Fix T38811: Cycles particle ids are inconsistent when using multiple particle systems.

Problem is that the particle systems in the cycles database are not
stored in a well-defined order. This means the particle_id for dupli
objects can not simply be assigned using a global running index during
sync.

Now the particle index is assigned locally for each particle system.
When transferring particle data to the device as a single texture, the
particle indices are offset based on the final order of particle systems
in the database.

Reviewers: brecht

Reviewed By: brecht

CC: Andreas80

Differential Revision: https://developer.blender.org/D352

1 files changed, 5 insertions, 0 deletions

diff --git a/intern/cycles/blender/blender_particles.cpp b/intern/cycles/blender/blender_particles.cpp
index ef832ed39c0..5b2782ec2ac 100644
--- a/intern/cycles/blender/blender_particles.cpp
+++ b/intern/cycles/blender/blender_particles.cpp
@@ -76,6 +76,11 @@ bool BlenderSync::sync_dupli_particle(BL::Object b_ob, BL::DupliObject b_dup, Ob
 
 	psys->particles.push_back(pa);
 
+	if (object->particle_index != psys->particles.size() - 1)
+		scene->object_manager->tag_update(scene);
+	object->particle_system = psys;
+	object->particle_index = psys->particles.size() - 1;
+
 	/* return that this object has particle data */
 	return true;
 }