To keep performance, load gltf binary as compressed texture

Uses COMPRESSION_MODE_BASIS_UNIVERSAL.

modules/gltf/gltf_document.cpp

@@ -44,6 +44,7 @@
 #include "gltf_state.h"
 #include "gltf_texture.h"
 
+#include "core/config/project_settings.h"
 #include "core/crypto/crypto_core.h"
 #include "core/error/error_macros.h"
 #include "core/io/dir_access.h"
@@ -69,6 +70,7 @@
 #include "scene/resources/mesh.h"
 #include "scene/resources/multimesh.h"
 #include "scene/resources/surface_tool.h"
+#include "scene/resources/texture.h"
 
 #include "modules/modules_enabled.gen.h" // For csg, gridmap.
 
@@ -3131,6 +3133,7 @@ Error GLTFDocument::_parse_images(Ref<GLTFState> state, const String &p_base_pat
 				Ref<Texture2D> texture = ResourceLoader::load(uri);
 				if (texture.is_valid()) {
 					state->images.push_back(texture);
+					state->source_images.push_back(texture->get_image());
 					continue;
 				} else if (mimetype == "image/png" || mimetype == "image/jpeg") {
 					// Fallback to loading as byte array.
@@ -3202,11 +3205,11 @@ Error GLTFDocument::_parse_images(Ref<GLTFState> state, const String &p_base_pat
 			state->images.push_back(Ref<Texture2D>());
 			continue;
 		}
-
-		Ref<ImageTexture> t;
+		Ref<PortableCompressedTexture2D> t;
 		t.instantiate();
-		t->create_from_image(img);
-
+		state->source_images.push_back(img->duplicate());
+		img->generate_mipmaps();
+		t->create_from_image(img, PortableCompressedTexture2D::COMPRESSION_MODE_BASIS_UNIVERSAL);
 		state->images.push_back(t);
 	}
 
@@ -3266,13 +3269,22 @@ GLTFTextureIndex GLTFDocument::_set_texture(Ref<GLTFState> state, Ref<Texture2D>
 	return gltf_texture_i;
 }
 
-Ref<Texture2D> GLTFDocument::_get_texture(Ref<GLTFState> state, const GLTFTextureIndex p_texture) {
+Ref<Texture2D> GLTFDocument::_get_texture(Ref<GLTFState> state, const GLTFTextureIndex p_texture, bool p_is_normal) {
 	ERR_FAIL_INDEX_V(p_texture, state->textures.size(), Ref<Texture2D>());
 	const GLTFImageIndex image = state->textures[p_texture]->get_src_image();
 
 	ERR_FAIL_INDEX_V(image, state->images.size(), Ref<Texture2D>());
-
-	return state->images[image];
+	if (!p_is_normal) {
+		return state->images[image];
+	}
+	Ref<PortableCompressedTexture2D> portable_texture;
+	portable_texture.instantiate();
+	ERR_FAIL_INDEX_V(image, state->source_images.size(), Ref<Texture2D>());
+	Ref<Image> new_img = state->source_images[image];
+	ERR_FAIL_NULL_V(new_img, Ref<Texture2D>());
+	new_img->generate_mipmaps(true);
+	portable_texture->create_from_image(new_img, PortableCompressedTexture2D::COMPRESSION_MODE_BASIS_UNIVERSAL, true);
+	return portable_texture;
 }
 
 Error GLTFDocument::_serialize_materials(Ref<GLTFState> state) {
@@ -3654,7 +3666,7 @@ Error GLTFDocument::_parse_materials(Ref<GLTFState> state) {
 		if (d.has("normalTexture")) {
 			const Dictionary &bct = d["normalTexture"];
 			if (bct.has("index")) {
-				material->set_texture(BaseMaterial3D::TEXTURE_NORMAL, _get_texture(state, bct["index"]));
+				material->set_texture(BaseMaterial3D::TEXTURE_NORMAL, _get_texture(state, bct["index"], true));
 				material->set_feature(BaseMaterial3D::FEATURE_NORMAL_MAPPING, true);
 			}
 			if (bct.has("scale")) {

modules/gltf/gltf_document.h

@@ -187,7 +187,7 @@ class GLTFDocument : public Resource {
 			const String &p_name);
 	GLTFTextureIndex _set_texture(Ref<GLTFState> state, Ref<Texture2D> p_texture);
 	Ref<Texture2D> _get_texture(Ref<GLTFState> state,
-			const GLTFTextureIndex p_texture);
+			const GLTFTextureIndex p_texture, bool p_is_normal_texture = false);
 	Error _parse_json(const String &p_path, Ref<GLTFState> state);
 	Error _parse_glb(Ref<FileAccess> f, Ref<GLTFState> state);
 	void _compute_node_heights(Ref<GLTFState> state);

modules/gltf/gltf_state.h

@@ -76,7 +76,9 @@ class GLTFState : public Resource {
 	String scene_name;
 	Vector<int> root_nodes;
 	Vector<Ref<GLTFTexture>> textures;
+
 	Vector<Ref<Texture2D>> images;
+	Vector<Ref<Image>> source_images;
 
 	Vector<Ref<GLTFSkin>> skins;
 	Vector<Ref<GLTFCamera>> cameras;