Cycles: add "density", "flame" and "color" attributes for smoke domains.

These can currently be accessed by adding an Attribute node and specifying one
of those three names. A Smoke/Fire node should be added at some point to make
this more convenient.

These values might change still before the release, in particular for flame the
meaning seems unclear, it's just values in the 0..1 range. This is useful for
color ramps, but it might be good if this was also available as temperature in
kelvin so it can be plugged into the blackbody node. But I couldn't figure out
from the smoke code if or how this corresponds to a physical unit.

Here's a (quite poor) example file for a fire + smoke setup:
http://www.pasteall.org/blend/27990

1 files changed, 36 insertions, 0 deletions

diff --git a/intern/cycles/blender/blender_mesh.cpp b/intern/cycles/blender/blender_mesh.cpp
index 8c9734283ea..fb667d1ba2f 100644
--- a/intern/cycles/blender/blender_mesh.cpp
+++ b/intern/cycles/blender/blender_mesh.cpp
@@ -206,6 +206,40 @@ static void mikk_compute_tangents(BL::Mesh b_mesh, BL::MeshTextureFaceLayer b_la
 	}
 }
 
+/* Create Volume Attribute */
+
+static void create_mesh_volume_attribute(BL::Object b_ob, Mesh *mesh, ImageManager *image_manager, AttributeStandard std)
+{
+	BL::SmokeDomainSettings b_domain = object_smoke_domain_find(b_ob);
+
+	if(!b_domain)
+		return;
+	
+	Attribute *attr = mesh->attributes.add(std);
+	VoxelAttribute *volume_data = attr->data_voxel();
+	bool is_float, is_linear;
+	bool animated = false;
+
+	volume_data->manager = image_manager;
+	volume_data->slot = image_manager->add_image(Attribute::standard_name(std),
+		b_ob.ptr.data, animated, is_float, is_linear, INTERPOLATION_LINEAR);
+}
+
+static void create_mesh_volume_attributes(Scene *scene, BL::Object b_ob, Mesh *mesh)
+{
+	/* for smoke volume rendering */
+	if(mesh->need_attribute(scene, ATTR_STD_VOLUME_DENSITY))
+		create_mesh_volume_attribute(b_ob, mesh, scene->image_manager, ATTR_STD_VOLUME_DENSITY);
+	if(mesh->need_attribute(scene, ATTR_STD_VOLUME_COLOR))
+		create_mesh_volume_attribute(b_ob, mesh, scene->image_manager, ATTR_STD_VOLUME_COLOR);
+	if(mesh->need_attribute(scene, ATTR_STD_VOLUME_FLAME))
+		create_mesh_volume_attribute(b_ob, mesh, scene->image_manager, ATTR_STD_VOLUME_FLAME);
+	if(mesh->need_attribute(scene, ATTR_STD_VOLUME_HEAT))
+		create_mesh_volume_attribute(b_ob, mesh, scene->image_manager, ATTR_STD_VOLUME_HEAT);
+	if(mesh->need_attribute(scene, ATTR_STD_VOLUME_VELOCITY))
+		create_mesh_volume_attribute(b_ob, mesh, scene->image_manager, ATTR_STD_VOLUME_VELOCITY);
+}
+
 /* Create Mesh */
 
 static void create_mesh(Scene *scene, Mesh *mesh, BL::Mesh b_mesh, const vector<uint>& used_shaders)
@@ -501,6 +535,8 @@ Mesh *BlenderSync::sync_mesh(BL::Object b_ob, bool object_updated, bool hide_tri
 					create_subd_mesh(scene, mesh, b_mesh, &cmesh, used_shaders);
 				else
 					create_mesh(scene, mesh, b_mesh, used_shaders);
+
+				create_mesh_volume_attributes(scene, b_ob, mesh);
 			}
 
 			if(render_layer.use_hair)