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Diffstat (limited to 'source/blender/simulation/intern/implicit_blender.c')
-rw-r--r-- | source/blender/simulation/intern/implicit_blender.c | 2360 |
1 files changed, 2360 insertions, 0 deletions
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 */ |