import: Fix uv2 by avoiding premature ImporterMesh::get_mesh()

Implements create_convex_shape in ImpoterMesh.
Note: ImporterMeshInstance3D::get_mesh() is safe.
The only dangerous function with side effects is ImpoterMesh::get_mesh()

editor/import/resource_importer_scene.cpp

@@ -353,13 +353,12 @@ static String _fixstr(const String &p_what, const String &p_str) {
 
 static void _pre_gen_shape_list(Ref<ImporterMesh> &mesh, Vector<Ref<Shape3D>> &r_shape_list, bool p_convex) {
 	ERR_FAIL_NULL_MSG(mesh, "Cannot generate shape list with null mesh value");
-	ERR_FAIL_NULL_MSG(mesh->get_mesh(), "Cannot generate shape list with null mesh value");
 	if (!p_convex) {
 		Ref<ConcavePolygonShape3D> shape = mesh->create_trimesh_shape();
 		r_shape_list.push_back(shape);
 	} else {
 		Vector<Ref<Shape3D>> cd;
-		cd.push_back(mesh->get_mesh()->create_convex_shape(true, /*Passing false, otherwise VHACD will be used to simplify (Decompose) the Mesh.*/ false));
+		cd.push_back(mesh->create_convex_shape(true, /*Passing false, otherwise VHACD will be used to simplify (Decompose) the Mesh.*/ false));
 		if (cd.size()) {
 			for (int i = 0; i < cd.size(); i++) {
 				r_shape_list.push_back(cd[i]);
@@ -1230,7 +1229,7 @@ Node *ResourceImporterScene::_post_fix_node(Node *p_node, Node *p_root, HashMap<
 						shapes = collision_map[m];
 					} else {
 						shapes = get_collision_shapes(
-								m->get_mesh(),
+								m,
 								node_settings,
 								p_applied_root_scale);
 					}

editor/import/resource_importer_scene.h

@@ -39,6 +39,7 @@
 #include "scene/resources/box_shape_3d.h"
 #include "scene/resources/capsule_shape_3d.h"
 #include "scene/resources/cylinder_shape_3d.h"
+#include "scene/resources/importer_mesh.h"
 #include "scene/resources/mesh.h"
 #include "scene/resources/shape_3d.h"
 #include "scene/resources/sphere_shape_3d.h"
@@ -298,7 +299,7 @@ public:
 	ResourceImporterScene(bool p_animation_import = false);
 
 	template <class M>
-	static Vector<Ref<Shape3D>> get_collision_shapes(const Ref<Mesh> &p_mesh, const M &p_options, float p_applied_root_scale);
+	static Vector<Ref<Shape3D>> get_collision_shapes(const Ref<ImporterMesh> &p_mesh, const M &p_options, float p_applied_root_scale);
 
 	template <class M>
 	static Transform3D get_collision_shapes_transform(const M &p_options);
@@ -314,7 +315,8 @@ public:
 };
 
 template <class M>
-Vector<Ref<Shape3D>> ResourceImporterScene::get_collision_shapes(const Ref<Mesh> &p_mesh, const M &p_options, float p_applied_root_scale) {
+Vector<Ref<Shape3D>> ResourceImporterScene::get_collision_shapes(const Ref<ImporterMesh> &p_mesh, const M &p_options, float p_applied_root_scale) {
+	ERR_FAIL_COND_V(p_mesh.is_null(), Vector<Ref<Shape3D>>());
 	ShapeType generate_shape_type = SHAPE_TYPE_DECOMPOSE_CONVEX;
 	if (p_options.has(SNAME("physics/shape_type"))) {
 		generate_shape_type = (ShapeType)p_options[SNAME("physics/shape_type")].operator int();

editor/import/scene_import_settings.cpp

@@ -444,9 +444,45 @@ void SceneImportSettings::_update_view_gizmos() {
 		collider_view->set_visible(show_collider_view);
 		if (generate_collider) {
 			// This collider_view doesn't have a mesh so we need to generate a new one.
+			Ref<ImporterMesh> mesh;
+			mesh.instantiate();
+			// ResourceImporterScene::get_collision_shapes() expects ImporterMesh, not Mesh.
+			// TODO: Duplicate code with EditorSceneFormatImporterESCN::import_scene()
+			// Consider making a utility function to convert from Mesh to ImporterMesh.
+			Ref<Mesh> mesh_3d_mesh = mesh_node->get_mesh();
+			Ref<ArrayMesh> array_mesh_3d_mesh = mesh_3d_mesh;
+			if (array_mesh_3d_mesh.is_valid()) {
+				// For the MeshInstance3D nodes, we need to convert the ArrayMesh to an ImporterMesh specially.
+				mesh->set_name(array_mesh_3d_mesh->get_name());
+				for (int32_t blend_i = 0; blend_i < array_mesh_3d_mesh->get_blend_shape_count(); blend_i++) {
+					mesh->add_blend_shape(array_mesh_3d_mesh->get_blend_shape_name(blend_i));
+				}
+				for (int32_t surface_i = 0; surface_i < array_mesh_3d_mesh->get_surface_count(); surface_i++) {
+					mesh->add_surface(array_mesh_3d_mesh->surface_get_primitive_type(surface_i),
+							array_mesh_3d_mesh->surface_get_arrays(surface_i),
+							array_mesh_3d_mesh->surface_get_blend_shape_arrays(surface_i),
+							array_mesh_3d_mesh->surface_get_lods(surface_i),
+							array_mesh_3d_mesh->surface_get_material(surface_i),
+							array_mesh_3d_mesh->surface_get_name(surface_i),
+							array_mesh_3d_mesh->surface_get_format(surface_i));
+				}
+				mesh->set_blend_shape_mode(array_mesh_3d_mesh->get_blend_shape_mode());
+			} else if (mesh_3d_mesh.is_valid()) {
+				// For the MeshInstance3D nodes, we need to convert the Mesh to an ImporterMesh specially.
+				mesh->set_name(mesh_3d_mesh->get_name());
+				for (int32_t surface_i = 0; surface_i < mesh_3d_mesh->get_surface_count(); surface_i++) {
+					mesh->add_surface(mesh_3d_mesh->surface_get_primitive_type(surface_i),
+							mesh_3d_mesh->surface_get_arrays(surface_i),
+							Array(),
+							mesh_3d_mesh->surface_get_lods(surface_i),
+							mesh_3d_mesh->surface_get_material(surface_i),
+							mesh_3d_mesh->surface_get_material(surface_i).is_valid() ? mesh_3d_mesh->surface_get_material(surface_i)->get_name() : String(),
+							mesh_3d_mesh->surface_get_format(surface_i));
+				}
+			}
 
 			// Generate the mesh collider.
-			Vector<Ref<Shape3D>> shapes = ResourceImporterScene::get_collision_shapes(mesh_node->get_mesh(), e.value.settings, 1.0);
+			Vector<Ref<Shape3D>> shapes = ResourceImporterScene::get_collision_shapes(mesh, e.value.settings, 1.0);
 			const Transform3D transform = ResourceImporterScene::get_collision_shapes_transform(e.value.settings);
 
 			Ref<ArrayMesh> collider_view_mesh;

scene/resources/importer_mesh.cpp

@@ -31,6 +31,7 @@
 #include "importer_mesh.h"
 
 #include "core/io/marshalls.h"
+#include "core/math/convex_hull.h"
 #include "core/math/random_pcg.h"
 #include "core/math/static_raycaster.h"
 #include "scene/resources/surface_tool.h"
@@ -984,6 +985,43 @@ Vector<Ref<Shape3D>> ImporterMesh::convex_decompose(const Mesh::ConvexDecomposit
 	return ret;
 }
 
+Ref<ConvexPolygonShape3D> ImporterMesh::create_convex_shape(bool p_clean, bool p_simplify) const {
+	if (p_simplify) {
+		Mesh::ConvexDecompositionSettings settings;
+		settings.max_convex_hulls = 1;
+		Vector<Ref<Shape3D>> decomposed = convex_decompose(settings);
+		if (decomposed.size() == 1) {
+			return decomposed[0];
+		} else {
+			ERR_PRINT("Convex shape simplification failed, falling back to simpler process.");
+		}
+	}
+
+	Vector<Vector3> vertices;
+	for (int i = 0; i < get_surface_count(); i++) {
+		Array a = get_surface_arrays(i);
+		ERR_FAIL_COND_V(a.is_empty(), Ref<ConvexPolygonShape3D>());
+		Vector<Vector3> v = a[Mesh::ARRAY_VERTEX];
+		vertices.append_array(v);
+	}
+
+	Ref<ConvexPolygonShape3D> shape = memnew(ConvexPolygonShape3D);
+
+	if (p_clean) {
+		Geometry3D::MeshData md;
+		Error err = ConvexHullComputer::convex_hull(vertices, md);
+		if (err == OK) {
+			shape->set_points(md.vertices);
+			return shape;
+		} else {
+			ERR_PRINT("Convex shape cleaning failed, falling back to simpler process.");
+		}
+	}
+
+	shape->set_points(vertices);
+	return shape;
+}
+
 Ref<ConcavePolygonShape3D> ImporterMesh::create_trimesh_shape() const {
 	Vector<Face3> faces = get_faces();
 	if (faces.size() == 0) {

scene/resources/importer_mesh.h

@@ -119,6 +119,7 @@ public:
 
 	Vector<Face3> get_faces() const;
 	Vector<Ref<Shape3D>> convex_decompose(const Mesh::ConvexDecompositionSettings &p_settings) const;
+	Ref<ConvexPolygonShape3D> create_convex_shape(bool p_clean = true, bool p_simplify = false) const;
 	Ref<ConcavePolygonShape3D> create_trimesh_shape() const;
 	Ref<NavigationMesh> create_navigation_mesh();
 	Error lightmap_unwrap_cached(const Transform3D &p_base_transform, float p_texel_size, const Vector<uint8_t> &p_src_cache, Vector<uint8_t> &r_dst_cache);