Commit: 5fea59db5b116a702790b498dd1f4e06820ac6be
Author: Lukas Tönne
Date: Sat Oct 4 16:45:22 2014 +0200
Branches: hair_system
https://developer.blender.org/rB5fea59db5b116a702790b498dd1f4e06820ac6be
Stretch spring force for the new hair solver data.
===================================================================
M source/blender/physics/intern/BPH_mass_spring.cpp
===================================================================
diff --git a/source/blender/physics/intern/BPH_mass_spring.cpp
b/source/blender/physics/intern/BPH_mass_spring.cpp
index 1c40460..04f41c1 100644
--- a/source/blender/physics/intern/BPH_mass_spring.cpp
+++ b/source/blender/physics/intern/BPH_mass_spring.cpp
@@ -839,8 +839,121 @@ void BPH_hair_solver_set_positions(HairSolverData *data,
Object *ob, HairSystem
}
}
-static void hair_calc_force(HairSolverData *data, HairParams *params, float
time, SimDebugData *debug_data)
+static void hair_calc_spring_force(HairSolverData *data, Object *ob,
HairSystem *hsys, float time, SimDebugData *debug_data)
{
+ HairParams *params = &hsys->params;
+ const bool no_compress = true;
+
+ float obmat[4][4];
+ copy_m4_m4(obmat, ob->obmat);
+
+ int max_points = 0;
+ HairCurve *curve = hsys->curves;
+ for (int i = 0; i < hsys->totcurves; ++i, ++curve) {
+ if (curve->totpoints > max_points)
+ max_points = curve->totpoints;
+ }
+ if (max_points < 2)
+ return;
+ /* local caching of rest length for each hair */
+ float *restlen = (float *)MEM_mallocN(sizeof(float) * max_points, "hair
rest length");
+
+ int kstart = 0;
+ curve = hsys->curves;
+ for (int i = 0; i < hsys->totcurves; ++i, ++curve) {
+ HairPoint *point;
+
+ /* precalculate segment rest lengths */
+ point = curve->points;
+ for (int k = 0; k < curve->totpoints - 1; ++k, ++point) {
+ float a[3], b[3];
+ mul_v3_m4v3(a, obmat, point->rest_co);
+ mul_v3_m4v3(b, obmat, (point+1)->rest_co);
+ restlen[k] = len_v3v3(a, b);
+ }
+
+#ifdef CLOTH_FORCE_SPRING_STRUCTURAL
+ point = curve->points;
+ for (int k = 0; k < curve->totpoints - 1; ++k, ++point) {
+ BPH_mass_spring_force_spring_linear(data->id, kstart +
k, kstart + k + 1, restlen[k],
+
params->stretch_stiffness, params->stretch_damping, no_compress, 0.0f,
+ NULL, NULL, NULL);
+ }
+#endif
+
+#if 0
+#ifdef CLOTH_FORCE_SPRING_GOAL
+ float goal_x[3], goal_v[3];
+ float k, scaling;
+
+ s->flags |= CLOTH_SPRING_FLAG_NEEDED;
+
+ // current_position = xold + t * (newposition - xold)
+ interp_v3_v3v3(goal_x, verts[s->ij].xold,
verts[s->ij].xconst, time);
+ sub_v3_v3v3(goal_v, verts[s->ij].xconst,
verts[s->ij].xold); // distance covered over dt==1
+
+ scaling = parms->goalspring + s->stiffness *
fabsf(parms->max_struct - parms->goalspring);
+ k = verts[s->ij].goal * scaling /
(parms->avg_spring_len + FLT_EPSILON);
+
+ BPH_mass_spring_force_spring_goal(data, s->ij,
s->matrix_ij_kl, goal_x, goal_v, k, parms->goalfrict * 0.01f, s->f, s->dfdx,
s->dfdv);
+#endif
+
+#ifdef CLOTH_FORCE_SPRING_BEND
+ float kb, cb, scaling;
+
+ s->flags |= CLOTH_SPRING_FLAG_NEEDED;
+
+ scaling = parms->bending + s->stiffness *
fabsf(parms->max_bend - parms->bending);
+ kb = scaling / (20.0f * (parms->avg_spring_len +
FLT_EPSILON));
+
+ scaling = parms->bending_damping;
+ cb = scaling / (20.0f * (parms->avg_spring_len +
FLT_EPSILON));
+
+ BPH_mass_spring_force_spring_bending(data, s->ij,
s->kl, s->matrix_ij_kl, s->restlen, kb, cb, s->f, s->dfdx, s->dfdv);
+#endif
+
+#ifdef CLOTH_FORCE_SPRING_BEND
+ float kb, cb, scaling;
+
+ s->flags |= CLOTH_SPRING_FLAG_NEEDED;
+
+ scaling = parms->bending + s->stiffness *
fabsf(parms->max_bend - parms->bending);
+ kb = scaling / (20.0f * (parms->avg_spring_len +
FLT_EPSILON));
+
+ scaling = parms->bending_damping;
+ cb = scaling / (20.0f * (parms->avg_spring_len +
FLT_EPSILON));
+
+ /* XXX assuming same restlen for ij and jk segments
here, this can be done correctly for hair later */
+ BPH_mass_spring_force_spring_bending_angular(data,
s->ij, s->kl, s->mn, s->matrix_ij_kl, s->matrix_kl_mn, s->matrix_ij_mn,
s->target, kb, cb);
+
+ {
+ 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", hash_vertex(7980, s->kl));
+ BKE_sim_debug_data_add_line(clmd->debug_data,
x_kl, x_mn, 0.8, 0.8, 0.8, "target", hash_vertex(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", hash_vertex(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", hash_vertex(7983, s->kl));
+ }
+#endif
+#endif
+
+ kstart += curve->totpoints;
+ }
+
+ MEM_freeN(restlen);
+}
+
+static void hair_calc_force(HairSolverData *data, Object *ob, HairSystem
*hsys, float time, SimDebugData *debug_data)
+{
+ HairParams *params = &hsys->params;
+
#ifdef CLOTH_FORCE_GRAVITY
/* global acceleration (gravitation) */
float gravity[3];
@@ -885,15 +998,9 @@ static void hair_calc_force(HairSolverData *data,
HairParams *params, float time
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, time);
- }
#endif
+
+ hair_calc_spring_force(data, ob, hsys, time, debug_data);
}
/* Init constraint matrix
@@ -1009,7 +1116,7 @@ void BPH_hair_solve(HairSolverData *data, Object *ob,
HairSystem *hsys, float ti
hair_setup_constraints(data, ob, hsys, contacts, totcolliders,
dt);
// calculate forces
- hair_calc_force(data, params, time, debug_data);
+ hair_calc_force(data, ob, hsys, time, debug_data);
// calculate new velocity and position
BPH_mass_spring_solve(data->id, dt, &result);
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