Implement shadow meshes

-When importing, a vertex-only version of the mesh is created.
-This version is used when rendering shadows, and improves performance by reducing bandwidth
-It's automatic, but can optionally be used by users, in case they want to make special versions of geometry for shadow casting.

2 files changed, 21 insertions, 0 deletions

diff --git a/scene/resources/mesh.cpp b/scene/resources/mesh.cpp
index 32fede1e5f..e812ad3a01 100644
--- a/scene/resources/mesh.cpp
+++ b/scene/resources/mesh.cpp
@@ -1565,6 +1565,19 @@ Error ArrayMesh::lightmap_unwrap_cached(int *&r_cache_data, unsigned int &r_cach
 	return OK;
 }
 
+void ArrayMesh::set_shadow_mesh(const Ref<ArrayMesh> &p_mesh) {
+	shadow_mesh = p_mesh;
+	if (shadow_mesh.is_valid()) {
+		RS::get_singleton()->mesh_set_shadow_mesh(mesh, shadow_mesh->get_rid());
+	} else {
+		RS::get_singleton()->mesh_set_shadow_mesh(mesh, RID());
+	}
+}
+
+Ref<ArrayMesh> ArrayMesh::get_shadow_mesh() const {
+	return shadow_mesh;
+}
+
 void ArrayMesh::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("add_blend_shape", "name"), &ArrayMesh::add_blend_shape);
 	ClassDB::bind_method(D_METHOD("get_blend_shape_count"), &ArrayMesh::get_blend_shape_count);
@@ -1596,6 +1609,9 @@ void ArrayMesh::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_custom_aabb", "aabb"), &ArrayMesh::set_custom_aabb);
 	ClassDB::bind_method(D_METHOD("get_custom_aabb"), &ArrayMesh::get_custom_aabb);
 
+	ClassDB::bind_method(D_METHOD("set_shadow_mesh", "mesh"), &ArrayMesh::set_shadow_mesh);
+	ClassDB::bind_method(D_METHOD("get_shadow_mesh"), &ArrayMesh::get_shadow_mesh);
+
 	ClassDB::bind_method(D_METHOD("_set_blend_shape_names", "blend_shape_names"), &ArrayMesh::_set_blend_shape_names);
 	ClassDB::bind_method(D_METHOD("_get_blend_shape_names"), &ArrayMesh::_get_blend_shape_names);
 
@@ -1606,6 +1622,7 @@ void ArrayMesh::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::ARRAY, "_surfaces", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NOEDITOR | PROPERTY_USAGE_INTERNAL), "_set_surfaces", "_get_surfaces");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "blend_shape_mode", PROPERTY_HINT_ENUM, "Normalized,Relative"), "set_blend_shape_mode", "get_blend_shape_mode");
 	ADD_PROPERTY(PropertyInfo(Variant::AABB, "custom_aabb", PROPERTY_HINT_NONE, ""), "set_custom_aabb", "get_custom_aabb");
+	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "shadow_mesh", PROPERTY_HINT_RESOURCE_TYPE, "ArrayMesh"), "set_shadow_mesh", "get_shadow_mesh");
 }
 
 void ArrayMesh::reload_from_file() {
diff --git a/scene/resources/mesh.h b/scene/resources/mesh.h
index 2f25ecd60b..1fd45c880a 100644
--- a/scene/resources/mesh.h
+++ b/scene/resources/mesh.h
@@ -176,6 +176,7 @@ class ArrayMesh : public Mesh {
 
 	Array _get_surfaces() const;
 	void _set_surfaces(const Array &p_data);
+	Ref<ArrayMesh> shadow_mesh;
 
 private:
 	struct Surface {
@@ -259,6 +260,9 @@ public:
 
 	virtual void reload_from_file() override;
 
+	void set_shadow_mesh(const Ref<ArrayMesh> &p_mesh);
+	Ref<ArrayMesh> get_shadow_mesh() const;
+
 	ArrayMesh();
 
 	~ArrayMesh();