GPUMaterial: Add a domain property.

This let us know efficiently if a material has a dedicated nodetree for each of it's output node input.

Only works for Eevee at this moment.

source/blender/blenkernel/BKE_node.h

@@ -816,6 +816,7 @@ extern void (*node_shader_lamp_loop)(struct ShadeInput *, struct ShadeResult *);
 void            set_node_shader_lamp_loop(void (*lamp_loop_func)(struct ShadeInput *, struct ShadeResult *));
 
 void            ntreeGPUMaterialNodes(struct bNodeTree *ntree, struct GPUMaterial *mat, short compatibility);
+void            ntreeGPUMaterialDomain(struct bNodeTree *ntree, bool *has_surface_output, bool *has_volume_output);
 
 /** \} */
 

source/blender/gpu/GPU_material.h

@@ -267,6 +267,8 @@ void GPU_material_vertex_attributes(GPUMaterial *material,
 bool GPU_material_do_color_management(GPUMaterial *mat);
 bool GPU_material_use_new_shading_nodes(GPUMaterial *mat);
 bool GPU_material_use_world_space_shading(GPUMaterial *mat);
+bool GPU_material_use_domain_surface(GPUMaterial *mat);
+bool GPU_material_use_domain_volume(GPUMaterial *mat);
 
 /* Exported shading */
 

source/blender/gpu/intern/gpu_material.c

@@ -135,9 +135,20 @@ struct GPUMaterial {
 	bool bound;
 
 	bool is_opensubdiv;
+
+	/* XXX: Should be in Material. But it depends on the output node
+	 * used and since the output selection is difference for GPUMaterial...
+	 */
+	int domain;
+
 	GPUUniformBuffer *ubo; /* UBOs for shader uniforms. */
 };
 
+enum {
+	GPU_DOMAIN_SURFACE    = (1 << 0),
+	GPU_DOMAIN_VOLUME     = (1 << 1)
+};
+
 /* Forward declaration so shade_light_textures() can use this, while still keeping the code somewhat organized */
 static void texture_rgb_blend(
         GPUMaterial *mat, GPUNodeLink *tex, GPUNodeLink *out, GPUNodeLink *fact, GPUNodeLink *facg,
@@ -509,6 +520,16 @@ bool GPU_material_use_world_space_shading(GPUMaterial *mat)
 	return BKE_scene_use_world_space_shading(mat->scene);
 }
 
+bool GPU_material_use_domain_surface(GPUMaterial *mat)
+{
+	return (mat->domain & GPU_DOMAIN_SURFACE);
+}
+
+bool GPU_material_use_domain_volume(GPUMaterial *mat)
+{
+	return (mat->domain & GPU_DOMAIN_VOLUME);
+}
+
 static GPUNodeLink *lamp_get_visibility(GPUMaterial *mat, GPULamp *lamp, GPUNodeLink **lv, GPUNodeLink **dist)
 {
 	GPUNodeLink *visifac;
@@ -2145,6 +2166,7 @@ GPUMaterial *GPU_material_from_nodetree(
 	GPUMaterial *mat;
 	GPUNodeLink *outlink;
 	LinkData *link;
+	bool has_volume_output, has_surface_output;
 
 	/* Caller must re-use materials. */
 	BLI_assert(GPU_material_from_nodetree_find(gpumaterials, engine_type, options) == NULL);
@@ -2156,6 +2178,14 @@ GPUMaterial *GPU_material_from_nodetree(
 	mat->options = options;
 
 	ntreeGPUMaterialNodes(ntree, mat, NODE_NEW_SHADING | NODE_NEWER_SHADING);
+	ntreeGPUMaterialDomain(ntree, &has_surface_output, &has_volume_output);
+
+	if (has_surface_output) {
+		mat->domain |= GPU_DOMAIN_SURFACE;
+	}
+	if (has_volume_output) {
+		mat->domain |= GPU_DOMAIN_VOLUME;
+	}
 
 	/* Let Draw manager finish the construction. */
 	if (mat->outlink) {

source/blender/nodes/shader/node_shader_tree.c

@@ -527,6 +527,35 @@ static void ntree_shader_tag_ssr_node(bNodeTree *ntree, short compatibility)
 	nodeChainIter(ntree, output_node, ntree_tag_ssr_bsdf_cb, &lobe_count, true);
 }
 
+/* EEVEE: Find which material domain are used (volume, surface ...).
+ */
+void ntreeGPUMaterialDomain(bNodeTree *ntree, bool *has_surface_output, bool *has_volume_output)
+{
+	/* localize tree to create links for reroute and mute */
+	bNodeTree *localtree = ntreeLocalize(ntree);
+
+	struct bNode *output = ntree_shader_output_node(localtree);
+
+	*has_surface_output = false;
+	*has_volume_output = false;
+
+	if (output != NULL) {
+		bNodeSocket *surface_sock = ntree_shader_node_find_input(output, "Surface");
+		bNodeSocket *volume_sock = ntree_shader_node_find_input(output, "Volume");
+
+		if (surface_sock != NULL) {
+			*has_surface_output = (nodeCountSocketLinks(localtree, surface_sock) > 0);
+		}
+
+		if (volume_sock != NULL) {
+			*has_volume_output = (nodeCountSocketLinks(localtree, volume_sock) > 0);
+		}
+	}
+
+	ntreeFreeTree(localtree);
+	MEM_freeN(localtree);
+}
+
 void ntreeGPUMaterialNodes(bNodeTree *ntree, GPUMaterial *mat, short compatibility)
 {
 	/* localize tree to create links for reroute and mute */