Fix #33113: cycles not rendering motion blur correct with dying particles.

There were a bunch of other issues with dupli motion blur and syncing, the problem
being that there was no proper way to detect corresponding duplis between frames
or updates. As a solution, a persistent_id was added to the DupliObject. It's an
extension of the previous index value, with one index for each dupli level. This
can be used to reliably find matching dupli objects between frames. Works with
nested duplis, multiple particle systems, etc.

1 files changed, 6 insertions, 5 deletions

diff --git a/intern/cycles/blender/blender_sync.h b/intern/cycles/blender/blender_sync.h
index 36cd5e684a7..9a478118c04 100644
--- a/intern/cycles/blender/blender_sync.h
+++ b/intern/cycles/blender/blender_sync.h
@@ -42,6 +42,7 @@ class Film;
 class Light;
 class Mesh;
 class Object;
+class ParticleSystem;
 class Scene;
 class Shader;
 class ShaderGraph;
@@ -80,20 +81,20 @@ private:
 
 	void sync_nodes(Shader *shader, BL::ShaderNodeTree b_ntree);
 	Mesh *sync_mesh(BL::Object b_ob, bool object_updated);
-	void sync_object(BL::Object b_parent, int b_index, BL::DupliObject b_dupli_object, Transform& tfm, uint layer_flag, int motion, int particle_id);
-	void sync_light(BL::Object b_parent, int b_index, BL::Object b_ob, Transform& tfm);
+	Object *sync_object(BL::Object b_parent, int persistent_id[OBJECT_PERSISTENT_ID_SIZE], BL::DupliObject b_dupli_object, Transform& tfm, uint layer_flag, int motion);
+	void sync_light(BL::Object b_parent, int persistent_id[OBJECT_PERSISTENT_ID_SIZE], BL::Object b_ob, Transform& tfm);
 	void sync_background_light();
 	void sync_mesh_motion(BL::Object b_ob, Mesh *mesh, int motion);
 	void sync_camera_motion(BL::Object b_ob, int motion);
-	void sync_particles(BL::Object b_ob, BL::ParticleSystem b_psys);
+
+	/* particles */
+	bool sync_dupli_particle(BL::Object b_ob, BL::DupliObject b_dup, Object *object);
 
 	/* util */
 	void find_shader(BL::ID id, vector<uint>& used_shaders, int default_shader);
 	bool BKE_object_is_modified(BL::Object b_ob);
 	bool object_is_mesh(BL::Object b_ob);
 	bool object_is_light(BL::Object b_ob);
-	bool psys_need_update(BL::ParticleSystem b_psys);
-	int object_count_particles(BL::Object b_ob);
 
 	/* variables */
 	BL::RenderEngine b_engine;