Merge pull request #106562 from zeux/lod-metrics

Adjust LOD selection metrics to use attribute error

editor/import/3d/resource_importer_scene.cpp

@@ -2080,7 +2080,7 @@ void ResourceImporterScene::get_internal_import_options(InternalImportCategory p
 			r_options->push_back(ImportOption(PropertyInfo(Variant::INT, "generate/shadow_meshes", PROPERTY_HINT_ENUM, "Default,Enable,Disable"), 0));
 			r_options->push_back(ImportOption(PropertyInfo(Variant::INT, "generate/lightmap_uv", PROPERTY_HINT_ENUM, "Default,Enable,Disable"), 0));
 			r_options->push_back(ImportOption(PropertyInfo(Variant::INT, "generate/lods", PROPERTY_HINT_ENUM, "Default,Enable,Disable"), 0));
-			r_options->push_back(ImportOption(PropertyInfo(Variant::FLOAT, "lods/normal_merge_angle", PROPERTY_HINT_RANGE, "0,180,0.1,degrees"), 60.0f));
+			r_options->push_back(ImportOption(PropertyInfo(Variant::FLOAT, "lods/normal_merge_angle", PROPERTY_HINT_RANGE, "0,180,1,degrees"), 20.0f));
 		} break;
 		case INTERNAL_IMPORT_CATEGORY_MATERIAL: {
 			r_options->push_back(ImportOption(PropertyInfo(Variant::BOOL, "use_external/enabled", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_DEFAULT | PROPERTY_USAGE_UPDATE_ALL_IF_MODIFIED), false));
@@ -2514,7 +2514,7 @@ Node *ResourceImporterScene::_generate_meshes(Node *p_node, const Dictionary &p_
 				//do mesh processing
 
 				bool generate_lods = p_generate_lods;
-				float merge_angle = 60.0f;
+				float merge_angle = 20.0f;
 				bool create_shadow_meshes = p_create_shadow_meshes;
 				bool bake_lightmaps = p_light_bake_mode == LIGHT_BAKE_STATIC_LIGHTMAPS;
 				String save_to_file;

scene/resources/3d/importer_mesh.cpp

@@ -443,8 +443,8 @@ void ImporterMesh::generate_lods(float p_normal_merge_angle, Array p_bone_transf
 
 		float attrib_weights[attrib_count] = {};
 
-		// Give more weight to normal preservation
-		attrib_weights[0] = attrib_weights[1] = attrib_weights[2] = 2.0f;
+		// Give some weight to normal preservation
+		attrib_weights[0] = attrib_weights[1] = attrib_weights[2] = 1.0f;
 
 		// Give some weight to colors but only if present to avoid redundant computations during simplification
 		if (colors_ptr) {
@@ -474,7 +474,7 @@ void ImporterMesh::generate_lods(float p_normal_merge_angle, Array p_bone_transf
 		unsigned int index_target = 12; // Start with the smallest target, 4 triangles
 		unsigned int last_index_count = 0;
 
-		const float max_mesh_error = FLT_MAX; // We don't want to limit by error, just by index target
+		const float max_mesh_error = 1.0f; // we only need LODs that can be selected by error threshold
 		float mesh_error = 0.0f;
 
 		while (index_target < index_count) {

thirdparty/meshoptimizer/patches/0001-simplifier-distance-only-error.patch

@@ -1,13 +0,0 @@
-diff --git a/thirdparty/meshoptimizer/simplifier.cpp b/thirdparty/meshoptimizer/simplifier.cpp
-index af64cbda49..8a7072fe4e 100644
---- a/thirdparty/meshoptimizer/simplifier.cpp
-+++ b/thirdparty/meshoptimizer/simplifier.cpp
-@@ -2048,7 +2048,7 @@ size_t meshopt_simplifyEdge(unsigned int* destination, const unsigned int* indic
- 
- 	// result_error is quadratic; we need to remap it back to linear
- 	if (out_result_error)
--		*out_result_error = sqrtf(result_error) * error_scale;
-+		*out_result_error = sqrtf(vertex_error) * error_scale;
- 
- 	return result_count;
- }

thirdparty/meshoptimizer/simplifier.cpp

@@ -2048,7 +2048,7 @@ size_t meshopt_simplifyEdge(unsigned int* destination, const unsigned int* indic
 
 	// result_error is quadratic; we need to remap it back to linear
 	if (out_result_error)
-		*out_result_error = sqrtf(vertex_error) * error_scale;
+		*out_result_error = sqrtf(result_error) * error_scale;
 
 	return result_count;
 }