diff options
Diffstat (limited to 'source/blender/physics/intern/strands.cpp')
| -rw-r--r-- | source/blender/physics/intern/strands.cpp | 48 |
1 files changed, 25 insertions, 23 deletions
diff --git a/source/blender/physics/intern/strands.cpp b/source/blender/physics/intern/strands.cpp index c53749cbb06..624bb70a5d1 100644 --- a/source/blender/physics/intern/strands.cpp +++ b/source/blender/physics/intern/strands.cpp @@ -429,7 +429,7 @@ static void strands_solve_inverse_kinematics(Object *ob, BMEditStrands *edit, fl /* Solve edge constraints and collisions for a single strand based on * "Linear-Time Dynamics using Lagrange Multipliers" (Baraff, 1996) */ -static void strand_solve(BMesh *UNUSED(bm), BMVert *root, float (*orig)[3], int numverts, +static void strand_solve(BMesh *bm, BMVert *root, float (*orig)[3], int numverts, const Eigen::Vector3f &root_v) { using Eigen::Vector3f; @@ -439,7 +439,7 @@ static void strand_solve(BMesh *UNUSED(bm), BMVert *root, float (*orig)[3], int VectorX x(3 * numverts); VectorX x0(3 * numverts); VectorX v0(3 * numverts); -// VectorX L(numverts); + VectorX L(numverts); { BMIter iter; BMVert *vert; @@ -448,7 +448,7 @@ static void strand_solve(BMesh *UNUSED(bm), BMVert *root, float (*orig)[3], int copy_v3_v3(&x.coeffRef(3*k), vert->co); copy_v3_v3(&x0.coeffRef(3*k), orig[k]); sub_v3_v3v3(&v0.coeffRef(3*k), vert->co, orig[k]); -// L.coeffRef(k) = BM_elem_float_data_named_get(&bm->vdata, vert, CD_PROP_FLT, CD_HAIR_SEGMENT_LENGTH); + L.coeffRef(k) = BM_elem_float_data_named_get(&bm->vdata, vert, CD_PROP_FLT, CD_HAIR_SEGMENT_LENGTH); #ifdef DO_DEBUG BKE_sim_debug_data_add_line(orig[k], vert->co, 0,0,1, "hair solve", 3874, BLI_ghashutil_ptrhash(root), k); #endif @@ -467,35 +467,39 @@ static void strand_solve(BMesh *UNUSED(bm), BMVert *root, float (*orig)[3], int int numcons_edges = numverts - 1; /* distance constraints */ int numcons = numcons_edges + numcons_roots; MatrixX J = MatrixX::Zero(numcons, 3 * numverts); + /* Constraint velocities */ + VectorX c = VectorX::Zero(numcons); /* root velocity constraint */ J.block<3,3>(0, 0) = Matrix3f::Identity(); + c.block<3,1>(0, 0) = -root_v; /* distance constraints */ for (int i = 0; i < numcons_edges; ++i) { -// float target_length = L[i+1]; -// if (target_length > 0.0f) { - int ka = i * 3; - int kb = (i+1) * 3; - Vector3f xa(x.block<3,1>(ka, 0)); - Vector3f xb(x.block<3,1>(kb, 0)); -// Vector3f j = (xb - xa) / target_length; - Vector3f j = (xb - xa); - j.normalize(); + int ka = i * 3; + int kb = (i+1) * 3; + Vector3f xa(x.block<3,1>(ka, 0)); + Vector3f xb(x.block<3,1>(kb, 0)); + Vector3f j = (xb - xa); + float length = j.norm(); + float target_length = L[i+1]; + j.normalize(); #ifdef DO_DEBUG - BKE_sim_debug_data_add_vector(xb.data(), j.data(), 0,1,0, "hair solve", 3274, BLI_ghashutil_ptrhash(root), i); + BKE_sim_debug_data_add_vector(xb.data(), j.data(), 0,1,0, "hair solve", 3274, BLI_ghashutil_ptrhash(root), i); #endif - - int con = numcons_roots + i; - J.block<1,3>(con, ka) = -j.transpose(); - J.block<1,3>(con, kb) = j.transpose(); -// } + + int con = numcons_roots + i; + J.block<1,3>(con, ka) = -j.transpose(); + J.block<1,3>(con, kb) = j.transpose(); + + /* counteract drift with velocity along the edge */ + c.coeffRef(con) = length - target_length; } - /* A = J * M^-1 * J^T */ MatrixX A = J * M_inv * J.transpose(); + /* force vector */ VectorX F = M * v0; /* bending force: smoothes the hair */ - float stiffness = 0.1; + float stiffness = 0.0; for (int i = 1; i < numverts - 1; ++i) { int ka = (i-1) * 3; int kb = i * 3; @@ -508,9 +512,7 @@ static void strand_solve(BMesh *UNUSED(bm), BMVert *root, float (*orig)[3], int F.block<3,1>(kc, 0) += f; F.block<3,1>(kb, 0) += -f; } - /* constant constraint velocities */ - VectorX c = VectorX::Zero(numcons); - c.block<3,1>(0, 0) = -root_v; + /* b = -(J * M^-1 * F + c) */ VectorX b = -(J * M_inv * F + c); |