diff options
Diffstat (limited to 'source/blender/blenkernel/intern/mesh_evaluate.c')
| -rw-r--r-- | source/blender/blenkernel/intern/mesh_evaluate.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/source/blender/blenkernel/intern/mesh_evaluate.c b/source/blender/blenkernel/intern/mesh_evaluate.c index cb0386b1203..7e547ec4c25 100644 --- a/source/blender/blenkernel/intern/mesh_evaluate.c +++ b/source/blender/blenkernel/intern/mesh_evaluate.c @@ -1096,6 +1096,125 @@ bool BKE_mesh_center_centroid(Mesh *me, float cent[3]) /* -------------------------------------------------------------------- */ +/** \name Mesh Volume Calculation + * \{ */ + +static bool mesh_calc_center_centroid_ex(MVert *mverts, int UNUSED(numVerts), + MFace *mfaces, int numFaces, + float center[3]) +{ + float totweight; + int f; + + zero_v3(center); + + if (numFaces == 0) + return false; + + totweight = 0.0f; + for (f = 0; f < numFaces; ++f) { + MFace *face = &mfaces[f]; + MVert *v1 = &mverts[face->v1]; + MVert *v2 = &mverts[face->v2]; + MVert *v3 = &mverts[face->v3]; + MVert *v4 = &mverts[face->v4]; + float area; + + area = area_tri_v3(v1->co, v2->co, v3->co); + madd_v3_v3fl(center, v1->co, area); + madd_v3_v3fl(center, v2->co, area); + madd_v3_v3fl(center, v3->co, area); + totweight += area; + + if (face->v4) { + area = area_tri_v3(v3->co, v4->co, v1->co); + madd_v3_v3fl(center, v3->co, area); + madd_v3_v3fl(center, v4->co, area); + madd_v3_v3fl(center, v1->co, area); + totweight += area; + } + } + if (totweight == 0.0f) + return false; + + mul_v3_fl(center, 1.0f / (3.0f * totweight)); + + return true; +} + +void BKE_mesh_calc_volume(MVert *mverts, int numVerts, + MFace *mfaces, int numFaces, + float *r_vol, float *r_com) +{ + float center[3]; + float totvol; + int f; + + if (r_vol) *r_vol = 0.0f; + if (r_com) zero_v3(r_com); + + if (numFaces == 0) + return; + + if (!mesh_calc_center_centroid_ex(mverts, numVerts, mfaces, numFaces, center)) + return; + + totvol = 0.0f; + for (f = 0; f < numFaces; ++f) { + MFace *face = &mfaces[f]; + MVert *v1 = &mverts[face->v1]; + MVert *v2 = &mverts[face->v2]; + MVert *v3 = &mverts[face->v3]; + MVert *v4 = &mverts[face->v4]; + float vol; + + vol = volume_tetrahedron_signed_v3(center, v1->co, v2->co, v3->co); + if (r_vol) { + totvol += vol; + } + if (r_com) { + /* averaging factor 1/4 is applied in the end */ + madd_v3_v3fl(r_com, center, vol); // XXX could extract this + madd_v3_v3fl(r_com, v1->co, vol); + madd_v3_v3fl(r_com, v2->co, vol); + madd_v3_v3fl(r_com, v3->co, vol); + } + + if (face->v4) { + vol = volume_tetrahedron_signed_v3(center, v3->co, v4->co, v1->co); + + if (r_vol) { + totvol += vol; + } + if (r_com) { + /* averaging factor 1/4 is applied in the end */ + madd_v3_v3fl(r_com, center, vol); // XXX could extract this + madd_v3_v3fl(r_com, v3->co, vol); + madd_v3_v3fl(r_com, v4->co, vol); + madd_v3_v3fl(r_com, v1->co, vol); + } + } + } + + /* Note: Depending on arbitrary centroid position, + * totvol can become negative even for a valid mesh. + * The true value is always the positive value. + */ + if (r_vol) { + *r_vol = fabsf(totvol); + } + if (r_com) { + /* Note: Factor 1/4 is applied once for all vertices here. + * This also automatically negates the vector if totvol is negative. + */ + if (totvol != 0.0f) + mul_v3_fl(r_com, 0.25f / totvol); + } +} + + +/* -------------------------------------------------------------------- */ + /** \name NGon Tessellation (NGon/Tessface Conversion) * \{ */ |