Cloth: Collision improvements

This commit includes several performance, stability, and reliability
improvements to cloth collisions.

Most notably:
* The implementation of a new self-collisions system.
* Multithreading of collision detection.
* Implementation of single sided collisions and normal overrides.
* Replacement of the `plNearestPoints` function from Bullet with a
dedicated solution.

Further, this also includes several bug fixes, and algorithmic
improvements.

Reviewed By: brecht

Differential Revision: http://developer.blender.org/D3712

2 files changed, 15 insertions, 5 deletions

diff --git a/source/blender/blenlib/BLI_math_geom.h b/source/blender/blenlib/BLI_math_geom.h
index 640f3143009..ccdb94c3317 100644
--- a/source/blender/blenlib/BLI_math_geom.h
+++ b/source/blender/blenlib/BLI_math_geom.h
@@ -373,6 +373,8 @@ bool clip_segment_v3_plane_n(
         const float p1[3], const float p2[3], const float plane_array[][4], const int plane_tot,
         float r_p1[3], float r_p2[3]);
 
+bool point_in_slice_seg(float p[3], float l1[3], float l2[3]);
+
 /****************************** Interpolation ********************************/
 void interp_weights_tri_v3(float w[3], const float a[3], const float b[3], const float c[3], const float p[3]);
 void interp_weights_quad_v3(float w[4], const float a[3], const float b[3], const float c[3], const float d[3], const float p[3]);
diff --git a/source/blender/blenlib/intern/math_geom.c b/source/blender/blenlib/intern/math_geom.c
index 12246473523..fb2a1e47895 100644
--- a/source/blender/blenlib/intern/math_geom.c
+++ b/source/blender/blenlib/intern/math_geom.c
@@ -2979,19 +2979,27 @@ static bool point_in_slice(const float p[3], const float v1[3], const float l1[3
 	return (h >= 0.0f && h <= 1.0f);
 }
 
-#if 0
-
 /* adult sister defining the slice planes by the origin and the normal
  * NOTE |normal| may not be 1 but defining the thickness of the slice */
-static int point_in_slice_as(float p[3], float origin[3], float normal[3])
+static bool point_in_slice_as(float p[3], float origin[3], float normal[3])
 {
 	float h, rp[3];
 	sub_v3_v3v3(rp, p, origin);
 	h = dot_v3v3(normal, rp) / dot_v3v3(normal, normal);
-	if (h < 0.0f || h > 1.0f) return 0;
-	return 1;
+	if (h < 0.0f || h > 1.0f) return false;
+	return true;
 }
 
+bool point_in_slice_seg(float p[3], float l1[3], float l2[3])
+{
+	float normal[3];
+
+	sub_v3_v3v3(normal, l2, l1);
+
+	return point_in_slice_as(p, l1, normal);
+}
+
+#if 0
 /*mama (knowing the squared length of the normal) */
 static int point_in_slice_m(float p[3], float origin[3], float normal[3], float lns)
 {