIENT_H__ + +#include <Eigen/Core> + +namespace Eigen { + +namespace internal { + +/** \internal Low-level conjugate gradient algorithm + * \param mat: The matrix A + * \param rhs: The right hand side vector b + * \param x: On input and initial solution, on output the computed solution. + * \param precond: A preconditioner being able to efficiently solve for an + * approximation of Ax=b (regardless of b) + * \param iters: On input the max number of iteration, + * on output the number of performed iterations. + * \param tol_error: On input the tolerance error, + * on output an estimation of the relative error. + */ +template<typename MatrixType, + typename Rhs, + typename Dest, + typename FilterMatrixType, + typename Preconditioner> +EIGEN_DONT_INLINE void constrained_conjugate_gradient(const MatrixType &mat, + const Rhs &rhs, + Dest &x, + const FilterMatrixType &filter, + const Preconditioner &precond, + int &iters, + typename Dest::RealScalar &tol_error) +{ + using std::abs; + using std::sqrt; + typedef typename Dest::RealScalar RealScalar; + typedef typename Dest::Scalar Scalar; + typedef Matrix<Scalar, Dynamic, 1> VectorType; + + RealScalar tol = tol_error; + int maxIters = iters; + + int n = mat.cols(); + + VectorType residual = filter * (rhs - mat * x); // initial residual + + RealScalar rhsNorm2 = (filter * rhs).squaredNorm(); + if (rhsNorm2 == 0) { + /* XXX TODO set constrained result here */ + x.setZero(); + iters = 0; + tol_error = 0; + return; + } + RealScalar threshold = tol * tol * rhsNorm2; + RealScalar residualNorm2 = residual.squaredNorm(); + if (residualNorm2 < threshold) { + iters = 0; + tol_error = sqrt(residualNorm2 / rhsNorm2); + return; + } + + VectorType p(n); + p = filter * precond.solve(residual); // initial search direction + + VectorType z(n), tmp(n); + RealScalar absNew = numext::real( + residual.dot(p)); // the square of the absolute value of r scaled by invM + int i = 0; + while (i < maxIters) { + tmp.noalias() = filter * (mat * p); // the bottleneck of the algorithm + + Scalar alpha = absNew / p.dot(tmp); // the amount we travel on dir + x += alpha * p; // update solution + residual -= alpha * tmp; // update residue + + residualNorm2 = residual.squaredNorm(); + if (residualNorm2 < threshold) { + break; + } + + z = precond.solve(residual); // approximately solve for "A z = residual" + + RealScalar absOld = absNew; + absNew = numext::real(residual.dot(z)); // update the absolute value of r + RealScalar beta = + absNew / + absOld; // calculate the Gram-Schmidt value used to create the new search direction + p = filter * (z + beta * p); // update search direction + i++; + } + tol_error = sqrt(residualNorm2 / rhsNorm2); + iters = i; +} + +} // namespace internal + +#if 0 /* unused */ +template<typename MatrixType> struct MatrixFilter { + MatrixFilter() : m_cmat(NULL) + { + } + + MatrixFilter(const MatrixType &cmat) : m_cmat(&cmat) + { + } + + void setMatrix(const MatrixType &cmat) + { + m_cmat = &cmat; + } + + template<typename VectorType> void apply(VectorType v) const + { + v = (*m_cmat) * v; + } + + protected: + const MatrixType *m_cmat; +}; +#endif + +template<typename _MatrixType, + int _UpLo = Lower, + typename _FilterMatrixType = _MatrixType, + typename _Preconditioner = DiagonalPreconditioner<typename _MatrixType::Scalar>> +class ConstrainedConjugateGradient; + +namespace internal { + +template<typename _MatrixType, int _UpLo, typename _FilterMatrixType, typename _Preconditioner> +struct traits< + ConstrainedConjugateGradient<_MatrixType, _UpLo, _FilterMatrixType, _Preconditioner>> { + typedef _MatrixType MatrixType; + typedef _FilterMatrixType FilterMatrixType; + typedef _Preconditioner Preconditioner; +}; + +} // namespace internal + +/** \ingroup IterativeLinearSolvers_Module + * \brief A conjugate gradient solver for sparse self-adjoint problems with additional constraints + * + * This class allows to solve for A.x = b sparse linear problems using a conjugate gradient + * algorithm. The sparse matrix A must be selfadjoint. The vectors x and b can be either dense or + * sparse. + * + * \tparam _MatrixType the type of the sparse matrix A, can be a dense or a sparse matrix. + * \tparam _UpLo the triangular part that will be used for the computations. It can be Lower + * or Upper. Default is Lower. + * \tparam _Preconditioner the type of the preconditioner. Default is DiagonalPreconditioner + * + * The maximal number of iterations and tolerance value can be controlled via the + * setMaxIterations() and setTolerance() methods. The defaults are the size of the problem for the + * maximal number of iterations and NumTraits<Scalar>::epsilon() for the tolerance. + * + * This class can be used as the direct solver classes. Here is a typical usage example: + * \code + * int n = 10000; + * VectorXd x(n), b(n); + * SparseMatrix<double> A(n,n); + * // fill A and b + * ConjugateGradient<SparseMatrix<double> > cg; + * cg.compute(A); + * x = cg.solve(b); + * std::cout << "#iterations: " << cg.iterations() << std::endl; + * std::cout << "estimated error: " << cg.error() << std::endl; + * // update b, and solve again + * x = cg.solve(b); + * \endcode + * + * By default the iterations start with x=0 as an initial guess of the solution. + * One can control the start using the solveWithGuess() method. Here is a step by + * step execution example starting with a random guess and printing the evolution + * of the estimated error: + * * \code + * x = VectorXd::Random(n); + * cg.setMaxIterations(1); + * int i = 0; + * do { + * x = cg.solveWithGuess(b,x); + * std::cout << i << " : " << cg.error() << std::endl; + * ++i; + * } while (cg.info()!=Success && i<100); + * \endcode + * Note that such a step by step execution is slightly slower. + * + * \sa class SimplicialCholesky, DiagonalPreconditioner, IdentityPreconditioner + */ +template<typename _MatrixType, int _UpLo, typename _FilterMatrixType, typename _Preconditioner> +class ConstrainedConjugateGradient + : public IterativeSolverBase< + ConstrainedConjugateGradient<_MatrixType, _UpLo, _FilterMatrixType, _Preconditioner>> { + typedef IterativeSolverBase<ConstrainedConjugateGradient> Base; + using Base::m_error; + using Base::m_info; + using Base::m_isInitialized; + using Base::m_iterations; + using Base::mp_matrix; + + public: + typedef _MatrixType MatrixType; + typedef typename MatrixType::Scalar Scalar; + typedef typename MatrixType::Index Index; + typedef typename MatrixType::RealScalar RealScalar; + typedef _FilterMatrixType FilterMatrixType; + typedef _Preconditioner Preconditioner; + + enum { UpLo = _UpLo }; + + public: + /** Default constructor. */ + ConstrainedConjugateGradient() : Base() + { + } + + /** Initialize the solver with matrix \a A for further \c Ax=b solving. + * + * This constructor is a shortcut for the default constructor followed + * by a call to compute(). + * + * \warning this class stores a reference to the matrix A as well as some + * precomputed values that depend on it. Therefore, if \a A is changed + * this class becomes invalid. Call compute() to update it with the new + * matrix A, or modify a copy of A. + */ + ConstrainedConjugateGradient(const MatrixType &A) : Base(A) + { + } + + ~ConstrainedConjugateGradient() + { + } + + FilterMatrixType &filter() + { + return m_filter; + } + const FilterMatrixType &filter() const + { + return m_filter; + } + + /** \returns the solution x of \f$ A x = b \f$ using the current decomposition of A + * \a x0 as an initial solution. + * + * \sa compute() + */ + template<typename Rhs, typename Guess> + inline const internal::solve_retval_with_guess<ConstrainedConjugateGradient, Rhs, Guess> + solveWithGuess(const MatrixBase<Rhs> &b, const Guess &x0) const + { + eigen_assert(m_isInitialized && "ConjugateGradient is not initialized."); + eigen_assert( + Base::rows() == b.rows() && + "ConjugateGradient::solve(): invalid number of rows of the right hand side matrix b"); + return internal::solve_retval_with_guess<ConstrainedConjugateGradient, Rhs, Guess>( + *this, b.derived(), x0); + } + + /** \internal */ + template<typename Rhs, typename Dest> void _solveWithGuess(const Rhs &b, Dest &x) const + { + m_iterations = Base::maxIterations(); + m_error = Base::m_tolerance; + + for (int j = 0; j < b.cols(); j++) { + m_iterations = Base::maxIterations(); + m_error = Base::m_tolerance; + + typename Dest::ColXpr xj(x, j); + internal::constrained_conjugate_gradient(mp_matrix->template selfadjointView<UpLo>(), + b.col(j), + xj, + m_filter, + Base::m_preconditioner, + m_iterations, + m_error); + } + + m_isInitialized = true; + m_info = m_error <= Base::m_tolerance ? Success : NoConvergence; + } + + /** \internal */ + template<typename Rhs, typename Dest> void _solve(const Rhs &b, Dest &x) const + { + x.setOnes(); + _solveWithGuess(b, x); + } + + protected: + FilterMatrixType m_filter; +}; + +namespace internal { + +template<typename _MatrixType, int _UpLo, typename _Filter, typename _Preconditioner, typename Rhs> +struct solve_retval<ConstrainedConjugateGradient<_MatrixType, _UpLo, _Filter, _Preconditioner>, + Rhs> + : solve_retval_base<ConstrainedConjugateGradient<_MatrixType, _UpLo, _Filter, _Preconditioner>, + Rhs> { + typedef ConstrainedConjugateGradient<_MatrixType, _UpLo, _Filter, _Preconditioner> Dec; + EIGEN_MAKE_SOLVE_HELPERS(Dec, Rhs) + + template<typename Dest> void evalTo(Dest &dst) const + { + dec()._solve(rhs(), dst); + } +}; + +} // end namespace internal + +} // end namespace Eigen + +#endif // __CONSTRAINEDCONJUGATEGRADIENT_H__ diff --git a/source/blender/simulation/intern/eigen_utils.h b/source/blender/simulation/intern/eigen_utils.h new file mode 100644 index 00000000000..c186cf567df --- /dev/null +++ b/source/blender/simulation/intern/eigen_utils.h @@ -0,0 +1,236 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * The Original Code is Copyright (C) Blender Foundation + * All rights reserved. + */ + +#ifndef __EIGEN_UTILS_H__ +#define __EIGEN_UTILS_H__ + +/** \file + * \ingroup bph + */ + +#if defined(__GNUC__) && !defined(__clang__) +# pragma GCC diagnostic push +/* XXX suppress verbose warnings in eigen */ +# pragma GCC diagnostic ignored "-Wlogical-op" +#endif + +#include <Eigen/Sparse> +#include <Eigen/src/Core/util/DisableStupidWarnings.h> + +#ifdef __GNUC__ +# pragma GCC diagnostic pop +#endif + +#include "BLI_utildefines.h" +#include "implicit.h" + +typedef float Scalar; + +/* slightly extended Eigen vector class + * with conversion to/from plain C float array + */ +class Vector3 : public Eigen::Vector3f { + public: + typedef float *ctype; + + Vector3() + { + } + + Vector3(const ctype &v) + { + for (int k = 0; k < 3; k++) { + coeffRef(k) = v[k]; + } + } + + Vector3 &operator=(const ctype &v) + { + for (int k = 0; k < 3; k++) { + coeffRef(k) = v[k]; + } + return *this; + } + + operator ctype() + { + return data(); + } +}; + +/* slightly extended Eigen matrix class + * with conversion to/from plain C float array + */ +class Matrix3 : public Eigen::Matrix3f { + public: + typedef float (*ctype)[3]; + + Matrix3() + { + } + + Matrix3(const ctype &v) + { + for (int k = 0; k < 3; k++) { + for (int l = 0; l < 3; l++) { + coeffRef(l, k) = v[k][l]; + } + } + } + + Matrix3 &operator=(const ctype &v) + { + for (int k = 0; k < 3; k++) { + for (int l = 0; l < 3; l++) { + coeffRef(l, k) = v[k][l]; + } + } + return *this; + } + + operator ctype() + { + return (ctype)data(); + } +}; + +typedef Eigen::VectorXf lVector; + +/* Extension of dense Eigen vectors, + * providing 3-float block access for blenlib math functions + */ +class lVector3f : public Eigen::VectorXf { + public: + typedef Eigen::VectorXf base_t; + + lVector3f() + { + } + + template<typename T> lVector3f &operator=(T rhs) + { + base_t::operator=(rhs); + return *this; + } + + float *v3(int vertex) + { + return &coeffRef(3 * vertex); + } + + const float *v3(int vertex) const + { + return &coeffRef(3 * vertex); + } +}; + +typedef Eigen::Triplet<Scalar> Triplet; +typedef std::vector<Triplet> TripletList; + +typedef Eigen::SparseMatrix<Scalar> lMatrix; + +/* Constructor type that provides more convenient handling of Eigen triplets + * for efficient construction of sparse 3x3 block matrices. + * This should be used for building lMatrix instead of writing to such lMatrix directly (which is + * very inefficient). After all elements have been defined using the set() method, the actual + * matrix can be filled using construct(). + */ +struct lMatrix3fCtor { + lMatrix3fCtor() + { + } + + void reset() + { + m_trips.clear(); + } + + void reserve(int numverts) + { + /* reserve for diagonal entries */ + m_trips.reserve(numverts * 9); + } + + void add(int i, int j, const Matrix3 &m) + { + i *= 3; + j *= 3; + for (int k = 0; k < 3; k++) { + for (int l = 0; l < 3; l++) { + m_trips.push_back(Triplet(i + k, j + l, m.coeff(l, k))); + } + } + } + + void sub(int i, int j, const Matrix3 &m) + { + i *= 3; + j *= 3; + for (int k = 0; k < 3; k++) { + for (int l = 0; l < 3; l++) { + m_trips.push_back(Triplet(i + k, j + l, -m.coeff(l, k))); + } + } + } + + inline void construct(lMatrix &m) + { + m.setFromTriplets(m_trips.begin(), m_trips.end()); + m_trips.clear(); + } + + private: + TripletList m_trips; +}; + +typedef Eigen::ConjugateGradient<lMatrix, Eigen::Lower, Eigen::DiagonalPreconditioner<Scalar>> + ConjugateGradient; + +using Eigen::ComputationInfo; + +BLI_INLINE void print_lvector(const lVector3f &v) +{ + for (int i = 0; i < v.rows(); i++) { + if (i > 0 && i % 3 == 0) { + printf("\n"); + } + + printf("%f,\n", v[i]); + } +} + +BLI_INLINE void print_lmatrix(const lMatrix &m) +{ + for (int j = 0; j < m.rows(); j++) { + if (j > 0 && j % 3 == 0) { + printf("\n"); + } + + for (int i = 0; i < m.cols(); i++) { + if (i > 0 && i % 3 == 0) { + printf(" "); + } + + implicit_print_matrix_elem(m.coeff(j, i)); + } + printf("\n"); + } +} + +#endif diff --git a/source/blender/simulation/intern/hair_volume.cpp b/source/blender/simulation/intern/hair_volume.cpp new file mode 100644 index 00000000000..1764d0a910c --- /dev/null +++ b/source/blender/simulation/intern/hair_volume.cpp @@ -0,0 +1,1274 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * The Original Code is Copyright (C) Blender Foundation + * All rights reserved. + */ + +/** \file + * \ingroup bph + */ + +#include "MEM_guardedalloc.h" + +#include "BLI_math.h" +#include "BLI_utildefines.h" + +#include "DNA_texture_types.h" + +#include "BKE_effect.h" + +#include "eigen_utils.h" +#include "implicit.h" + +/* ================ Volumetric Hair Interaction ================ + * adapted from + * + * Volumetric Methods for Simulation and Rendering of Hair + * (Petrovic, Henne, Anderson, Pixar Technical Memo #06-08, Pixar Animation Studios) + * + * as well as + * + * "Detail Preserving Continuum Simulation of Straight Hair" + * (McAdams, Selle 2009) + */ + +/* Note about array indexing: + * Generally the arrays here are one-dimensional. + * The relation between 3D indices and the array offset is + * offset = x + res_x * y + res_x * res_y * z + */ + +static float I[3][3] = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}; + +BLI_INLINE int floor_int(float value) +{ + return value > 0.0f ? (int)value : ((int)value) - 1; +} + +BLI_INLINE float floor_mod(float value) +{ + return value - floorf(value); +} + +BLI_INLINE int hair_grid_size(const int res[3]) +{ + return res[0] * res[1] * res[2]; +} + +typedef struct HairGridVert { + int samples; + float velocity[3]; + float density; + + float velocity_smooth[3]; +} HairGridVert; + +typedef struct HairGrid { + HairGridVert *verts; + int res[3]; + float gmin[3], gmax[3]; + float cellsize, inv_cellsize; +} HairGrid; + +#define HAIR_GRID_INDEX_AXIS(vec, res, gmin, scale, axis) \ + (min_ii(max_ii((int)((vec[axis] - gmin[axis]) * scale), 0), res[axis] - 2)) + +BLI_INLINE int hair_grid_offset(const float vec[3], + const int res[3], + const float gmin[3], + float scale) +{ + int i, j, k; + i = HAIR_GRID_INDEX_AXIS(vec, res, gmin, scale, 0); + j = HAIR_GRID_INDEX_AXIS(vec, res, gmin, scale, 1); + k = HAIR_GRID_INDEX_AXIS(vec, res, gmin, scale, 2); + return i + (j + k * res[1]) * res[0]; +} + +BLI_INLINE int hair_grid_interp_weights( + const int res[3], const float gmin[3], float scale, const float vec[3], float uvw[3]) +{ + int i, j, k, offset; + + i = HAIR_GRID_INDEX_AXIS(vec, res, gmin, scale, 0); + j = HAIR_GRID_INDEX_AXIS(vec, res, gmin, scale, 1); + k = HAIR_GRID_INDEX_AXIS(vec, res, gmin, scale, 2); + offset = i + (j + k * res[1]) * res[0]; + + uvw[0] = (vec[0] - gmin[0]) * scale - (float)i; + uvw[1] = (vec[1] - gmin[1]) * scale - (float)j; + uvw[2] = (vec[2] - gmin[2]) * scale - (float)k; + + // BLI_assert(0.0f <= uvw[0] && uvw[0] <= 1.0001f); + // BLI_assert(0.0f <= uvw[1] && uvw[1] <= 1.0001f); + // BLI_assert(0.0f <= uvw[2] && uvw[2] <= 1.0001f); + + return offset; +} + +BLI_INLINE void hair_grid_interpolate(const HairGridVert *grid, + const int res[3], + const float gmin[3], + float scale, + const float vec[3], + float *density, + float velocity[3], + float vel_smooth[3], + float density_gradient[3], + float velocity_gradient[3][3]) +{ + HairGridVert data[8]; + float uvw[3], muvw[3]; + int res2 = res[1] * res[0]; + int offset; + + offset = hair_grid_interp_weights(res, gmin, scale, vec, uvw); + muvw[0] = 1.0f - uvw[0]; + muvw[1] = 1.0f - uvw[1]; + muvw[2] = 1.0f - uvw[2]; + + data[0] = grid[offset]; + data[1] = grid[offset + 1]; + data[2] = grid[offset + res[0]]; + data[3] = grid[offset + res[0] + 1]; + data[4] = grid[offset + res2]; + data[5] = grid[offset + res2 + 1]; + data[6] = grid[offset + res2 + res[0]]; + data[7] = grid[offset + res2 + res[0] + 1]; + + if (density) { + *density = muvw[2] * (muvw[1] * (muvw[0] * data[0].density + uvw[0] * data[1].density) + + uvw[1] * (muvw[0] * data[2].density + uvw[0] * data[3].density)) + + uvw[2] * (muvw[1] * (muvw[0] * data[4].density + uvw[0] * data[5].density) + + uvw[1] * (muvw[0] * data[6].density + uvw[0] * data[7].density)); + } + + if (velocity) { + int k; + for (k = 0; k < 3; k++) { + velocity[k] = muvw[2] * + (muvw[1] * (muvw[0] * data[0].velocity[k] + uvw[0] * data[1].velocity[k]) + + uvw[1] * (muvw[0] * data[2].velocity[k] + uvw[0] * data[3].velocity[k])) + + uvw[2] * + (muvw[1] * (muvw[0] * data[4].velocity[k] + uvw[0] * data[5].velocity[k]) + + uvw[1] * (muvw[0] * data[6].velocity[k] + uvw[0] * data[7].velocity[k])); + } + } + + if (vel_smooth) { + int k; + for (k = 0; k < 3; k++) { + vel_smooth[k] = muvw[2] * (muvw[1] * (muvw[0] * data[0].velocity_smooth[k] + + uvw[0] * data[1].velocity_smooth[k]) + + uvw[1] * (muvw[0] * data[2].velocity_smooth[k] + + uvw[0] * data[3].velocity_smooth[k])) + + uvw[2] * (muvw[1] * (muvw[0] * data[4].velocity_smooth[k] + + uvw[0] * data[5].velocity_smooth[k]) + + uvw[1] * (muvw[0] * data[6].velocity_smooth[k] + + uvw[0] * data[7].velocity_smooth[k])); + } + } + + if (density_gradient) { + density_gradient[0] = muvw[1] * muvw[2] * (data[0].density - data[1].density) + + uvw[1] * muvw[2] * (data[2].density - data[3].density) + + muvw[1] * uvw[2] * (data[4].density - data[5].density) + + uvw[1] * uvw[2] * (data[6].density - data[7].density); + + density_gradient[1] = muvw[2] * muvw[0] * (data[0].density - data[2].density) + + uvw[2] * muvw[0] * (data[4].density - data[6].density) + + muvw[2] * uvw[0] * (data[1].density - data[3].density) + + uvw[2] * uvw[0] * (data[5].density - data[7].density); + + density_gradient[2] = muvw[2] * muvw[0] * (data[0].density - data[4].density) + + uvw[2] * muvw[0] * (data[1].density - data[5].density) + + muvw[2] * uvw[0] * (data[2].density - data[6].density) + + uvw[2] * uvw[0] * (data[3].density - data[7].density); + } + + if (velocity_gradient) { + /* XXX TODO */ + zero_m3(velocity_gradient); + } +} + +void BPH_hair_volume_vertex_grid_forces(HairGrid *grid, + const float x[3], + const float v[3], + float smoothfac, + float pressurefac, + float minpressure, + float f[3], + float dfdx[3][3], + float dfdv[3][3]) +{ + float gdensity, gvelocity[3], ggrad[3], gvelgrad[3][3], gradlen; + + hair_grid_interpolate(grid->verts, + grid->res, + grid->gmin, + grid->inv_cellsize, + x, + &gdensity, + gvelocity, + NULL, + ggrad, + gvelgrad); + + zero_v3(f); + sub_v3_v3(gvelocity, v); + mul_v3_v3fl(f, gvelocity, smoothfac); + + gradlen = normalize_v3(ggrad) - minpressure; + if (gradlen > 0.0f) { + mul_v3_fl(ggrad, gradlen); + madd_v3_v3fl(f, ggrad, pressurefac); + } + + zero_m3(dfdx); + + sub_m3_m3m3(dfdv, gvelgrad, I); + mul_m3_fl(dfdv, smoothfac); +} + +void BPH_hair_volume_grid_interpolate(HairGrid *grid, + const float x[3], + float *density, + float velocity[3], + float velocity_smooth[3], + float density_gradient[3], + float velocity_gradient[3][3]) +{ + hair_grid_interpolate(grid->verts, + grid->res, + grid->gmin, + grid->inv_cellsize, + x, + density, + velocity, + velocity_smooth, + density_gradient, + velocity_gradient); +} + +void BPH_hair_volume_grid_velocity( + HairGrid *grid, const float x[3], const float v[3], float fluid_factor, float r_v[3]) +{ + float gdensity, gvelocity[3], gvel_smooth[3], ggrad[3], gvelgrad[3][3]; + float v_pic[3], v_flip[3]; + + hair_grid_interpolate(grid->verts, + grid->res, + grid->gmin, + grid->inv_cellsize, + x, + &gdensity, + gvelocity, + gvel_smooth, + ggrad, + gvelgrad); + + /* velocity according to PIC method (Particle-in-Cell) */ + copy_v3_v3(v_pic, gvel_smooth); + + /* velocity according to FLIP method (Fluid-Implicit-Particle) */ + sub_v3_v3v3(v_flip, gvel_smooth, gvelocity); + add_v3_v3(v_flip, v); + + interp_v3_v3v3(r_v, v_pic, v_flip, fluid_factor); +} + +void BPH_hair_volume_grid_clear(HairGrid *grid) +{ + const int size = hair_grid_size(grid->res); + int i; + for (i = 0; i < size; i++) { + zero_v3(grid->verts[i].velocity); + zero_v3(grid->verts[i].velocity_smooth); + grid->verts[i].density = 0.0f; + grid->verts[i].samples = 0; + } +} + +BLI_INLINE bool hair_grid_point_valid(const float vec[3], const float gmin[3], const float gmax[3]) +{ + return !(vec[0] < gmin[0] || vec[1] < gmin[1] || vec[2] < gmin[2] || vec[0] > gmax[0] || + vec[1] > gmax[1] || vec[2] > gmax[2]); +} + +BLI_INLINE float dist_tent_v3f3(const float a[3], float x, float y, float z) +{ + float w = (1.0f - fabsf(a[0] - x)) * (1.0f - fabsf(a[1] - y)) * (1.0f - fabsf(a[2] - z)); + return w; +} + +BLI_INLINE float weights_sum(const float weights[8]) +{ + float totweight = 0.0f; + int i; + for (i = 0; i < 8; i++) { + totweight += weights[i]; + } + return totweight; +} + +/* returns the grid array offset as well to avoid redundant calculation */ +BLI_INLINE int hair_grid_weights( + const int res[3], const float gmin[3], float scale, const float vec[3], float weights[8]) +{ + int i, j, k, offset; + float uvw[3]; + + i = HAIR_GRID_INDEX_AXIS(vec, res, gmin, scale, 0); + j = HAIR_GRID_INDEX_AXIS(vec, res, gmin, scale, 1); + k = HAIR_GRID_INDEX_AXIS(vec, res, gmin, scale, 2); + offset = i + (j + k * res[1]) * res[0]; + + uvw[0] = (vec[0] - gmin[0]) * scale; + uvw[1] = (vec[1] - gmin[1]) * scale; + uvw[2] = (vec[2] - gmin[2]) * scale; + + weights[0] = dist_tent_v3f3(uvw, (float)i, (float)j, (float)k); + weights[1] = dist_tent_v3f3(uvw, (float)(i + 1), (float)j, (float)k); + weights[2] = dist_tent_v3f3(uvw, (float)i, (float)(j + 1), (float)k); + weights[3] = dist_tent_v3f3(uvw, (float)(i + 1), (float)(j + 1), (float)k); + weights[4] = dist_tent_v3f3(uvw, (float)i, (float)j, (float)(k + 1)); + weights[5] = dist_tent_v3f3(uvw, (float)(i + 1), (float)j, (float)(k + 1)); + weights[6] = dist_tent_v3f3(uvw, (float)i, (float)(j + 1), (float)(k + 1)); + weights[7] = dist_tent_v3f3(uvw, (float)(i + 1), (float)(j + 1), (float)(k + 1)); + + // BLI_assert(fabsf(weights_sum(weights) - 1.0f) < 0.0001f); + + return offset; +} + +BLI_INLINE void grid_to_world(HairGrid *grid, float vecw[3], const float vec[3]) +{ + copy_v3_v3(vecw, vec); + mul_v3_fl(vecw, grid->cellsize); + add_v3_v3(vecw, grid->gmin); +} + +void BPH_hair_volume_add_vertex(HairGrid *grid, const float x[3], const float v[3]) +{ + const int res[3] = {grid->res[0], grid->res[1], grid->res[2]}; + float weights[8]; + int di, dj, dk; + int offset; + + if (!hair_grid_point_valid(x, grid->gmin, grid->gmax)) { + return; + } + + offset = hair_grid_weights(res, grid->gmin, grid->inv_cellsize, x, weights); + + for (di = 0; di < 2; di++) { + for (dj = 0; dj < 2; dj++) { + for (dk = 0; dk < 2; dk++) { + int voffset = offset + di + (dj + dk * res[1]) * res[0]; + int iw = di + dj * 2 + dk * 4; + + grid->verts[voffset].density += weights[iw]; + madd_v3_v3fl(grid->verts[voffset].velocity, v, weights[iw]); + } + } + } +} + +#if 0 +BLI_INLINE void hair_volume_eval_grid_vertex(HairGridVert *vert, + const float loc[3], + float radius, + float dist_scale, + const float x2[3], + const float v2[3], + const float x3[3], + const float v3[3]) +{ + float closest[3], lambda, dist, weight; + + lambda = closest_to_line_v3(closest, loc, x2, x3); + dist = len_v3v3(closest, loc); + + weight = (radius - dist) * dist_scale; + + if (weight > 0.0f) { + float vel[3]; + + interp_v3_v3v3(vel, v2, v3, lambda); + madd_v3_v3fl(vert->velocity, vel, weight); + vert->density += weight; + vert->samples += 1; + } +} + +BLI_INLINE int major_axis_v3(const float v[3]) +{ + const float a = fabsf(v[0]); + const float b = fabsf(v[1]); + const float c = fabsf(v[2]); + return a > b ? (a > c ? 0 : 2) : (b > c ? 1 : 2); +} + +BLI_INLINE void hair_volume_add_segment_2D(HairGrid *grid, + const float UNUSED(x1[3]), + const float UNUSED(v1[3]), + const float x2[3], + const float v2[3], + const float x3[3], + const float v3[3], + const float UNUSED(x4[3]), + const float UNUSED(v4[3]), + const float UNUSED(dir1[3]), + const float dir2[3], + const float UNUSED(dir3[3]), + int resj, + int resk, + int jmin, + int jmax, + int kmin, + int kmax, + HairGridVert *vert, + int stride_j, + int stride_k, + const float loc[3], + int axis_j, + int axis_k, + int debug_i) +{ + const float radius = 1.5f; + const float dist_scale = grid->inv_cellsize; + + int j, k; + + /* boundary checks to be safe */ + CLAMP_MIN(jmin, 0); + CLAMP_MAX(jmax, resj - 1); + CLAMP_MIN(kmin, 0); + CLAMP_MAX(kmax, resk - 1); + + HairGridVert *vert_j = vert + jmin * stride_j; + float loc_j[3] = {loc[0], loc[1], loc[2]}; + loc_j[axis_j] += (float)jmin; + for (j = jmin; j <= jmax; j++, vert_j += stride_j, loc_j[axis_j] += 1.0f) { + + HairGridVert *vert_k = vert_j + kmin * stride_k; + float loc_k[3] = {loc_j[0], loc_j[1], loc_j[2]}; + loc_k[axis_k] += (float)kmin; + for (k = kmin; k <= kmax; k++, vert_k += stride_k, loc_k[axis_k] += 1.0f) { + + hair_volume_eval_grid_vertex(vert_k, loc_k, radius, dist_scale, x2, v2, x3, v3); + +# if 0 + { + float wloc[3], x2w[3], x3w[3]; + grid_to_world(grid, wloc, loc_k); + grid_to_world(grid, x2w, x2); + grid_to_world(grid, x3w, x3); + + if (vert_k->samples > 0) { + BKE_sim_debug_data_add_circle(wloc, 0.01f, 1.0, 1.0, 0.3, "grid", 2525, debug_i, j, k); + } + + if (grid->debug_value) { + BKE_sim_debug_data_add_dot(wloc, 1, 0, 0, "grid", 93, debug_i, j, k); + BKE_sim_debug_data_add_dot(x2w, 0.1, 0.1, 0.7, "grid", 649, debug_i, j, k); + BKE_sim_debug_data_add_line(wloc, x2w, 0.3, 0.8, 0.3, "grid", 253, debug_i, j, k); + BKE_sim_debug_data_add_line(wloc, x3w, 0.8, 0.3, 0.3, "grid", 254, debug_i, j, k); + // BKE_sim_debug_data_add_circle( + // x2w, len_v3v3(wloc, x2w), 0.2, 0.7, 0.2, + // "grid", 255, i, j, k); + } + } +# endif + } + } +} + +/* Uses a variation of Bresenham's algorithm for rasterizing a 3D grid with a line segment. + * + * The radius of influence around a segment is assumed to be at most 2*cellsize, + * i.e. only cells containing the segment and their direct neighbors are examined. + */ +void BPH_hair_volume_add_segment(HairGrid *grid, + const float x1[3], + const float v1[3], + const float x2[3], + const float v2[3], + const float x3[3], + const float v3[3], + const float x4[3], + const float v4[3], + const float dir1[3], + const float dir2[3], + const float dir3[3]) +{ + const int res[3] = {grid->res[0], grid->res[1], grid->res[2]}; + + /* find the primary direction from the major axis of the direction vector */ + const int axis0 = major_axis_v3(dir2); + const int axis1 = (axis0 + 1) % 3; + const int axis2 = (axis0 + 2) % 3; + + /* vertex buffer offset factors along cardinal axes */ + const int strides[3] = {1, res[0], res[0] * res[1]}; + const int stride0 = strides[axis0]; + const int stride1 = strides[axis1]; + const int stride2 = strides[axis2]; + + /* increment of secondary directions per step in the primary direction + * note: we always go in the positive direction along axis0, so the sign can be inverted + */ + const float inc1 = dir2[axis1] / dir2[axis0]; + const float inc2 = dir2[axis2] / dir2[axis0]; + + /* start/end points, so increment along axis0 is always positive */ + const float *start = x2[axis0] < x3[axis0] ? x2 : x3; + const float *end = x2[axis0] < x3[axis0] ? x3 : x2; + const float start0 = start[axis0], start1 = start[axis1], start2 = start[axis2]; + const float end0 = end[axis0]; + + /* range along primary direction */ + const int imin = max_ii(floor_int(start[axis0]) - 1, 0); + const int imax = min_ii(floor_int(end[axis0]) + 2, res[axis0] - 1); + + float h = 0.0f; + HairGridVert *vert0; + float loc0[3]; + int j0, k0, j0_prev, k0_prev; + int i; + + for (i = imin; i <= imax; i++) { + float shift1, shift2; /* fraction of a full cell shift [0.0, 1.0) */ + int jmin, jmax, kmin, kmax; + + h = CLAMPIS((float)i, start0, end0); + + shift1 = start1 + (h - start0) * inc1; + shift2 = start2 + (h - start0) * inc2; + + j0_prev = j0; + j0 = floor_int(shift1); + + k0_prev = k0; + k0 = floor_int(shift2); + + if (i > imin) { + jmin = min_ii(j0, j0_prev); + jmax = max_ii(j0, j0_prev); + kmin = min_ii(k0, k0_prev); + kmax = max_ii(k0, k0_prev); + } + else { + jmin = jmax = j0; + kmin = kmax = k0; + } + + vert0 = grid->verts + i * stride0; + loc0[axis0] = (float)i; + loc0[axis1] = 0.0f; + loc0[axis2] = 0.0f; + + hair_volume_add_segment_2D(grid, + x1, + v1, + x2, + v2, + x3, + v3, + x4, + v4, + dir1, + dir2, + dir3, + res[axis1], + res[axis2], + jmin - 1, + jmax + 2, + kmin - 1, + kmax + 2, + vert0, + stride1, + stride2, + loc0, + axis1, + axis2, + i); + } +} +#else +BLI_INLINE void hair_volume_eval_grid_vertex_sample(HairGridVert *vert, + const float loc[3], + float radius, + float dist_scale, + const float x[3], + const float v[3]) +{ + float dist, weight; + + dist = len_v3v3(x, loc); + + weight = (radius - dist) * dist_scale; + + if (weight > 0.0f) { + madd_v3_v3fl(vert->velocity, v, weight); + vert->density += weight; + vert->samples += 1; + } +} + +/* XXX simplified test implementation using a series of discrete sample along the segment, + * instead of finding the closest point for all affected grid vertices. + */ +void BPH_hair_volume_add_segment(HairGrid *grid, + const float UNUSED(x1[3]), + const float UNUSED(v1[3]), + const float x2[3], + const float v2[3], + const float x3[3], + const float v3[3], + const float UNUSED(x4[3]), + const float UNUSED(v4[3]), + const float UNUSED(dir1[3]), + const float UNUSED(dir2[3]), + const float UNUSED(dir3[3])) +{ + const float radius = 1.5f; + const float dist_scale = grid->inv_cellsize; + + const int res[3] = {grid->res[0], grid->res[1], grid->res[2]}; + const int stride[3] = {1, res[0], res[0] * res[1]}; + const int num_samples = 10; + + int s; + + for (s = 0; s < num_samples; s++) { + float x[3], v[3]; + int i, j, k; + + float f = (float)s / (float)(num_samples - 1); + interp_v3_v3v3(x, x2, x3, f); + interp_v3_v3v3(v, v2, v3, f); + + int imin = max_ii(floor_int(x[0]) - 2, 0); + int imax = min_ii(floor_int(x[0]) + 2, res[0] - 1); + int jmin = max_ii(floor_int(x[1]) - 2, 0); + int jmax = min_ii(floor_int(x[1]) + 2, res[1] - 1); + int kmin = max_ii(floor_int(x[2]) - 2, 0); + int kmax = min_ii(floor_int(x[2]) + 2, res[2] - 1); + + for (k = kmin; k <= kmax; k++) { + for (j = jmin; j <= jmax; j++) { + for (i = imin; i <= imax; i++) { + float loc[3] = {(float)i, (float)j, (float)k}; + HairGridVert *vert = grid->verts + i * stride[0] + j * stride[1] + k * stride[2]; + + hair_volume_eval_grid_vertex_sample(vert, loc, radius, dist_scale, x, v); + } + } + } + } +} +#endif + +void BPH_hair_volume_normalize_vertex_grid(HairGrid *grid) +{ + int i, size = hair_grid_size(grid->res); + /* divide velocity with density */ + for (i = 0; i < size; i++) { + float density = grid->verts[i].density; + if (density > 0.0f) { + mul_v3_fl(grid->verts[i].velocity, 1.0f / density); + } + } +} + +/* Cells with density below this are considered empty. */ +static const float density_threshold = 0.001f; + +/* Contribution of target density pressure to the laplacian in the pressure poisson equation. + * This is based on the model found in + * "Two-way Coupled SPH and Particle Level Set Fluid Simulation" (Losasso et al., 2008) + */ +BLI_INLINE float hair_volume_density_divergence(float density, + float target_density, + float strength) +{ + if (density > density_threshold && density > target_density) { + return strength * logf(target_density / density); + } + else { + return 0.0f; + } +} + +bool BPH_hair_volume_solve_divergence(HairGrid *grid, + float /*dt*/, + float target_density, + float target_strength) +{ + const float flowfac = grid->cellsize; + const float inv_flowfac = 1.0f / grid->cellsize; + + /*const int num_cells = hair_grid_size(grid->res);*/ + const int res[3] = {grid->res[0], grid->res[1], grid->res[2]}; + const int resA[3] = {grid->res[0] + 2, grid->res[1] + 2, grid->res[2] + 2}; + + const int stride0 = 1; + const int stride1 = grid->res[0]; + const int stride2 = grid->res[1] * grid->res[0]; + const int strideA0 = 1; + const int strideA1 = grid->res[0] + 2; + const int strideA2 = (grid->res[1] + 2) * (grid->res[0] + 2); + + const int num_cells = res[0] * res[1] * res[2]; + const int num_cellsA = (res[0] + 2) * (res[1] + 2) * (res[2] + 2); + + HairGridVert *vert_start = grid->verts - (stride0 + stride1 + stride2); + HairGridVert *vert; + int i, j, k; + +#define MARGIN_i0 (i < 1) +#define MARGIN_j0 (j < 1) +#define MARGIN_k0 (k < 1) +#define MARGIN_i1 (i >= resA[0] - 1) +#define MARGIN_j1 (j >= resA[1] - 1) +#define MARGIN_k1 (k >= resA[2] - 1) + +#define NEIGHBOR_MARGIN_i0 (i < 2) +#define NEIGHBOR_MARGIN_j0 (j < 2) +#define NEIGHBOR_MARGIN_k0 (k < 2) +#define NEIGHBOR_MARGIN_i1 (i >= resA[0] - 2) +#define NEIGHBOR_MARGIN_j1 (j >= resA[1] - 2) +#define NEIGHBOR_MARGIN_k1 (k >= resA[2] - 2) + + BLI_assert(num_cells >= 1); + + /* Calculate divergence */ + lVector B(num_cellsA); + for (k = 0; k < resA[2]; k++) { + for (j = 0; j < resA[1]; j++) { + for (i = 0; i < resA[0]; i++) { + int u = i * strideA0 + j * strideA1 + k * strideA2; + bool is_margin = MARGIN_i0 || MARGIN_i1 || MARGIN_j0 || MARGIN_j1 || MARGIN_k0 || + MARGIN_k1; + + if (is_margin) { + B[u] = 0.0f; + continue; + } + + vert = vert_start + i * stride0 + j * stride1 + k * stride2; + + const float *v0 = vert->velocity; + float dx = 0.0f, dy = 0.0f, dz = 0.0f; + if (!NEIGHBOR_MARGIN_i0) { + dx += v0[0] - (vert - stride0)->velocity[0]; + } + if (!NEIGHBOR_MARGIN_i1) { + dx += (vert + stride0)->velocity[0] - v0[0]; + } + if (!NEIGHBOR_MARGIN_j0) { + dy += v0[1] - (vert - stride1)->velocity[1]; + } + if (!NEIGHBOR_MARGIN_j1) { + dy += (vert + stride1)->velocity[1] - v0[1]; + } + if (!NEIGHBOR_MARGIN_k0) { + dz += v0[2] - (vert - stride2)->velocity[2]; + } + if (!NEIGHBOR_MARGIN_k1) { + dz += (vert + stride2)->velocity[2] - v0[2]; + } + + float divergence = -0.5f * flowfac * (dx + dy + dz); + + /* adjustment term for target density */ + float target = hair_volume_density_divergence( + vert->density, target_density, target_strength); + + /* B vector contains the finite difference approximation of the velocity divergence. + * Note: according to the discretized Navier-Stokes equation the rhs vector + * and resulting pressure gradient should be multiplied by the (inverse) density; + * however, this is already included in the weighting of hair velocities on the grid! + */ + B[u] = divergence - target; + +#if 0 + { + float wloc[3], loc[3]; + float col0[3] = {0.0, 0.0, 0.0}; + float colp[3] = {0.0, 1.0, 1.0}; + float coln[3] = {1.0, 0.0, 1.0}; + float col[3]; + float fac; + + loc[0] = (float)(i - 1); + loc[1] = (float)(j - 1); + loc[2] = (float)(k - 1); + grid_to_world(grid, wloc, loc); + + if (divergence > 0.0f) { + fac = CLAMPIS(divergence * target_strength, 0.0, 1.0); + interp_v3_v3v3(col, col0, colp, fac); + } + else { + fac = CLAMPIS(-divergence * target_strength, 0.0, 1.0); + interp_v3_v3v3(col, col0, coln, fac); + } + if (fac > 0.05f) { + BKE_sim_debug_data_add_circle( + grid->debug_data, wloc, 0.01f, col[0], col[1], col[2], "grid", 5522, i, j, k); + } + } +#endif + } + } + } + + /* Main Poisson equation system: + * This is derived from the discretezation of the Poisson equation + * div(grad(p)) = div(v) + * + * The finite difference approximation yields the linear equation system described here: + * https://en.wikipedia.org/wiki/Discrete_Poisson_equation + */ + lMatrix A(num_cellsA, num_cellsA); + /* Reserve space for the base equation system (without boundary conditions). + * Each column contains a factor 6 on the diagonal + * and up to 6 factors -1 on other places. + */ + A.reserve(Eigen::VectorXi::Constant(num_cellsA, 7)); + + for (k = 0; k < resA[2]; k++) { + for (j = 0; j < resA[1]; j++) { + for (i = 0; i < resA[0]; i++) { + int u = i * strideA0 + j * strideA1 + k * strideA2; + bool is_margin = MARGIN_i0 || MARGIN_i1 || MARGIN_j0 || MARGIN_j1 || MARGIN_k0 || + MARGIN_k1; + + vert = vert_start + i * stride0 + j * stride1 + k * stride2; + if (!is_margin && vert->density > density_threshold) { + int neighbors_lo = 0; + int neighbors_hi = 0; + int non_solid_neighbors = 0; + int neighbor_lo_index[3]; + int neighbor_hi_index[3]; + int n; + + /* check for upper bounds in advance + * to get the correct number of neighbors, + * needed for the diagonal element + */ + if (!NEIGHBOR_MARGIN_k0 && (vert - stride2)->density > density_threshold) { + neighbor_lo_index[neighbors_lo++] = u - strideA2; + } + if (!NEIGHBOR_MARGIN_j0 && (vert - stride1)->density > density_threshold) { + neighbor_lo_index[neighbors_lo++] = u - strideA1; + } + if (!NEIGHBOR_MARGIN_i0 && (vert - stride0)->density > density_threshold) { + neighbor_lo_index[neighbors_lo++] = u - strideA0; + } + if (!NEIGHBOR_MARGIN_i1 && (vert + stride0)->density > density_threshold) { + neighbor_hi_index[neighbors_hi++] = u + strideA0; + } + if (!NEIGHBOR_MARGIN_j1 && (vert + stride1)->density > density_threshold) { + neighbor_hi_index[neighbors_hi++] = u + strideA1; + } + if (!NEIGHBOR_MARGIN_k1 && (vert + stride2)->density > density_threshold) { + neighbor_hi_index[neighbors_hi++] = u + strideA2; + } + + /*int liquid_neighbors = neighbors_lo + neighbors_hi;*/ + non_solid_neighbors = 6; + + for (n = 0; n < neighbors_lo; n++) { + A.insert(neighbor_lo_index[n], u) = -1.0f; + } + A.insert(u, u) = (float)non_solid_neighbors; + for (n = 0; n < neighbors_hi; n++) { + A.insert(neighbor_hi_index[n], u) = -1.0f; + } + } + else { + A.insert(u, u) = 1.0f; + } + } + } + } + + ConjugateGradient cg; + cg.setMaxIterations(100); + cg.setTolerance(0.01f); + + cg.compute(A); + + lVector p = cg.solve(B); + + if (cg.info() == Eigen::Success) { + /* Calculate velocity = grad(p) */ + for (k = 0; k < resA[2]; k++) { + for (j = 0; j < resA[1]; j++) { + for (i = 0; i < resA[0]; i++) { + int u = i * strideA0 + j * strideA1 + k * strideA2; + bool is_margin = MARGIN_i0 || MARGIN_i1 || MARGIN_j0 || MARGIN_j1 || MARGIN_k0 || + MARGIN_k1; + if (is_margin) { + continue; + } + + vert = vert_start + i * stride0 + j * stride1 + k * stride2; + if (vert->density > density_threshold) { + float p_left = p[u - strideA0]; + float p_right = p[u + strideA0]; + float p_down = p[u - strideA1]; + float p_up = p[u + strideA1]; + float p_bottom = p[u - strideA2]; + float p_top = p[u + strideA2]; + + /* finite difference estimate of pressure gradient */ + float dvel[3]; + dvel[0] = p_right - p_left; + dvel[1] = p_up - p_down; + dvel[2] = p_top - p_bottom; + mul_v3_fl(dvel, -0.5f * inv_flowfac); + + /* pressure gradient describes velocity delta */ + add_v3_v3v3(vert->velocity_smooth, vert->velocity, dvel); + } + else { + zero_v3(vert->velocity_smooth); + } + } + } + } + +#if 0 + { + int axis = 0; + float offset = 0.0f; + + int slice = (offset - grid->gmin[axis]) / grid->cellsize; + + for (k = 0; k < resA[2]; k++) { + for (j = 0; j < resA[1]; j++) { + for (i = 0; i < resA[0]; i++) { + int u = i * strideA0 + j * strideA1 + k * strideA2; + bool is_margin = MARGIN_i0 || MARGIN_i1 || MARGIN_j0 || MARGIN_j1 || MARGIN_k0 || + MARGIN_k1; + if (i != slice) { + continue; + } + + vert = vert_start + i * stride0 + j * stride1 + k * stride2; + + float wloc[3], loc[3]; + float col0[3] = {0.0, 0.0, 0.0}; + float colp[3] = {0.0, 1.0, 1.0}; + float coln[3] = {1.0, 0.0, 1.0}; + float col[3]; + float fac; + + loc[0] = (float)(i - 1); + loc[1] = (float)(j - 1); + loc[2] = (float)(k - 1); + grid_to_world(grid, wloc, loc); + + float pressure = p[u]; + if (pressure > 0.0f) { + fac = CLAMPIS(pressure * grid->debug1, 0.0, 1.0); + interp_v3_v3v3(col, col0, colp, fac); + } + else { + fac = CLAMPIS(-pressure * grid->debug1, 0.0, 1.0); + interp_v3_v3v3(col, col0, coln, fac); + } + if (fac > 0.05f) { + BKE_sim_debug_data_add_circle( + grid->debug_data, wloc, 0.01f, col[0], col[1], col[2], "grid", 5533, i, j, k); + } + + if (!is_margin) { + float dvel[3]; + sub_v3_v3v3(dvel, vert->velocity_smooth, vert->velocity); + // BKE_sim_debug_data_add_vector( + // grid->debug_data, wloc, dvel, 1, 1, 1, + // "grid", 5566, i, j, k); + } + + if (!is_margin) { + float d = CLAMPIS(vert->density * grid->debug2, 0.0f, 1.0f); + float col0[3] = {0.3, 0.3, 0.3}; + float colp[3] = {0.0, 0.0, 1.0}; + float col[3]; + + interp_v3_v3v3(col, col0, colp, d); + // if (d > 0.05f) { + // BKE_sim_debug_data_add_dot( + // grid->debug_data, wloc, col[0], col[1], col[2], + // "grid", 5544, i, j, k); + // } + } + } + } + } + } +#endif + + return true; + } + else { + /* Clear result in case of error */ + for (i = 0, vert = grid->verts; i < num_cells; i++, vert++) { + zero_v3(vert->velocity_smooth); + } + + return false; + } +} + +#if 0 /* XXX weighting is incorrect, disabled for now */ +/* Velocity filter kernel + * See https://en.wikipedia.org/wiki/Filter_%28large_eddy_simulation%29 + */ + +BLI_INLINE void hair_volume_filter_box_convolute( + HairVertexGrid *grid, float invD, const int kernel_size[3], int i, int j, int k) +{ + int res = grid->res; + int p, q, r; + int minp = max_ii(i - kernel_size[0], 0), maxp = min_ii(i + kernel_size[0], res - 1); + int minq = max_ii(j - kernel_size[1], 0), maxq = min_ii(j + kernel_size[1], res - 1); + int minr = max_ii(k - kernel_size[2], 0), maxr = min_ii(k + kernel_size[2], res - 1); + int offset, kernel_offset, kernel_dq, kernel_dr; + HairGridVert *verts; + float *vel_smooth; + + offset = i + (j + k * res) * res; + verts = grid->verts; + vel_smooth = verts[offset].velocity_smooth; + + kernel_offset = minp + (minq + minr * res) * res; + kernel_dq = res; + kernel_dr = res * res; + for (r = minr; r <= maxr; r++) { + for (q = minq; q <= maxq; q++) { + for (p = minp; p <= maxp; p++) { + + madd_v3_v3fl(vel_smooth, verts[kernel_offset].velocity, invD); + + kernel_offset += 1; + } + kernel_offset += kernel_dq; + } + kernel_offset += kernel_dr; + } +} + +void BPH_hair_volume_vertex_grid_filter_box(HairVertexGrid *grid, int kernel_size) +{ + int size = hair_grid_size(grid->res); + int kernel_sizev[3] = {kernel_size, kernel_size, kernel_size}; + int tot; + float invD; + int i, j, k; + + if (kernel_size <= 0) { + return; + } + + tot = kernel_size * 2 + 1; + invD = 1.0f / (float)(tot * tot * tot); + + /* clear values for convolution */ + for (i = 0; i < size; i++) { + zero_v3(grid->verts[i].velocity_smooth); + } + + for (i = 0; i < grid->res; i++) { + for (j = 0; j < grid->res; j++) { + for (k = 0; k < grid->res; k++) { + hair_volume_filter_box_convolute(grid, invD, kernel_sizev, i, j, k); + } + } + } + + /* apply as new velocity */ + for (i = 0; i < size; i++) { + copy_v3_v3(grid->verts[i].velocity, grid->verts[i].velocity_smooth); + } +} +#endif + +HairGrid *BPH_hair_volume_create_vertex_grid(float cellsize, + const float gmin[3], + const float gmax[3]) +{ + float scale; + float extent[3]; + int resmin[3], resmax[3], res[3]; + float gmin_margin[3], gmax_margin[3]; + int size; + HairGrid *grid; + int i; + + /* sanity check */ + if (cellsize <= 0.0f) { + cellsize = 1.0f; + } + scale = 1.0f / cellsize; + + sub_v3_v3v3(extent, gmax, gmin); + for (i = 0; i < 3; i++) { + resmin[i] = floor_int(gmin[i] * scale); + resmax[i] = floor_int(gmax[i] * scale) + 1; + + /* add margin of 1 cell */ + resmin[i] -= 1; + resmax[i] += 1; + + res[i] = resmax[i] - resmin[i] + 1; + /* sanity check: avoid null-sized grid */ + if (res[i] < 4) { + res[i] = 4; + resmax[i] = resmin[i] + 4; + } + /* sanity check: avoid too large grid size */ + if (res[i] > MAX_HAIR_GRID_RES) { + res[i] = MAX_HAIR_GRID_RES; + resmax[i] = resmin[i] + MAX_HAIR_GRID_RES; + } + + gmin_margin[i] = (float)resmin[i] * cellsize; + gmax_margin[i] = (float)resmax[i] * cellsize; + } + size = hair_grid_size(res); + + grid = (HairGrid *)MEM_callocN(sizeof(HairGrid), "hair grid"); + grid->res[0] = res[0]; + grid->res[1] = res[1]; + grid->res[2] = res[2]; + copy_v3_v3(grid->gmin, gmin_margin); + copy_v3_v3(grid->gmax, gmax_margin); + grid->cellsize = cellsize; + grid->inv_cellsize = scale; + grid->verts = (HairGridVert *)MEM_callocN(sizeof(HairGridVert) * size, "hair voxel data"); + + return grid; +} + +void BPH_hair_volume_free_vertex_grid(HairGrid *grid) +{ + if (grid) { + if (grid->verts) { + MEM_freeN(grid->verts); + } + MEM_freeN(grid); + } +} + +void BPH_hair_volume_grid_geometry( + HairGrid *grid, float *cellsize, int res[3], float gmin[3], float gmax[3]) +{ + if (cellsize) { + *cellsize = grid->cellsize; + } + if (res) { + copy_v3_v3_int(res, grid->res); + } + if (gmin) { + copy_v3_v3(gmin, grid->gmin); + } + if (gmax) { + copy_v3_v3(gmax, grid->gmax); + } +} + +#if 0 +static HairGridVert *hair_volume_create_collision_grid(ClothModifierData *clmd, + lfVector *lX, + unsigned int numverts) +{ + int res = hair_grid_res; + int size = hair_grid_size(res); + HairGridVert *collgrid; + ListBase *colliders; + ColliderCache *col = NULL; + float gmin[3], gmax[3], scale[3]; + /* 2.0f is an experimental value that seems to give good results */ + float collfac = 2.0f * clmd->sim_parms->collider_friction; + unsigned int v = 0; + int i = 0; + + hair_volume_get_boundbox(lX, numverts, gmin, gmax); + hair_grid_get_scale(res, gmin, gmax, scale); + + collgrid = MEM_mallocN(sizeof(HairGridVert) * size, "hair collider voxel data"); + + /* initialize grid */ + for (i = 0; i < size; i++) { + zero_v3(collgrid[i].velocity); + collgrid[i].density = 0.0f; + } + + /* gather colliders */ + colliders = BKE_collider_cache_create(depsgraph, NULL, NULL); + if (colliders && collfac > 0.0f) { + for (col = colliders->first; col; col = col->next) { + MVert *loc0 = col->collmd->x; + MVert *loc1 = col->collmd->xnew; + float vel[3]; + float weights[8]; + int di, dj, dk; + + for (v = 0; v < col->collmd->numverts; v++, loc0++, loc1++) { + int offset; + + if (!hair_grid_point_valid(loc1->co, gmin, gmax)) { + continue; + } + + offset = hair_grid_weights(res, gmin, scale, lX[v], weights); + + sub_v3_v3v3(vel, loc1->co, loc0->co); + + for (di = 0; di < 2; di++) { + for (dj = 0; dj < 2; dj++) { + for (dk = 0; dk < 2; dk++) { + int voffset = offset + di + (dj + dk * res) * res; + int iw = di + dj * 2 + dk * 4; + + collgrid[voffset].density += weights[iw]; + madd_v3_v3fl(collgrid[voffset].velocity, vel, weights[iw]); + } + } + } + } + } + } + BKE_collider_cache_free(&colliders); + + /* divide velocity with density */ + for (i = 0; i < size; i++) { + float density = collgrid[i].density; + if (density > 0.0f) { + mul_v3_fl(collgrid[i].velocity, 1.0f / density); + } + } + + return collgrid; +} +#endif diff --git a/source/blender/simulation/intern/implicit.h b/source/blender/simulation/intern/implicit.h new file mode 100644 index 00000000000..8bc09755180 --- /dev/null +++ b/source/blender/simulation/intern/implicit.h @@ -0,0 +1,272 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * The Original Code is Copyright (C) Blender Foundation + * All rights reserved. + */ + +#ifndef __IMPLICIT_H__ +#define __IMPLICIT_H__ + +/** \file + * \ingroup bph + */ + +#include "stdio.h" + +#include "BLI_utildefines.h" + +#include "BKE_collision.h" + +#ifdef __cplusplus +extern "C" { +#endif + +//#define IMPLICIT_SOLVER_EIGEN +#define IMPLICIT_SOLVER_BLENDER + +#define CLOTH_ROOT_FRAME /* enable use of root frame coordinate transform */ + +#define CLOTH_FORCE_GRAVITY +#define CLOTH_FORCE_DRAG +#define CLOTH_FORCE_SPRING_STRUCTURAL +#define CLOTH_FORCE_SPRING_SHEAR +#define CLOTH_FORCE_SPRING_BEND +#define CLOTH_FORCE_SPRING_GOAL +#define CLOTH_FORCE_EFFECTORS + +//#define IMPLICIT_PRINT_SOLVER_INPUT_OUTPUT + +//#define IMPLICIT_ENABLE_EIGEN_DEBUG + +struct Implicit_Data; + +typedef struct ImplicitSolverResult { + int status; + + int iterations; + float error; +} ImplicitSolverResult; + +BLI_INLINE void implicit_print_matrix_elem(float v) +{ + printf("%-8.3f", v); +} + +void BPH_mass_spring_set_vertex_mass(struct Implicit_Data *data, int index, float mass); +void BPH_mass_spring_set_rest_transform(struct Implicit_Data *data, int index, float rot[3][3]); + +void BPH_mass_spring_set_motion_state(struct Implicit_Data *data, + int index, + const float x[3], + const float v[3]); +void BPH_mass_spring_set_position(struct Implicit_Data *data, int index, const float x[3]); +void BPH_mass_spring_set_velocity(struct Implicit_Data *data, int index, const float v[3]); +void BPH_mass_spring_get_motion_state(struct Implicit_Data *data, + int index, + float x[3], + float v[3]); +void BPH_mass_spring_get_position(struct Implicit_Data *data, int index, float x[3]); +void BPH_mass_spring_get_velocity(struct Implicit_Data *data, int index, float v[3]); + +/* access to modified motion state during solver step */ +void BPH_mass_spring_get_new_position(struct Implicit_Data *data, int index, float x[3]); +void BPH_mass_spring_set_new_position(struct Implicit_Data *data, int index, const float x[3]); +void BPH_mass_spring_get_new_velocity(struct Implicit_Data *data, int index, float v[3]); +void BPH_mass_spring_set_new_velocity(struct Implicit_Data *data, int index, const float v[3]); + +void BPH_mass_spring_clear_constraints(struct Implicit_Data *data); +void BPH_mass_spring_add_constraint_ndof0(struct Implicit_Data *data, + int index, + const float dV[3]); +void BPH_mass_spring_add_constraint_ndof1(struct Implicit_Data *data, + int index, + const float c1[3], + const float c2[3], + const float dV[3]); +void BPH_mass_spring_add_constraint_ndof2(struct Implicit_Data *data, + int index, + const float c1[3], + const float dV[3]); + +bool BPH_mass_spring_solve_velocities(struct Implicit_Data *data, + float dt, + struct ImplicitSolverResult *result); +bool BPH_mass_spring_solve_positions(struct Implicit_Data *data, float dt); +void BPH_mass_spring_apply_result(struct Implicit_Data *data); + +/* Clear the force vector at the beginning of the time step */ +void BPH_mass_spring_clear_forces(struct Implicit_Data *data); +/* Fictitious forces introduced by moving coordinate systems */ +void BPH_mass_spring_force_reference_frame(struct Implicit_Data *data, + int index, + const float acceleration[3], + const float omega[3], + const float domega_dt[3], + float mass); +/* Simple uniform gravity force */ +void BPH_mass_spring_force_gravity(struct Implicit_Data *data, + int index, + float mass, + const float g[3]); +/* Global drag force (velocity damping) */ +void BPH_mass_spring_force_drag(struct Implicit_Data *data, float drag); +/* Custom external force */ +void BPH_mass_spring_force_extern( + struct Implicit_Data *data, int i, const float f[3], float dfdx[3][3], float dfdv[3][3]); +/* Wind force, acting on a face (only generates pressure from the normal component) */ +void BPH_mass_spring_force_face_wind( + struct Implicit_Data *data, int v1, int v2, int v3, const float (*winvec)[3]); +/* Arbitrary per-unit-area vector force field acting on a face. */ +void BPH_mass_spring_force_face_extern( + struct Implicit_Data *data, int v1, int v2, int v3, const float (*forcevec)[3]); +/* Wind force, acting on an edge */ +void BPH_mass_spring_force_edge_wind(struct Implicit_Data *data, + int v1, + int v2, + float radius1, + float radius2, + const float (*winvec)[3]); +/* Wind force, acting on a vertex */ +void BPH_mass_spring_force_vertex_wind(struct Implicit_Data *data, + int v, + float radius, + const float (*winvec)[3]); +/* Linear spring force between two points */ +bool BPH_mass_spring_force_spring_linear(struct Implicit_Data *data, + int i, + int j, + float restlen, + float stiffness_tension, + float damping_tension, + float stiffness_compression, + float damping_compression, + bool resist_compress, + bool new_compress, + float clamp_force); +/* Angular spring force between two polygons */ +bool BPH_mass_spring_force_spring_angular(struct Implicit_Data *data, + int i, + int j, + int *i_a, + int *i_b, + int len_a, + int len_b, + float restang, + float stiffness, + float damping); +/* Bending force, forming a triangle at the base of two structural springs */ +bool BPH_mass_spring_force_spring_bending( + struct Implicit_Data *data, int i, int j, float restlen, float kb, float cb); +/* Angular bending force based on local target vectors */ +bool BPH_mass_spring_force_spring_bending_hair(struct Implicit_Data *data, + int i, + int j, + int k, + const float target[3], + float stiffness, + float damping); +/* Global goal spring */ +bool BPH_mass_spring_force_spring_goal(struct Implicit_Data *data, + int i, + const float goal_x[3], + const float goal_v[3], + float stiffness, + float damping); + +float BPH_tri_tetra_volume_signed_6x(struct Implicit_Data *data, int v1, int v2, int v3); +float BPH_tri_area(struct Implicit_Data *data, int v1, int v2, int v3); + +void BPH_mass_spring_force_pressure(struct Implicit_Data *data, + int v1, + int v2, + int v3, + float common_pressure, + const float *vertex_pressure, + const float weights[3]); + +/* ======== Hair Volumetric Forces ======== */ + +struct HairGrid; + +#define MAX_HAIR_GRID_RES 256 + +struct HairGrid *BPH_hair_volume_create_vertex_grid(float cellsize, + const float gmin[3], + const float gmax[3]); +void BPH_hair_volume_free_vertex_grid(struct HairGrid *grid); +void BPH_hair_volume_grid_geometry( + struct HairGrid *grid, float *cellsize, int res[3], float gmin[3], float gmax[3]); + +void BPH_hair_volume_grid_clear(struct HairGrid *grid); +void BPH_hair_volume_add_vertex(struct HairGrid *grid, const float x[3], const float v[3]); +void BPH_hair_volume_add_segment(struct HairGrid *grid, + const float x1[3], + const float v1[3], + const float x2[3], + const float v2[3], + const float x3[3], + const float v3[3], + const float x4[3], + const float v4[3], + const float dir1[3], + const float dir2[3], + const float dir3[3]); + +void BPH_hair_volume_normalize_vertex_grid(struct HairGrid *grid); + +bool BPH_hair_volume_solve_divergence(struct HairGrid *grid, + float dt, + float target_density, + float target_strength); +#if 0 /* XXX weighting is incorrect, disabled for now */ +void BPH_hair_volume_vertex_grid_filter_box(struct HairVertexGrid *grid, int kernel_size); +#endif + +void BPH_hair_volume_grid_interpolate(struct HairGrid *grid, + const float x[3], + float *density, + float velocity[3], + float velocity_smooth[3], + float density_gradient[3], + float velocity_gradient[3][3]); + +/* Effect of fluid simulation grid on velocities. + * fluid_factor controls blending between PIC (Particle-in-Cell) + * and FLIP (Fluid-Implicit-Particle) methods (0 = only PIC, 1 = only FLIP) + */ +void BPH_hair_volume_grid_velocity( + struct HairGrid *grid, const float x[3], const float v[3], float fluid_factor, float r_v[3]); +/* XXX Warning: expressing grid effects on velocity as a force is not very stable, + * due to discontinuities in interpolated values! + * Better use hybrid approaches such as described in + * "Detail Preserving Continuum Simulation of Straight Hair" + * (McAdams, Selle 2009) + */ +void BPH_hair_volume_vertex_grid_forces(struct HairGrid *grid, + const float x[3], + const float v[3], + float smoothfac, + float pressurefac, + float minpressure, + float f[3], + float dfdx[3][3], + float dfdv[3][3]); + +#ifdef __cplusplus +} +#endif + +#endif diff --git a/source/blender/simulation/intern/implicit_blender.c b/source/blender/simulation/intern/implicit_blender.c new file mode 100644 index 00000000000..54d38f3c10b --- /dev/null +++ b/source/blender/simulation/intern/implicit_blender.c @@ -0,0 +1,2360 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * The Original Code is Copyright (C) Blender Foundation + * All rights reserved. + */ + +/** \file + * \ingroup bph + */ + +#include "implicit.h" + +#ifdef IMPLICIT_SOLVER_BLENDER + +# include "MEM_guardedalloc.h" + +# include "DNA_meshdata_types.h" +# include "DNA_object_force_types.h" +# include "DNA_object_types.h" +# include "DNA_scene_types.h" +# include "DNA_texture_types.h" + +# include "BLI_math.h" +# include "BLI_utildefines.h" + +# include "BKE_cloth.h" +# include "BKE_collision.h" +# include "BKE_effect.h" + +# include "BPH_mass_spring.h" + +# ifdef __GNUC__ +# pragma GCC diagnostic ignored "-Wtype-limits" +# endif + +# ifdef _OPENMP +# define CLOTH_OPENMP_LIMIT 512 +# endif + +//#define DEBUG_TIME + +# ifdef DEBUG_TIME +# include "PIL_time.h" +# endif + +static float I[3][3] = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}; +static float ZERO[3][3] = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}; + +# if 0 +# define C99 +# ifdef C99 +# defineDO_INLINE inline +# else +# defineDO_INLINE static +# endif +# endif /* if 0 */ + +struct Cloth; + +////////////////////////////////////////// +/* fast vector / matrix library, enhancements are welcome :) -dg */ +///////////////////////////////////////// + +/* DEFINITIONS */ +typedef float lfVector[3]; +typedef struct fmatrix3x3 { + float m[3][3]; /* 3x3 matrix */ + unsigned int c, r; /* column and row number */ + /* int pinned; // is this vertex allowed to move? */ + float n1, n2, n3; /* three normal vectors for collision constrains */ + unsigned int vcount; /* vertex count */ + unsigned int scount; /* spring count */ +} fmatrix3x3; + +/////////////////////////// +// float[3] vector +/////////////////////////// +/* simple vector code */ +/* STATUS: verified */ +DO_INLINE void mul_fvector_S(float to[3], const float from[3], float scalar) +{ + to[0] = from[0] * scalar; + to[1] = from[1] * scalar; + to[2] = from[2] * scalar; +} +/* simple v^T * v product ("outer product") */ +/* STATUS: HAS TO BE verified (*should* work) */ +DO_INLINE void mul_fvectorT_fvector(float to[3][3], float vectorA[3], float vectorB[3]) +{ + mul_fvector_S(to[0], vectorB, vectorA[0]); + mul_fvector_S(to[1], vectorB, vectorA[1]); + mul_fvector_S(to[2], vectorB, vectorA[2]); +} +/* simple v^T * v product with scalar ("outer product") */ +/* STATUS: HAS TO BE verified (*should* work) */ +DO_INLINE void mul_fvectorT_fvectorS(float to[3][3], float vectorA[3], float vectorB[3], float aS) +{ + mul_fvectorT_fvector(to, vectorA, vectorB); + + mul_fvector_S(to[0], to[0], aS); + mul_fvector_S(to[1], to[1], aS); + mul_fvector_S(to[2], to[2], aS); +} + +# if 0 +/* printf vector[3] on console: for debug output */ +static void print_fvector(float m3[3]) +{ + printf("%f\n%f\n%f\n\n", m3[0], m3[1], m3[2]); +} + +/////////////////////////// +// long float vector float (*)[3] +/////////////////////////// +/* print long vector on console: for debug output */ +DO_INLINE void print_lfvector(float (*fLongVector)[3], unsigned int verts) +{ + unsigned int i = 0; + for (i = 0; i < verts; i++) { + print_fvector(fLongVector[i]); + } +} +# endif + +/* create long vector */ +DO_INLINE lfVector *create_lfvector(unsigned int verts) +{ + /* TODO: check if memory allocation was successful */ + return (lfVector *)MEM_callocN(verts * sizeof(lfVector), "cloth_implicit_alloc_vector"); + // return (lfVector *)cloth_aligned_malloc(&MEMORY_BASE, verts * sizeof(lfVector)); +} +/* delete long vector */ +DO_INLINE void del_lfvector(float (*fLongVector)[3]) +{ + if (fLongVector != NULL) { + MEM_freeN(fLongVector); + // cloth_aligned_free(&MEMORY_BASE, fLongVector); + } +} +/* copy long vector */ +DO_INLINE void cp_lfvector(float (*to)[3], float (*from)[3], unsigned int verts) +{ + memcpy(to, from, verts * sizeof(lfVector)); +} +/* init long vector with float[3] */ +DO_INLINE void init_lfvector(float (*fLongVector)[3], float vector[3], unsigned int verts) +{ + unsigned int i = 0; + for (i = 0; i < verts; i++) { + copy_v3_v3(fLongVector[i], vector); + } +} +/* zero long vector with float[3] */ +DO_INLINE void zero_lfvector(float (*to)[3], unsigned int verts) +{ + memset(to, 0.0f, verts * sizeof(lfVector)); +} +/* multiply long vector with scalar*/ +DO_INLINE void mul_lfvectorS(float (*to)[3], + float (*fLongVector)[3], + float scalar, + unsigned int verts) +{ + unsigned int i = 0; + + for (i = 0; i < verts; i++) { + mul_fvector_S(to[i], fLongVector[i], scalar); + } +} +/* multiply long vector with scalar*/ +/* A -= B * float */ +DO_INLINE void submul_lfvectorS(float (*to)[3], + float (*fLongVector)[3], + float scalar, + unsigned int verts) +{ + unsigned int i = 0; + for (i = 0; i < verts; i++) { + VECSUBMUL(to[i], fLongVector[i], scalar); + } +} +/* dot product for big vector */ +DO_INLINE float dot_lfvector(float (*fLongVectorA)[3], + float (*fLongVectorB)[3], + unsigned int verts) +{ + long i = 0; + float temp = 0.0; + // XXX brecht, disabled this for now (first schedule line was already disabled), + // due to non-commutative nature of floating point ops this makes the sim give + // different results each time you run it! + // schedule(guided, 2) + //#pragma omp parallel for reduction(+: temp) if (verts > CLOTH_OPENMP_LIMIT) + for (i = 0; i < (long)verts; i++) { + temp += dot_v3v3(fLongVectorA[i], fLongVectorB[i]); + } + return temp; +} +/* A = B + C --> for big vector */ +DO_INLINE void add_lfvector_lfvector(float (*to)[3], + float (*fLongVectorA)[3], + float (*fLongVectorB)[3], + unsigned int verts) +{ + unsigned int i = 0; + + for (i = 0; i < verts; i++) { + add_v3_v3v3(to[i], fLongVectorA[i], fLongVectorB[i]); + } +} +/* A = B + C * float --> for big vector */ +DO_INLINE void add_lfvector_lfvectorS(float (*to)[3], + float (*fLongVectorA)[3], + float (*fLongVectorB)[3], + float bS, + unsigned int verts) +{ + unsigned int i = 0; + + for (i = 0; i < verts; i++) { + VECADDS(to[i], fLongVectorA[i], fLongVectorB[i], bS); + } +} +/* A = B * float + C * float --> for big vector */ +DO_INLINE void add_lfvectorS_lfvectorS(float (*to)[3], + float (*fLongVectorA)[3], + float aS, + float (*fLongVectorB)[3], + float bS, + unsigned int verts) +{ + unsigned int i = 0; + + for (i = 0; i < verts; i++) { + VECADDSS(to[i], fLongVectorA[i], aS, fLongVectorB[i], bS); + } +} +/* A = B - C * float --> for big vector */ +DO_INLINE void sub_lfvector_lfvectorS(float (*to)[3], + float (*fLongVectorA)[3], + float (*fLongVectorB)[3], + float bS, + unsigned int verts) +{ + unsigned int i = 0; + for (i = 0; i < verts; i++) { + VECSUBS(to[i], fLongVectorA[i], fLongVectorB[i], bS); + } +} +/* A = B - C --> for big vector */ +DO_INLINE void sub_lfvector_lfvector(float (*to)[3], + float (*fLongVectorA)[3], + float (*fLongVectorB)[3], + unsigned int verts) +{ + unsigned int i = 0; + + for (i = 0; i < verts; i++) { + sub_v3_v3v3(to[i], fLongVectorA[i], fLongVectorB[i]); + } +} +/////////////////////////// +// 3x3 matrix +/////////////////////////// +# if 0 +/* printf 3x3 matrix on console: for debug output */ +static void print_fmatrix(float m3[3][3]) +{ + printf("%f\t%f\t%f\n", m3[0][0], m3[0][1], m3[0][2]); + printf("%f\t%f\t%f\n", m3[1][0], m3[1][1], m3[1][2]); + printf("%f\t%f\t%f\n\n", m3[2][0], m3[2][1], m3[2][2]); +} + +static void print_sparse_matrix(fmatrix3x3 *m) +{ + if (m) { + unsigned int i; + for (i = 0; i < m[0].vcount + m[0].scount; i++) { + printf("%d:\n", i); + print_fmatrix(m[i].m); + } + } +} +# endif + +# if 0 +static void print_lvector(lfVector *v, int numverts) +{ + int i; + for (i = 0; i < numverts; i++) { + if (i > 0) { + printf("\n"); + } + + printf("%f,\n", v[i][0]); + printf("%f,\n", v[i][1]); + printf("%f,\n", v[i][2]); + } +} +# endif + +# if 0 +static void print_bfmatrix(fmatrix3x3 *m) +{ + int tot = m[0].vcount + m[0].scount; + int size = m[0].vcount * 3; + float *t = MEM_callocN(sizeof(float) * size * size, "bfmatrix"); + int q, i, j; + + for (q = 0; q < tot; q++) { + int k = 3 * m[q].r; + int l = 3 * m[q].c; + + for (j = 0; j < 3; j++) { + for (i = 0; i < 3; i++) { + // if (t[k + i + (l + j) * size] != 0.0f) { + // printf("warning: overwriting value at %d, %d\n", m[q].r, m[q].c); + // } + if (k == l) { + t[k + i + (k + j) * size] += m[q].m[i][j]; + } + else { + t[k + i + (l + j) * size] += m[q].m[i][j]; + t[l + j + (k + i) * size] += m[q].m[j][i]; + } + } + } + } + + for (j = 0; j < size; j++) { + if (j > 0 && j % 3 == 0) { + printf("\n"); + } + + for (i = 0; i < size; i++) { + if (i > 0 && i % 3 == 0) { + printf(" "); + } + + implicit_print_matrix_elem(t[i + j * size]); + } + printf("\n"); + } + + MEM_freeN(t); +} +# endif + +/* copy 3x3 matrix */ +DO_INLINE void cp_fmatrix(float to[3][3], float from[3][3]) +{ + // memcpy(to, from, sizeof (float) * 9); + copy_v3_v3(to[0], from[0]); + copy_v3_v3(to[1], from[1]); + copy_v3_v3(to[2], from[2]); +} + +/* copy 3x3 matrix */ +DO_INLINE void initdiag_fmatrixS(float to[3][3], float aS) +{ + cp_fmatrix(to, ZERO); + + to[0][0] = aS; + to[1][1] = aS; + to[2][2] = aS; +} + +# if 0 +/* calculate determinant of 3x3 matrix */ +DO_INLINE float det_fmatrix(float m[3][3]) +{ + return m[0][0] * m[1][1] * m[2][2] + m[1][0] * m[2][1] * m[0][2] + m[0][1] * m[1][2] * m[2][0] - + m[0][0] * m[1][2] * m[2][1] - m[0][1] * m[1][0] * m[2][2] - m[2][0] * m[1][1] * m[0][2]; +} + +DO_INLINE void inverse_fmatrix(float to[3][3], float from[3][3]) +{ + unsigned int i, j; + float d; + + if ((d = det_fmatrix(from)) == 0) { + printf("can't build inverse"); + exit(0); + } + for (i = 0; i < 3; i++) { + for (j = 0; j < 3; j++) { + int i1 = (i + 1) % 3; + int i2 = (i + 2) % 3; + int j1 = (j + 1) % 3; + int j2 = (j + 2) % 3; + /** Reverse indexes i&j to take transpose. */ + to[j][i] = (from[i1][j1] * from[i2][j2] - from[i1][j2] * from[i2][j1]) / d; + /** + * <pre> + * if (i == j) { + * to[i][j] = 1.0f / from[i][j]; + * } + * else { + * to[i][j] = 0; + * } + * </pre> + */ + } + } +} +# endif + +/* 3x3 matrix multiplied by a scalar */ +/* STATUS: verified */ +DO_INLINE void mul_fmatrix_S(float matrix[3][3], float scalar) +{ + mul_fvector_S(matrix[0], matrix[0], scalar); + mul_fvector_S(matrix[1], matrix[1], scalar); + mul_fvector_S(matrix[2], matrix[2], scalar); +} + +/* a vector multiplied by a 3x3 matrix */ +/* STATUS: verified */ +DO_INLINE void mul_fvector_fmatrix(float *to, const float *from, float matrix[3][3]) +{ + to[0] = matrix[0][0] * from[0] + matrix[1][0] * from[1] + matrix[2][0] * from[2]; + to[1] = matrix[0][1] * from[0] + matrix[1][1] * from[1] + matrix[2][1] * from[2]; + to[2] = matrix[0][2] * from[0] + matrix[1][2] * from[1] + matrix[2][2] * from[2]; +} + +/* 3x3 matrix multiplied by a vector */ +/* STATUS: verified */ +DO_INLINE void mul_fmatrix_fvector(float *to, float matrix[3][3], float from[3]) +{ + to[0] = dot_v3v3(matrix[0], from); + to[1] = dot_v3v3(matrix[1], from); + to[2] = dot_v3v3(matrix[2], from); +} +/* 3x3 matrix addition with 3x3 matrix */ +DO_INLINE void add_fmatrix_fmatrix(float to[3][3], float matrixA[3][3], float matrixB[3][3]) +{ + add_v3_v3v3(to[0], matrixA[0], matrixB[0]); + add_v3_v3v3(to[1], matrixA[1], matrixB[1]); + add_v3_v3v3(to[2], matrixA[2], matrixB[2]); +} +/* A -= B*x + C*y (3x3 matrix sub-addition with 3x3 matrix) */ +DO_INLINE void subadd_fmatrixS_fmatrixS( + float to[3][3], float matrixA[3][3], float aS, float matrixB[3][3], float bS) +{ + VECSUBADDSS(to[0], matrixA[0], aS, matrixB[0], bS); + VECSUBADDSS(to[1], matrixA[1], aS, matrixB[1], bS); + VECSUBADDSS(to[2], matrixA[2], aS, matrixB[2], bS); +} +/* A = B - C (3x3 matrix subtraction with 3x3 matrix) */ +DO_INLINE void sub_fmatrix_fmatrix(float to[3][3], float matrixA[3][3], float matrixB[3][3]) +{ + sub_v3_v3v3(to[0], matrixA[0], matrixB[0]); + sub_v3_v3v3(to[1], matrixA[1], matrixB[1]); + sub_v3_v3v3(to[2], matrixA[2], matrixB[2]); +} +///////////////////////////////////////////////////////////////// +// special functions +///////////////////////////////////////////////////////////////// +/* 3x3 matrix multiplied+added by a vector */ +/* STATUS: verified */ +DO_INLINE void muladd_fmatrix_fvector(float to[3], float matrix[3][3], float from[3]) +{ + to[0] += dot_v3v3(matrix[0], from); + to[1] += dot_v3v3(matrix[1], from); + to[2] += dot_v3v3(matrix[2], from); +} + +DO_INLINE void muladd_fmatrixT_fvector(float to[3], float matrix[3][3], const float from[3]) +{ + to[0] += matrix[0][0] * from[0] + matrix[1][0] * from[1] + matrix[2][0] * from[2]; + to[1] += matrix[0][1] * from[0] + matrix[1][1] * from[1] + matrix[2][1] * from[2]; + to[2] += matrix[0][2] * from[0] + matrix[1][2] * from[1] + matrix[2][2] * from[2]; +} + +BLI_INLINE void outerproduct(float r[3][3], const float a[3], const float b[3]) +{ + mul_v3_v3fl(r[0], a, b[0]); + mul_v3_v3fl(r[1], a, b[1]); + mul_v3_v3fl(r[2], a, b[2]); +} + +BLI_INLINE void cross_m3_v3m3(float r[3][3], const float v[3], float m[3][3]) +{ + cross_v3_v3v3(r[0], v, m[0]); + cross_v3_v3v3(r[1], v, m[1]); + cross_v3_v3v3(r[2], v, m[2]); +} + +BLI_INLINE void cross_v3_identity(float r[3][3], const float v[3]) +{ + r[0][0] = 0.0f; + r[1][0] = v[2]; + r[2][0] = -v[1]; + r[0][1] = -v[2]; + r[1][1] = 0.0f; + r[2][1] = v[0]; + r[0][2] = v[1]; + r[1][2] = -v[0]; + r[2][2] = 0.0f; +} + +BLI_INLINE void madd_m3_m3fl(float r[3][3], float m[3][3], float f) +{ + r[0][0] += m[0][0] * f; + r[0][1] += m[0][1] * f; + r[0][2] += m[0][2] * f; + r[1][0] += m[1][0] * f; + r[1][1] += m[1][1] * f; + r[1][2] += m[1][2] * f; + r[2][0] += m[2][0] * f; + r[2][1] += m[2][1] * f; + r[2][2] += m[2][2] * f; +} + +///////////////////////////////////////////////////////////////// + +/////////////////////////// +// SPARSE SYMMETRIC big matrix with 3x3 matrix entries +/////////////////////////// +/* printf a big matrix on console: for debug output */ +# if 0 +static void print_bfmatrix(fmatrix3x3 *m3) +{ + unsigned int i = 0; + + for (i = 0; i < m3[0].vcount + m3[0].scount; i++) { + print_fmatrix(m3[i].m); + } +} +# endif + +BLI_INLINE void init_fmatrix(fmatrix3x3 *matrix, int r, int c) +{ + matrix->r = r; + matrix->c = c; +} + +/* create big matrix */ +DO_INLINE fmatrix3x3 *create_bfmatrix(unsigned int verts, unsigned int springs) +{ + // TODO: check if memory allocation was successful */ + fmatrix3x3 *temp = (fmatrix3x3 *)MEM_callocN(sizeof(fmatrix3x3) * (verts + springs), + "cloth_implicit_alloc_matrix"); + int i; + + temp[0].vcount = verts; + temp[0].scount = springs; + + /* vertex part of the matrix is diagonal blocks */ + for (i = 0; i < verts; i++) { + init_fmatrix(temp + i, i, i); + } + + return temp; +} +/* delete big matrix */ +DO_INLINE void del_bfmatrix(fmatrix3x3 *matrix) +{ + if (matrix != NULL) { + MEM_freeN(matrix); + } +} + +/* copy big matrix */ +DO_INLINE void cp_bfmatrix(fmatrix3x3 *to, fmatrix3x3 *from) +{ + // TODO bounds checking + memcpy(to, from, sizeof(fmatrix3x3) * (from[0].vcount + from[0].scount)); +} + +/* init big matrix */ +// slow in parallel +DO_INLINE void init_bfmatrix(fmatrix3x3 *matrix, float m3[3][3]) +{ + unsigned int i; + + for (i = 0; i < matrix[0].vcount + matrix[0].scount; i++) { + cp_fmatrix(matrix[i].m, m3); + } +} + +/* init the diagonal of big matrix */ +// slow in parallel +DO_INLINE void initdiag_bfmatrix(fmatrix3x3 *matrix, float m3[3][3]) +{ + unsigned int i, j; + float tmatrix[3][3] = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}; + + for (i = 0; i < matrix[0].vcount; i++) { + cp_fmatrix(matrix[i].m, m3); + } + for (j = matrix[0].vcount; j < matrix[0].vcount + matrix[0].scount; j++) { + cp_fmatrix(matrix[j].m, tmatrix); + } +} + +/* SPARSE SYMMETRIC multiply big matrix with long vector*/ +/* STATUS: verified */ +DO_INLINE void mul_bfmatrix_lfvector(float (*to)[3], fmatrix3x3 *from, lfVector *fLongVector) +{ + unsigned int vcount = from[0].vcount; + lfVector *temp = create_lfvector(vcount); + + zero_lfvector(to, vcount); + +# pragma omp parallel sections if (vcount > CLOTH_OPENMP_LIMIT) + { +# pragma omp section + { + for (unsigned int i = from[0].vcount; i < from[0].vcount + from[0].scount; i++) { + /* This is the lower triangle of the sparse matrix, + * therefore multiplication occurs with transposed submatrices. */ + muladd_fmatrixT_fvector(to[from[i].c], from[i].m, fLongVector[from[i].r]); + } + } +# pragma omp section + { + for (unsigned int i = 0; i < from[0].vcount + from[0].scount; i++) { + muladd_fmatrix_fvector(temp[from[i].r], from[i].m, fLongVector[from[i].c]); + } + } + } + add_lfvector_lfvector(to, to, temp, from[0].vcount); + + del_lfvector(temp); +} + +/* SPARSE SYMMETRIC sub big matrix with big matrix*/ +/* A -= B * float + C * float --> for big matrix */ +/* VERIFIED */ +DO_INLINE void subadd_bfmatrixS_bfmatrixS( + fmatrix3x3 *to, fmatrix3x3 *from, float aS, fmatrix3x3 *matrix, float bS) +{ + unsigned int i = 0; + + /* process diagonal elements */ + for (i = 0; i < matrix[0].vcount + matrix[0].scount; i++) { + subadd_fmatrixS_fmatrixS(to[i].m, from[i].m, aS, matrix[i].m, bS); + } +} + +/////////////////////////////////////////////////////////////////// +// simulator start +/////////////////////////////////////////////////////////////////// + +typedef struct Implicit_Data { + /* inputs */ + fmatrix3x3 *bigI; /* identity (constant) */ + fmatrix3x3 *tfm; /* local coordinate transform */ + fmatrix3x3 *M; /* masses */ + lfVector *F; /* forces */ + fmatrix3x3 *dFdV, *dFdX; /* force jacobians */ + int num_blocks; /* number of off-diagonal blocks (springs) */ + + /* motion state data */ + lfVector *X, *Xnew; /* positions */ + lfVector *V, *Vnew; /* velocities */ + + /* internal solver data */ + lfVector *B; /* B for A*dV = B */ + fmatrix3x3 *A; /* A for A*dV = B */ + + lfVector *dV; /* velocity change (solution of A*dV = B) */ + lfVector *z; /* target velocity in constrained directions */ + fmatrix3x3 *S; /* filtering matrix for constraints */ + fmatrix3x3 *P, *Pinv; /* pre-conditioning matrix */ +} Implicit_Data; + +Implicit_Data *BPH_mass_spring_solver_create(int numverts, int numsprings) +{ + Implicit_Data *id = (Implicit_Data *)MEM_callocN(sizeof(Implicit_Data), "implicit vecmat"); + + /* process diagonal elements */ + id->tfm = create_bfmatrix(numverts, 0); + id->A = create_bfmatrix(numverts, numsprings); + id->dFdV = create_bfmatrix(numverts, numsprings); + id->dFdX = create_bfmatrix(numverts, numsprings); + id->S = create_bfmatrix(numverts, 0); + id->Pinv = create_bfmatrix(numverts, numsprings); + id->P = create_bfmatrix(numverts, numsprings); + id->bigI = create_bfmatrix(numverts, numsprings); // TODO 0 springs + id->M = create_bfmatrix(numverts, numsprings); + id->X = create_lfvector(numverts); + id->Xnew = create_lfvector(numverts); + id->V = create_lfvector(numverts); + id->Vnew = create_lfvector(numverts); + id->F = create_lfvector(numverts); + id->B = create_lfvector(numverts); + id->dV = create_lfvector(numverts); + id->z = create_lfvector(numverts); + + initdiag_bfmatrix(id->bigI, I); + + return id; +} + +void BPH_mass_spring_solver_free(Implicit_Data *id) +{ + del_bfmatrix(id->tfm); + del_bfmatrix(id->A); + del_bfmatrix(id->dFdV); + del_bfmatrix(id->dFdX); + del_bfmatrix(id->S); + del_bfmatrix(id->P); + del_bfmatrix(id->Pinv); + del_bfmatrix(id->bigI); + del_bfmatrix(id->M); + + del_lfvector(id->X); + del_lfvector(id->Xnew); + del_lfvector(id->V); + del_lfvector(id->Vnew); + del_lfvector(id->F); + del_lfvector(id->B); + del_lfvector(id->dV); + del_lfvector(id->z); + + MEM_freeN(id); +} + +/* ==== Transformation from/to root reference frames ==== */ + +BLI_INLINE void world_to_root_v3(Implicit_Data *data, int index, float r[3], const float v[3]) +{ + copy_v3_v3(r, v); + mul_transposed_m3_v3(data->tfm[index].m, r); +} + +BLI_INLINE void root_to_world_v3(Implicit_Data *data, int index, float r[3], const float v[3]) +{ + mul_v3_m3v3(r, data->tfm[index].m, v); +} + +BLI_INLINE void world_to_root_m3(Implicit_Data *data, int index, float r[3][3], float m[3][3]) +{ + float trot[3][3]; + copy_m3_m3(trot, data->tfm[index].m); + transpose_m3(trot); + mul_m3_m3m3(r, trot, m); +} + +BLI_INLINE void root_to_world_m3(Implicit_Data *data, int index, float r[3][3], float m[3][3]) +{ + mul_m3_m3m3(r, data->tfm[index].m, m); +} + +/* ================================ */ + +DO_INLINE void filter(lfVector *V, fmatrix3x3 *S) +{ + unsigned int i = 0; + + for (i = 0; i < S[0].vcount; i++) { + mul_m3_v3(S[i].m, V[S[i].r]); + } +} + +/* this version of the CG algorithm does not work very well with partial constraints + * (where S has non-zero elements). */ +# if 0 +static int cg_filtered(lfVector *ldV, fmatrix3x3 *lA, lfVector *lB, lfVector *z, fmatrix3x3 *S) +{ + // Solves for unknown X in equation AX=B + unsigned int conjgrad_loopcount = 0, conjgrad_looplimit = 100; + float conjgrad_epsilon = 0.0001f /* , conjgrad_lasterror=0 */ /* UNUSED */; + lfVector *q, *d, *tmp, *r; + float s, starget, a, s_prev; + unsigned int numverts = lA[0].vcount; + q = create_lfvector(numverts); + d = create_lfvector(numverts); + tmp = create_lfvector(numverts); + r = create_lfvector(numverts); + + // zero_lfvector(ldV, CLOTHPARTICLES); + filter(ldV, S); + + add_lfvector_lfvector(ldV, ldV, z, numverts); + + // r = B - Mul(tmp, A, X); // just use B if X known to be zero + cp_lfvector(r, lB, numverts); + mul_bfmatrix_lfvector(tmp, lA, ldV); + sub_lfvector_lfvector(r, r, tmp, numverts); + + filter(r, S); + + cp_lfvector(d, r, numverts); + + s = dot_lfvector(r, r, numverts); + starget = s * sqrtf(conjgrad_epsilon); + + while (s > starget && conjgrad_loopcount < conjgrad_looplimit) { + // Mul(q, A, d); // q = A*d; + mul_bfmatrix_lfvector(q, lA, d); + + filter(q, S); + + a = s / dot_lfvector(d, q, numverts); + + // X = X + d*a; + add_lfvector_lfvectorS(ldV, ldV, d, a, numverts); + + // r = r - q*a; + sub_lfvector_lfvectorS(r, r, q, a, numverts); + + s_prev = s; + s = dot_lfvector(r, r, numverts); + + //d = r+d*(s/s_prev); + add_lfvector_lfvectorS(d, r, d, (s / s_prev), numverts); + + filter(d, S); + + conjgrad_loopcount++; + } + /* conjgrad_lasterror = s; */ /* UNUSED */ + + del_lfvector(q); + del_lfvector(d); + del_lfvector(tmp); + del_lfvector(r); + // printf("W/O conjgrad_loopcount: %d\n", conjgrad_loopcount); + + return conjgrad_loopcount < + conjgrad_looplimit; // true means we reached desired accuracy in given time - ie stable +} +# endif + +static int cg_filtered(lfVector *ldV, + fmatrix3x3 *lA, + lfVector *lB, + lfVector *z, + fmatrix3x3 *S, + ImplicitSolverResult *result) +{ + // Solves for unknown X in equation AX=B + unsigned int conjgrad_loopcount = 0, conjgrad_looplimit = 100; + float conjgrad_epsilon = 0.01f; + + unsigned int numverts = lA[0].vcount; + lfVector *fB = create_lfvector(numverts); + lfVector *AdV = create_lfvector(numverts); + lfVector *r = create_lfvector(numverts); + lfVector *c = create_lfvector(numverts); + lfVector *q = create_lfvector(numverts); + lfVector *s = create_lfvector(numverts); + float bnorm2, delta_new, delta_old, delta_target, alpha; + + cp_lfvector(ldV, z, numverts); + + /* d0 = filter(B)^T * P * filter(B) */ + cp_lfvector(fB, lB, numverts); + filter(fB, S); + bnorm2 = dot_lfvector(fB, fB, numverts); + delta_target = conjgrad_epsilon * conjgrad_epsilon * bnorm2; + + /* r = filter(B - A * dV) */ + mul_bfmatrix_lfvector(AdV, lA, ldV); + sub_lfvector_lfvector(r, lB, AdV, numverts); + filter(r, S); + + /* c = filter(P^-1 * r) */ + cp_lfvector(c, r, numverts); + filter(c, S); + + /* delta = r^T * c */ + delta_new = dot_lfvector(r, c, numverts); + +# ifdef IMPLICIT_PRINT_SOLVER_INPUT_OUTPUT + printf("==== A ====\n"); + print_bfmatrix(lA); + printf("==== z ====\n"); + print_lvector(z, numverts); + printf("==== B ====\n"); + print_lvector(lB, numverts); + printf("==== S ====\n"); + print_bfmatrix(S); +# endif + + while (delta_new > delta_target && conjgrad_loopcount < conjgrad_looplimit) { + mul_bfmatrix_lfvector(q, lA, c); + filter(q, S); + + alpha = delta_new / dot_lfvector(c, q, numverts); + + add_lfvector_lfvectorS(ldV, ldV, c, alpha, numverts); + + add_lfvector_lfvectorS(r, r, q, -alpha, numverts); + + /* s = P^-1 * r */ + cp_lfvector(s, r, numverts); + delta_old = delta_new; + delta_new = dot_lfvector(r, s, numverts); + + add_lfvector_lfvectorS(c, s, c, delta_new / delta_old, numverts); + filter(c, S); + + conjgrad_loopcount++; + } + +# ifdef IMPLICIT_PRINT_SOLVER_INPUT_OUTPUT + printf("==== dV ====\n"); + print_lvector(ldV, numverts); + printf("========\n"); +# endif + + del_lfvector(fB); + del_lfvector(AdV); + del_lfvector(r); + del_lfvector(c); + del_lfvector(q); + del_lfvector(s); + // printf("W/O conjgrad_loopcount: %d\n", conjgrad_loopcount); + + result->status = conjgrad_loopcount < conjgrad_looplimit ? BPH_SOLVER_SUCCESS : + BPH_SOLVER_NO_CONVERGENCE; + result->iterations = conjgrad_loopcount; + result->error = bnorm2 > 0.0f ? sqrtf(delta_new / bnorm2) : 0.0f; + + return conjgrad_loopcount < + conjgrad_looplimit; // true means we reached desired accuracy in given time - ie stable +} + +# if 0 +// block diagonalizer +DO_INLINE void BuildPPinv(fmatrix3x3 *lA, fmatrix3x3 *P, fmatrix3x3 *Pinv) +{ + unsigned int i = 0; + + // Take only the diagonal blocks of A + // #pragma omp parallel for private(i) if (lA[0].vcount > CLOTH_OPENMP_LIMIT) + for (i = 0; i < lA[0].vcount; i++) { + // block diagonalizer + cp_fmatrix(P[i].m, lA[i].m); + inverse_fmatrix(Pinv[i].m, P[i].m); + } +} + +# if 0 +// version 1.3 +static int cg_filtered_pre(lfVector *dv, + fmatrix3x3 *lA, + lfVector *lB, + lfVector *z, + fmatrix3x3 *S, + fmatrix3x3 *P, + fmatrix3x3 *Pinv) +{ + unsigned int numverts = lA[0].vcount, iterations = 0, conjgrad_looplimit = 100; + float delta0 = 0, deltaNew = 0, deltaOld = 0, alpha = 0; + float conjgrad_epsilon = 0.0001; // 0.2 is dt for steps=5 + lfVector *r = create_lfvector(numverts); + lfVector *p = create_lfvector(numverts); + lfVector *s = create_lfvector(numverts); + lfVector *h = create_lfvector(numverts); + + BuildPPinv(lA, P, Pinv); + + filter(dv, S); + add_lfvector_lfvector(dv, dv, z, numverts); + + mul_bfmatrix_lfvector(r, lA, dv); + sub_lfvector_lfvector(r, lB, r, numverts); + filter(r, S); + + mul_prevfmatrix_lfvector(p, Pinv, r); + filter(p, S); + + deltaNew = dot_lfvector(r, p, numverts); + + delta0 = deltaNew * sqrt(conjgrad_epsilon); + +# ifdef DEBUG_TIME + double start = PIL_check_seconds_timer(); +# endif + + while ((deltaNew > delta0) && (iterations < conjgrad_looplimit)) { + iterations++; + + mul_bfmatrix_lfvector(s, lA, p); + filter(s, S); + + alpha = deltaNew / dot_lfvector(p, s, numverts); + + add_lfvector_lfvectorS(dv, dv, p, alpha, numverts); + + add_lfvector_lfvectorS(r, r, s, -alpha, numverts); + + mul_prevfmatrix_lfvector(h, Pinv, r); + filter(h, S); + + deltaOld = deltaNew; + + deltaNew = dot_lfvector(r, h, numverts); + + add_lfvector_lfvectorS(p, h, p, deltaNew / deltaOld, numverts); + + filter(p, S); + } + +# ifdef DEBUG_TIME + double end = PIL_check_seconds_timer(); + printf("cg_filtered_pre time: %f\n", (float)(end - start)); +# endif + + del_lfvector(h); + del_lfvector(s); + del_lfvector(p); + del_lfvector(r); + + printf("iterations: %d\n", iterations); + + return iterations < conjgrad_looplimit; +} +# endif + +// version 1.4 +static int cg_filtered_pre(lfVector *dv, + fmatrix3x3 *lA, + lfVector *lB, + lfVector *z, + fmatrix3x3 *S, + fmatrix3x3 *P, + fmatrix3x3 *Pinv, + fmatrix3x3 *bigI) +{ + unsigned int numverts = lA[0].vcount, iterations = 0, conjgrad_looplimit = 100; + float delta0 = 0, deltaNew = 0, deltaOld = 0, alpha = 0, tol = 0; + lfVector *r = create_lfvector(numverts); + lfVector *p = create_lfvector(numverts); + lfVector *s = create_lfvector(numverts); + lfVector *h = create_lfvector(numverts); + lfVector *bhat = create_lfvector(numverts); + lfVector *btemp = create_lfvector(numverts); + + BuildPPinv(lA, P, Pinv); + + initdiag_bfmatrix(bigI, I); + sub_bfmatrix_Smatrix(bigI, bigI, S); + + // x = Sx_0+(I-S)z + filter(dv, S); + add_lfvector_lfvector(dv, dv, z, numverts); + + // b_hat = S(b-A(I-S)z) + mul_bfmatrix_lfvector(r, lA, z); + mul_bfmatrix_lfvector(bhat, bigI, r); + sub_lfvector_lfvector(bhat, lB, bhat, numverts); + + // r = S(b-Ax) + mul_bfmatrix_lfvector(r, lA, dv); + sub_lfvector_lfvector(r, lB, r, numverts); + filter(r, S); + + // p = SP^-1r + mul_prevfmatrix_lfvector(p, Pinv, r); + filter(p, S); + + // delta0 = bhat^TP^-1bhat + mul_prevfmatrix_lfvector(btemp, Pinv, bhat); + delta0 = dot_lfvector(bhat, btemp, numverts); + + // deltaNew = r^TP + deltaNew = dot_lfvector(r, p, numverts); + +# if 0 + filter(dv, S); + add_lfvector_lfvector(dv, dv, z, numverts); + + mul_bfmatrix_lfvector(r, lA, dv); + sub_lfvector_lfvector(r, lB, r, numverts); + filter(r, S); + + mul_prevfmatrix_lfvector(p, Pinv, r); + filter(p, S); + + deltaNew = dot_lfvector(r, p, numverts); + + delta0 = deltaNew * sqrt(conjgrad_epsilon); +# endif + +# ifdef DEBUG_TIME + double start = PIL_check_seconds_timer(); +# endif + + tol = (0.01 * 0.2); + + while ((deltaNew > delta0 * tol * tol) && (iterations < conjgrad_looplimit)) { + iterations++; + + mul_bfmatrix_lfvector(s, lA, p); + filter(s, S); + + alpha = deltaNew / dot_lfvector(p, s, numverts); + + add_lfvector_lfvectorS(dv, dv, p, alpha, numverts); + + add_lfvector_lfvectorS(r, r, s, -alpha, numverts); + + mul_prevfmatrix_lfvector(h, Pinv, r); + filter(h, S); + + deltaOld = deltaNew; + + deltaNew = dot_lfvector(r, h, numverts); + + add_lfvector_lfvectorS(p, h, p, deltaNew / deltaOld, numverts); + + filter(p, S); + } + +# ifdef DEBUG_TIME + double end = PIL_check_seconds_timer(); + printf("cg_filtered_pre time: %f\n", (float)(end - start)); +# endif + + del_lfvector(btemp); + del_lfvector(bhat); + del_lfvector(h); + del_lfvector(s); + del_lfvector(p); + del_lfvector(r); + + // printf("iterations: %d\n", iterations); + + return iterations < conjgrad_looplimit; +} +# endif + +bool BPH_mass_spring_solve_velocities(Implicit_Data *data, float dt, ImplicitSolverResult *result) +{ + unsigned int numverts = data->dFdV[0].vcount; + + lfVector *dFdXmV = create_lfvector(numverts); + zero_lfvector(data->dV, numverts); + + cp_bfmatrix(data->A, data->M); + + subadd_bfmatrixS_bfmatrixS(data->A, data->dFdV, dt, data->dFdX, (dt * dt)); + + mul_bfmatrix_lfvector(dFdXmV, data->dFdX, data->V); + + add_lfvectorS_lfvectorS(data->B, data->F, dt, dFdXmV, (dt * dt), numverts); + +# ifdef DEBUG_TIME + double start = PIL_check_seconds_timer(); +# endif + + /* Conjugate gradient algorithm to solve Ax=b. */ + cg_filtered(data->dV, data->A, data->B, data->z, data->S, result); + + // cg_filtered_pre(id->dV, id->A, id->B, id->z, id->S, id->P, id->Pinv, id->bigI); + +# ifdef DEBUG_TIME + double end = PIL_check_seconds_timer(); + printf("cg_filtered calc time: %f\n", (float)(end - start)); +# endif + + // advance velocities + add_lfvector_lfvector(data->Vnew, data->V, data->dV, numverts); + + del_lfvector(dFdXmV); + + return result->status == BPH_SOLVER_SUCCESS; +} + +bool BPH_mass_spring_solve_positions(Implicit_Data *data, float dt) +{ + int numverts = data->M[0].vcount; + + // advance positions + add_lfvector_lfvectorS(data->Xnew, data->X, data->Vnew, dt, numverts); + + return true; +} + +void BPH_mass_spring_apply_result(Implicit_Data *data) +{ + int numverts = data->M[0].vcount; + cp_lfvector(data->X, data->Xnew, numverts); + cp_lfvector(data->V, data->Vnew, numverts); +} + +void BPH_mass_spring_set_vertex_mass(Implicit_Data *data, int index, float mass) +{ + unit_m3(data->M[index].m); + mul_m3_fl(data->M[index].m, mass); +} + +void BPH_mass_spring_set_rest_transform(Implicit_Data *data, int index, float tfm[3][3]) +{ +# ifdef CLOTH_ROOT_FRAME + copy_m3_m3(data->tfm[index].m, tfm); +# else + unit_m3(data->tfm[index].m); + (void)tfm; +# endif +} + +void BPH_mass_spring_set_motion_state(Implicit_Data *data, + int index, + const float x[3], + const float v[3]) +{ + world_to_root_v3(data, index, data->X[index], x); + world_to_root_v3(data, index, data->V[index], v); +} + +void BPH_mass_spring_set_position(Implicit_Data *data, int index, const float x[3]) +{ + world_to_root_v3(data, index, data->X[index], x); +} + +void BPH_mass_spring_set_velocity(Implicit_Data *data, int index, const float v[3]) +{ + world_to_root_v3(data, index, data->V[index], v); +} + +void BPH_mass_spring_get_motion_state(struct Implicit_Data *data, + int index, + float x[3], + float v[3]) +{ + if (x) { + root_to_world_v3(data, index, x, data->X[index]); + } + if (v) { + root_to_world_v3(data, index, v, data->V[index]); + } +} + +void BPH_mass_spring_get_position(struct Implicit_Data *data, int index, float x[3]) +{ + root_to_world_v3(data, index, x, data->X[index]); +} + +void BPH_mass_spring_get_velocity(struct Implicit_Data *data, int index, float v[3]) +{ + root_to_world_v3(data, index, v, data->V[index]); +} + +void BPH_mass_spring_get_new_position(struct Implicit_Data *data, int index, float x[3]) +{ + root_to_world_v3(data, index, x, data->Xnew[index]); +} + +void BPH_mass_spring_set_new_position(struct Implicit_Data *data, int index, const float x[3]) +{ + world_to_root_v3(data, index, data->Xnew[index], x); +} + +void BPH_mass_spring_get_new_velocity(struct Implicit_Data *data, int index, float v[3]) +{ + root_to_world_v3(data, index, v, data->Vnew[index]); +} + +void BPH_mass_spring_set_new_velocity(struct Implicit_Data *data, int index, const float v[3]) +{ + world_to_root_v3(data, index, data->Vnew[index], v); +} + +/* -------------------------------- */ + +static int BPH_mass_spring_add_block(Implicit_Data *data, int v1, int v2) +{ + int s = data->M[0].vcount + data->num_blocks; /* index from array start */ + BLI_assert(s < data->M[0].vcount + data->M[0].scount); + ++data->num_blocks; + + /* tfm and S don't have spring entries (diagonal blocks only) */ + init_fmatrix(data->bigI + s, v1, v2); + init_fmatrix(data->M + s, v1, v2); + init_fmatrix(data->dFdX + s, v1, v2); + init_fmatrix(data->dFdV + s, v1, v2); + init_fmatrix(data->A + s, v1, v2); + init_fmatrix(data->P + s, v1, v2); + init_fmatrix(data->Pinv + s, v1, v2); + + return s; +} + +void BPH_mass_spring_clear_constraints(Implicit_Data *data) +{ + int i, numverts = data->S[0].vcount; + for (i = 0; i < numverts; i++) { + unit_m3(data->S[i].m); + zero_v3(data->z[i]); + } +} + +void BPH_mass_spring_add_constraint_ndof0(Implicit_Data *data, int index, const float dV[3]) +{ + zero_m3(data->S[index].m); + + world_to_root_v3(data, index, data->z[index], dV); +} + +void BPH_mass_spring_add_constraint_ndof1( + Implicit_Data *data, int index, const float c1[3], const float c2[3], const float dV[3]) +{ + float m[3][3], p[3], q[3], u[3], cmat[3][3]; + + world_to_root_v3(data, index, p, c1); + mul_fvectorT_fvector(cmat, p, p); + sub_m3_m3m3(m, I, cmat); + + world_to_root_v3(data, index, q, c2); + mul_fvectorT_fvector(cmat, q, q); + sub_m3_m3m3(m, m, cmat); + + /* XXX not sure but multiplication should work here */ + copy_m3_m3(data->S[index].m, m); + // mul_m3_m3m3(data->S[index].m, data->S[index].m, m); + + world_to_root_v3(data, index, u, dV); + add_v3_v3(data->z[index], u); +} + +void BPH_mass_spring_add_constraint_ndof2(Implicit_Data *data, + int index, + const float c1[3], + const float dV[3]) +{ + float m[3][3], p[3], u[3], cmat[3][3]; + + world_to_root_v3(data, index, p, c1); + mul_fvectorT_fvector(cmat, p, p); + sub_m3_m3m3(m, I, cmat); + + copy_m3_m3(data->S[index].m, m); + // mul_m3_m3m3(data->S[index].m, data->S[index].m, m); + + world_to_root_v3(data, index, u, dV); + add_v3_v3(data->z[index], u); +} + +void BPH_mass_spring_clear_forces(Implicit_Data *data) +{ + int numverts = data->M[0].vcount; + zero_lfvector(data->F, numverts); + init_bfmatrix(data->dFdX, ZERO); + init_bfmatrix(data->dFdV, ZERO); + + data->num_blocks = 0; +} + +void BPH_mass_spring_force_reference_frame(Implicit_Data *data, + int index, + const float acceleration[3], + const float omega[3], + const float domega_dt[3], + float mass) +{ +# ifdef CLOTH_ROOT_FRAME + float acc[3], w[3], dwdt[3]; + float f[3], dfdx[3][3], dfdv[3][3]; + float euler[3], coriolis[3], centrifugal[3], rotvel[3]; + float deuler[3][3], dcoriolis[3][3], dcentrifugal[3][3], drotvel[3][3]; + + world_to_root_v3(data, index, acc, acceleration); + world_to_root_v3(data, index, w, omega); + world_to_root_v3(data, index, dwdt, domega_dt); + + cross_v3_v3v3(euler, dwdt, data->X[index]); + cross_v3_v3v3(coriolis, w, data->V[index]); + mul_v3_fl(coriolis, 2.0f); + cross_v3_v3v3(rotvel, w, data->X[index]); + cross_v3_v3v3(centrifugal, w, rotvel); + + sub_v3_v3v3(f, acc, euler); + sub_v3_v3(f, coriolis); + sub_v3_v3(f, centrifugal); + + mul_v3_fl(f, mass); /* F = m * a */ + + cross_v3_identity(deuler, dwdt); + cross_v3_identity(dcoriolis, w); + mul_m3_fl(dcoriolis, 2.0f); + cross_v3_identity(drotvel, w); + cross_m3_v3m3(dcentrifugal, w, drotvel); + + add_m3_m3m3(dfdx, deuler, dcentrifugal); + negate_m3(dfdx); + mul_m3_fl(dfdx, mass); + + copy_m3_m3(dfdv, dcoriolis); + negate_m3(dfdv); + mul_m3_fl(dfdv, mass); + + add_v3_v3(data->F[index], f); + add_m3_m3m3(data->dFdX[index].m, data->dFdX[index].m, dfdx); + add_m3_m3m3(data->dFdV[index].m, data->dFdV[index].m, dfdv); +# else + (void)data; + (void)index; + (void)acceleration; + (void)omega; + (void)domega_dt; +# endif +} + +void BPH_mass_spring_force_gravity(Implicit_Data *data, int index, float mass, const float g[3]) +{ + /* force = mass * acceleration (in this case: gravity) */ + float f[3]; + world_to_root_v3(data, index, f, g); + mul_v3_fl(f, mass); + + add_v3_v3(data->F[index], f); +} + +void BPH_mass_spring_force_drag(Implicit_Data *data, float drag) +{ + int i, numverts = data->M[0].vcount; + for (i = 0; i < numverts; i++) { + float tmp[3][3]; + + /* NB: uses root space velocity, no need to transform */ + madd_v3_v3fl(data->F[i], data->V[i], -drag); + + copy_m3_m3(tmp, I); + mul_m3_fl(tmp, -drag); + add_m3_m3m3(data->dFdV[i].m, data->dFdV[i].m, tmp); + } +} + +void BPH_mass_spring_force_extern( + struct Implicit_Data *data, int i, const float f[3], float dfdx[3][3], float dfdv[3][3]) +{ + float tf[3], tdfdx[3][3], tdfdv[3][3]; + world_to_root_v3(data, i, tf, f); + world_to_root_m3(data, i, tdfdx, dfdx); + world_to_root_m3(data, i, tdfdv, dfdv); + + add_v3_v3(data->F[i], tf); + add_m3_m3m3(data->dFdX[i].m, data->dFdX[i].m, tdfdx); + add_m3_m3m3(data->dFdV[i].m, data->dFdV[i].m, tdfdv); +} + +static float calc_nor_area_tri(float nor[3], + const float v1[3], + const float v2[3], + const float v3[3]) +{ + float n1[3], n2[3]; + + sub_v3_v3v3(n1, v1, v2); + sub_v3_v3v3(n2, v2, v3); + + cross_v3_v3v3(nor, n1, n2); + return normalize_v3(nor) / 2.0f; +} + +/* XXX does not support force jacobians yet, since the effector system does not provide them either + */ +void BPH_mass_spring_force_face_wind( + Implicit_Data *data, int v1, int v2, int v3, const float (*winvec)[3]) +{ + const float effector_scale = 0.02f; + int vs[3] = {v1, v2, v3}; + float win[3], nor[3], area; + float factor, base_force; + float force[3]; + + /* calculate face normal and area */ + area = calc_nor_area_tri(nor, data->X[v1], data->X[v2], data->X[v3]); + /* The force is calculated and split up evenly for each of the three face verts */ + factor = effector_scale * area / 3.0f; + + /* Calculate wind pressure at each vertex by projecting the wind field on the normal. */ + for (int i = 0; i < 3; i++) { + world_to_root_v3(data, vs[i], win, winvec[vs[i]]); + + force[i] = dot_v3v3(win, nor); + } + + /* Compute per-vertex force values from local pressures. + * From integrating the pressure over the triangle and deriving + * equivalent vertex forces, it follows that: + * + * force[idx] = (sum(pressure) + pressure[idx]) * area / 12 + * + * Effectively, 1/4 of the pressure acts just on its vertex, + * while 3/4 is split evenly over all three. + */ + mul_v3_fl(force, factor / 4.0f); + + base_force = force[0] + force[1] + force[2]; + + /* add pressure to each of the face verts */ + madd_v3_v3fl(data->F[v1], nor, base_force + force[0]); + madd_v3_v3fl(data->F[v2], nor, base_force + force[1]); + madd_v3_v3fl(data->F[v3], nor, base_force + force[2]); +} + +void BPH_mass_spring_force_face_extern( + Implicit_Data *data, int v1, int v2, int v3, const float (*forcevec)[3]) +{ + const float effector_scale = 0.02f; + int vs[3] = {v1, v2, v3}; + float nor[3], area; + float factor, base_force[3]; + float force[3][3]; + + /* calculate face normal and area */ + area = calc_nor_area_tri(nor, data->X[v1], data->X[v2], data->X[v3]); + /* The force is calculated and split up evenly for each of the three face verts */ + factor = effector_scale * area / 3.0f; + + /* Compute common and per-vertex force vectors from the original inputs. */ + zero_v3(base_force); + + for (int i = 0; i < 3; i++) { + world_to_root_v3(data, vs[i], force[i], forcevec[vs[i]]); + + mul_v3_fl(force[i], factor / 4.0f); + add_v3_v3(base_force, force[i]); + } + + /* Apply the common and vertex components to all vertices. */ + for (int i = 0; i < 3; i++) { + add_v3_v3(force[i], base_force); + add_v3_v3(data->F[vs[i]], force[i]); + } +} + +float BPH_tri_tetra_volume_signed_6x(Implicit_Data *data, int v1, int v2, int v3) +{ + /* The result will be 6x the volume */ + return volume_tri_tetrahedron_signed_v3_6x(data->X[v1], data->X[v2], data->X[v3]); +} + +float BPH_tri_area(struct Implicit_Data *data, int v1, int v2, int v3) +{ + float nor[3]; + + return calc_nor_area_tri(nor, data->X[v1], data->X[v2], data->X[v3]); +} + +void BPH_mass_spring_force_pressure(Implicit_Data *data, + int v1, + int v2, + int v3, + float common_pressure, + const float *vertex_pressure, + const float weights[3]) +{ + float nor[3], area; + float factor, base_force; + float force[3]; + + /* calculate face normal and area */ + area = calc_nor_area_tri(nor, data->X[v1], data->X[v2], data->X[v3]); + /* The force is calculated and split up evenly for each of the three face verts */ + factor = area / 3.0f; + base_force = common_pressure * factor; + + /* Compute per-vertex force values from local pressures. + * From integrating the pressure over the triangle and deriving + * equivalent vertex forces, it follows that: + * + * force[idx] = (sum(pressure) + pressure[idx]) * area / 12 + * + * Effectively, 1/4 of the pressure acts just on its vertex, + * while 3/4 is split evenly over all three. + */ + if (vertex_pressure) { + copy_v3_fl3(force, vertex_pressure[v1], vertex_pressure[v2], vertex_pressure[v3]); + mul_v3_fl(force, factor / 4.0f); + + base_force += force[0] + force[1] + force[2]; + } + else { + zero_v3(force); + } + + /* add pressure to each of the face verts */ + madd_v3_v3fl(data->F[v1], nor, (base_force + force[0]) * weights[0]); + madd_v3_v3fl(data->F[v2], nor, (base_force + force[1]) * weights[1]); + madd_v3_v3fl(data->F[v3], nor, (base_force + force[2]) * weights[2]); +} + +static void edge_wind_vertex(const float dir[3], + float length, + float radius, + const float wind[3], + float f[3], + float UNUSED(dfdx[3][3]), + float UNUSED(dfdv[3][3])) +{ + const float density = 0.01f; /* XXX arbitrary value, corresponds to effect of air density */ + float cos_alpha, sin_alpha, cross_section; + float windlen = len_v3(wind); + + if (windlen == 0.0f) { + zero_v3(f); + return; + } + + /* angle of wind direction to edge */ + cos_alpha = dot_v3v3(wind, dir) / windlen; + sin_alpha = sqrtf(1.0f - cos_alpha * cos_alpha); + cross_section = radius * ((float)M_PI * radius * sin_alpha + length * cos_alpha); + + mul_v3_v3fl(f, wind, density * cross_section); +} + +void BPH_mass_spring_force_edge_wind( + Implicit_Data *data, int v1, int v2, float radius1, float radius2, const float (*winvec)[3]) +{ + float win[3], dir[3], length; + float f[3], dfdx[3][3], dfdv[3][3]; + + sub_v3_v3v3(dir, data->X[v1], data->X[v2]); + length = normalize_v3(dir); + + world_to_root_v3(data, v1, win, winvec[v1]); + edge_wind_vertex(dir, length, radius1, win, f, dfdx, dfdv); + add_v3_v3(data->F[v1], f); + + world_to_root_v3(data, v2, win, winvec[v2]); + edge_wind_vertex(dir, length, radius2, win, f, dfdx, dfdv); + add_v3_v3(data->F[v2], f); +} + +void BPH_mass_spring_force_vertex_wind(Implicit_Data *data, + int v, + float UNUSED(radius), + const float (*winvec)[3]) +{ + const float density = 0.01f; /* XXX arbitrary value, corresponds to effect of air density */ + + float wind[3]; + float f[3]; + + world_to_root_v3(data, v, wind, winvec[v]); + mul_v3_v3fl(f, wind, density); + add_v3_v3(data->F[v], f); +} + +BLI_INLINE void dfdx_spring(float to[3][3], const float dir[3], float length, float L, float k) +{ + // dir is unit length direction, rest is spring's restlength, k is spring constant. + // return ( (I-outerprod(dir, dir))*Min(1.0f, rest/length) - I) * -k; + outerproduct(to, dir, dir); + sub_m3_m3m3(to, I, to); + + mul_m3_fl(to, (L / length)); + sub_m3_m3m3(to, to, I); + mul_m3_fl(to, k); +} + +/* unused */ +# if 0 +BLI_INLINE void dfdx_damp(float to[3][3], + const float dir[3], + float length, + const float vel[3], + float rest, + float damping) +{ + // inner spring damping vel is the relative velocity of the endpoints. + // return (I-outerprod(dir, dir)) * (-damping * -(dot(dir, vel)/Max(length, rest))); + mul_fvectorT_fvector(to, dir, dir); + sub_fmatrix_fmatrix(to, I, to); + mul_fmatrix_S(to, (-damping * -(dot_v3v3(dir, vel) / MAX2(length, rest)))); +} +# endif + +BLI_INLINE void dfdv_damp(float to[3][3], const float dir[3], float damping) +{ + // derivative of force wrt velocity + outerproduct(to, dir, dir); + mul_m3_fl(to, -damping); +} + +BLI_INLINE float fb(float length, float L) +{ + float x = length / L; + float xx = x * x; + float xxx = xx * x; + float xxxx = xxx * x; + return (-11.541f * xxxx + 34.193f * xxx - 39.083f * xx + 23.116f * x - 9.713f); +} + +BLI_INLINE float fbderiv(float length, float L) +{ + float x = length / L; + float xx = x * x; + float xxx = xx * x; + return (-46.164f * xxx + 102.579f * xx - 78.166f * x + 23.116f); +} + +BLI_INLINE float fbstar(float length, float L, float kb, float cb) +{ + float tempfb_fl = kb * fb(length, L); + float fbstar_fl = cb * (length - L); + + if (tempfb_fl < fbstar_fl) { + return fbstar_fl; + } + else { + return tempfb_fl; + } +} + +// function to calculae bending spring force (taken from Choi & Co) +BLI_INLINE float fbstar_jacobi(float length, float L, float kb, float cb) +{ + float tempfb_fl = kb * fb(length, L); + float fbstar_fl = cb * (length - L); + + if (tempfb_fl < fbstar_fl) { + return -cb; + } + else { + return -kb * fbderiv(length, L); + } +} + +/* calculate elonglation */ +BLI_INLINE bool spring_length(Implicit_Data *data, + int i, + int j, + float r_extent[3], + float r_dir[3], + float *r_length, + float r_vel[3]) +{ + sub_v3_v3v3(r_extent, data->X[j], data->X[i]); + sub_v3_v3v3(r_vel, data->V[j], data->V[i]); + *r_length = len_v3(r_extent); + + if (*r_length > ALMOST_ZERO) { +# if 0 + if (length > L) { + if ((clmd->sim_parms->flags & CSIMSETT_FLAG_TEARING_ENABLED) && + (((length - L) * 100.0f / L) > clmd->sim_parms->maxspringlen)) { + // cut spring! + s->flags |= CSPRING_FLAG_DEACTIVATE; + return false; + } + } +# endif + mul_v3_v3fl(r_dir, r_extent, 1.0f / (*r_length)); + } + else { + zero_v3(r_dir); + } + + return true; +} + +BLI_INLINE void apply_spring( + Implicit_Data *data, int i, int j, const float f[3], float dfdx[3][3], float dfdv[3][3]) +{ + int block_ij = BPH_mass_spring_add_block(data, i, j); + + add_v3_v3(data->F[i], f); + sub_v3_v3(data->F[j], f); + + add_m3_m3m3(data->dFdX[i].m, data->dFdX[i].m, dfdx); + add_m3_m3m3(data->dFdX[j].m, data->dFdX[j].m, dfdx); + sub_m3_m3m3(data->dFdX[block_ij].m, data->dFdX[block_ij].m, dfdx); + + add_m3_m3m3(data->dFdV[i].m, data->dFdV[i].m, dfdv); + add_m3_m3m3(data->dFdV[j].m, data->dFdV[j].m, dfdv); + sub_m3_m3m3(data->dFdV[block_ij].m, data->dFdV[block_ij].m, dfdv); +} + +bool BPH_mass_spring_force_spring_linear(Implicit_Data *data, + int i, + int j, + float restlen, + float stiffness_tension, + float damping_tension, + float stiffness_compression, + float damping_compression, + bool resist_compress, + bool new_compress, + float clamp_force) +{ + float extent[3], length, dir[3], vel[3]; + float f[3], dfdx[3][3], dfdv[3][3]; + float damping = 0; + + // calculate elonglation + spring_length(data, i, j, extent, dir, &length, vel); + + /* This code computes not only the force, but also its derivative. + * Zero derivative effectively disables the spring for the implicit solver. + * Thus length > restlen makes cloth unconstrained at the start of simulation. */ + if ((length >= restlen && length > 0) || resist_compress) { + float stretch_force; + + damping = damping_tension; + + stretch_force = stiffness_tension * (length - restlen); + if (clamp_force > 0.0f && stretch_force > clamp_force) { + stretch_force = clamp_force; + } + mul_v3_v3fl(f, dir, stretch_force); + + dfdx_spring(dfdx, dir, length, restlen, stiffness_tension); + } + else if (new_compress) { + /* This is based on the Choi and Ko bending model, + * which works surprisingly well for compression. */ + float kb = stiffness_compression; + float cb = kb; /* cb equal to kb seems to work, but a factor can be added if necessary */ + + damping = damping_compression; + + mul_v3_v3fl(f, dir, fbstar(length, restlen, kb, cb)); + + outerproduct(dfdx, dir, dir); + mul_m3_fl(dfdx, fbstar_jacobi(length, restlen, kb, cb)); + } + else { + return false; + } + + madd_v3_v3fl(f, dir, damping * dot_v3v3(vel, dir)); + dfdv_damp(dfdv, dir, damping); + + apply_spring(data, i, j, f, dfdx, dfdv); + + return true; +} + +/* See "Stable but Responsive Cloth" (Choi, Ko 2005) */ +bool BPH_mass_spring_force_spring_bending( + Implicit_Data *data, int i, int j, float restlen, float kb, float cb) +{ + float extent[3], length, dir[3], vel[3]; + + // calculate elonglation + spring_length(data, i, j, extent, dir, &length, vel); + + if (length < restlen) { + float f[3], dfdx[3][3], dfdv[3][3]; + + mul_v3_v3fl(f, dir, fbstar(length, restlen, kb, cb)); + + outerproduct(dfdx, dir, dir); + mul_m3_fl(dfdx, fbstar_jacobi(length, restlen, kb, cb)); + + /* XXX damping not supported */ + zero_m3(dfdv); + + apply_spring(data, i, j, f, dfdx, dfdv); + + return true; + } + else { + return false; + } +} + +BLI_INLINE void poly_avg(lfVector *data, const int *inds, int len, float r_avg[3]) +{ + float fact = 1.0f / (float)len; + + zero_v3(r_avg); + + for (int i = 0; i < len; i++) { + madd_v3_v3fl(r_avg, data[inds[i]], fact); + } +} + +BLI_INLINE void poly_norm(lfVector *data, int i, int j, int *inds, int len, float r_dir[3]) +{ + float mid[3]; + + poly_avg(data, inds, len, mid); + + normal_tri_v3(r_dir, data[i], data[j], mid); +} + +BLI_INLINE void edge_avg(lfVector *data, int i, int j, float r_avg[3]) +{ + r_avg[0] = (data[i][0] + data[j][0]) * 0.5f; + r_avg[1] = (data[i][1] + data[j][1]) * 0.5f; + r_avg[2] = (data[i][2] + data[j][2]) * 0.5f; +} + +BLI_INLINE void edge_norm(lfVector *data, int i, int j, float r_dir[3]) +{ + sub_v3_v3v3(r_dir, data[i], data[j]); + normalize_v3(r_dir); +} + +BLI_INLINE float bend_angle(float dir_a[3], float dir_b[3], float dir_e[3]) +{ + float cos, sin; + float tmp[3]; + + cos = dot_v3v3(dir_a, dir_b); + + cross_v3_v3v3(tmp, dir_a, dir_b); + sin = dot_v3v3(tmp, dir_e); + + return atan2f(sin, cos); +} + +BLI_INLINE void spring_angle(Implicit_Data *data, + int i, + int j, + int *i_a, + int *i_b, + int len_a, + int len_b, + float r_dir_a[3], + float r_dir_b[3], + float *r_angle, + float r_vel_a[3], + float r_vel_b[3]) +{ + float dir_e[3], vel_e[3]; + + poly_norm(data->X, j, i, i_a, len_a, r_dir_a); + poly_norm(data->X, i, j, i_b, len_b, r_dir_b); + + edge_norm(data->X, i, j, dir_e); + + *r_angle = bend_angle(r_dir_a, r_dir_b, dir_e); + + poly_avg(data->V, i_a, len_a, r_vel_a); + poly_avg(data->V, i_b, len_b, r_vel_b); + + edge_avg(data->V, i, j, vel_e); + + sub_v3_v3(r_vel_a, vel_e); + sub_v3_v3(r_vel_b, vel_e); +} + +/* Angular springs roughly based on the bending model proposed by Baraff and Witkin in "Large Steps + * in Cloth Simulation". */ +bool BPH_mass_spring_force_spring_angular(Implicit_Data *data, + int i, + int j, + int *i_a, + int *i_b, + int len_a, + int len_b, + float restang, + float stiffness, + float damping) +{ + float angle, dir_a[3], dir_b[3], vel_a[3], vel_b[3]; + float f_a[3], f_b[3], f_e[3]; + float force; + int x; + + spring_angle(data, i, j, i_a, i_b, len_a, len_b, dir_a, dir_b, &angle, vel_a, vel_b); + + /* spring force */ + force = stiffness * (angle - restang); + + /* damping force */ + force += -damping * (dot_v3v3(vel_a, dir_a) + dot_v3v3(vel_b, dir_b)); + + mul_v3_v3fl(f_a, dir_a, force / len_a); + mul_v3_v3fl(f_b, dir_b, force / len_b); + + for (x = 0; x < len_a; x++) { + add_v3_v3(data->F[i_a[x]], f_a); + } + + for (x = 0; x < len_b; x++) { + add_v3_v3(data->F[i_b[x]], f_b); + } + + mul_v3_v3fl(f_a, dir_a, force * 0.5f); + mul_v3_v3fl(f_b, dir_b, force * 0.5f); + + add_v3_v3v3(f_e, f_a, f_b); + + sub_v3_v3(data->F[i], f_e); + sub_v3_v3(data->F[j], f_e); + + return true; +} + +/* Jacobian of a direction vector. + * Basically the part of the differential orthogonal to the direction, + * inversely proportional to the length of the edge. + * + * dD_ij/dx_i = -dD_ij/dx_j = (D_ij * D_ij^T - I) / len_ij + */ +BLI_INLINE void spring_grad_dir( + Implicit_Data *data, int i, int j, float edge[3], float dir[3], float grad_dir[3][3]) +{ + float length; + + sub_v3_v3v3(edge, data->X[j], data->X[i]); + length = normalize_v3_v3(dir, edge); + + if (length > ALMOST_ZERO) { + outerproduct(grad_dir, dir, dir); + sub_m3_m3m3(grad_dir, I, grad_dir); + mul_m3_fl(grad_dir, 1.0f / length); + } + else { + zero_m3(grad_dir); + } +} + +BLI_INLINE void spring_hairbend_forces(Implicit_Data *data, + int i, + int j, + int k, + const float goal[3], + float stiffness, + float damping, + int q, + const float dx[3], + const float dv[3], + float r_f[3]) +{ + float edge_ij[3], dir_ij[3]; + float edge_jk[3], dir_jk[3]; + float vel_ij[3], vel_jk[3], vel_ortho[3]; + float f_bend[3], f_damp[3]; + float fk[3]; + float dist[3]; + + zero_v3(fk); + + sub_v3_v3v3(edge_ij, data->X[j], data->X[i]); + if (q == i) { + sub_v3_v3(edge_ij, dx); + } + if (q == j) { + add_v3_v3(edge_ij, dx); + } + normalize_v3_v3(dir_ij, edge_ij); + + sub_v3_v3v3(edge_jk, data->X[k], data->X[j]); + if (q == j) { + sub_v3_v3(edge_jk, dx); + } + if (q == k) { + add_v3_v3(edge_jk, dx); + } + normalize_v3_v3(dir_jk, edge_jk); + + sub_v3_v3v3(vel_ij, data->V[j], data->V[i]); + if (q == i) { + sub_v3_v3(vel_ij, dv); + } + if (q == j) { + add_v3_v3(vel_ij, dv); + } + + sub_v3_v3v3(vel_jk, data->V[k], data->V[j]); + if (q == j) { + sub_v3_v3(vel_jk, dv); + } + if (q == k) { + add_v3_v3(vel_jk, dv); + } + + /* bending force */ + sub_v3_v3v3(dist, goal, edge_jk); + mul_v3_v3fl(f_bend, dist, stiffness); + + add_v3_v3(fk, f_bend); + + /* damping force */ + madd_v3_v3v3fl(vel_ortho, vel_jk, dir_jk, -dot_v3v3(vel_jk, dir_jk)); + mul_v3_v3fl(f_damp, vel_ortho, damping); + + sub_v3_v3(fk, f_damp); + + copy_v3_v3(r_f, fk); +} + +/* Finite Differences method for estimating the jacobian of the force */ +BLI_INLINE void spring_hairbend_estimate_dfdx(Implicit_Data *data, + int i, + int j, + int k, + const float goal[3], + float stiffness, + float damping, + int q, + float dfdx[3][3]) +{ + const float delta = 0.00001f; // TODO find a good heuristic for this + float dvec_null[3][3], dvec_pos[3][3], dvec_neg[3][3]; + float f[3]; + int a, b; + + zero_m3(dvec_null); + unit_m3(dvec_pos); + mul_m3_fl(dvec_pos, delta * 0.5f); + copy_m3_m3(dvec_neg, dvec_pos); + negate_m3(dvec_neg); + + /* XXX TODO offset targets to account for position dependency */ + + for (a = 0; a < 3; a++) { + spring_hairbend_forces( + data, i, j, k, goal, stiffness, damping, q, dvec_pos[a], dvec_null[a], f); + copy_v3_v3(dfdx[a], f); + + spring_hairbend_forces( + data, i, j, k, goal, stiffness, damping, q, dvec_neg[a], dvec_null[a], f); + sub_v3_v3(dfdx[a], f); + + for (b = 0; b < 3; b++) { + dfdx[a][b] /= delta; + } + } +} + +/* Finite Differences method for estimating the jacobian of the force */ +BLI_INLINE void spring_hairbend_estimate_dfdv(Implicit_Data *data, + int i, + int j, + int k, + const float goal[3], + float stiffness, + float damping, + int q, + float dfdv[3][3]) +{ + const float delta = 0.00001f; // TODO find a good heuristic for this + float dvec_null[3][3], dvec_pos[3][3], dvec_neg[3][3]; + float f[3]; + int a, b; + + zero_m3(dvec_null); + unit_m3(dvec_pos); + mul_m3_fl(dvec_pos, delta * 0.5f); + copy_m3_m3(dvec_neg, dvec_pos); + negate_m3(dvec_neg); + + /* XXX TODO offset targets to account for position dependency */ + + for (a = 0; a < 3; a++) { + spring_hairbend_forces( + data, i, j, k, goal, stiffness, damping, q, dvec_null[a], dvec_pos[a], f); + copy_v3_v3(dfdv[a], f); + + spring_hairbend_forces( + data, i, j, k, goal, stiffness, damping, q, dvec_null[a], dvec_neg[a], f); + sub_v3_v3(dfdv[a], f); + + for (b = 0; b < 3; b++) { + dfdv[a][b] /= delta; + } + } +} + +/* Angular spring that pulls the vertex toward the local target + * See "Artistic Simulation of Curly Hair" (Pixar technical memo #12-03a) + */ +bool BPH_mass_spring_force_spring_bending_hair(Implicit_Data *data, + int i, + int j, + int k, + const float target[3], + float stiffness, + float damping) +{ + float goal[3]; + float fj[3], fk[3]; + float dfj_dxi[3][3], dfj_dxj[3][3], dfk_dxi[3][3], dfk_dxj[3][3], dfk_dxk[3][3]; + float dfj_dvi[3][3], dfj_dvj[3][3], dfk_dvi[3][3], dfk_dvj[3][3], dfk_dvk[3][3]; + + const float vecnull[3] = {0.0f, 0.0f, 0.0f}; + + int block_ij = BPH_mass_spring_add_block(data, i, j); + int block_jk = BPH_mass_spring_add_block(data, j, k); + int block_ik = BPH_mass_spring_add_block(data, i, k); + + world_to_root_v3(data, j, goal, target); + + spring_hairbend_forces(data, i, j, k, goal, stiffness, damping, k, vecnull, vecnull, fk); + negate_v3_v3(fj, fk); /* counterforce */ + + spring_hairbend_estimate_dfdx(data, i, j, k, goal, stiffness, damping, i, dfk_dxi); + spring_hairbend_estimate_dfdx(data, i, j, k, goal, stiffness, damping, j, dfk_dxj); + spring_hairbend_estimate_dfdx(data, i, j, k, goal, stiffness, damping, k, dfk_dxk); + copy_m3_m3(dfj_dxi, dfk_dxi); + negate_m3(dfj_dxi); + copy_m3_m3(dfj_dxj, dfk_dxj); + negate_m3(dfj_dxj); + + spring_hairbend_estimate_dfdv(data, i, j, k, goal, stiffness, damping, i, dfk_dvi); + spring_hairbend_estimate_dfdv(data, i, j, k, goal, stiffness, damping, j, dfk_dvj); + spring_hairbend_estimate_dfdv(data, i, j, k, goal, stiffness, damping, k, dfk_dvk); + copy_m3_m3(dfj_dvi, dfk_dvi); + negate_m3(dfj_dvi); + copy_m3_m3(dfj_dvj, dfk_dvj); + negate_m3(dfj_dvj); + + /* add forces and jacobians to the solver data */ + + add_v3_v3(data->F[j], fj); + add_v3_v3(data->F[k], fk); + + add_m3_m3m3(data->dFdX[j].m, data->dFdX[j].m, dfj_dxj); + add_m3_m3m3(data->dFdX[k].m, data->dFdX[k].m, dfk_dxk); + + add_m3_m3m3(data->dFdX[block_ij].m, data->dFdX[block_ij].m, dfj_dxi); + add_m3_m3m3(data->dFdX[block_jk].m, data->dFdX[block_jk].m, dfk_dxj); + add_m3_m3m3(data->dFdX[block_ik].m, data->dFdX[block_ik].m, dfk_dxi); + + add_m3_m3m3(data->dFdV[j].m, data->dFdV[j].m, dfj_dvj); + add_m3_m3m3(data->dFdV[k].m, data->dFdV[k].m, dfk_dvk); + + add_m3_m3m3(data->dFdV[block_ij].m, data->dFdV[block_ij].m, dfj_dvi); + add_m3_m3m3(data->dFdV[block_jk].m, data->dFdV[block_jk].m, dfk_dvj); + add_m3_m3m3(data->dFdV[block_ik].m, data->dFdV[block_ik].m, dfk_dvi); + + /* XXX analytical calculation of derivatives below is incorrect. + * This proved to be difficult, but for now just using the finite difference method for + * estimating the jacobians should be sufficient. + */ +# if 0 + float edge_ij[3], dir_ij[3], grad_dir_ij[3][3]; + float edge_jk[3], dir_jk[3], grad_dir_jk[3][3]; + float dist[3], vel_jk[3], vel_jk_ortho[3], projvel[3]; + float target[3]; + float tmp[3][3]; + float fi[3], fj[3], fk[3]; + float dfi_dxi[3][3], dfj_dxi[3][3], dfj_dxj[3][3], dfk_dxi[3][3], dfk_dxj[3][3], dfk_dxk[3][3]; + float dfdvi[3][3]; + + // TESTING + damping = 0.0f; + + zero_v3(fi); + zero_v3(fj); + zero_v3(fk); + zero_m3(dfi_dxi); + zero_m3(dfj_dxi); + zero_m3(dfk_dxi); + zero_m3(dfk_dxj); + zero_m3(dfk_dxk); + + /* jacobian of direction vectors */ + spring_grad_dir(data, i, j, edge_ij, dir_ij, grad_dir_ij); + spring_grad_dir(data, j, k, edge_jk, dir_jk, grad_dir_jk); + + sub_v3_v3v3(vel_jk, data->V[k], data->V[j]); + + /* bending force */ + mul_v3_v3fl(target, dir_ij, restlen); + sub_v3_v3v3(dist, target, edge_jk); + mul_v3_v3fl(fk, dist, stiffness); + + /* damping force */ + madd_v3_v3v3fl(vel_jk_ortho, vel_jk, dir_jk, -dot_v3v3(vel_jk, dir_jk)); + madd_v3_v3fl(fk, vel_jk_ortho, damping); + + /* XXX this only holds true as long as we assume straight rest shape! + * eventually will become a bit more involved since the opposite segment + * gets its own target, under condition of having equal torque on both sides. + */ + copy_v3_v3(fi, fk); + + /* counterforce on the middle point */ + sub_v3_v3(fj, fi); + sub_v3_v3(fj, fk); + + /* === derivatives === */ + + madd_m3_m3fl(dfk_dxi, grad_dir_ij, stiffness * restlen); + + madd_m3_m3fl(dfk_dxj, grad_dir_ij, -stiffness * restlen); + madd_m3_m3fl(dfk_dxj, I, stiffness); + + madd_m3_m3fl(dfk_dxk, I, -stiffness); + + copy_m3_m3(dfi_dxi, dfk_dxk); + negate_m3(dfi_dxi); + + /* dfj_dfi == dfi_dfj due to symmetry, + * dfi_dfj == dfk_dfj due to fi == fk + * XXX see comment above on future bent rest shapes + */ + copy_m3_m3(dfj_dxi, dfk_dxj); + + /* dfj_dxj == -(dfi_dxj + dfk_dxj) due to fj == -(fi + fk) */ + sub_m3_m3m3(dfj_dxj, dfj_dxj, dfj_dxi); + sub_m3_m3m3(dfj_dxj, dfj_dxj, dfk_dxj); + + /* add forces and jacobians to the solver data */ + add_v3_v3(data->F[i], fi); + add_v3_v3(data->F[j], fj); + add_v3_v3(data->F[k], fk); + + add_m3_m3m3(data->dFdX[i].m, data->dFdX[i].m, dfi_dxi); + add_m3_m3m3(data->dFdX[j].m, data->dFdX[j].m, dfj_dxj); + add_m3_m3m3(data->dFdX[k].m, data->dFdX[k].m, dfk_dxk); + + add_m3_m3m3(data->dFdX[block_ij].m, data->dFdX[block_ij].m, dfj_dxi); + add_m3_m3m3(data->dFdX[block_jk].m, data->dFdX[block_jk].m, dfk_dxj); + add_m3_m3m3(data->dFdX[block_ik].m, data->dFdX[block_ik].m, dfk_dxi); +# endif + + return true; +} + +bool BPH_mass_spring_force_spring_goal(Implicit_Data *data, + int i, + const float goal_x[3], + const float goal_v[3], + float stiffness, + float damping) +{ + float root_goal_x[3], root_goal_v[3], extent[3], length, dir[3], vel[3]; + float f[3], dfdx[3][3], dfdv[3][3]; + + /* goal is in world space */ + world_to_root_v3(data, i, root_goal_x, goal_x); + world_to_root_v3(data, i, root_goal_v, goal_v); + + sub_v3_v3v3(extent, root_goal_x, data->X[i]); + sub_v3_v3v3(vel, root_goal_v, data->V[i]); + length = normalize_v3_v3(dir, extent); + + if (length > ALMOST_ZERO) { + mul_v3_v3fl(f, dir, stiffness * length); + + // Ascher & Boxman, p.21: Damping only during elonglation + // something wrong with it... + madd_v3_v3fl(f, dir, damping * dot_v3v3(vel, dir)); + + dfdx_spring(dfdx, dir, length, 0.0f, stiffness); + dfdv_damp(dfdv, dir, damping); + + add_v3_v3(data->F[i], f); + add_m3_m3m3(data->dFdX[i].m, data->dFdX[i].m, dfdx); + add_m3_m3m3(data->dFdV[i].m, data->dFdV[i].m, dfdv); + + return true; + } + else { + return false; + } +} + +#endif /* IMPLICIT_SOLVER_BLENDER */ diff --git a/source/blender/simulation/intern/implicit_eigen.cpp b/source/blender/simulation/intern/implicit_eigen.cpp new file mode 100644 index 00000000000..58538c13116 --- /dev/null +++ b/source/blender/simulation/intern/implicit_eigen.cpp @@ -0,0 +1,1509 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * The Original Code is Copyright (C) Blender Foundation + * All rights reserved. + */ + +/** \file + * \ingroup bph + */ + +#include "implicit.h" + +#ifdef IMPLICIT_SOLVER_EIGEN + +//#define USE_EIGEN_CORE +# define USE_EIGEN_CONSTRAINED_CG + +# ifdef __GNUC__ +# pragma GCC diagnostic push +/* XXX suppress verbose warnings in eigen */ +//# pragma GCC diagnostic ignored "-Wlogical-op" +# endif + +# ifndef IMPLICIT_ENABLE_EIGEN_DEBUG +# ifdef NDEBUG +# define IMPLICIT_NDEBUG +# endif +# define NDEBUG +# endif + +# include <Eigen/Sparse> +# include <Eigen/src/Core/util/DisableStupidWarnings.h> + +# ifdef USE_EIGEN_CONSTRAINED_CG +# include <intern/ConstrainedConjugateGradient.h> +# endif + +# ifndef IMPLICIT_ENABLE_EIGEN_DEBUG +# ifndef IMPLICIT_NDEBUG +# undef NDEBUG +# else +# undef IMPLICIT_NDEBUG +# endif +# endif + +# ifdef __GNUC__ +# pragma GCC diagnostic pop +# endif + +# include "MEM_guardedalloc.h" + +extern "C" { +# include "DNA_meshdata_types.h" +# include "DNA_object_force_types.h" +# include "DNA_object_types.h" +# include "DNA_scene_types.h" +# include "DNA_texture_types.h" + +# include "BLI_linklist.h" +# include "BLI_math.h" +# include "BLI_utildefines.h" + +# include "BKE_cloth.h" +# include "BKE_collision.h" +# include "BKE_effect.h" +# include "BKE_global.h" + +# include "BPH_mass_spring.h" +} + +typedef float Scalar; + +static float I[3][3] = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}; + +/* slightly extended Eigen vector class + * with conversion to/from plain C float array + */ +class fVector : public Eigen::Vector3f { + public: + typedef float *ctype; + + fVector() + { + } + + fVector(const ctype &v) + { + for (int k = 0; k < 3; k++) { + coeffRef(k) = v[k]; + } + } + + fVector &operator=(const ctype &v) + { + for (int k = 0; k < 3; k++) { + coeffRef(k) = v[k]; + } + return *this; + } + + operator ctype() + { + return data(); + } +}; + +/* slightly extended Eigen matrix class + * with conversion to/from plain C float array + */ +class fMatrix : public Eigen::Matrix3f { + public: + typedef float (*ctype)[3]; + + fMatrix() + { + } + + fMatrix(const ctype &v) + { + for (int k = 0; k < 3; k++) { + for (int l = 0; l < 3; l++) { + coeffRef(l, k) = v[k][l]; + } + } + } + + fMatrix &operator=(const ctype &v) + { + for (int k = 0; k < 3; k++) { + for (int l = 0; l < 3; l++) { + coeffRef(l, k) = v[k][l]; + } + } + return *this; + } + + operator ctype() + { + return (ctype)data(); + } +}; + +/* Extension of dense Eigen vectors, + * providing 3-float block access for blenlib math functions + */ +class lVector : public Eigen::VectorXf { + public: + typedef Eigen::VectorXf base_t; + + lVector() + { + } + + template<typename T> lVector &operator=(T rhs) + { + base_t::operator=(rhs); + return *this; + } + + float *v3(int vertex) + { + return &coeffRef(3 * vertex); + } + + const float *v3(int vertex) const + { + return &coeffRef(3 * vertex); + } +}; + +typedef Eigen::Triplet<Scalar> Triplet; +typedef std::vector<Triplet> TripletList; + +typedef Eigen::SparseMatrix<Scalar> lMatrix; + +/* Constructor type that provides more convenient handling of Eigen triplets + * for efficient construction of sparse 3x3 block matrices. + * This should be used for building lMatrix instead of writing to such lMatrix directly (which is + * very inefficient). After all elements have been defined using the set() method, the actual + * matrix can be filled using construct(). + */ +struct lMatrixCtor { + lMatrixCtor() + { + } + + void reset() + { + m_trips.clear(); + } + + void reserve(int numverts) + { + /* reserve for diagonal entries */ + m_trips.reserve(numverts * 9); + } + + void add(int i, int j, const fMatrix &m) + { + i *= 3; + j *= 3; + for (int k = 0; k < 3; k++) { + for (int l = 0; l < 3; l++) { + m_trips.push_back(Triplet(i + k, j + l, m.coeff(l, k))); + } + } + } + + void sub(int i, int j, const fMatrix &m) + { + i *= 3; + j *= 3; + for (int k = 0; k < 3; k++) { + for (int l = 0; l < 3; l++) { + m_trips.push_back(Triplet(i + k, j + l, -m.coeff(l, k))); + } + } + } + + inline void construct(lMatrix &m) + { + m.setFromTriplets(m_trips.begin(), m_trips.end()); + m_trips.clear(); + } + + private: + TripletList m_trips; +}; + +# ifdef USE_EIGEN_CORE +typedef Eigen::ConjugateGradient<lMatrix, Eigen::Lower, Eigen::DiagonalPreconditioner<Scalar>> + ConjugateGradient; +# endif +# ifdef USE_EIGEN_CONSTRAINED_CG +typedef Eigen::ConstrainedConjugateGradient<lMatrix, + Eigen::Lower, + lMatrix, + Eigen::DiagonalPreconditioner<Scalar>> + ConstraintConjGrad; +# endif +using Eigen::ComputationInfo; + +static void print_lvector(const lVector &v) +{ + for (int i = 0; i < v.rows(); i++) { + if (i > 0 && i % 3 == 0) { + printf("\n"); + } + + printf("%f,\n", v[i]); + } +} + +static void print_lmatrix(const lMatrix &m) +{ + for (int j = 0; j < m.rows(); j++) { + if (j > 0 && j % 3 == 0) { + printf("\n"); + } + + for (int i = 0; i < m.cols(); i++) { + if (i > 0 && i % 3 == 0) { + printf(" "); + } + + implicit_print_matrix_elem(m.coeff(j, i)); + } + printf("\n"); + } +} + +BLI_INLINE void lMatrix_reserve_elems(lMatrix &m, int num) +{ + m.reserve(Eigen::VectorXi::Constant(m.cols(), num)); +} + +BLI_INLINE float *lVector_v3(lVector &v, int vertex) +{ + return v.data() + 3 * vertex; +} + +BLI_INLINE const float *lVector_v3(const lVector &v, int vertex) +{ + return v.data() + 3 * vertex; +} + +# if 0 +BLI_INLINE void triplets_m3(TripletList &tlist, float m[3][3], int i, int j) +{ + i *= 3; + j *= 3; + for (int l = 0; l < 3; l++) { + for (int k = 0; k < 3; k++) { + tlist.push_back(Triplet(i + k, j + l, m[k][l])); + } + } +} + +BLI_INLINE void triplets_m3fl(TripletList &tlist, float m[3][3], int i, int j, float factor) +{ + i *= 3; + j *= 3; + for (int l = 0; l < 3; l++) { + for (int k = 0; k < 3; k++) { + tlist.push_back(Triplet(i + k, j + l, m[k][l] * factor)); + } + } +} + +BLI_INLINE void lMatrix_add_triplets(lMatrix &r, const TripletList &tlist) +{ + lMatrix t(r.rows(), r.cols()); + t.setFromTriplets(tlist.begin(), tlist.end()); + r += t; +} + +BLI_INLINE void lMatrix_madd_triplets(lMatrix &r, const TripletList &tlist, float f) +{ + lMatrix t(r.rows(), r.cols()); + t.setFromTriplets(tlist.begin(), tlist.end()); + r += f * t; +} + +BLI_INLINE void lMatrix_sub_triplets(lMatrix &r, const TripletList &tlist) +{ + lMatrix t(r.rows(), r.cols()); + t.setFromTriplets(tlist.begin(), tlist.end()); + r -= t; +} +# endif + +BLI_INLINE void outerproduct(float r[3][3], const float a[3], const float b[3]) +{ + mul_v3_v3fl(r[0], a, b[0]); + mul_v3_v3fl(r[1], a, b[1]); + mul_v3_v3fl(r[2], a, b[2]); +} + +BLI_INLINE void cross_m3_v3m3(float r[3][3], const float v[3], float m[3][3]) +{ + cross_v3_v3v3(r[0], v, m[0]); + cross_v3_v3v3(r[1], v, m[1]); + cross_v3_v3v3(r[2], v, m[2]); +} + +BLI_INLINE void cross_v3_identity(float r[3][3], const float v[3]) +{ + r[0][0] = 0.0f; + r[1][0] = v[2]; + r[2][0] = -v[1]; + r[0][1] = -v[2]; + r[1][1] = 0.0f; + r[2][1] = v[0]; + r[0][2] = v[1]; + r[1][2] = -v[0]; + r[2][2] = 0.0f; +} + +BLI_INLINE void madd_m3_m3fl(float r[3][3], float m[3][3], float f) +{ + r[0][0] += m[0][0] * f; + r[0][1] += m[0][1] * f; + r[0][2] += m[0][2] * f; + r[1][0] += m[1][0] * f; + r[1][1] += m[1][1] * f; + r[1][2] += m[1][2] * f; + r[2][0] += m[2][0] * f; + r[2][1] += m[2][1] * f; + r[2][2] += m[2][2] * f; +} + +BLI_INLINE void madd_m3_m3m3fl(float r[3][3], float a[3][3], float b[3][3], float f) +{ + r[0][0] = a[0][0] + b[0][0] * f; + r[0][1] = a[0][1] + b[0][1] * f; + r[0][2] = a[0][2] + b[0][2] * f; + r[1][0] = a[1][0] + b[1][0] * f; + r[1][1] = a[1][1] + b[1][1] * f; + r[1][2] = a[1][2] + b[1][2] * f; + r[2][0] = a[2][0] + b[2][0] * f; + r[2][1] = a[2][1] + b[2][1] * f; + r[2][2] = a[2][2] + b[2][2] * f; +} + +struct Implicit_Data { + typedef std::vector<fMatrix> fMatrixVector; + + Implicit_Data(int numverts) + { + resize(numverts); + } + + void resize(int numverts) + { + this->numverts = numverts; + int tot = 3 * numverts; + + M.resize(tot, tot); + F.resize(tot); + dFdX.resize(tot, tot); + dFdV.resize(tot, tot); + + tfm.resize(numverts, I); + + X.resize(tot); + Xnew.resize(tot); + V.resize(tot); + Vnew.resize(tot); + + A.resize(tot, tot); + B.resize(tot); + + dV.resize(tot); + z.resize(tot); + S.resize(tot, tot); + + iM.reserve(numverts); + idFdX.reserve(numverts); + idFdV.reserve(numverts); + iS.reserve(numverts); + } + + int numverts; + + /* inputs */ + lMatrix M; /* masses */ + lVector F; /* forces */ + lMatrix dFdX, dFdV; /* force jacobians */ + + fMatrixVector tfm; /* local coordinate transform */ + + /* motion state data */ + lVector X, Xnew; /* positions */ + lVector V, Vnew; /* velocities */ + + /* internal solver data */ + lVector B; /* B for A*dV = B */ + lMatrix A; /* A for A*dV = B */ + + lVector dV; /* velocity change (solution of A*dV = B) */ + lVector z; /* target velocity in constrained directions */ + lMatrix S; /* filtering matrix for constraints */ + + /* temporary constructors */ + lMatrixCtor iM; /* masses */ + lMatrixCtor idFdX, idFdV; /* force jacobians */ + lMatrixCtor iS; /* filtering matrix for constraints */ +}; + +Implicit_Data *BPH_mass_spring_solver_create(int numverts, int numsprings) +{ + Implicit_Data *id = new Implicit_Data(numverts); + return id; +} + +void BPH_mass_spring_solver_free(Implicit_Data *id) +{ + if (id) { + delete id; + } +} + +int BPH_mass_spring_solver_numvert(Implicit_Data *id) +{ + if (id) { + return id->numverts; + } + else { + return 0; + } +} + +/* ==== Transformation from/to root reference frames ==== */ + +BLI_INLINE void world_to_root_v3(Implicit_Data *data, int index, float r[3], const float v[3]) +{ + copy_v3_v3(r, v); + mul_transposed_m3_v3(data->tfm[index], r); +} + +BLI_INLINE void root_to_world_v3(Implicit_Data *data, int index, float r[3], const float v[3]) +{ + mul_v3_m3v3(r, data->tfm[index], v); +} + +BLI_INLINE void world_to_root_m3(Implicit_Data *data, int index, float r[3][3], float m[3][3]) +{ + float trot[3][3]; + copy_m3_m3(trot, data->tfm[index]); + transpose_m3(trot); + mul_m3_m3m3(r, trot, m); +} + +BLI_INLINE void root_to_world_m3(Implicit_Data *data, int index, float r[3][3], float m[3][3]) +{ + mul_m3_m3m3(r, data->tfm[index], m); +} + +/* ================================ */ + +bool BPH_mass_spring_solve_velocities(Implicit_Data *data, float dt, ImplicitSolverResult *result) +{ +# ifdef USE_EIGEN_CORE + typedef ConjugateGradient solver_t; +# endif +# ifdef USE_EIGEN_CONSTRAINED_CG + typedef ConstraintConjGrad solver_t; +# endif + + data->iM.construct(data->M); + data->idFdX.construct(data->dFdX); + data->idFdV.construct(data->dFdV); + data->iS.construct(data->S); + + solver_t cg; + cg.setMaxIterations(100); + cg.setTolerance(0.01f); + +# ifdef USE_EIGEN_CONSTRAINED_CG + cg.filter() = data->S; +# endif + + data->A = data->M - dt * data->dFdV - dt * dt * data->dFdX; + cg.compute(data->A); + + data->B = dt * data->F + dt * dt * data->dFdX * data->V; + +# ifdef IMPLICIT_PRINT_SOLVER_INPUT_OUTPUT + printf("==== A ====\n"); + print_lmatrix(id->A); + printf("==== z ====\n"); + print_lvector(id->z); + printf("==== B ====\n"); + print_lvector(id->B); + printf("==== S ====\n"); + print_lmatrix(id->S); +# endif + +# ifdef USE_EIGEN_CORE + data->dV = cg.solve(data->B); +# endif +# ifdef USE_EIGEN_CONSTRAINED_CG + data->dV = cg.solveWithGuess(data->B, data->z); +# endif + +# ifdef IMPLICIT_PRINT_SOLVER_INPUT_OUTPUT + printf("==== dV ====\n"); + print_lvector(id->dV); + printf("========\n"); +# endif + + data->Vnew = data->V + data->dV; + + switch (cg.info()) { + case Eigen::Success: + result->status = BPH_SOLVER_SUCCESS; + break; + case Eigen::NoConvergence: + result->status = BPH_SOLVER_NO_CONVERGENCE; + break; + case Eigen::InvalidInput: + result->status = BPH_SOLVER_INVALID_INPUT; + break; + case Eigen::NumericalIssue: + result->status = BPH_SOLVER_NUMERICAL_ISSUE; + break; + } + + result->iterations = cg.iterations(); + result->error = cg.error(); + + return cg.info() == Eigen::Success; +} + +bool BPH_mass_spring_solve_positions(Implicit_Data *data, float dt) +{ + data->Xnew = data->X + data->Vnew * dt; + return true; +} + +/* ================================ */ + +void BPH_mass_spring_apply_result(Implicit_Data *data) +{ + data->X = data->Xnew; + data->V = data->Vnew; +} + +void BPH_mass_spring_set_vertex_mass(Implicit_Data *data, int index, float mass) +{ + float m[3][3]; + copy_m3_m3(m, I); + mul_m3_fl(m, mass); + data->iM.add(index, index, m); +} + +void BPH_mass_spring_set_rest_transform(Implicit_Data *data, int index, float tfm[3][3]) +{ +# ifdef CLOTH_ROOT_FRAME + copy_m3_m3(data->tfm[index], tfm); +# else + unit_m3(data->tfm[index]); + (void)tfm; +# endif +} + +void BPH_mass_spring_set_motion_state(Implicit_Data *data, + int index, + const float x[3], + const float v[3]) +{ + world_to_root_v3(data, index, data->X.v3(index), x); + world_to_root_v3(data, index, data->V.v3(index), v); +} + +void BPH_mass_spring_set_position(Implicit_Data *data, int index, const float x[3]) +{ + world_to_root_v3(data, index, data->X.v3(index), x); +} + +void BPH_mass_spring_set_velocity(Implicit_Data *data, int index, const float v[3]) +{ + world_to_root_v3(data, index, data->V.v3(index), v); +} + +void BPH_mass_spring_get_motion_state(struct Implicit_Data *data, + int index, + float x[3], + float v[3]) +{ + if (x) { + root_to_world_v3(data, index, x, data->X.v3(index)); + } + if (v) { + root_to_world_v3(data, index, v, data->V.v3(index)); + } +} + +void BPH_mass_spring_get_position(struct Implicit_Data *data, int index, float x[3]) +{ + root_to_world_v3(data, index, x, data->X.v3(index)); +} + +void BPH_mass_spring_get_new_velocity(Implicit_Data *data, int index, float v[3]) +{ + root_to_world_v3(data, index, v, data->V.v3(index)); +} + +void BPH_mass_spring_set_new_velocity(Implicit_Data *data, int index, const float v[3]) +{ + world_to_root_v3(data, index, data->V.v3(index), v); +} + +void BPH_mass_spring_clear_constraints(Implicit_Data *data) +{ + int numverts = data->numverts; + for (int i = 0; i < numverts; i++) { + data->iS.add(i, i, I); + zero_v3(data->z.v3(i)); + } +} + +void BPH_mass_spring_add_constraint_ndof0(Implicit_Data *data, int index, const float dV[3]) +{ + data->iS.sub(index, index, I); + + world_to_root_v3(data, index, data->z.v3(index), dV); +} + +void BPH_mass_spring_add_constraint_ndof1( + Implicit_Data *data, int index, const float c1[3], const float c2[3], const float dV[3]) +{ + float m[3][3], p[3], q[3], u[3], cmat[3][3]; + + world_to_root_v3(data, index, p, c1); + outerproduct(cmat, p, p); + copy_m3_m3(m, cmat); + + world_to_root_v3(data, index, q, c2); + outerproduct(cmat, q, q); + add_m3_m3m3(m, m, cmat); + + /* XXX not sure but multiplication should work here */ + data->iS.sub(index, index, m); + // mul_m3_m3m3(data->S[index].m, data->S[index].m, m); + + world_to_root_v3(data, index, u, dV); + add_v3_v3(data->z.v3(index), u); +} + +void BPH_mass_spring_add_constraint_ndof2(Implicit_Data *data, + int index, + const float c1[3], + const float dV[3]) +{ + float m[3][3], p[3], u[3], cmat[3][3]; + + world_to_root_v3(data, index, p, c1); + outerproduct(cmat, p, p); + copy_m3_m3(m, cmat); + + data->iS.sub(index, index, m); + // mul_m3_m3m3(data->S[index].m, data->S[index].m, m); + + world_to_root_v3(data, index, u, dV); + add_v3_v3(data->z.v3(index), u); +} + +void BPH_mass_spring_clear_forces(Implicit_Data *data) +{ + data->F.setZero(); + data->dFdX.setZero(); + data->dFdV.setZero(); +} + +void BPH_mass_spring_force_reference_frame(Implicit_Data *data, + int index, + const float acceleration[3], + const float omega[3], + const float domega_dt[3], + float mass) +{ +# ifdef CLOTH_ROOT_FRAME + float acc[3], w[3], dwdt[3]; + float f[3], dfdx[3][3], dfdv[3][3]; + float euler[3], coriolis[3], centrifugal[3], rotvel[3]; + float deuler[3][3], dcoriolis[3][3], dcentrifugal[3][3], drotvel[3][3]; + + world_to_root_v3(data, index, acc, acceleration); + world_to_root_v3(data, index, w, omega); + world_to_root_v3(data, index, dwdt, domega_dt); + + cross_v3_v3v3(euler, dwdt, data->X.v3(index)); + cross_v3_v3v3(coriolis, w, data->V.v3(index)); + mul_v3_fl(coriolis, 2.0f); + cross_v3_v3v3(rotvel, w, data->X.v3(index)); + cross_v3_v3v3(centrifugal, w, rotvel); + + sub_v3_v3v3(f, acc, euler); + sub_v3_v3(f, coriolis); + sub_v3_v3(f, centrifugal); + + mul_v3_fl(f, mass); /* F = m * a */ + + cross_v3_identity(deuler, dwdt); + cross_v3_identity(dcoriolis, w); + mul_m3_fl(dcoriolis, 2.0f); + cross_v3_identity(drotvel, w); + cross_m3_v3m3(dcentrifugal, w, drotvel); + + add_m3_m3m3(dfdx, deuler, dcentrifugal); + negate_m3(dfdx); + mul_m3_fl(dfdx, mass); + + copy_m3_m3(dfdv, dcoriolis); + negate_m3(dfdv); + mul_m3_fl(dfdv, mass); + + add_v3_v3(data->F.v3(index), f); + data->idFdX.add(index, index, dfdx); + data->idFdV.add(index, index, dfdv); +# else + (void)data; + (void)index; + (void)acceleration; + (void)omega; + (void)domega_dt; +# endif +} + +void BPH_mass_spring_force_gravity(Implicit_Data *data, int index, float mass, const float g[3]) +{ + /* force = mass * acceleration (in this case: gravity) */ + float f[3]; + world_to_root_v3(data, index, f, g); + mul_v3_fl(f, mass); + + add_v3_v3(data->F.v3(index), f); +} + +void BPH_mass_spring_force_drag(Implicit_Data *data, float drag) +{ + int numverts = data->numverts; + for (int i = 0; i < numverts; i++) { + float tmp[3][3]; + + /* NB: uses root space velocity, no need to transform */ + madd_v3_v3fl(data->F.v3(i), data->V.v3(i), -drag); + + copy_m3_m3(tmp, I); + mul_m3_fl(tmp, -drag); + data->idFdV.add(i, i, tmp); + } +} + +void BPH_mass_spring_force_extern( + struct Implicit_Data *data, int i, const float f[3], float dfdx[3][3], float dfdv[3][3]) +{ + float tf[3], tdfdx[3][3], tdfdv[3][3]; + world_to_root_v3(data, i, tf, f); + world_to_root_m3(data, i, tdfdx, dfdx); + world_to_root_m3(data, i, tdfdv, dfdv); + + add_v3_v3(data->F.v3(i), tf); + data->idFdX.add(i, i, tdfdx); + data->idFdV.add(i, i, tdfdv); +} + +static float calc_nor_area_tri(float nor[3], + const float v1[3], + const float v2[3], + const float v3[3]) +{ + float n1[3], n2[3]; + + sub_v3_v3v3(n1, v1, v2); + sub_v3_v3v3(n2, v2, v3); + + cross_v3_v3v3(nor, n1, n2); + return normalize_v3(nor) / 2.0f; +} + +/* XXX does not support force jacobians yet, + * since the effector system does not provide them either. */ +void BPH_mass_spring_force_face_wind( + Implicit_Data *data, int v1, int v2, int v3, const float (*winvec)[3]) +{ + const float effector_scale = 0.02f; + float win[3], nor[3], area; + float factor; + + // calculate face normal and area + area = calc_nor_area_tri(nor, data->X.v3(v1), data->X.v3(v2), data->X.v3(v3)); + factor = effector_scale * area / 3.0f; + + world_to_root_v3(data, v1, win, winvec[v1]); + madd_v3_v3fl(data->F.v3(v1), nor, factor * dot_v3v3(win, nor)); + + world_to_root_v3(data, v2, win, winvec[v2]); + madd_v3_v3fl(data->F.v3(v2), nor, factor * dot_v3v3(win, nor)); + + world_to_root_v3(data, v3, win, winvec[v3]); + madd_v3_v3fl(data->F.v3(v3), nor, factor * dot_v3v3(win, nor)); +} + +void BPH_mass_spring_force_edge_wind(Implicit_Data *data, int v1, int v2, const float (*winvec)[3]) +{ + const float effector_scale = 0.01; + float win[3], dir[3], nor[3], length; + + sub_v3_v3v3(dir, data->X.v3(v1), data->X.v3(v2)); + length = normalize_v3(dir); + + world_to_root_v3(data, v1, win, winvec[v1]); + madd_v3_v3v3fl(nor, win, dir, -dot_v3v3(win, dir)); + madd_v3_v3fl(data->F.v3(v1), nor, effector_scale * length); + + world_to_root_v3(data, v2, win, winvec[v2]); + madd_v3_v3v3fl(nor, win, dir, -dot_v3v3(win, dir)); + madd_v3_v3fl(data->F.v3(v2), nor, effector_scale * length); +} + +BLI_INLINE void dfdx_spring(float to[3][3], const float dir[3], float length, float L, float k) +{ + /* dir is unit length direction, rest is spring's restlength, k is spring constant. */ + // return ((I - outerprod(dir, dir)) * Min(1.0f, rest / length) - I) * -k; + outerproduct(to, dir, dir); + sub_m3_m3m3(to, I, to); + + mul_m3_fl(to, (L / length)); + sub_m3_m3m3(to, to, I); + mul_m3_fl(to, k); +} + +/* unused */ +# if 0 +BLI_INLINE void dfdx_damp(float to[3][3], + const float dir[3], + float length, + const float vel[3], + float rest, + float damping) +{ + // inner spring damping vel is the relative velocity of the endpoints. + // return (I-outerprod(dir, dir)) * (-damping * -(dot(dir, vel)/Max(length, rest))); + mul_fvectorT_fvector(to, dir, dir); + sub_fmatrix_fmatrix(to, I, to); + mul_fmatrix_S(to, (-damping * -(dot_v3v3(dir, vel) / MAX2(length, rest)))); +} +# endif + +BLI_INLINE void dfdv_damp(float to[3][3], const float dir[3], float damping) +{ + // derivative of force wrt velocity + outerproduct(to, dir, dir); + mul_m3_fl(to, -damping); +} + +BLI_INLINE float fb(float length, float L) +{ + float x = length / L; + return (-11.541f * powf(x, 4) + 34.193f * powf(x, 3) - 39.083f * powf(x, 2) + 23.116f * x - + 9.713f); +} + +BLI_INLINE float fbderiv(float length, float L) +{ + float x = length / L; + + return (-46.164f * powf(x, 3) + 102.579f * powf(x, 2) - 78.166f * x + 23.116f); +} + +BLI_INLINE float fbstar(float length, float L, float kb, float cb) +{ + float tempfb_fl = kb * fb(length, L); + float fbstar_fl = cb * (length - L); + + if (tempfb_fl < fbstar_fl) { + return fbstar_fl; + } + else { + return tempfb_fl; + } +} + +// function to calculae bending spring force (taken from Choi & Co) +BLI_INLINE float fbstar_jacobi(float length, float L, float kb, float cb) +{ + float tempfb_fl = kb * fb(length, L); + float fbstar_fl = cb * (length - L); + + if (tempfb_fl < fbstar_fl) { + return -cb; + } + else { + return -kb * fbderiv(length, L); + } +} + +/* calculate elonglation */ +BLI_INLINE bool spring_length(Implicit_Data *data, + int i, + int j, + float r_extent[3], + float r_dir[3], + float *r_length, + float r_vel[3]) +{ + sub_v3_v3v3(r_extent, data->X.v3(j), data->X.v3(i)); + sub_v3_v3v3(r_vel, data->V.v3(j), data->V.v3(i)); + *r_length = len_v3(r_extent); + + if (*r_length > ALMOST_ZERO) { +# if 0 + if (length > L) { + if ((clmd->sim_parms->flags & CSIMSETT_FLAG_TEARING_ENABLED) && + (((length - L) * 100.0f / L) > clmd->sim_parms->maxspringlen)) { + // cut spring! + s->flags |= CSPRING_FLAG_DEACTIVATE; + return false; + } + } +# endif + mul_v3_v3fl(r_dir, r_extent, 1.0f / (*r_length)); + } + else { + zero_v3(r_dir); + } + + return true; +} + +BLI_INLINE void apply_spring( + Implicit_Data *data, int i, int j, const float f[3], float dfdx[3][3], float dfdv[3][3]) +{ + add_v3_v3(data->F.v3(i), f); + sub_v3_v3(data->F.v3(j), f); + + data->idFdX.add(i, i, dfdx); + data->idFdX.add(j, j, dfdx); + data->idFdX.sub(i, j, dfdx); + data->idFdX.sub(j, i, dfdx); + + data->idFdV.add(i, i, dfdv); + data->idFdV.add(j, j, dfdv); + data->idFdV.sub(i, j, dfdv); + data->idFdV.sub(j, i, dfdv); +} + +bool BPH_mass_spring_force_spring_linear(Implicit_Data *data, + int i, + int j, + float restlen, + float stiffness, + float damping, + bool no_compress, + float clamp_force, + float r_f[3], + float r_dfdx[3][3], + float r_dfdv[3][3]) +{ + float extent[3], length, dir[3], vel[3]; + + // calculate elonglation + spring_length(data, i, j, extent, dir, &length, vel); + + if (length > restlen || no_compress) { + float stretch_force, f[3], dfdx[3][3], dfdv[3][3]; + + stretch_force = stiffness * (length - restlen); + if (clamp_force > 0.0f && stretch_force > clamp_force) { + stretch_force = clamp_force; + } + mul_v3_v3fl(f, dir, stretch_force); + + // Ascher & Boxman, p.21: Damping only during elonglation + // something wrong with it... + madd_v3_v3fl(f, dir, damping * dot_v3v3(vel, dir)); + + dfdx_spring(dfdx, dir, length, restlen, stiffness); + dfdv_damp(dfdv, dir, damping); + + apply_spring(data, i, j, f, dfdx, dfdv); + + if (r_f) { + copy_v3_v3(r_f, f); + } + if (r_dfdx) { + copy_m3_m3(r_dfdx, dfdx); + } + if (r_dfdv) { + copy_m3_m3(r_dfdv, dfdv); + } + + return true; + } + else { + if (r_f) { + zero_v3(r_f); + } + if (r_dfdx) { + zero_m3(r_dfdx); + } + if (r_dfdv) { + zero_m3(r_dfdv); + } + + return false; + } +} + +/* See "Stable but Responsive Cloth" (Choi, Ko 2005) */ +bool BPH_mass_spring_force_spring_bending(Implicit_Data *data, + int i, + int j, + float restlen, + float kb, + float cb, + float r_f[3], + float r_dfdx[3][3], + float r_dfdv[3][3]) +{ + float extent[3], length, dir[3], vel[3]; + + // calculate elonglation + spring_length(data, i, j, extent, dir, &length, vel); + + if (length < restlen) { + float f[3], dfdx[3][3], dfdv[3][3]; + + mul_v3_v3fl(f, dir, fbstar(length, restlen, kb, cb)); + + outerproduct(dfdx, dir, dir); + mul_m3_fl(dfdx, fbstar_jacobi(length, restlen, kb, cb)); + + /* XXX damping not supported */ + zero_m3(dfdv); + + apply_spring(data, i, j, f, dfdx, dfdv); + + if (r_f) { + copy_v3_v3(r_f, f); + } + if (r_dfdx) { + copy_m3_m3(r_dfdx, dfdx); + } + if (r_dfdv) { + copy_m3_m3(r_dfdv, dfdv); + } + + return true; + } + else { + if (r_f) { + zero_v3(r_f); + } + if (r_dfdx) { + zero_m3(r_dfdx); + } + if (r_dfdv) { + zero_m3(r_dfdv); + } + + return false; + } +} + +/* Jacobian of a direction vector. + * Basically the part of the differential orthogonal to the direction, + * inversely proportional to the length of the edge. + * + * dD_ij/dx_i = -dD_ij/dx_j = (D_ij * D_ij^T - I) / len_ij + */ +BLI_INLINE void spring_grad_dir( + Implicit_Data *data, int i, int j, float edge[3], float dir[3], float grad_dir[3][3]) +{ + float length; + + sub_v3_v3v3(edge, data->X.v3(j), data->X.v3(i)); + length = normalize_v3_v3(dir, edge); + + if (length > ALMOST_ZERO) { + outerproduct(grad_dir, dir, dir); + sub_m3_m3m3(grad_dir, I, grad_dir); + mul_m3_fl(grad_dir, 1.0f / length); + } + else { + zero_m3(grad_dir); + } +} + +BLI_INLINE void spring_angbend_forces(Implicit_Data *data, + int i, + int j, + int k, + const float goal[3], + float stiffness, + float damping, + int q, + const float dx[3], + const float dv[3], + float r_f[3]) +{ + float edge_ij[3], dir_ij[3]; + float edge_jk[3], dir_jk[3]; + float vel_ij[3], vel_jk[3], vel_ortho[3]; + float f_bend[3], f_damp[3]; + float fk[3]; + float dist[3]; + + zero_v3(fk); + + sub_v3_v3v3(edge_ij, data->X.v3(j), data->X.v3(i)); + if (q == i) { + sub_v3_v3(edge_ij, dx); + } + if (q == j) { + add_v3_v3(edge_ij, dx); + } + normalize_v3_v3(dir_ij, edge_ij); + + sub_v3_v3v3(edge_jk, data->X.v3(k), data->X.v3(j)); + if (q == j) { + sub_v3_v3(edge_jk, dx); + } + if (q == k) { + add_v3_v3(edge_jk, dx); + } + normalize_v3_v3(dir_jk, edge_jk); + + sub_v3_v3v3(vel_ij, data->V.v3(j), data->V.v3(i)); + if (q == i) { + sub_v3_v3(vel_ij, dv); + } + if (q == j) { + add_v3_v3(vel_ij, dv); + } + + sub_v3_v3v3(vel_jk, data->V.v3(k), data->V.v3(j)); + if (q == j) { + sub_v3_v3(vel_jk, dv); + } + if (q == k) { + add_v3_v3(vel_jk, dv); + } + + /* bending force */ + sub_v3_v3v3(dist, goal, edge_jk); + mul_v3_v3fl(f_bend, dist, stiffness); + + add_v3_v3(fk, f_bend); + + /* damping force */ + madd_v3_v3v3fl(vel_ortho, vel_jk, dir_jk, -dot_v3v3(vel_jk, dir_jk)); + mul_v3_v3fl(f_damp, vel_ortho, damping); + + sub_v3_v3(fk, f_damp); + + copy_v3_v3(r_f, fk); +} + +/* Finite Differences method for estimating the jacobian of the force */ +BLI_INLINE void spring_angbend_estimate_dfdx(Implicit_Data *data, + int i, + int j, + int k, + const float goal[3], + float stiffness, + float damping, + int q, + float dfdx[3][3]) +{ + const float delta = 0.00001f; // TODO find a good heuristic for this + float dvec_null[3][3], dvec_pos[3][3], dvec_neg[3][3]; + float f[3]; + int a, b; + + zero_m3(dvec_null); + unit_m3(dvec_pos); + mul_m3_fl(dvec_pos, delta * 0.5f); + copy_m3_m3(dvec_neg, dvec_pos); + negate_m3(dvec_neg); + + /* XXX TODO offset targets to account for position dependency */ + + for (a = 0; a < 3; a++) { + spring_angbend_forces( + data, i, j, k, goal, stiffness, damping, q, dvec_pos[a], dvec_null[a], f); + copy_v3_v3(dfdx[a], f); + + spring_angbend_forces( + data, i, j, k, goal, stiffness, damping, q, dvec_neg[a], dvec_null[a], f); + sub_v3_v3(dfdx[a], f); + + for (b = 0; b < 3; b++) { + dfdx[a][b] /= delta; + } + } +} + +/* Finite Differences method for estimating the jacobian of the force */ +BLI_INLINE void spring_angbend_estimate_dfdv(Implicit_Data *data, + int i, + int j, + int k, + const float goal[3], + float stiffness, + float damping, + int q, + float dfdv[3][3]) +{ + const float delta = 0.00001f; // TODO find a good heuristic for this + float dvec_null[3][3], dvec_pos[3][3], dvec_neg[3][3]; + float f[3]; + int a, b; + + zero_m3(dvec_null); + unit_m3(dvec_pos); + mul_m3_fl(dvec_pos, delta * 0.5f); + copy_m3_m3(dvec_neg, dvec_pos); + negate_m3(dvec_neg); + + /* XXX TODO offset targets to account for position dependency */ + + for (a = 0; a < 3; a++) { + spring_angbend_forces( + data, i, j, k, goal, stiffness, damping, q, dvec_null[a], dvec_pos[a], f); + copy_v3_v3(dfdv[a], f); + + spring_angbend_forces( + data, i, j, k, goal, stiffness, damping, q, dvec_null[a], dvec_neg[a], f); + sub_v3_v3(dfdv[a], f); + + for (b = 0; b < 3; b++) { + dfdv[a][b] /= delta; + } + } +} + +/* Angular spring that pulls the vertex toward the local target + * See "Artistic Simulation of Curly Hair" (Pixar technical memo #12-03a) + */ +bool BPH_mass_spring_force_spring_bending_angular(Implicit_Data *data, + int i, + int j, + int k, + const float target[3], + float stiffness, + float damping) +{ + float goal[3]; + float fj[3], fk[3]; + float dfj_dxi[3][3], dfj_dxj[3][3], dfk_dxi[3][3], dfk_dxj[3][3], dfk_dxk[3][3]; + float dfj_dvi[3][3], dfj_dvj[3][3], dfk_dvi[3][3], dfk_dvj[3][3], dfk_dvk[3][3]; + + const float vecnull[3] = {0.0f, 0.0f, 0.0f}; + + world_to_root_v3(data, j, goal, target); + + spring_angbend_forces(data, i, j, k, goal, stiffness, damping, k, vecnull, vecnull, fk); + negate_v3_v3(fj, fk); /* counterforce */ + + spring_angbend_estimate_dfdx(data, i, j, k, goal, stiffness, damping, i, dfk_dxi); + spring_angbend_estimate_dfdx(data, i, j, k, goal, stiffness, damping, j, dfk_dxj); + spring_angbend_estimate_dfdx(data, i, j, k, goal, stiffness, damping, k, dfk_dxk); + copy_m3_m3(dfj_dxi, dfk_dxi); + negate_m3(dfj_dxi); + copy_m3_m3(dfj_dxj, dfk_dxj); + negate_m3(dfj_dxj); + + spring_angbend_estimate_dfdv(data, i, j, k, goal, stiffness, damping, i, dfk_dvi); + spring_angbend_estimate_dfdv(data, i, j, k, goal, stiffness, damping, j, dfk_dvj); + spring_angbend_estimate_dfdv(data, i, j, k, goal, stiffness, damping, k, dfk_dvk); + copy_m3_m3(dfj_dvi, dfk_dvi); + negate_m3(dfj_dvi); + copy_m3_m3(dfj_dvj, dfk_dvj); + negate_m3(dfj_dvj); + + /* add forces and jacobians to the solver data */ + + add_v3_v3(data->F.v3(j), fj); + add_v3_v3(data->F.v3(k), fk); + + data->idFdX.add(j, j, dfj_dxj); + data->idFdX.add(k, k, dfk_dxk); + + data->idFdX.add(i, j, dfj_dxi); + data->idFdX.add(j, i, dfj_dxi); + data->idFdX.add(j, k, dfk_dxj); + data->idFdX.add(k, j, dfk_dxj); + data->idFdX.add(i, k, dfk_dxi); + data->idFdX.add(k, i, dfk_dxi); + + data->idFdV.add(j, j, dfj_dvj); + data->idFdV.add(k, k, dfk_dvk); + + data->idFdV.add(i, j, dfj_dvi); + data->idFdV.add(j, i, dfj_dvi); + data->idFdV.add(j, k, dfk_dvj); + data->idFdV.add(k, j, dfk_dvj); + data->idFdV.add(i, k, dfk_dvi); + data->idFdV.add(k, i, dfk_dvi); + + /* XXX analytical calculation of derivatives below is incorrect. + * This proved to be difficult, but for now just using the finite difference method for + * estimating the jacobians should be sufficient. + */ +# if 0 + float edge_ij[3], dir_ij[3], grad_dir_ij[3][3]; + float edge_jk[3], dir_jk[3], grad_dir_jk[3][3]; + float dist[3], vel_jk[3], vel_jk_ortho[3], projvel[3]; + float target[3]; + float tmp[3][3]; + float fi[3], fj[3], fk[3]; + float dfi_dxi[3][3], dfj_dxi[3][3], dfj_dxj[3][3], dfk_dxi[3][3], dfk_dxj[3][3], dfk_dxk[3][3]; + float dfdvi[3][3]; + + // TESTING + damping = 0.0f; + + zero_v3(fi); + zero_v3(fj); + zero_v3(fk); + zero_m3(dfi_dxi); + zero_m3(dfj_dxi); + zero_m3(dfk_dxi); + zero_m3(dfk_dxj); + zero_m3(dfk_dxk); + + /* jacobian of direction vectors */ + spring_grad_dir(data, i, j, edge_ij, dir_ij, grad_dir_ij); + spring_grad_dir(data, j, k, edge_jk, dir_jk, grad_dir_jk); + + sub_v3_v3v3(vel_jk, data->V[k], data->V[j]); + + /* bending force */ + mul_v3_v3fl(target, dir_ij, restlen); + sub_v3_v3v3(dist, target, edge_jk); + mul_v3_v3fl(fk, dist, stiffness); + + /* damping force */ + madd_v3_v3v3fl(vel_jk_ortho, vel_jk, dir_jk, -dot_v3v3(vel_jk, dir_jk)); + madd_v3_v3fl(fk, vel_jk_ortho, damping); + + /* XXX this only holds true as long as we assume straight rest shape! + * eventually will become a bit more involved since the opposite segment + * gets its own target, under condition of having equal torque on both sides. + */ + copy_v3_v3(fi, fk); + + /* counterforce on the middle point */ + sub_v3_v3(fj, fi); + sub_v3_v3(fj, fk); + + /* === derivatives === */ + + madd_m3_m3fl(dfk_dxi, grad_dir_ij, stiffness * restlen); + + madd_m3_m3fl(dfk_dxj, grad_dir_ij, -stiffness * restlen); + madd_m3_m3fl(dfk_dxj, I, stiffness); + + madd_m3_m3fl(dfk_dxk, I, -stiffness); + + copy_m3_m3(dfi_dxi, dfk_dxk); + negate_m3(dfi_dxi); + + /* dfj_dfi == dfi_dfj due to symmetry, + * dfi_dfj == dfk_dfj due to fi == fk + * XXX see comment above on future bent rest shapes + */ + copy_m3_m3(dfj_dxi, dfk_dxj); + + /* dfj_dxj == -(dfi_dxj + dfk_dxj) due to fj == -(fi + fk) */ + sub_m3_m3m3(dfj_dxj, dfj_dxj, dfj_dxi); + sub_m3_m3m3(dfj_dxj, dfj_dxj, dfk_dxj); + + /* add forces and jacobians to the solver data */ + add_v3_v3(data->F[i], fi); + add_v3_v3(data->F[j], fj); + add_v3_v3(data->F[k], fk); + + add_m3_m3m3(data->dFdX[i].m, data->dFdX[i].m, dfi_dxi); + add_m3_m3m3(data->dFdX[j].m, data->dFdX[j].m, dfj_dxj); + add_m3_m3m3(data->dFdX[k].m, data->dFdX[k].m, dfk_dxk); + + add_m3_m3m3(data->dFdX[block_ij].m, data->dFdX[block_ij].m, dfj_dxi); + add_m3_m3m3(data->dFdX[block_jk].m, data->dFdX[block_jk].m, dfk_dxj); + add_m3_m3m3(data->dFdX[block_ik].m, data->dFdX[block_ik].m, dfk_dxi); +# endif + + return true; +} + +bool BPH_mass_spring_force_spring_goal(Implicit_Data *data, + int i, + const float goal_x[3], + const float goal_v[3], + float stiffness, + float damping, + float r_f[3], + float r_dfdx[3][3], + float r_dfdv[3][3]) +{ + float root_goal_x[3], root_goal_v[3], extent[3], length, dir[3], vel[3]; + float f[3], dfdx[3][3], dfdv[3][3]; + + /* goal is in world space */ + world_to_root_v3(data, i, root_goal_x, goal_x); + world_to_root_v3(data, i, root_goal_v, goal_v); + + sub_v3_v3v3(extent, root_goal_x, data->X.v3(i)); + sub_v3_v3v3(vel, root_goal_v, data->V.v3(i)); + length = normalize_v3_v3(dir, extent); + + if (length > ALMOST_ZERO) { + mul_v3_v3fl(f, dir, stiffness * length); + + // Ascher & Boxman, p.21: Damping only during elonglation + // something wrong with it... + madd_v3_v3fl(f, dir, damping * dot_v3v3(vel, dir)); + + dfdx_spring(dfdx, dir, length, 0.0f, stiffness); + dfdv_damp(dfdv, dir, damping); + + add_v3_v3(data->F.v3(i), f); + data->idFdX.add(i, i, dfdx); + data->idFdV.add(i, i, dfdv); + + if (r_f) { + copy_v3_v3(r_f, f); + } + if (r_dfdx) { + copy_m3_m3(r_dfdx, dfdx); + } + if (r_dfdv) { + copy_m3_m3(r_dfdv, dfdv); + } + + return true; + } + else { + if (r_f) { + zero_v3(r_f); + } + if (r_dfdx) { + zero_m3(r_dfdx); + } + if (r_dfdv) { + zero_m3(r_dfdv); + } + + return false; + } +} + +#endif /* IMPLICIT_SOLVER_EIGEN */ |