Added a particle index output to the Particle Info Cycles node. This is required to get consistent ID numbers for particles. The Object ID is not usable since it's a user defined value of the instanced object, which does not vary per instance. Also the random value from the object info node is not consistent over time, since it only depends on the index in the dupli list (so each emitted or dying particle shifts the value).

The particle index is always the same for a specific particle. Randomized values can be generated from this with the use of a noise texture.

1 files changed, 6 insertions, 0 deletions

diff --git a/intern/cycles/kernel/svm/svm_geometry.h b/intern/cycles/kernel/svm/svm_geometry.h
index 88127b56474..3cfce1d087a 100644
--- a/intern/cycles/kernel/svm/svm_geometry.h
+++ b/intern/cycles/kernel/svm/svm_geometry.h
@@ -101,6 +101,12 @@ __device void svm_node_particle_info(KernelGlobals *kg, ShaderData *sd, float *s
 	float data;
 
 	switch(type) {
+		case NODE_INFO_PAR_INDEX: {
+			uint particle_id = object_particle_id(kg, sd->object);
+			data = particle_index(kg, particle_id);
+			stack_store_float(stack, out_offset, data);
+			break;
+		}
 		case NODE_INFO_PAR_AGE: {
 			uint particle_id = object_particle_id(kg, sd->object);
 			data = particle_age(kg, particle_id);