diff options
author | Sebastian Parborg <darkdefende@gmail.com> | 2019-11-27 16:56:16 +0300 |
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committer | Sebastian Parborg <darkdefende@gmail.com> | 2019-11-27 17:01:15 +0300 |
commit | f6cefbef22c8c6583b4927c179dabac3eb57aa22 (patch) | |
tree | 96785e2ee93f34bb14975a53bc2a4e003ee3fb59 /source/blender/physics/intern/BPH_mass_spring.cpp | |
parent | eb798de101ac7946e2d719e763ad1f0fd3e26acd (diff) |
Fix T30941: Add cloth air pressure simulation
This adds some basic simulation of internal air pressure inside of
closed cloth mesh objects.
Reviewed By: Jacques Lucke
Differential Revision: http://developer.blender.org/D5473
Diffstat (limited to 'source/blender/physics/intern/BPH_mass_spring.cpp')
-rw-r--r-- | source/blender/physics/intern/BPH_mass_spring.cpp | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/source/blender/physics/intern/BPH_mass_spring.cpp b/source/blender/physics/intern/BPH_mass_spring.cpp index c057e74b72b..259eed88756 100644 --- a/source/blender/physics/intern/BPH_mass_spring.cpp +++ b/source/blender/physics/intern/BPH_mass_spring.cpp @@ -74,6 +74,25 @@ static int cloth_count_nondiag_blocks(Cloth *cloth) return nondiag; } +static float cloth_calc_volume(ClothModifierData *clmd) +{ + /* calc the (closed) cloth volume */ + Cloth *cloth = clmd->clothObject; + const MVertTri *tri = cloth->tri; + Implicit_Data *data = cloth->implicit; + float vol = 0; + + for (unsigned int i = 0; i < cloth->tri_num; i++) { + const MVertTri *vt = &tri[i]; + 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; +} + int BPH_cloth_solver_init(Object *UNUSED(ob), ClothModifierData *clmd) { Cloth *cloth = clmd->clothObject; @@ -127,6 +146,13 @@ void BKE_cloth_solver_set_positions(ClothModifierData *clmd) } } +void BKE_cloth_solver_set_volume(ClothModifierData *clmd) +{ + Cloth *cloth = clmd->clothObject; + + cloth->initial_mesh_volume = cloth_calc_volume(clmd); +} + static bool collision_response(ClothModifierData *clmd, CollisionModifierData *collmd, CollPair *collpair, @@ -526,6 +552,7 @@ static void cloth_calc_force( { /* 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 */ @@ -570,6 +597,48 @@ static void cloth_calc_force( #ifdef CLOTH_FORCE_DRAG BPH_mass_spring_force_drag(data, drag); #endif + /* handle pressure forces */ + if (parms->flags & CLOTH_SIMSETTINGS_FLAG_PRESSURE) { + /* The difference in pressure between the inside and outside of the mesh.*/ + float pressure_difference = 0.0f; + + 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); + + /* Calculate an artifical maximum value for cloth pressure. */ + f = fabs(clmd->sim_parms->uniform_pressure_force) + 200.0f; + + /* Clamp the cloth pressure to the calculated maximum value. */ + if (vol * f < init_vol) { + pressure_difference = f; + } + else { + /* If the volume is the same don't apply any pressure. */ + pressure_difference = (init_vol / vol) - 1; + } + } + pressure_difference += clmd->sim_parms->uniform_pressure_force; + + pressure_difference *= clmd->sim_parms->pressure_factor; + + for (i = 0; i < cloth->tri_num; i++) { + const MVertTri *vt = &tri[i]; + if (fabs(pressure_difference) > 1E-6f) { + BPH_mass_spring_force_pressure( + data, vt->tri[0], vt->tri[1], vt->tri[2], pressure_difference); + } + } + } /* handle external forces like wind */ if (effectors) { |