Options to clean/simplify convex hull generated from mesh

Clean: remove duplicate and interior vertices (uses Bullet algorithm)
Simplify: modify the geometry for further simplification (uses VHACD
algorithm)

In the editor, single convex hull now uses the clean option.
Added a new editor entry to create a simplified convex hull, can be
useful for creating convex hull from highly tessellated triangle meshes.

3 files changed, 17 insertions, 5 deletions

diff --git a/editor/import/scene_importer_mesh.cpp b/editor/import/scene_importer_mesh.cpp
index ce78166d1e..f8e93df382 100644
--- a/editor/import/scene_importer_mesh.cpp
+++ b/editor/import/scene_importer_mesh.cpp
@@ -506,7 +506,7 @@ Vector<Ref<Shape3D>> EditorSceneImporterMesh::convex_decompose() const {
 
 	const Vector<Face3> faces = get_faces();
 
-	Vector<Vector<Face3>> decomposed = Mesh::convex_composition_function(faces);
+	Vector<Vector<Face3>> decomposed = Mesh::convex_composition_function(faces, -1);
 
 	Vector<Ref<Shape3D>> ret;
 
diff --git a/editor/plugins/mesh_instance_3d_editor_plugin.cpp b/editor/plugins/mesh_instance_3d_editor_plugin.cpp
index 0d2b2ea2f5..7434accc1a 100644
--- a/editor/plugins/mesh_instance_3d_editor_plugin.cpp
+++ b/editor/plugins/mesh_instance_3d_editor_plugin.cpp
@@ -153,14 +153,18 @@ void MeshInstance3DEditor::_menu_option(int p_option) {
 			ur->add_undo_method(node->get_parent(), "remove_child", cshape);
 			ur->commit_action();
 		} break;
-		case MENU_OPTION_CREATE_SINGLE_CONVEX_COLLISION_SHAPE: {
+
+		case MENU_OPTION_CREATE_SINGLE_CONVEX_COLLISION_SHAPE:
+		case MENU_OPTION_CREATE_SIMPLIFIED_CONVEX_COLLISION_SHAPE: {
 			if (node == get_tree()->get_edited_scene_root()) {
 				err_dialog->set_text(TTR("Can't create a single convex collision shape for the scene root."));
 				err_dialog->popup_centered();
 				return;
 			}
 
-			Ref<Shape3D> shape = mesh->create_convex_shape();
+			bool simplify = (p_option == MENU_OPTION_CREATE_SIMPLIFIED_CONVEX_COLLISION_SHAPE);
+
+			Ref<Shape3D> shape = mesh->create_convex_shape(true, simplify);
 
 			if (shape.is_null()) {
 				err_dialog->set_text(TTR("Couldn't create a single convex collision shape."));
@@ -169,7 +173,11 @@ void MeshInstance3DEditor::_menu_option(int p_option) {
 			}
 			UndoRedo *ur = EditorNode::get_singleton()->get_undo_redo();
 
-			ur->create_action(TTR("Create Single Convex Shape"));
+			if (simplify) {
+				ur->create_action(TTR("Create Simplified Convex Shape"));
+			} else {
+				ur->create_action(TTR("Create Single Convex Shape"));
+			}
 
 			CollisionShape3D *cshape = memnew(CollisionShape3D);
 			cshape->set_shape(shape);
@@ -186,6 +194,7 @@ void MeshInstance3DEditor::_menu_option(int p_option) {
 			ur->commit_action();
 
 		} break;
+
 		case MENU_OPTION_CREATE_MULTIPLE_CONVEX_COLLISION_SHAPES: {
 			if (node == get_tree()->get_edited_scene_root()) {
 				err_dialog->set_text(TTR("Can't create multiple convex collision shapes for the scene root."));
@@ -441,8 +450,10 @@ MeshInstance3DEditor::MeshInstance3DEditor() {
 	options->get_popup()->set_item_tooltip(options->get_popup()->get_item_count() - 1, TTR("Creates a polygon-based collision shape.\nThis is the most accurate (but slowest) option for collision detection."));
 	options->get_popup()->add_item(TTR("Create Single Convex Collision Sibling"), MENU_OPTION_CREATE_SINGLE_CONVEX_COLLISION_SHAPE);
 	options->get_popup()->set_item_tooltip(options->get_popup()->get_item_count() - 1, TTR("Creates a single convex collision shape.\nThis is the fastest (but least accurate) option for collision detection."));
+	options->get_popup()->add_item(TTR("Create Simplified Convex Collision Sibling"), MENU_OPTION_CREATE_SIMPLIFIED_CONVEX_COLLISION_SHAPE);
+	options->get_popup()->set_item_tooltip(options->get_popup()->get_item_count() - 1, TTR("Creates a simplified convex collision shape.\nThis is similar to single collision shape, but can result in a simpler geometry in some cases, at the cost of accuracy."));
 	options->get_popup()->add_item(TTR("Create Multiple Convex Collision Siblings"), MENU_OPTION_CREATE_MULTIPLE_CONVEX_COLLISION_SHAPES);
-	options->get_popup()->set_item_tooltip(options->get_popup()->get_item_count() - 1, TTR("Creates a polygon-based collision shape.\nThis is a performance middle-ground between the two above options."));
+	options->get_popup()->set_item_tooltip(options->get_popup()->get_item_count() - 1, TTR("Creates a polygon-based collision shape.\nThis is a performance middle-ground between a single convex collision and a polygon-based collision."));
 	options->get_popup()->add_separator();
 	options->get_popup()->add_item(TTR("Create Navigation Mesh"), MENU_OPTION_CREATE_NAVMESH);
 	options->get_popup()->add_separator();
diff --git a/editor/plugins/mesh_instance_3d_editor_plugin.h b/editor/plugins/mesh_instance_3d_editor_plugin.h
index 69f494de7f..98b667c978 100644
--- a/editor/plugins/mesh_instance_3d_editor_plugin.h
+++ b/editor/plugins/mesh_instance_3d_editor_plugin.h
@@ -43,6 +43,7 @@ class MeshInstance3DEditor : public Control {
 		MENU_OPTION_CREATE_STATIC_TRIMESH_BODY,
 		MENU_OPTION_CREATE_TRIMESH_COLLISION_SHAPE,
 		MENU_OPTION_CREATE_SINGLE_CONVEX_COLLISION_SHAPE,
+		MENU_OPTION_CREATE_SIMPLIFIED_CONVEX_COLLISION_SHAPE,
 		MENU_OPTION_CREATE_MULTIPLE_CONVEX_COLLISION_SHAPES,
 		MENU_OPTION_CREATE_NAVMESH,
 		MENU_OPTION_CREATE_OUTLINE_MESH,