Cycles: Write Cryptomatte metadata according to the specification

Reviewers: brecht, sergey, swerner

Subscribers: creamsurfer, Tanguy, Noss, SteffenD

Differential Revision: https://developer.blender.org/D3862

intern/cycles/blender/blender_session.cpp

@@ -35,6 +35,7 @@
 #include "util/util_function.h"
 #include "util/util_hash.h"
 #include "util/util_logging.h"
+#include "util/util_murmurhash.h"
 #include "util/util_progress.h"
 #include "util/util_time.h"
 
@@ -370,6 +371,17 @@ void BlenderSession::update_render_tile(RenderTile& rtile, bool highlight)
 		do_write_update_render_tile(rtile, false, false);
 }
 
+static void add_cryptomatte_layer(BL::RenderResult& b_rr, string name, string manifest)
+{
+	string identifier = string_printf("%08x", util_murmur_hash3(name.c_str(), name.length(), 0));
+	string prefix = "cryptomatte/" + identifier.substr(0, 7) + "/";
+
+	render_add_metadata(b_rr, prefix+"name", name);
+	render_add_metadata(b_rr, prefix+"hash", "MurmurHash3_32");
+	render_add_metadata(b_rr, prefix+"conversion", "uint32_to_float32");
+	render_add_metadata(b_rr, prefix+"manifest", manifest);
+}
+
 void BlenderSession::render()
 {
 	/* set callback to write out render results */
@@ -477,15 +489,28 @@ void BlenderSession::render()
 				break;
 		}
 
+		BL::RenderResult b_full_rr = b_engine.get_result();
 		if(is_single_layer) {
-			BL::RenderResult b_rr = b_engine.get_result();
 			string num_aa_samples = string_printf("%d", session->params.samples);
-			b_rr.stamp_data_add_field("Cycles Samples", num_aa_samples.c_str());
+			render_add_metadata(b_full_rr, "Cycles Samples", num_aa_samples);
 			/* TODO(sergey): Report whether we're doing resumable render
 			 * and also start/end sample if so.
 			 */
 		}
 
+		if(scene->film->cryptomatte_passes & CRYPT_OBJECT) {
+			add_cryptomatte_layer(b_full_rr, b_rlay_name+".CryptoObject",
+			                      scene->object_manager->get_cryptomatte_objects(scene));
+		}
+		if(scene->film->cryptomatte_passes & CRYPT_MATERIAL) {
+			add_cryptomatte_layer(b_full_rr, b_rlay_name+".CryptoMaterial",
+			                      scene->shader_manager->get_cryptomatte_materials(scene));
+		}
+		if(scene->film->cryptomatte_passes & CRYPT_ASSET) {
+			add_cryptomatte_layer(b_full_rr, b_rlay_name+".CryptoAsset",
+			                      scene->object_manager->get_cryptomatte_assets(scene));
+		}
+
 		/* free result without merging */
 		end_render_result(b_engine, b_rr, true, true, false);
 

intern/cycles/blender/blender_session.h

@@ -169,6 +169,9 @@ protected:
 
 	/* Update tile manager to reflect resumable render settings. */
 	void update_resumable_tile_manager(int num_samples);
+
+	/* Add metadata for cryptomatte layers to the render result. */
+	void add_cryptomatte_metadata(string layer_prefix);
 };
 
 CCL_NAMESPACE_END

intern/cycles/blender/blender_util.h

@@ -243,6 +243,12 @@ static inline float *image_get_float_pixels_for_frame(BL::Image& image,
 	return BKE_image_get_float_pixels_for_frame(image.ptr.data, frame);
 }
 
+static inline void render_add_metadata(BL::RenderResult& b_rr, string name, string value)
+{
+	b_rr.stamp_data_add_field(name.c_str(), value.c_str());
+}
+
+
 /* Utilities */
 
 static inline Transform get_transform(const BL::Array<float, 16>& array)

intern/cycles/render/object.cpp

@@ -27,6 +27,7 @@
 #include "util/util_logging.h"
 #include "util/util_map.h"
 #include "util/util_progress.h"
+#include "util/util_set.h"
 #include "util/util_vector.h"
 #include "util/util_murmurhash.h"
 
@@ -844,4 +845,37 @@ void ObjectManager::tag_update(Scene *scene)
 	scene->light_manager->need_update = true;
 }
 
+string ObjectManager::get_cryptomatte_objects(Scene *scene)
+{
+	string manifest = "{";
+
+	unordered_set<ustring, ustringHash> objects;
+	foreach(Object *object, scene->objects) {
+		if(objects.count(object->name)) {
+			continue;
+		}
+		objects.insert(object->name);
+		uint32_t hash_name = util_murmur_hash3(object->name.c_str(), object->name.length(), 0);
+		manifest += string_printf("\"%s\":\"%08x\",", object->name.c_str(), hash_name);
+	}
+	manifest[manifest.size()-1] = '}';
+	return manifest;
+}
+
+string ObjectManager::get_cryptomatte_assets(Scene *scene)
+{
+	string manifest = "{";
+	unordered_set<ustring, ustringHash> assets;
+	foreach(Object *ob, scene->objects) {
+		if(assets.count(ob->asset_name)) {
+			continue;
+		}
+		assets.insert(ob->asset_name);
+		uint32_t hash_asset = util_murmur_hash3(ob->asset_name.c_str(), ob->asset_name.length(), 0);
+		manifest += string_printf("\"%s\":\"%08x\",", ob->asset_name.c_str(), hash_asset);
+	}
+	manifest[manifest.size()-1] = '}';
+	return manifest;
+}
+
 CCL_NAMESPACE_END

intern/cycles/render/object.h

@@ -116,6 +116,9 @@ public:
 
 	void apply_static_transforms(DeviceScene *dscene, Scene *scene, Progress& progress);
 
+	string get_cryptomatte_objects(Scene *scene);
+	string get_cryptomatte_assets(Scene *scene);
+
 protected:
 	void device_update_object_transform(UpdateObjectTransformState *state,
 	                                    Object *ob,

intern/cycles/render/shader.cpp

@@ -699,4 +699,20 @@ float ShaderManager::linear_rgb_to_gray(float3 c)
 	return dot(c, rgb_to_y);
 }
 
+string ShaderManager::get_cryptomatte_materials(Scene *scene)
+{
+	string manifest = "{";
+	unordered_set<ustring, ustringHash> materials;
+	foreach(Shader *shader, scene->shaders) {
+		if(materials.count(shader->name)) {
+			continue;
+		}
+		materials.insert(shader->name);
+		uint32_t cryptomatte_id = util_murmur_hash3(shader->name.c_str(), shader->name.length(), 0);
+		manifest += string_printf("\"%s\":\"%08x\",", shader->name.c_str(), cryptomatte_id);
+	}
+	manifest[manifest.size()-1] = '}';
+	return manifest;
+}
+
 CCL_NAMESPACE_END

intern/cycles/render/shader.h

@@ -197,6 +197,8 @@ public:
 
 	float linear_rgb_to_gray(float3 c);
 
+	string get_cryptomatte_materials(Scene *scene);
+
 protected:
 	ShaderManager();