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, 41 insertions, 153 deletions

diff --git a/intern/cycles/blender/blender_particles.cpp b/intern/cycles/blender/blender_particles.cpp
index c4c6d2f79a3..769cd9f532d 100644
--- a/intern/cycles/blender/blender_particles.cpp
+++ b/intern/cycles/blender/blender_particles.cpp
@@ -17,6 +17,7 @@
  */
 
 #include "mesh.h"
+#include "object.h"
 #include "particles.h"
 
 #include "blender_sync.h"
@@ -28,170 +29,57 @@ CCL_NAMESPACE_BEGIN
 
 /* Utilities */
 
-
-/* Particles Sync */
-
-bool BlenderSync::psys_need_update(BL::ParticleSystem b_psys)
-{
-	/* Particle data is only needed for
-	 * a) Billboard render mode if object's own material uses particle info
-	 * b) object/group render mode if any dupli object's material uses particle info
-	 *
-	 * Note: Meshes have to be synced at this point!
-	 */
-	bool need_update = false;
-	
-	switch (b_psys.settings().render_type()) {
-		/* XXX not implemented yet! 
-		 * billboards/strands would become part of the mesh data (?),
-		 * so the mesh attributes would store whether particle info is required.
-		 */
-		#if 0
-		case BL::ParticleSettings::render_type_BILLBOARD:
-		case BL::ParticleSettings::render_type_PATH: {	/* for strand rendering */
-			BL::ID key = (BKE_object_is_modified(b_ob))? b_ob: b_ob.data();
-			Mesh *mesh = mesh_map.find(key);
-			if(mesh) {
-				need_update |= mesh->need_attribute(scene, ATTR_STD_PARTICLE) && mesh->need_update;
-			}
-			break;
-		}
-		#endif
-		
-		case BL::ParticleSettings::render_type_OBJECT: {
-			BL::Object b_dupli_ob = b_psys.settings().dupli_object();
-			if(b_dupli_ob) {
-				BL::ID key = (BKE_object_is_modified(b_dupli_ob))? b_dupli_ob: b_dupli_ob.data();
-				Mesh *mesh = mesh_map.find(key);
-				if(mesh) {
-					need_update |= mesh->need_attribute(scene, ATTR_STD_PARTICLE) && mesh->need_update;
-				}
-			}
-			break;
-		}
-		
-		case BL::ParticleSettings::render_type_GROUP: {
-			BL::Group b_dupli_group = b_psys.settings().dupli_group();
-			if(b_dupli_group) {
-				BL::Group::objects_iterator b_gob;
-				for (b_dupli_group.objects.begin(b_gob); b_gob != b_dupli_group.objects.end(); ++b_gob) {
-					BL::ID key = (BKE_object_is_modified(*b_gob))? *b_gob: b_gob->data();
-					Mesh *mesh = mesh_map.find(key);
-					if(mesh) {
-						need_update |= mesh->need_attribute(scene, ATTR_STD_PARTICLE) && mesh->need_update;
-					}
-				}
-			}
-			break;
-		}
-		
-		default:
-			/* avoid compiler warning */
-			break;
-	}
-	
-	return need_update;
-}
-
-static bool use_particle_system(BL::ParticleSystem b_psys)
-{
-	/* only use duplicator particles? disabled particle info for
-	 * halo and billboard to reduce particle count.
-	 * Probably not necessary since particles don't contain a huge amount
-	 * of data compared to other textures.
-	 */
-	#if 0
-	int render_type = b_psys->settings().render_type();
-	return (render_type == BL::ParticleSettings::render_type_OBJECT
-	        || render_type == BL::ParticleSettings::render_type_GROUP);
-	#endif
-	
-	return true;
-}
-
-static bool use_particle(BL::Particle b_pa, bool preview, bool show_unborn, bool use_dead)
-{
-	return b_pa.is_exist() && (!preview || b_pa.is_visible()) &&
-		(b_pa.alive_state() != BL::Particle::alive_state_UNBORN || show_unborn) &&
-		(b_pa.alive_state() != BL::Particle::alive_state_DEAD || use_dead);
-}
-
-static int psys_count_particles(BL::ParticleSystem b_psys, bool preview)
+bool BlenderSync::sync_dupli_particle(BL::Object b_ob, BL::DupliObject b_dup, Object *object)
 {
-	BL::ParticleSystem::particles_iterator b_pa;
-	bool show_unborn = b_psys.settings().show_unborn();
-	bool use_dead = b_psys.settings().use_dead();
-	int num = 0;
+	/* test if this dupli was generated from a particle sytem */
+	BL::ParticleSystem b_psys = b_dup.particle_system();
+	if(!b_psys)
+		return false;
 
-	for(b_psys.particles.begin(b_pa); b_pa != b_psys.particles.end(); ++b_pa)
-		if(use_particle(*b_pa, preview, show_unborn, use_dead))
-			++num;
+	/* test if we need particle data */
+	if(!object->mesh->need_attribute(scene, ATTR_STD_PARTICLE))
+		return false;
 
-	return num;
-}
+	/* don't handle child particles yet */
+	BL::Array<int, OBJECT_PERSISTENT_ID_SIZE> persistent_id = b_dup.persistent_id();
 
-int BlenderSync::object_count_particles(BL::Object b_ob)
-{
-	BL::Object::particle_systems_iterator b_psys;
-	int num = 0;
+	if(persistent_id[0] >= b_psys.particles.length())
+		return false;
 
-	for(b_ob.particle_systems.begin(b_psys); b_psys != b_ob.particle_systems.end(); ++b_psys)
-		if(use_particle_system(*b_psys))
-			num += psys_count_particles(*b_psys, preview);
+	/* find particle system */
+	ParticleSystemKey key(b_ob, persistent_id);
+	ParticleSystem *psys;
 
-	return num;
-}
+	bool first_use = !particle_system_map.is_used(key);
+	bool need_update = particle_system_map.sync(&psys, b_ob, b_dup.object(), key);
 
-void BlenderSync::sync_particles(BL::Object b_ob, BL::ParticleSystem b_psys)
-{
-	/* depending on settings the psys may not even be rendered */
-	if(!use_particle_system(b_psys))
-		return;
-	
-	/* key to lookup particle system */
-	ParticleSystemKey key(b_ob, b_psys);
-	ParticleSystem *psys;
-	
-	/* test if we need to sync */
-	bool object_updated = false;
-	
-	if(particle_system_map.sync(&psys, b_ob, b_ob, key))
-		object_updated = true;
-	
-	bool need_update = psys_need_update(b_psys);
-	
-	if(object_updated || need_update) {
-		bool show_unborn = b_psys.settings().show_unborn();
-		bool use_dead = b_psys.settings().use_dead();
+	/* no update needed? */
+	if(!need_update && !object->mesh->need_update && !scene->object_manager->need_update)
+		return true;
 
-		int num = psys_count_particles(b_psys, preview);
+	/* first time used in this sync loop? clear and tag update */
+	if(first_use) {
 		psys->particles.clear();
-		psys->particles.reserve(num);
-		
-		BL::ParticleSystem::particles_iterator b_pa;
-		int index = 0;
-
-		for(b_psys.particles.begin(b_pa); b_pa != b_psys.particles.end(); ++b_pa) {
-			if(use_particle(*b_pa, preview, show_unborn, use_dead)) {
-				Particle pa;
-				
-				pa.index = index;
-				pa.age = b_scene.frame_current() - b_pa->birth_time();
-				pa.lifetime = b_pa->lifetime();
-				pa.location = get_float3(b_pa->location());
-				pa.rotation = get_float4(b_pa->rotation());
-				pa.size = b_pa->size();
-				pa.velocity = get_float3(b_pa->velocity());
-				pa.angular_velocity = get_float3(b_pa->angular_velocity());
-				
-				psys->particles.push_back(pa);
-			}
-			
-			++index;
-		}
-		
 		psys->tag_update(scene);
 	}
+
+	/* add particle */
+	BL::Particle b_pa = b_psys.particles[persistent_id[0]];
+	Particle pa;
+	
+	pa.index = persistent_id[0];
+	pa.age = b_scene.frame_current() - b_pa.birth_time();
+	pa.lifetime = b_pa.lifetime();
+	pa.location = get_float3(b_pa.location());
+	pa.rotation = get_float4(b_pa.rotation());
+	pa.size = b_pa.size();
+	pa.velocity = get_float3(b_pa.velocity());
+	pa.angular_velocity = get_float3(b_pa.angular_velocity());
+
+	psys->particles.push_back(pa);
+
+	/* return that this object has particle data */
+	return true;
 }
 
 CCL_NAMESPACE_END