Remove obsolete GLES3 backend

Due to the port to Vulkan and complete redesign of the rendering backend,
the `drivers/gles3` code is no longer usable in this state and is not
planned to be ported to the new architecture.

The GLES2 backend is kept (while still disabled and non-working) as it
will eventually be ported to serve as the low-end renderer for Godot 4.0.

Some GLES3 features might be selectively ported to the updated GLES2
backend if there's a need for them, and extensions we can use for that.

So long, OpenGL driver bugs!

1 files changed, 1 insertions, 3 deletions

diff --git a/main/main.cpp b/main/main.cpp
index 1b8b95c4c3..00ce8c6f7b 100644
--- a/main/main.cpp
+++ b/main/main.cpp
@@ -689,7 +689,7 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 			editor = true;
 #ifdef DEBUG_METHODS_ENABLED
 		} else if (I->get() == "--gdnative-generate-json-api") {
-			// Register as an editor instance to use the GLES2 fallback automatically on hardware that doesn't support the GLES3 backend
+			// Register as an editor instance to use low-end fallback if relevant.
 			editor = true;
 
 			// We still pass it to the main arguments since the argument handling itself is not done in this function
@@ -1000,8 +1000,6 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 		video_driver = GLOBAL_GET("rendering/quality/driver/driver_name");
 	}
 
-	GLOBAL_DEF("rendering/quality/driver/fallback_to_gles2", false);
-
 	// Assigning here even though it's GLES2-specific, to be sure that it appears in docs
 	GLOBAL_DEF("rendering/quality/2d/gles2_use_nvidia_rect_flicker_workaround", false);