Particle Info node for Cycles. This can be used to access particle information in material shaders for dupli objects. For now only the particle Age and individual Lifetime (in frames) are supported, more attributes can be added when needed.

The particle data is stored in a separate texture if any of the dupli objects uses particle info nodes in shaders. To map dupli objects onto particles the store an additional particle_index value, which is different from the simple dupli object index (only visible particles, also works for particle dupli groups mode).

Some simple use cases on the code.blender.org blog:
http://code.blender.org/index.php/2012/05/particle-info-node/

5 files changed, 190 insertions, 21 deletions

diff --git a/intern/cycles/blender/CMakeLists.txt b/intern/cycles/blender/CMakeLists.txt
index 003c6c84f8f..a8c7eef89fa 100644
--- a/intern/cycles/blender/CMakeLists.txt
+++ b/intern/cycles/blender/CMakeLists.txt
@@ -22,6 +22,7 @@ set(SRC
 	blender_camera.cpp
 	blender_mesh.cpp
 	blender_object.cpp
+	blender_particles.cpp
 	blender_python.cpp
 	blender_session.cpp
 	blender_shader.cpp
diff --git a/intern/cycles/blender/blender_object.cpp b/intern/cycles/blender/blender_object.cpp
index cea3b0256bd..b70491a7b82 100644
--- a/intern/cycles/blender/blender_object.cpp
+++ b/intern/cycles/blender/blender_object.cpp
@@ -192,7 +192,7 @@ void BlenderSync::sync_background_light()
 
 /* Object */
 
-void BlenderSync::sync_object(BL::Object b_parent, int b_index, BL::Object b_ob, Transform& tfm, uint layer_flag, int motion)
+void BlenderSync::sync_object(BL::Object b_parent, int b_index, BL::Object b_ob, Transform& tfm, uint layer_flag, int motion, int particle_id)
 {
 	/* light is handled separately */
 	if(object_is_light(b_ob)) {
@@ -270,6 +270,12 @@ void BlenderSync::sync_object(BL::Object b_parent, int b_index, BL::Object b_ob,
 			object->visibility &= ~PATH_RAY_CAMERA;
 		}
 
+		object->particle_id = particle_id;
+
+		/* particle sync */
+		if (object_use_particles(b_ob))
+			sync_particles(object, b_ob);
+	
 		object->tag_update(scene);
 	}
 }
@@ -292,54 +298,51 @@ void BlenderSync::sync_objects(BL::SpaceView3D b_v3d, int motion)
 	/* object loop */
 	BL::Scene::objects_iterator b_ob;
 	BL::Scene b_sce = b_scene;
+	int particle_offset = 0;
 
 	for(; b_sce; b_sce = b_sce.background_set()) {
 		for(b_sce.objects.begin(b_ob); b_ob != b_sce.objects.end(); ++b_ob) {
 			bool hide = (render_layer.use_viewport_visibility)? b_ob->hide(): b_ob->hide_render();
 			uint ob_layer = get_layer(b_ob->layers());
+			hide = hide || !(ob_layer & scene_layer);
+
+			if(!hide) {
+
+				int num_particles = object_count_particles(*b_ob);
 
-			if(!hide && (ob_layer & scene_layer)) {
 				if(b_ob->is_duplicator()) {
+					hide = true;	/* duplicators hidden by default */
+
 					/* dupli objects */
 					object_create_duplilist(*b_ob, b_scene);
 
 					BL::Object::dupli_list_iterator b_dup;
-					int b_index = 0;
-
 					for(b_ob->dupli_list.begin(b_dup); b_dup != b_ob->dupli_list.end(); ++b_dup) {
 						Transform tfm = get_transform(b_dup->matrix());
 						BL::Object b_dup_ob = b_dup->object();
 						bool dup_hide = (b_v3d)? b_dup_ob.hide(): b_dup_ob.hide_render();
 
-						if(!(b_dup->hide() || dup_hide))
-							sync_object(*b_ob, b_index, b_dup_ob, tfm, ob_layer, motion);
-
-						b_index++;
+						if(!(b_dup->hide() || dup_hide)) {
+							sync_object(*b_ob, b_dup->index(), b_dup_ob, tfm, ob_layer, motion, b_dup->particle_index() + particle_offset);
+						}
 					}
 
 					object_free_duplilist(*b_ob);
-
-					hide = true;
 				}
 
 				/* check if we should render or hide particle emitter */
 				BL::Object::particle_systems_iterator b_psys;
-				bool render_emitter = false;
-
-				for(b_ob->particle_systems.begin(b_psys); b_psys != b_ob->particle_systems.end(); ++b_psys) {
-					if(b_psys->settings().use_render_emitter()) {
+				for(b_ob->particle_systems.begin(b_psys); b_psys != b_ob->particle_systems.end(); ++b_psys)
+					if(b_psys->settings().use_render_emitter())
 						hide = false;
-						render_emitter = true;
-					}
-					else if(!render_emitter)
-						hide = true;
-				}
 
 				if(!hide) {
 					/* object itself */
 					Transform tfm = get_transform(b_ob->matrix_world());
-					sync_object(*b_ob, 0, *b_ob, tfm, ob_layer, motion);
+					sync_object(*b_ob, 0, *b_ob, tfm, ob_layer, motion, 0);
 				}
+
+				particle_offset += num_particles;
 			}
 		}
 	}
diff --git a/intern/cycles/blender/blender_particles.cpp b/intern/cycles/blender/blender_particles.cpp
new file mode 100644
index 00000000000..8a208cb5676
--- /dev/null
+++ b/intern/cycles/blender/blender_particles.cpp
@@ -0,0 +1,158 @@
+/*
+ * Copyright 2011, Blender Foundation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include "object.h"
+
+#include "mesh.h"
+#include "blender_sync.h"
+#include "blender_util.h"
+
+#include "util_foreach.h"
+
+CCL_NAMESPACE_BEGIN
+
+/* Utilities */
+
+
+/* Particles Sync */
+
+bool BlenderSync::object_use_particles(BL::Object b_ob)
+{
+	/* 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 use_particles = false;
+	
+	BL::Object::particle_systems_iterator b_psys;
+	for (b_ob.particle_systems.begin(b_psys); b_psys != b_ob.particle_systems.end(); ++b_psys) {
+		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) {
+				use_particles |= mesh->need_attribute(scene, ATTR_STD_PARTICLE);
+			}
+			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) {
+					use_particles |= mesh->need_attribute(scene, ATTR_STD_PARTICLE);
+				}
+			}
+			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) {
+						use_particles |= mesh->need_attribute(scene, ATTR_STD_PARTICLE);
+					}
+				}
+			}
+			break;
+		}
+		}
+	}
+	
+	return use_particles;
+}
+
+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)
+{
+	return b_pa.is_exist() && b_pa.is_visible() && b_pa.alive_state()==BL::Particle::alive_state_ALIVE;
+}
+
+int BlenderSync::object_count_particles(BL::Object b_ob)
+{
+	int tot = 0;
+	BL::Object::particle_systems_iterator b_psys;
+	for(b_ob.particle_systems.begin(b_psys); b_psys != b_ob.particle_systems.end(); ++b_psys) {
+		if (use_particle_system(*b_psys)) {
+			BL::ParticleSystem::particles_iterator b_pa;
+			for(b_psys->particles.begin(b_pa); b_pa != b_psys->particles.end(); ++b_pa) {
+				if(use_particle(*b_pa))
+					++tot;
+			}
+		}
+	}
+	return tot;
+}
+
+void BlenderSync::sync_particles(Object *ob, BL::Object b_ob)
+{
+	int tot = object_count_particles(b_ob);
+	
+	ob->particles.clear();
+	ob->particles.reserve(tot);
+	
+	int index;
+	BL::Object::particle_systems_iterator b_psys;
+	for(b_ob.particle_systems.begin(b_psys); b_psys != b_ob.particle_systems.end(); ++b_psys) {
+		if (use_particle_system(*b_psys)) {
+			BL::ParticleSystem::particles_iterator b_pa;
+			for(b_psys->particles.begin(b_pa), index=0; b_pa != b_psys->particles.end(); ++b_pa, ++index) {
+				if(use_particle(*b_pa)) {
+					Particle pa;
+					
+					pa.age = b_scene.frame_current() - b_pa->birth_time();
+					pa.lifetime = b_pa->lifetime();
+					
+					ob->particles.push_back(pa);
+				}
+			}
+		}
+	}
+}
+
+CCL_NAMESPACE_END
diff --git a/intern/cycles/blender/blender_shader.cpp b/intern/cycles/blender/blender_shader.cpp
index 130b73a2808..a7be0a8fb54 100644
--- a/intern/cycles/blender/blender_shader.cpp
+++ b/intern/cycles/blender/blender_shader.cpp
@@ -337,6 +337,10 @@ static ShaderNode *add_node(BL::BlendData b_data, BL::Scene b_scene, ShaderGraph
 			node = new ObjectInfoNode();
 			break;
 		}
+		case BL::ShaderNode::type_PARTICLE_INFO: {
+			node = new ParticleInfoNode();
+			break;
+		}
 		case BL::ShaderNode::type_TEX_IMAGE: {
 			BL::ShaderNodeTexImage b_image_node(b_node);
 			BL::Image b_image(b_image_node.image());
diff --git a/intern/cycles/blender/blender_sync.h b/intern/cycles/blender/blender_sync.h
index bc6258d35ac..8c31c4b86ba 100644
--- a/intern/cycles/blender/blender_sync.h
+++ b/intern/cycles/blender/blender_sync.h
@@ -80,17 +80,20 @@ 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::Object b_object, Transform& tfm, uint layer_flag, int motion);
+	void sync_object(BL::Object b_parent, int b_index, BL::Object b_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);
 	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(Object *ob, BL::Object b_ob);
 
 	/* 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 object_use_particles(BL::Object b_ob);
+	int object_count_particles(BL::Object b_ob);
 
 	/* variables */
 	BL::BlendData b_data;