diff options
author | Lukas Tönne <lukas.toenne@gmail.com> | 2014-08-27 14:30:25 +0400 |
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committer | Lukas Tönne <lukas.toenne@gmail.com> | 2015-01-20 11:29:21 +0300 |
commit | efc0cd16580bfcafb4abddd5465f197ba1915dd9 (patch) | |
tree | 85bfb516b62512123f793643ebaad9c3ed6472a6 /source | |
parent | 5f41b19463bb4af38880ecda0839c2a20cf45d74 (diff) |
Fixed voxel grid initialization from hair points and colliders by using
the suggested tent function from the original paper.
Plain float->int conversion for the grid location otherwise leads to
skewed data and unnecessary loss of information.
Diffstat (limited to 'source')
-rw-r--r-- | source/blender/blenkernel/intern/implicit.c | 161 |
1 files changed, 112 insertions, 49 deletions
diff --git a/source/blender/blenkernel/intern/implicit.c b/source/blender/blenkernel/intern/implicit.c index 56d0d7dd0e5..0bc013efe00 100644 --- a/source/blender/blenkernel/intern/implicit.c +++ b/source/blender/blenkernel/intern/implicit.c @@ -1218,6 +1218,12 @@ static float calculateVertexWindForce(const float wind[3], const float vertexnor * Pixar Technical Memo #06-08, Pixar Animation Studios */ +/* 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_y * z + */ + /* TODO: This is an initial implementation and should be made much better in due time. * What should at least be implemented is a grid size parameter and a smoothing kernel * for bigger grids. @@ -1231,43 +1237,49 @@ static int hair_grid_size(int res) return res * res * res; } +BLI_INLINE void hair_grid_get_scale(int res, const float gmin[3], const float gmax[3], float scale[3]) +{ + sub_v3_v3v3(scale, gmax, gmin); + mul_v3_fl(scale, 1.0f / (res-1)); +} + typedef struct HairGridVert { float velocity[3]; float density; } HairGridVert; -#define HAIR_GRID_INDEX_AXIS(vec, min, max, axis) (int)((vec[axis] - min[axis]) / (max[axis] - min[axis]) * 9.99f) +#define HAIR_GRID_INDEX_AXIS(vec, res, gmin, scale, axis) ( min_ii( max_ii( (int)((vec[axis] - gmin[axis]) / scale[axis]), 0), res-2 ) ) -#if 0 -BLI_INLINE void hair_grid_index(lfVector *vec, int res, const float min[3], const float max[3], - float *r_i, float *r_j, float *r_k, float *r_offset) +BLI_INLINE int hair_grid_offset(const float vec[3], int res, const float gmin[3], const float scale[3]) { - *r_i = HAIR_GRID_INDEX_AXIS(vec, min, max, 0); - *r_j = HAIR_GRID_INDEX_AXIS(vec, min, max, 1); - *r_k = HAIR_GRID_INDEX_AXIS(vec, min, max, 2); - *r_offset = i + (j + k*res)*res; + 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)*res; } -#endif -BLI_INLINE int hair_grid_offset(const float vec[3], int res, const float min[3], const float max[3]) +BLI_INLINE void hair_grid_vertex_loc(int offset, int res, const float gmin[3], const float scale[3], float loc[3]) { - int i, j, k; - i = HAIR_GRID_INDEX_AXIS(vec, min, max, 0); - j = HAIR_GRID_INDEX_AXIS(vec, min, max, 1); - k = HAIR_GRID_INDEX_AXIS(vec, min, max, 2); - return i + (j + k*res)*res; + int v = offset; + float ijk[3]; + + ijk[0] = (float)(v % res); + v /= res; + ijk[1] = (float)(v % res); + v /= res; + ijk[2] = (float)(v % res); + + madd_v3_v3v3v3(loc, gmin, ijk, scale); } -static void hair_velocity_smoothing(const HairGridVert *hairgrid, const float gmin[3], const float gmax[3], float smoothfac, +static void hair_velocity_smoothing(const HairGridVert *hairgrid, const float gmin[3], const float scale[3], float smoothfac, lfVector *lF, lfVector *lX, lfVector *lV, unsigned int numverts) { - int size = hair_grid_size(hair_grid_res); int v; /* calculate forces */ for (v = 0; v < numverts; v++) { - int offset = hair_grid_offset(lX[v], hair_grid_res, gmin, gmax); - if (offset < 0 || offset >= size) - continue; + int offset = hair_grid_offset(lX[v], hair_grid_res, gmin, scale); lF[v][0] += smoothfac * (hairgrid[offset].velocity[0] - lV[v][0]); lF[v][1] += smoothfac * (hairgrid[offset].velocity[1] - lV[v][1]); @@ -1275,16 +1287,13 @@ static void hair_velocity_smoothing(const HairGridVert *hairgrid, const float gm } } -static void hair_velocity_collision(const HairGridVert *collgrid, const float gmin[3], const float gmax[3], float collfac, +static void hair_velocity_collision(const HairGridVert *collgrid, const float gmin[3], const float scale[3], float collfac, lfVector *lF, lfVector *lX, lfVector *lV, unsigned int numverts) { - int size = hair_grid_size(hair_grid_res); int v; /* calculate forces */ for (v = 0; v < numverts; v++) { - int offset = hair_grid_offset(lX[v], hair_grid_res, gmin, gmax); - if (offset < 0 || offset >= size) - continue; + int offset = hair_grid_offset(lX[v], hair_grid_res, gmin, scale); if (collgrid[offset].density > 0.0f) { lF[v][0] += collfac * (collgrid[offset].velocity[0] - lV[v][0]); @@ -1303,17 +1312,46 @@ static void hair_volume_get_boundbox(lfVector *lX, unsigned int numverts, float DO_MINMAX(lX[i], gmin, gmax); } +BLI_INLINE bool hair_grid_point_valid(const float vec[3], float gmin[3], 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) +{ + return (1.0f - fabsf(a[0] - x)) * (1.0f - fabsf(a[1] - y)) * (1.0f - fabsf(a[2] - z)); +} + +static void hair_grid_weights(int res, const float gmin[3], const float scale[3], const float vec[3], int offset, float weights[8]) +{ + float vloc[3]; + + hair_grid_vertex_loc(offset, res, gmin, scale, vloc); + + weights[0] = dist_tent_v3f3(vec, vloc[0], vloc[1], vloc[2] ); + weights[1] = dist_tent_v3f3(vec, vloc[0] + scale[0], vloc[1], vloc[2] ); + weights[2] = dist_tent_v3f3(vec, vloc[0], vloc[1] + scale[1], vloc[2] ); + weights[3] = dist_tent_v3f3(vec, vloc[0] + scale[0], vloc[1] + scale[1], vloc[2] ); + weights[4] = dist_tent_v3f3(vec, vloc[0], vloc[1], vloc[2] + scale[2]); + weights[5] = dist_tent_v3f3(vec, vloc[0] + scale[0], vloc[1], vloc[2] + scale[2]); + weights[6] = dist_tent_v3f3(vec, vloc[0], vloc[1] + scale[1], vloc[2] + scale[2]); + weights[7] = dist_tent_v3f3(vec, vloc[0] + scale[0], vloc[1] + scale[1], vloc[2] + scale[2]); +} + static HairGridVert *hair_volume_create_hair_grid(ClothModifierData *clmd, lfVector *lX, lfVector *lV, unsigned int numverts) { - int size = hair_grid_size(hair_grid_res); + int res = hair_grid_res; + int size = hair_grid_size(res); HairGridVert *hairgrid; - float gmin[3], gmax[3], density; + float gmin[3], gmax[3], scale[3]; /* 2.0f is an experimental value that seems to give good results */ float smoothfac = 2.0f * clmd->sim_parms->velocity_smooth; unsigned int v = 0; int i = 0; hair_volume_get_boundbox(lX, numverts, gmin, gmax); + hair_grid_get_scale(res, gmin, gmax, scale); hairgrid = MEM_mallocN(sizeof(HairGridVert) * size, "hair voxel data"); @@ -1326,23 +1364,35 @@ static HairGridVert *hair_volume_create_hair_grid(ClothModifierData *clmd, lfVec /* gather velocities & density */ if (smoothfac > 0.0f) { for (v = 0; v < numverts; v++) { - int offset = hair_grid_offset(lX[v], hair_grid_res, gmin, gmax); - if (offset < 0 || offset >= size) + float *V = lV[v]; + float weights[8]; + int di, dj, dk; + int offset = hair_grid_offset(lX[v], res, gmin, scale); + + if (!hair_grid_point_valid(lX[v], gmin, gmax)) continue; - add_v3_v3(hairgrid[offset].velocity, lV[v]); - hairgrid[offset].density += 1.0f; + hair_grid_weights(res, gmin, scale, lX[v], offset, 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)*res; + int iw = di + dj*2 + dk*4; + + hairgrid[voffset].density += weights[iw]; + madd_v3_v3fl(hairgrid[voffset].velocity, V, weights[iw]); + } + } + } } } /* divide velocity with density */ for (i = 0; i < size; i++) { - density = hairgrid[i].density; - if (density > 0.0f) { - hairgrid[i].velocity[0] /= density; - hairgrid[i].velocity[1] /= density; - hairgrid[i].velocity[2] /= density; - } + float density = hairgrid[i].density; + if (density > 0.0f) + mul_v3_fl(hairgrid[i].velocity, 1.0f/density); } return hairgrid; @@ -1351,17 +1401,19 @@ static HairGridVert *hair_volume_create_hair_grid(ClothModifierData *clmd, lfVec static HairGridVert *hair_volume_create_collision_grid(ClothModifierData *clmd, lfVector *lX, unsigned int numverts) { - int size = hair_grid_size(hair_grid_res); + int res = hair_grid_res; + int size = hair_grid_size(res); HairGridVert *collgrid; ListBase *colliders; ColliderCache *col = NULL; - float gmin[3], gmax[3], density; + 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"); @@ -1378,16 +1430,30 @@ static HairGridVert *hair_volume_create_collision_grid(ClothModifierData *clmd, 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 = hair_grid_offset(loc1->co, hair_grid_res, gmin, gmax); - if (offset < 0 || offset >= size) + int offset = hair_grid_offset(loc1->co, res, gmin, scale); + + if (!hair_grid_point_valid(loc1->co, gmin, gmax)) continue; sub_v3_v3v3(vel, loc1->co, loc0->co); - add_v3_v3(collgrid[offset].velocity, vel); - collgrid[offset].density += 1.0f; + hair_grid_weights(res, gmin, scale, lX[v], offset, 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)*res; + int iw = di + dj*2 + dk*4; + + collgrid[voffset].density += weights[iw]; + madd_v3_v3fl(collgrid[voffset].velocity, vel, weights[iw]); + } + } + } } } } @@ -1395,12 +1461,9 @@ static HairGridVert *hair_volume_create_collision_grid(ClothModifierData *clmd, /* divide velocity with density */ for (i = 0; i < size; i++) { - density = collgrid[i].density; - if (density > 0.0f) { - collgrid[i].velocity[0] /= density; - collgrid[i].velocity[1] /= density; - collgrid[i].velocity[2] /= density; - } + float density = collgrid[i].density; + if (density > 0.0f) + mul_v3_fl(collgrid[i].velocity, 1.0f/density); } return collgrid; |