Disable driver fallback to GLES2 by default

GLES2 is not designed to be a drop-in replacement for the GLES3 backend,
so the fallback mode has to be used knowingly. It *can* make sense for
simple projects which make sure to handle the differences between both
rendering backends, but most users should stick to one supported backend.

By making it opt-in, we can now use this parameter to define whether to
export ETC textures to Android and iOS when using GLES3 + Fallback.

When using GLES3 without Fallback on Android, set the proper min GLES
version in the AndroidManifest.

Also made the option boolean and renamed it for clarity and to avoid
conflict with the previous String option (which would always evaluate as
"true" otherwise).

Fixes #26569.

9 files changed, 23 insertions, 10 deletions

diff --git a/platform/android/export/export.cpp b/platform/android/export/export.cpp
index 8ffd355219..aab4bc3883 100644
--- a/platform/android/export/export.cpp
+++ b/platform/android/export/export.cpp
@@ -658,6 +658,8 @@ class EditorExportPlatformAndroid : public EditorExportPlatform {
 
 		int orientation = p_preset->get("screen/orientation");
 
+		bool min_gles3 = ProjectSettings::get_singleton()->get("rendering/quality/driver/driver_name") == "GLES3" &&
+						 !ProjectSettings::get_singleton()->get("rendering/quality/driver/fallback_to_gles2");
 		bool screen_support_small = p_preset->get("screen/support_small");
 		bool screen_support_normal = p_preset->get("screen/support_normal");
 		bool screen_support_large = p_preset->get("screen/support_large");
@@ -815,6 +817,11 @@ class EditorExportPlatformAndroid : public EditorExportPlatform {
 							}
 						}
 
+						if (tname == "uses-feature" && attrname == "glEsVersion") {
+
+							encode_uint32(min_gles3 ? 0x00030000 : 0x00020000, &p_manifest.write[iofs + 16]);
+						}
+
 						iofs += 20;
 					}
 
@@ -1119,6 +1126,9 @@ public:
 			r_features->push_back("etc");
 		} else if (driver == "GLES3") {
 			r_features->push_back("etc2");
+			if (ProjectSettings::get_singleton()->get("rendering/quality/driver/fallback_to_gles2")) {
+				r_features->push_back("etc");
+			}
 		}
 
 		Vector<String> abis = get_enabled_abis(p_preset);
diff --git a/platform/android/os_android.cpp b/platform/android/os_android.cpp
index b86976843c..8c4531213f 100644
--- a/platform/android/os_android.cpp
+++ b/platform/android/os_android.cpp
@@ -131,7 +131,7 @@ Error OS_Android::initialize(const VideoMode &p_desired, int p_video_driver, int
 				RasterizerGLES3::make_current();
 				break;
 			} else {
-				if (GLOBAL_GET("rendering/quality/driver/driver_fallback") == "Best") {
+				if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2")) {
 					p_video_driver = VIDEO_DRIVER_GLES2;
 					use_gl3 = false;
 					continue;
diff --git a/platform/iphone/export/export.cpp b/platform/iphone/export/export.cpp
index 67034388b9..f25c8a4a22 100644
--- a/platform/iphone/export/export.cpp
+++ b/platform/iphone/export/export.cpp
@@ -201,6 +201,9 @@ void EditorExportPlatformIOS::get_preset_features(const Ref<EditorExportPreset>
 		r_features->push_back("etc");
 	} else if (driver == "GLES3") {
 		r_features->push_back("etc2");
+		if (ProjectSettings::get_singleton()->get("rendering/quality/driver/fallback_to_gles2")) {
+			r_features->push_back("etc");
+		}
 	}
 
 	Vector<String> architectures = _get_preset_architectures(p_preset);
diff --git a/platform/iphone/os_iphone.cpp b/platform/iphone/os_iphone.cpp
index b44b3127c7..7d0fdd2078 100644
--- a/platform/iphone/os_iphone.cpp
+++ b/platform/iphone/os_iphone.cpp
@@ -120,7 +120,7 @@ Error OSIPhone::initialize(const VideoMode &p_desired, int p_video_driver, int p
 				RasterizerGLES3::make_current();
 				break;
 			} else {
-				if (GLOBAL_GET("rendering/quality/driver/driver_fallback") == "Best") {
+				if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2")) {
 					p_video_driver = VIDEO_DRIVER_GLES2;
 					use_gl3 = false;
 					continue;
diff --git a/platform/javascript/os_javascript.cpp b/platform/javascript/os_javascript.cpp
index 57ae1b6e26..34781ce365 100644
--- a/platform/javascript/os_javascript.cpp
+++ b/platform/javascript/os_javascript.cpp
@@ -829,7 +829,7 @@ Error OS_JavaScript::initialize(const VideoMode &p_desired, int p_video_driver,
 				RasterizerGLES3::make_current();
 				break;
 			} else {
-				if (GLOBAL_GET("rendering/quality/driver/driver_fallback") == "Best") {
+				if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2")) {
 					p_video_driver = VIDEO_DRIVER_GLES2;
 					gles3 = false;
 					continue;
diff --git a/platform/osx/os_osx.mm b/platform/osx/os_osx.mm
index 027a4e76f6..d72e6038d4 100644
--- a/platform/osx/os_osx.mm
+++ b/platform/osx/os_osx.mm
@@ -1420,7 +1420,7 @@ Error OS_OSX::initialize(const VideoMode &p_desired, int p_video_driver, int p_a
 				RasterizerGLES3::make_current();
 				break;
 			} else {
-				if (GLOBAL_GET("rendering/quality/driver/driver_fallback") == "Best" || editor) {
+				if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2") || editor) {
 					p_video_driver = VIDEO_DRIVER_GLES2;
 					gles3 = false;
 					continue;
diff --git a/platform/uwp/os_uwp.cpp b/platform/uwp/os_uwp.cpp
index 637ef5aaef..bc74da8a1b 100644
--- a/platform/uwp/os_uwp.cpp
+++ b/platform/uwp/os_uwp.cpp
@@ -202,7 +202,7 @@ Error OS_UWP::initialize(const VideoMode &p_desired, int p_video_driver, int p_a
 			memdelete(gl_context);
 			gl_context = NULL;
 
-			if (GLOBAL_GET("rendering/quality/driver/driver_fallback") == "Best") {
+			if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2")) {
 				if (p_video_driver == VIDEO_DRIVER_GLES2) {
 					gl_initialization_error = true;
 					break;
@@ -224,7 +224,7 @@ Error OS_UWP::initialize(const VideoMode &p_desired, int p_video_driver, int p_a
 				RasterizerGLES3::make_current();
 				break;
 			} else {
-				if (GLOBAL_GET("rendering/quality/driver/driver_fallback") == "Best") {
+				if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2")) {
 					p_video_driver = VIDEO_DRIVER_GLES2;
 					opengl_api_type = ContextEGL_UWP::GLES_2_0;
 					continue;
diff --git a/platform/windows/os_windows.cpp b/platform/windows/os_windows.cpp
index 1a5e97cfb1..6125455e74 100644
--- a/platform/windows/os_windows.cpp
+++ b/platform/windows/os_windows.cpp
@@ -1290,7 +1290,7 @@ Error OS_Windows::initialize(const VideoMode &p_desired, int p_video_driver, int
 			memdelete(gl_context);
 			gl_context = NULL;
 
-			if (GLOBAL_GET("rendering/quality/driver/driver_fallback") == "Best" || editor) {
+			if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2") || editor) {
 				if (p_video_driver == VIDEO_DRIVER_GLES2) {
 					gl_initialization_error = true;
 					break;
@@ -1312,7 +1312,7 @@ Error OS_Windows::initialize(const VideoMode &p_desired, int p_video_driver, int
 				RasterizerGLES3::make_current();
 				break;
 			} else {
-				if (GLOBAL_GET("rendering/quality/driver/driver_fallback") == "Best" || editor) {
+				if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2") || editor) {
 					p_video_driver = VIDEO_DRIVER_GLES2;
 					gles3_context = false;
 					continue;
diff --git a/platform/x11/os_x11.cpp b/platform/x11/os_x11.cpp
index cc4d57ea99..87b63c0982 100644
--- a/platform/x11/os_x11.cpp
+++ b/platform/x11/os_x11.cpp
@@ -299,7 +299,7 @@ Error OS_X11::initialize(const VideoMode &p_desired, int p_video_driver, int p_a
 			memdelete(context_gl);
 			context_gl = NULL;
 
-			if (GLOBAL_GET("rendering/quality/driver/driver_fallback") == "Best" || editor) {
+			if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2") || editor) {
 				if (p_video_driver == VIDEO_DRIVER_GLES2) {
 					gl_initialization_error = true;
 					break;
@@ -321,7 +321,7 @@ Error OS_X11::initialize(const VideoMode &p_desired, int p_video_driver, int p_a
 				RasterizerGLES3::make_current();
 				break;
 			} else {
-				if (GLOBAL_GET("rendering/quality/driver/driver_fallback") == "Best" || editor) {
+				if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2") || editor) {
 					p_video_driver = VIDEO_DRIVER_GLES2;
 					opengl_api_type = ContextGL_X11::GLES_2_0_COMPATIBLE;
 					continue;