Oops, particle collisions didn't take simulation subframes into account at all.

* This caused nearly all particles to leak through the collision surface if simulation subframes were used and the collision object was moving.
* In addition to fixing this I also did some more cleanup of the collision code and refined some of the comments.

1 files changed, 3 insertions, 1 deletions

diff --git a/source/blender/blenkernel/BKE_particle.h b/source/blender/blenkernel/BKE_particle.h
index 1416e1280cf..5bcd69865fc 100644
--- a/source/blender/blenkernel/BKE_particle.h
+++ b/source/blender/blenkernel/BKE_particle.h
@@ -171,7 +171,9 @@ typedef struct ParticleCollision
 	float co1[3], co2[3]; // ray start and end points
 	float ve1[3], ve2[3]; // particle velocities
 	float ray_len; // original length of co2-co1, needed for collision time evaluation
-	float t;	// time of previous collision, needed for substracting face velocity
+	float f;	// time factor of previous collision, needed for substracting face velocity
+	float cfra; // start of the timestep (during frame change, since previous integer frame)
+	float dfra; // duration of timestep in frames
 } ParticleCollision;
 
 typedef struct ParticleDrawData {