Color sources for point density textures based on mesh vertices

This patch adds support for coloring point density textures based on several mesh vertex attributes.

* Vertex Color: Use a vertex color layer for coloring the point density texture
* Vertex Weight: Use a weights from a vertex group as intensity values. (for Blender Render engine the additional color band is used)
* Vertex Normals: Use object-space vertex normals as RGB values.

The vertex color source enum is stored separately from the particle color source, to avoid invalid values when switching.

Note that vertex colors are technically "corner colors" (MLoop), so each vertex can have as many colors as faces it is part of.
For the purpose of point density the mloop colors are simply averaged, which is physically plausible because corners can be viewed
as multiple points in the same location.

1 files changed, 21 insertions, 3 deletions

diff --git a/source/blender/makesrna/intern/rna_texture.c b/source/blender/makesrna/intern/rna_texture.c
index b44482dc2c1..ad1ca12d4ea 100644
--- a/source/blender/makesrna/intern/rna_texture.c
+++ b/source/blender/makesrna/intern/rna_texture.c
@@ -1668,7 +1668,7 @@ static void rna_def_texture_pointdensity(BlenderRNA *brna)
 		{0, NULL, 0, NULL, NULL}
 	};
 	
-	static EnumPropertyItem color_source_items[] = {
+	static EnumPropertyItem particle_color_source_items[] = {
 		{TEX_PD_COLOR_CONSTANT, "CONSTANT", 0, "Constant", ""},
 		{TEX_PD_COLOR_PARTAGE, "PARTICLE_AGE", 0, "Particle Age", "Lifetime mapped as 0.0 - 1.0 intensity"},
 		{TEX_PD_COLOR_PARTSPEED, "PARTICLE_SPEED", 0, "Particle Speed",
@@ -1677,6 +1677,14 @@ static void rna_def_texture_pointdensity(BlenderRNA *brna)
 		{0, NULL, 0, NULL, NULL}
 	};
 	
+	static EnumPropertyItem vertex_color_source_items[] = {
+		{TEX_PD_COLOR_CONSTANT, "CONSTANT", 0, "Constant", ""},
+		{TEX_PD_COLOR_VERTCOL, "VERTEX_COLOR", 0, "Vertex Color", "Vertex color layer"},
+		{TEX_PD_COLOR_VERTWEIGHT, "VERTEX_WEIGHT", 0, "Vertex Weight", "Vertex group weight"},
+		{TEX_PD_COLOR_VERTNOR, "VERTEX_NORMAL", 0, "Vertex Normal", "XYZ normal vector mapped to RGB colors"},
+		{0, NULL, 0, NULL, NULL}
+	};
+	
 	static EnumPropertyItem turbulence_influence_items[] = {
 		{TEX_PD_NOISE_STATIC, "STATIC", 0, "Static",
 		                      "Noise patterns will remain unchanged, faster and suitable for stills"},
@@ -1742,12 +1750,22 @@ static void rna_def_texture_pointdensity(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Softness", "Softness of the 'soft' falloff option");
 	RNA_def_property_update(prop, 0, "rna_Texture_update");
 	
-	prop = RNA_def_property(srna, "color_source", PROP_ENUM, PROP_NONE);
+	prop = RNA_def_property(srna, "particle_color_source", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "color_source");
-	RNA_def_property_enum_items(prop, color_source_items);
+	RNA_def_property_enum_items(prop, particle_color_source_items);
 	RNA_def_property_ui_text(prop, "Color Source", "Data to derive color results from");
 	RNA_def_property_update(prop, 0, "rna_Texture_update");
 	
+	prop = RNA_def_property(srna, "vertex_color_source", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "ob_color_source");
+	RNA_def_property_enum_items(prop, vertex_color_source_items);
+	RNA_def_property_ui_text(prop, "Color Source", "Data to derive color results from");
+	RNA_def_property_update(prop, 0, "rna_Texture_update");
+	
+	prop = RNA_def_property(srna, "vertex_attribute_name", PROP_STRING, PROP_NONE);
+	RNA_def_property_ui_text(prop, "Vertex Attribute Name", "Vertex attribute to use for color");
+	RNA_def_property_update(prop, 0, "rna_Texture_update");
+	
 	prop = RNA_def_property(srna, "speed_scale", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "speed_scale");
 	RNA_def_property_range(prop, 0.001, 100.0);