[Bf-blender-cvs] [c75bd25cd87] master: Fix T52732: Particle system volume grid particles out of volume

[Sergey Sharybin]

Commit: c75bd25cd87e8648749f4b19bc90c269b2431251
Author: Sergey Sharybin
Date:   Thu Sep 14 19:43:00 2017 +0500
Branches: master
https://developer.blender.org/rBc75bd25cd87e8648749f4b19bc90c269b2431251

Fix T52732: Particle system volume grid particles out of volume

Use more watertight and robust intersection test.

It uses now ray to triangle intersection, but it's all fine because segment was
covering the whole bounding box anyway.

===================================================================

M	source/blender/blenkernel/intern/particle_distribute.c

===================================================================

diff --git a/source/blender/blenkernel/intern/particle_distribute.c b/source/blender/blenkernel/intern/particle_distribute.c
index fe84504327c..1ef4d005f0d 100644
--- a/source/blender/blenkernel/intern/particle_distribute.c
+++ b/source/blender/blenkernel/intern/particle_distribute.c
@@ -39,6 +39,7 @@
 #include "BLI_jitter.h"
 #include "BLI_kdtree.h"
 #include "BLI_math.h"
+#include "BLI_math_geom.h"
 #include "BLI_rand.h"
 #include "BLI_sort.h"
 #include "BLI_task.h"
@@ -213,14 +214,22 @@ static void distribute_grid(DerivedMesh *dm, ParticleSystem *psys)
 					copy_v3_v3(co2, co1);
 					co2[a] += delta[a] + 0.001f*d;
 					co1[a] -= 0.001f*d;
-					
+
+					struct IsectRayPrecalc isect_precalc;
+					float ray_direction[3];
+					sub_v3_v3v3(ray_direction, co2, co1);
+					isect_ray_tri_watertight_v3_precalc(&isect_precalc, ray_direction);
+
 					/* lets intersect the faces */
 					for (i=0; i<totface; i++,mface++) {
 						copy_v3_v3(v1, mvert[mface->v1].co);
 						copy_v3_v3(v2, mvert[mface->v2].co);
 						copy_v3_v3(v3, mvert[mface->v3].co);
 
-						bool intersects_tri = isect_axial_line_segment_tri_v3(a, co1, co2, v2, v3, v1, &lambda);
+						bool intersects_tri = isect_ray_tri_watertight_v3(co1,
+						                                                  &isect_precalc,
+						                                                  v1, v2, v3,
+						                                                  &lambda, NULL);
 						if (intersects_tri) {
 							if (from==PART_FROM_FACE)
 								(pa+(int)(lambda*size[a])*a0mul)->flag &= ~PARS_UNEXIST;
@@ -231,7 +240,10 @@ static void distribute_grid(DerivedMesh *dm, ParticleSystem *psys)
 						if (mface->v4 && (!intersects_tri || from==PART_FROM_VOLUME)) {
 							copy_v3_v3(v4, mvert[mface->v4].co);
 
-							if (isect_axial_line_segment_tri_v3(a, co1, co2, v4, v1, v3, &lambda)) {
+							if (isect_ray_tri_watertight_v3(co1,
+							                                &isect_precalc,
+							                                v1, v2, v3,
+							                                &lambda, NULL)) {
 								if (from==PART_FROM_FACE)
 									(pa+(int)(lambda*size[a])*a0mul)->flag &= ~PARS_UNEXIST;
 								else