gltf: Add GLTFHandleBinary::HANDLE_BINARY_EMBED_AS_UNCOMPRESSED

This option allows for a safe fallback for embedded gltf textures in cases where VRAM compression is not needed.
Add an is_editor_hint guard around GLTFHandleBinary::HANDLE_BINARY_EXTRACT_TEXTURES, to use EMBED_AS_UNCOMPRESSED by default at runtime.
This provides an option for pixel art to be stored losslessly.
Additionally, respect project importer defaults for texture import settings.
Avoid writing and reimporting extracted textures identical to version on disk.

5 files changed, 70 insertions, 27 deletions

diff --git a/modules/gltf/doc_classes/GLTFState.xml b/modules/gltf/doc_classes/GLTFState.xml
index b8943795a0..b322c07cec 100644
--- a/modules/gltf/doc_classes/GLTFState.xml
+++ b/modules/gltf/doc_classes/GLTFState.xml
@@ -264,10 +264,16 @@
 	</members>
 	<constants>
 		<constant name="HANDLE_BINARY_DISCARD_TEXTURES" value="0">
+			Discards all embedded textures and uses untextured materials.
 		</constant>
 		<constant name="HANDLE_BINARY_EXTRACT_TEXTURES" value="1">
+			Extracts embedded textures to be reimported and compressed. Editor only. Acts as uncompressed at runtime.
 		</constant>
 		<constant name="HANDLE_BINARY_EMBED_AS_BASISU" value="2">
+			Embeds textures VRAM compressed with Basis Universal into the generated scene.
+		</constant>
+		<constant name="HANDLE_BINARY_EMBED_AS_UNCOMPRESSED" value="3">
+			Embeds textures compressed losslessly into the generated scene, matching old behavior.
 		</constant>
 	</constants>
 </class>
diff --git a/modules/gltf/editor/editor_scene_importer_gltf.cpp b/modules/gltf/editor/editor_scene_importer_gltf.cpp
index 67bbf8dd15..012a144d52 100644
--- a/modules/gltf/editor/editor_scene_importer_gltf.cpp
+++ b/modules/gltf/editor/editor_scene_importer_gltf.cpp
@@ -51,8 +51,8 @@ Node *EditorSceneFormatImporterGLTF::import_scene(const String &p_path, uint32_t
 	doc.instantiate();
 	Ref<GLTFState> state;
 	state.instantiate();
-	if (p_options.has("meshes/handle_gltf_embedded_images")) {
-		int32_t enum_option = p_options["meshes/handle_gltf_embedded_images"];
+	if (p_options.has("gltf/embedded_image_handling")) {
+		int32_t enum_option = p_options["gltf/embedded_image_handling"];
 		state->set_handle_binary_image(enum_option);
 	}
 	Error err = doc->append_from_file(p_path, state, p_flags);
@@ -87,7 +87,7 @@ Node *EditorSceneFormatImporterGLTF::import_scene(const String &p_path, uint32_t
 
 void EditorSceneFormatImporterGLTF::get_import_options(const String &p_path,
 		List<ResourceImporter::ImportOption> *r_options) {
-	r_options->push_back(ResourceImporterScene::ImportOption(PropertyInfo(Variant::INT, "meshes/handle_gltf_embedded_images", PROPERTY_HINT_ENUM, "Discard All Textures,Extract Textures,Embed As Basis Universal", PROPERTY_USAGE_DEFAULT | PROPERTY_USAGE_UPDATE_ALL_IF_MODIFIED), GLTFState::HANDLE_BINARY_EXTRACT_TEXTURES));
+	r_options->push_back(ResourceImporterScene::ImportOption(PropertyInfo(Variant::INT, "gltf/embedded_image_handling", PROPERTY_HINT_ENUM, "Discard All Textures,Extract Textures,Embed As Basis Universal,Embed as Uncompressed", PROPERTY_USAGE_DEFAULT | PROPERTY_USAGE_UPDATE_ALL_IF_MODIFIED), GLTFState::HANDLE_BINARY_EXTRACT_TEXTURES));
 }
 
 #endif // TOOLS_ENABLED
diff --git a/modules/gltf/gltf_document.cpp b/modules/gltf/gltf_document.cpp
index 5950ad33b5..1a09b5bdcc 100644
--- a/modules/gltf/gltf_document.cpp
+++ b/modules/gltf/gltf_document.cpp
@@ -32,6 +32,7 @@
 
 #include "extensions/gltf_spec_gloss.h"
 
+#include "core/config/project_settings.h"
 #include "core/crypto/crypto_core.h"
 #include "core/io/config_file.h"
 #include "core/io/dir_access.h"
@@ -3220,8 +3221,8 @@ Error GLTFDocument::_parse_images(Ref<GLTFState> p_state, const String &p_base_p
 		if (GLTFState::GLTFHandleBinary(p_state->handle_binary_image) == GLTFState::GLTFHandleBinary::HANDLE_BINARY_DISCARD_TEXTURES) {
 			p_state->images.push_back(Ref<Texture2D>());
 			p_state->source_images.push_back(Ref<Image>());
-			continue;
-		} else if (GLTFState::GLTFHandleBinary(p_state->handle_binary_image) == GLTFState::GLTFHandleBinary::HANDLE_BINARY_EXTRACT_TEXTURES) {
+#ifdef TOOLS_ENABLED
+		} else if (Engine::get_singleton()->is_editor_hint() && GLTFState::GLTFHandleBinary(p_state->handle_binary_image) == GLTFState::GLTFHandleBinary::HANDLE_BINARY_EXTRACT_TEXTURES) {
 			if (p_state->base_path.is_empty()) {
 				p_state->images.push_back(Ref<Texture2D>());
 				p_state->source_images.push_back(Ref<Image>());
@@ -3230,26 +3231,56 @@ Error GLTFDocument::_parse_images(Ref<GLTFState> p_state, const String &p_base_p
 				p_state->images.push_back(Ref<Texture2D>());
 				p_state->source_images.push_back(Ref<Image>());
 			} else {
+				Error err = OK;
+				bool must_import = false;
 				String file_path = p_state->get_base_path() + "/" + p_state->filename.get_basename() + "_" + img->get_name() + ".png";
-				Ref<ConfigFile> config;
-				config.instantiate();
-				if (FileAccess::exists(file_path + ".import")) {
-					config->load(file_path + ".import");
+				if (!FileAccess::exists(file_path + ".import")) {
+					Ref<ConfigFile> config;
+					config.instantiate();
+					config->set_value("remap", "importer", "texture");
+					config->set_value("remap", "type", "Texture2D");
+					// Currently, it will likely use project defaults of Detect 3D, so textures will be reimported again.
+					if (!config->has_section_key("params", "mipmaps/generate")) {
+						config->set_value("params", "mipmaps/generate", true);
+					}
+
+					if (ProjectSettings::get_singleton()->has_setting("importer_defaults/texture")) {
+						//use defaults if exist
+						Dictionary importer_defaults = GLOBAL_GET("importer_defaults/texture");
+						List<Variant> importer_def_keys;
+						importer_defaults.get_key_list(&importer_def_keys);
+						for (const Variant &key : importer_def_keys) {
+							if (!config->has_section_key("params", (String)key)) {
+								config->set_value("params", (String)key, importer_defaults[key]);
+							}
+						}
+					}
+					err = config->save(file_path + ".import");
+					ERR_FAIL_COND_V(err != OK, err);
+					must_import = true;
 				}
-				config->set_value("remap", "importer", "texture");
-				config->set_value("remap", "type", "Texture2D");
-				if (!config->has_section_key("params", "compress/mode")) {
-					config->set_value("remap", "compress/mode", 2); //user may want another compression, so leave it bes
+				Vector<uint8_t> png_buffer = img->save_png_to_buffer();
+				if (ResourceLoader::exists(file_path)) {
+					Ref<FileAccess> file = FileAccess::open(file_path, FileAccess::READ, &err);
+					if (err == OK && file.is_valid()) {
+						Vector<uint8_t> orig_png_buffer = file->get_buffer(file->get_length());
+						if (png_buffer != orig_png_buffer) {
+							must_import = true;
+						}
+					}
+				} else {
+					must_import = true;
 				}
-				if (!config->has_section_key("params", "mipmaps/generate")) {
-					config->set_value("params", "mipmaps/generate", true);
+				if (must_import) {
+					Ref<FileAccess> file = FileAccess::open(file_path, FileAccess::WRITE, &err);
+					ERR_FAIL_COND_V(err != OK, err);
+					ERR_FAIL_COND_V(file.is_null(), FAILED);
+					file->store_buffer(png_buffer);
+					file->flush();
+					file.unref();
+					// ResourceLoader::import will crash if not is_editor_hint(), so this case is protected above and will fall through to uncompressed.
+					ResourceLoader::import(file_path);
 				}
-				Error err = OK;
-				err = config->save(file_path + ".import");
-				ERR_FAIL_COND_V(err != OK, err);
-				img->save_png(file_path);
-				ERR_FAIL_COND_V(err != OK, err);
-				ResourceLoader::import(file_path);
 				Ref<Texture2D> saved_image = ResourceLoader::load(file_path, "Texture2D");
 				if (saved_image.is_valid()) {
 					p_state->images.push_back(saved_image);
@@ -3261,7 +3292,7 @@ Error GLTFDocument::_parse_images(Ref<GLTFState> p_state, const String &p_base_p
 					p_state->source_images.push_back(Ref<Image>());
 				}
 			}
-			continue;
+#endif
 		} else if (GLTFState::GLTFHandleBinary(p_state->handle_binary_image) == GLTFState::GLTFHandleBinary::HANDLE_BINARY_EMBED_AS_BASISU) {
 			Ref<PortableCompressedTexture2D> tex;
 			tex.instantiate();
@@ -3271,11 +3302,15 @@ Error GLTFDocument::_parse_images(Ref<GLTFState> p_state, const String &p_base_p
 			tex->create_from_image(img, PortableCompressedTexture2D::COMPRESSION_MODE_BASIS_UNIVERSAL);
 			p_state->images.push_back(tex);
 			p_state->source_images.push_back(img);
-			continue;
+		} else {
+			// This handles two cases: if editor hint and HANDLE_BINARY_EXTRACT_TEXTURES; or if HANDLE_BINARY_EMBED_AS_UNCOMPRESSED
+			Ref<ImageTexture> tex;
+			tex.instantiate();
+			tex->set_name(img->get_name());
+			tex->set_image(img);
+			p_state->images.push_back(tex);
+			p_state->source_images.push_back(img);
 		}
-
-		p_state->images.push_back(Ref<Texture2D>());
-		p_state->source_images.push_back(Ref<Image>());
 	}
 
 	print_verbose("glTF: Total images: " + itos(p_state->images.size()));
diff --git a/modules/gltf/gltf_state.cpp b/modules/gltf/gltf_state.cpp
index b67484fc8e..b7b7113a97 100644
--- a/modules/gltf/gltf_state.cpp
+++ b/modules/gltf/gltf_state.cpp
@@ -120,11 +120,12 @@ void GLTFState::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::DICTIONARY, "skeleton_to_node", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_STORAGE | PROPERTY_USAGE_INTERNAL | PROPERTY_USAGE_EDITOR), "set_skeleton_to_node", "get_skeleton_to_node"); // RBMap<GLTFSkeletonIndex,
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "create_animations"), "set_create_animations", "get_create_animations"); // bool
 	ADD_PROPERTY(PropertyInfo(Variant::ARRAY, "animations", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_STORAGE | PROPERTY_USAGE_INTERNAL | PROPERTY_USAGE_EDITOR), "set_animations", "get_animations"); // Vector<Ref<GLTFAnimation>>
-	ADD_PROPERTY(PropertyInfo(Variant::INT, "handle_binary_image", PROPERTY_HINT_ENUM, "Discard All Textures,Extract Textures,Embed As Basis Universal", PROPERTY_USAGE_STORAGE | PROPERTY_USAGE_INTERNAL | PROPERTY_USAGE_EDITOR), "set_handle_binary_image", "get_handle_binary_image"); // enum
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "handle_binary_image", PROPERTY_HINT_ENUM, "Discard All Textures,Extract Textures,Embed As Basis Universal,Embed as Uncompressed", PROPERTY_USAGE_STORAGE | PROPERTY_USAGE_INTERNAL | PROPERTY_USAGE_EDITOR), "set_handle_binary_image", "get_handle_binary_image"); // enum
 
 	BIND_CONSTANT(HANDLE_BINARY_DISCARD_TEXTURES);
 	BIND_CONSTANT(HANDLE_BINARY_EXTRACT_TEXTURES);
 	BIND_CONSTANT(HANDLE_BINARY_EMBED_AS_BASISU);
+	BIND_CONSTANT(HANDLE_BINARY_EMBED_AS_UNCOMPRESSED);
 }
 
 void GLTFState::add_used_extension(const String &p_extension_name, bool p_required) {
diff --git a/modules/gltf/gltf_state.h b/modules/gltf/gltf_state.h
index 52d7949d03..b6979ca48e 100644
--- a/modules/gltf/gltf_state.h
+++ b/modules/gltf/gltf_state.h
@@ -108,6 +108,7 @@ public:
 		HANDLE_BINARY_DISCARD_TEXTURES = 0,
 		HANDLE_BINARY_EXTRACT_TEXTURES,
 		HANDLE_BINARY_EMBED_AS_BASISU,
+		HANDLE_BINARY_EMBED_AS_UNCOMPRESSED, // if this value changes from 3, ResourceImporterScene::pre_import must be changed as well.
 	};
 	int32_t get_handle_binary_image() {
 		return handle_binary_image;