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/

1 files changed, 158 insertions, 0 deletions

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