Mesh merging - refactor to be backward compatible for CPU / GPU storage

Allows the old `merge_meshes()` function to work from the editor.

scene/3d/merge_group.cpp

@@ -302,7 +302,7 @@ void MergeGroup::_split_mesh_by_surface(MeshInstance *p_mi, int p_num_surfaces)
 
 	_node_changed(parent);
 
-	p_mi->split_by_surface(siblings);
+	MergingTool::wrapped_split_by_surface(*p_mi, siblings, Mesh::STORAGE_MODE_CPU);
 
 	// Failed to split.
 	if (parent->get_child_count() <= first_sibling_id) {
@@ -827,7 +827,7 @@ void MergeGroup::_merge_list(const LocalVector<MeshInstance *> &p_mis, bool p_sh
 		varlist.push_back(Variant(p_mis[n]));
 	}
 
-	if (!merged->merge_meshes(varlist, false, false, p_shadows)) {
+	if (!MergingTool::wrapped_merge_meshes(*merged, varlist, false, false, p_shadows, Mesh::STORAGE_MODE_CPU)) {
 		_log("MERGE_MESHES failed.");
 		_delete_node(merged);
 		return;

scene/3d/mesh_instance.cpp

@@ -854,71 +854,8 @@ void MeshInstance::create_debug_tangents() {
 	}
 }
 
-bool MeshInstance::split_by_surface(Vector<Variant> p_destination_mesh_instances) {
-	ERR_FAIL_COND_V_MSG(!is_inside_tree(), false, "Source MeshInstance must be inside the SceneTree.");
-
-	// For simplicity we are requiring that the destination MeshInstances have the same parent
-	// as the source. This means we can use identical transforms.
-	Node *parent = get_parent();
-	ERR_FAIL_NULL_V_MSG(parent, false, "Source MeshInstance must have a parent node.");
-
-	// Bound function only support variants, so we need to convert to a list of MeshInstances.
-	Vector<MeshInstance *> mis;
-
-	for (int n = 0; n < p_destination_mesh_instances.size(); n++) {
-		MeshInstance *mi = Object::cast_to<MeshInstance>(p_destination_mesh_instances[n]);
-		if (mi) {
-			if (mi != this) {
-				ERR_FAIL_COND_V_MSG(mi->get_parent() != parent, false, "Destination MeshInstances must be siblings of the source MeshInstance.");
-
-				mis.push_back(mi);
-			} else {
-				ERR_FAIL_V_MSG(false, "Source MeshInstance cannot be a destination.");
-			}
-		} else {
-			ERR_FAIL_V_MSG(false, "Only MeshInstances can be split.");
-		}
-	}
-
-	ERR_FAIL_COND_V_MSG(!get_mesh().is_valid(), false, "Mesh is invalid.");
-	ERR_FAIL_COND_V_MSG(mis.size() != get_mesh()->get_surface_count(), false, "Number of surfaces and number of destination MeshInstances must match.");
-
-	// Go through each surface, and fill the relevant mesh instance.
-	const Mesh *source_mesh = get_mesh().ptr();
-	DEV_ASSERT(source_mesh);
-
-	ERR_FAIL_COND_V_MSG(source_mesh->get_surface_count() <= 1, false, "Source MeshInstance must contain multiple surfaces.");
-
-	for (int s = 0; s < source_mesh->get_surface_count(); s++) {
-		MergingTool::split_surface_to_mesh_instance(*this, s, *mis[s]);
-	}
-
-	return true;
-}
-
 bool MeshInstance::merge_meshes(Vector<Variant> p_list, bool p_use_global_space, bool p_check_compatibility, bool p_shadows_only) {
-	// Bound function only support variants, so we need to convert to a list of MeshInstances.
+	return MergingTool::wrapped_merge_meshes(*this, p_list, p_use_global_space, p_check_compatibility, p_shadows_only, Mesh::STORAGE_MODE_GPU);
-	Vector<MeshInstance *> mis;
-
-	for (int n = 0; n < p_list.size(); n++) {
-		MeshInstance *mi = Object::cast_to<MeshInstance>(p_list[n]);
-		if (mi) {
-			if (mi != this) {
-				mis.push_back(mi);
-			} else {
-				ERR_PRINT("Destination MeshInstance cannot be a source.");
-			}
-		} else {
-			ERR_PRINT("Only MeshInstances can be merged.");
-		}
-	}
-
-	ERR_FAIL_COND_V(!mis.size(), "Array contains no MeshInstances");
-
-	if (p_shadows_only) {
-		return MergingTool::merge_shadow_meshes(*this, mis, p_use_global_space, p_check_compatibility);
-	}
-	return MergingTool::merge_meshes(*this, mis, p_use_global_space, p_check_compatibility);
 }
 
 bool MeshInstance::is_mergeable_with(Node *p_other, bool p_shadows_only) const {

scene/3d/mesh_instance.h

@@ -140,7 +140,6 @@ public:
 	// Merging.
 	bool is_mergeable_with(Node *p_other, bool p_shadows_only) const;
 	bool merge_meshes(Vector<Variant> p_list, bool p_use_global_space, bool p_check_compatibility, bool p_shadows_only);
-	bool split_by_surface(Vector<Variant> p_destination_mesh_instances);
 
 	virtual AABB get_aabb() const;
 	virtual PoolVector<Face3> get_faces(uint32_t p_usage_flags) const;

scene/resources/merging_tool.cpp

@@ -40,6 +40,87 @@
 #include "modules/csg/csg_shape.h"
 #endif
 
+bool MergingTool::wrapped_split_by_surface(const MeshInstance &p_source_mi, Vector<Variant> p_destination_mesh_instances, Mesh::StorageMode p_storage_mode) {
+	ERR_FAIL_COND_V_MSG(!p_source_mi.is_inside_tree(), false, "Source MeshInstance must be inside the SceneTree.");
+	ERR_FAIL_COND_V_MSG(!p_source_mi.get_mesh().is_valid(), false, "Source MeshInstance must have a valid mesh to split.");
+
+	// For simplicity we are requiring that the destination MeshInstances have the same parent
+	// as the source. This means we can use identical transforms.
+	Node *parent = p_source_mi.get_parent();
+	ERR_FAIL_NULL_V_MSG(parent, false, "Source MeshInstance must have a parent node.");
+
+	// Bound function only support variants, so we need to convert to a list of MeshInstances.
+	Vector<MeshInstance *> mis;
+
+	for (int n = 0; n < p_destination_mesh_instances.size(); n++) {
+		MeshInstance *mi = Object::cast_to<MeshInstance>(p_destination_mesh_instances[n]);
+
+		ERR_FAIL_NULL_V_MSG(mi, false, "Can only be split to MeshInstances.");
+		ERR_FAIL_COND_V_MSG(mi == &p_source_mi, false, "Source MeshInstance cannot be a destination.");
+		ERR_FAIL_COND_V_MSG(mi->get_parent() != parent, false, "Destination MeshInstances must be siblings of the source MeshInstance.");
+		mis.push_back(mi);
+	}
+
+	ERR_FAIL_COND_V_MSG(mis.size() != p_source_mi.get_mesh()->get_surface_count(), false, "Number of source surfaces and number of destination MeshInstances must match.");
+
+	// Go through each surface, and fill the relevant mesh instance.
+	const Mesh *source_mesh = p_source_mi.get_mesh().ptr();
+	DEV_ASSERT(source_mesh);
+
+	ERR_FAIL_COND_V_MSG(source_mesh->get_surface_count() <= 1, false, "Source MeshInstance must contain multiple surfaces.");
+
+	for (int s = 0; s < source_mesh->get_surface_count(); s++) {
+		MeshInstance &dest_mi = *mis[s];
+		if (split_surface_to_mesh_instance(p_source_mi, s, dest_mi)) {
+			// Change storage mode if required.
+#ifdef TOOLS_ENABLED
+			Ref<Mesh> rmesh = dest_mi.get_mesh();
+			if (rmesh.is_valid()) {
+				_mesh_set_storage_mode(rmesh.ptr(), p_storage_mode);
+			}
+#endif
+		}
+	}
+
+	return true;
+}
+
+bool MergingTool::wrapped_merge_meshes(MeshInstance &r_dest_mi, Vector<Variant> p_list, bool p_use_global_space, bool p_check_compatibility, bool p_shadows_only, Mesh::StorageMode p_storage_mode) {
+	// Bound function only support variants, so we need to convert to a list of MeshInstances.
+	Vector<MeshInstance *> mis;
+
+	for (int n = 0; n < p_list.size(); n++) {
+		MeshInstance *mi = Object::cast_to<MeshInstance>(p_list[n]);
+		if (mi) {
+			ERR_FAIL_COND_V_MSG(mi == &r_dest_mi, false, "Destination MeshInstance cannot be a source.");
+			mis.push_back(mi);
+		} else {
+			ERR_PRINT("Only MeshInstances can be merged.");
+		}
+	}
+
+	ERR_FAIL_COND_V_MSG(!mis.size(), false, "Array contains no MeshInstances");
+
+	bool result;
+	if (p_shadows_only) {
+		result = merge_shadow_meshes(r_dest_mi, mis, p_use_global_space, p_check_compatibility);
+	} else {
+		result = merge_meshes(r_dest_mi, mis, p_use_global_space, p_check_compatibility);
+	}
+
+	// Change storage mode if required.
+	if (result) {
+#ifdef TOOLS_ENABLED
+		Ref<Mesh> rmesh = r_dest_mi.get_mesh();
+		if (rmesh.is_valid()) {
+			_mesh_set_storage_mode(rmesh.ptr(), p_storage_mode);
+		}
+#endif
+	}
+
+	return result;
+}
+
 bool MergingTool::_is_material_opaque(const Ref<Material> &p_mat) {
 	if (p_mat.is_null()) {
 		return true;

scene/resources/merging_tool.h

@@ -46,9 +46,19 @@ struct CSGBrush;
 // #define GODOT_MERGING_VERBOSE
 #endif
 
-// NOTE : These merging and joining functions DO NOT move children, or delete source nodes. That is the responsibility of the caller.
+// NOTE : These merging and joining functions DO NOT move children, or delete source nodes.
+// That is the responsibility of the caller.
+
 class MergingTool {
 public:
+	////////////////////////////////////////////////////////////////////////////////////
+	// WRAPPED versions are accessible via script via MeshInstance.
+	// These have to cope with Variants as lists of MeshInstances is not easy from script.
+	static bool wrapped_merge_meshes(MeshInstance &r_dest_mi, Vector<Variant> p_list, bool p_use_global_space, bool p_check_compatibility, bool p_shadows_only, Mesh::StorageMode p_storage_mode);
+	static bool wrapped_split_by_surface(const MeshInstance &p_source_mi, Vector<Variant> p_destination_mesh_instances, Mesh::StorageMode p_storage_mode);
+
+	////////////////////////////////////////////////////////////////////////////////////
+
 	// Are two mesh instances mergeable with each other?
 	static bool is_mergeable_with(const MeshInstance &p_mi, const MeshInstance &p_other, bool p_check_surface_material_match);
 	static bool is_shadow_mergeable_with(const MeshInstance &p_mi, const MeshInstance &p_other);