diff options
Diffstat (limited to 'source/blender/physics/intern/implicit_blender.c')
| -rw-r--r-- | source/blender/physics/intern/implicit_blender.c | 138 |
1 files changed, 123 insertions, 15 deletions
diff --git a/source/blender/physics/intern/implicit_blender.c b/source/blender/physics/intern/implicit_blender.c index 677e566ff39..0d897893ff5 100644 --- a/source/blender/physics/intern/implicit_blender.c +++ b/source/blender/physics/intern/implicit_blender.c @@ -1664,6 +1664,114 @@ bool BPH_mass_spring_force_spring_bending(Implicit_Data *data, int i, int j, flo } } +BLI_INLINE void poly_avg(lfVector *data, 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. @@ -1687,7 +1795,7 @@ BLI_INLINE void spring_grad_dir(Implicit_Data *data, int i, int j, float edge[3] } } -BLI_INLINE void spring_angbend_forces(Implicit_Data *data, int i, int j, int k, +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], @@ -1736,7 +1844,7 @@ BLI_INLINE void spring_angbend_forces(Implicit_Data *data, int i, int j, int k, } /* 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, +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]) @@ -1755,11 +1863,11 @@ BLI_INLINE void spring_angbend_estimate_dfdx(Implicit_Data *data, int i, int j, /* 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, + 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_angbend_forces(data, i, j, k, goal, stiffness, damping, + spring_hairbend_forces(data, i, j, k, goal, stiffness, damping, q, dvec_neg[a], dvec_null[a], f); sub_v3_v3(dfdx[a], f); @@ -1770,7 +1878,7 @@ BLI_INLINE void spring_angbend_estimate_dfdx(Implicit_Data *data, int i, int j, } /* 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, +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]) @@ -1789,11 +1897,11 @@ BLI_INLINE void spring_angbend_estimate_dfdv(Implicit_Data *data, int i, int j, /* 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, + 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_angbend_forces(data, i, j, k, goal, stiffness, damping, + spring_hairbend_forces(data, i, j, k, goal, stiffness, damping, q, dvec_null[a], dvec_neg[a], f); sub_v3_v3(dfdv[a], f); @@ -1806,7 +1914,7 @@ BLI_INLINE void spring_angbend_estimate_dfdv(Implicit_Data *data, int i, int j, /* 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, +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]; @@ -1822,18 +1930,18 @@ bool BPH_mass_spring_force_spring_bending_angular(Implicit_Data *data, int i, in world_to_root_v3(data, j, goal, target); - spring_angbend_forces(data, i, j, k, goal, stiffness, damping, k, vecnull, vecnull, fk); + spring_hairbend_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); + 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_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); + 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); |