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!

27 files changed, 68 insertions, 274 deletions

diff --git a/platform/android/export/export.cpp b/platform/android/export/export.cpp
index 7bbcb8cfa2..642b045f5b 100644
--- a/platform/android/export/export.cpp
+++ b/platform/android/export/export.cpp
@@ -683,8 +683,6 @@ 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");
@@ -839,11 +837,6 @@ class EditorExportPlatformAndroid : public EditorExportPlatform {
 							}
 						}
 
-						if (tname == "uses-feature" && attrname == "glEsVersion") {
-
-							encode_uint32(min_gles3 ? 0x00030000 : 0x00020000, &p_manifest.write[iofs + 16]);
-						}
-
 						// FIXME: `attr_value != 0xFFFFFFFF` below added as a stopgap measure for GH-32553,
 						// but the issue should be debugged further and properly addressed.
 						if (tname == "meta-data" && attrname == "name" && value == "xr_mode_metadata_name") {
@@ -1350,11 +1343,10 @@ public:
 		String driver = ProjectSettings::get_singleton()->get("rendering/quality/driver/driver_name");
 		if (driver == "GLES2") {
 			r_features->push_back("etc");
-		} else if (driver == "GLES3") {
+		}
+		// FIXME: Review what texture formats are used for Vulkan.
+		if (driver == "Vulkan") {
 			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/java/app/AndroidManifest.xml b/platform/android/java/app/AndroidManifest.xml
index 7e9ce70d80..4d2eb1ef65 100644
--- a/platform/android/java/app/AndroidManifest.xml
+++ b/platform/android/java/app/AndroidManifest.xml
@@ -15,7 +15,6 @@
         android:largeScreens="true"
         android:xlargeScreens="true" />
 
-    <!-- glEsVersion is modified by the exporter, changing this value here has no effect. -->
     <uses-feature
         android:glEsVersion="0x00020000"
         android:required="true" />
diff --git a/platform/android/java/lib/src/org/godotengine/godot/Godot.java b/platform/android/java/lib/src/org/godotengine/godot/Godot.java
index 2f6a93fbb1..021214b627 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/Godot.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/Godot.java
@@ -287,8 +287,6 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 	 */
 	@Keep
 	private void onVideoInit() {
-		boolean use_gl3 = getGLESVersionCode() >= 0x00030000;
-
 		final FrameLayout layout = new FrameLayout(this);
 		layout.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
 		setContentView(layout);
@@ -299,7 +297,7 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 		// ...add to FrameLayout
 		layout.addView(edittext);
 
-		mView = new GodotView(this, xrMode, use_gl3, use_32_bits, use_debug_opengl);
+		mView = new GodotView(this, xrMode, use_32_bits, use_debug_opengl);
 		layout.addView(mView, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
 		edittext.setView(mView);
 		io.setEdit(edittext);
diff --git a/platform/android/java/lib/src/org/godotengine/godot/GodotView.java b/platform/android/java/lib/src/org/godotengine/godot/GodotView.java
index f938583082..8d3c2ae319 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/GodotView.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/GodotView.java
@@ -73,9 +73,8 @@ public class GodotView extends GLSurfaceView {
 	private final GestureDetector detector;
 	private final GodotRenderer godotRenderer;
 
-	public GodotView(Godot activity, XRMode xrMode, boolean p_use_gl3, boolean p_use_32_bits, boolean p_use_debug_opengl) {
+	public GodotView(Godot activity, XRMode xrMode, boolean p_use_32_bits, boolean p_use_debug_opengl) {
 		super(activity);
-		GLUtils.use_gl3 = p_use_gl3;
 		GLUtils.use_32 = p_use_32_bits;
 		GLUtils.use_debug_opengl = p_use_debug_opengl;
 
diff --git a/platform/android/java/lib/src/org/godotengine/godot/utils/GLUtils.java b/platform/android/java/lib/src/org/godotengine/godot/utils/GLUtils.java
index bbf876ea1f..9d29551f89 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/utils/GLUtils.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/utils/GLUtils.java
@@ -44,7 +44,6 @@ public class GLUtils {
 
 	public static final boolean DEBUG = false;
 
-	public static boolean use_gl3 = false;
 	public static boolean use_32 = false;
 	public static boolean use_debug_opengl = false;
 
diff --git a/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularConfigChooser.java b/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularConfigChooser.java
index ce4defd7a7..8409e37f8f 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularConfigChooser.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularConfigChooser.java
@@ -45,6 +45,8 @@ public class RegularConfigChooser implements GLSurfaceView.EGLConfigChooser {
 
 	private int[] mValue = new int[1];
 
+	// FIXME: Add support for Vulkan.
+
 	/* This EGL config specification is used to specify 2.0 rendering.
 	 * We use a minimum size of 4 bits for red/green/blue, but will
 	 * perform actual matching in chooseConfig() below.
@@ -59,15 +61,6 @@ public class RegularConfigChooser implements GLSurfaceView.EGLConfigChooser {
 		EGL10.EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
 		EGL10.EGL_NONE
 	};
-	private static int[] s_configAttribs3 = {
-		EGL10.EGL_RED_SIZE, 4,
-		EGL10.EGL_GREEN_SIZE, 4,
-		EGL10.EGL_BLUE_SIZE, 4,
-		// EGL10.EGL_DEPTH_SIZE,     16,
-		//  EGL10.EGL_STENCIL_SIZE,   EGL10.EGL_DONT_CARE,
-		EGL10.EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT, //apparently there is no EGL_OPENGL_ES3_BIT
-		EGL10.EGL_NONE
-	};
 
 	public RegularConfigChooser(int r, int g, int b, int a, int depth, int stencil) {
 		mRedSize = r;
@@ -83,7 +76,7 @@ public class RegularConfigChooser implements GLSurfaceView.EGLConfigChooser {
 		/* Get the number of minimally matching EGL configurations
 		 */
 		int[] num_config = new int[1];
-		egl.eglChooseConfig(display, GLUtils.use_gl3 ? s_configAttribs3 : s_configAttribs2, null, 0, num_config);
+		egl.eglChooseConfig(display, s_configAttribs2, null, 0, num_config);
 
 		int numConfigs = num_config[0];
 
@@ -94,7 +87,7 @@ public class RegularConfigChooser implements GLSurfaceView.EGLConfigChooser {
 		/* Allocate then read the array of minimally matching EGL configs
 		 */
 		EGLConfig[] configs = new EGLConfig[numConfigs];
-		egl.eglChooseConfig(display, GLUtils.use_gl3 ? s_configAttribs3 : s_configAttribs2, configs, numConfigs, num_config);
+		egl.eglChooseConfig(display, s_configAttribs2, configs, numConfigs, num_config);
 
 		if (GLUtils.DEBUG) {
 			GLUtils.printConfigs(egl, display, configs);
diff --git a/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularContextFactory.java b/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularContextFactory.java
index 22bd4ced87..f2b4c95a2c 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularContextFactory.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularContextFactory.java
@@ -52,24 +52,17 @@ public class RegularContextFactory implements GLSurfaceView.EGLContextFactory {
 
 	public EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig eglConfig) {
 		String driver_name = GodotLib.getGlobal("rendering/quality/driver/driver_name");
-		if (GLUtils.use_gl3 && !driver_name.equals("GLES3")) {
-			GLUtils.use_gl3 = false;
-		}
-		if (GLUtils.use_gl3)
-			Log.w(TAG, "creating OpenGL ES 3.0 context :");
-		else
-			Log.w(TAG, "creating OpenGL ES 2.0 context :");
+		// FIXME: Add support for Vulkan.
+		Log.w(TAG, "creating OpenGL ES 2.0 context :");
 
 		GLUtils.checkEglError(TAG, "Before eglCreateContext", egl);
 		EGLContext context;
 		if (GLUtils.use_debug_opengl) {
 			int[] attrib_list2 = { EGL_CONTEXT_CLIENT_VERSION, 2, _EGL_CONTEXT_FLAGS_KHR, _EGL_CONTEXT_OPENGL_DEBUG_BIT_KHR, EGL10.EGL_NONE };
-			int[] attrib_list3 = { EGL_CONTEXT_CLIENT_VERSION, 3, _EGL_CONTEXT_FLAGS_KHR, _EGL_CONTEXT_OPENGL_DEBUG_BIT_KHR, EGL10.EGL_NONE };
-			context = egl.eglCreateContext(display, eglConfig, EGL10.EGL_NO_CONTEXT, GLUtils.use_gl3 ? attrib_list3 : attrib_list2);
+			context = egl.eglCreateContext(display, eglConfig, EGL10.EGL_NO_CONTEXT, attrib_list2);
 		} else {
 			int[] attrib_list2 = { EGL_CONTEXT_CLIENT_VERSION, 2, EGL10.EGL_NONE };
-			int[] attrib_list3 = { EGL_CONTEXT_CLIENT_VERSION, 3, EGL10.EGL_NONE };
-			context = egl.eglCreateContext(display, eglConfig, EGL10.EGL_NO_CONTEXT, GLUtils.use_gl3 ? attrib_list3 : attrib_list2);
+			context = egl.eglCreateContext(display, eglConfig, EGL10.EGL_NO_CONTEXT, attrib_list2);
 		}
 		GLUtils.checkEglError(TAG, "After eglCreateContext", egl);
 		return context;
diff --git a/platform/android/java_godot_wrapper.cpp b/platform/android/java_godot_wrapper.cpp
index 893b786c0b..9ac91b8ef6 100644
--- a/platform/android/java_godot_wrapper.cpp
+++ b/platform/android/java_godot_wrapper.cpp
@@ -99,13 +99,6 @@ jobject GodotJavaWrapper::get_class_loader() {
 	}
 }
 
-void GodotJavaWrapper::gfx_init(bool gl2) {
-	// beats me what this once did, there was no code,
-	// but we're getting false if our GLES3 driver is initialised
-	// and true for our GLES2 driver
-	// Maybe we're supposed to communicate this back or store it?
-}
-
 void GodotJavaWrapper::on_video_init(JNIEnv *p_env) {
 	if (_on_video_init)
 		if (p_env == NULL)
diff --git a/platform/android/java_godot_wrapper.h b/platform/android/java_godot_wrapper.h
index 655f5170bf..f378b1ea38 100644
--- a/platform/android/java_godot_wrapper.h
+++ b/platform/android/java_godot_wrapper.h
@@ -71,7 +71,6 @@ public:
 
 	jobject get_class_loader();
 
-	void gfx_init(bool gl2);
 	void on_video_init(JNIEnv *p_env = NULL);
 	void restart(JNIEnv *p_env = NULL);
 	void force_quit(JNIEnv *p_env = NULL);
diff --git a/platform/android/os_android.cpp b/platform/android/os_android.cpp
index e5d9bdc60c..e86e373630 100644
--- a/platform/android/os_android.cpp
+++ b/platform/android/os_android.cpp
@@ -33,7 +33,6 @@
 #include "core/io/file_access_buffered_fa.h"
 #include "core/project_settings.h"
 #include "drivers/gles2/rasterizer_gles2.h"
-#include "drivers/gles3/rasterizer_gles3.h"
 #include "drivers/unix/dir_access_unix.h"
 #include "drivers/unix/file_access_unix.h"
 #include "file_access_android.h"
@@ -67,8 +66,6 @@ int OS_Android::get_video_driver_count() const {
 const char *OS_Android::get_video_driver_name(int p_driver) const {
 
 	switch (p_driver) {
-		case VIDEO_DRIVER_GLES3:
-			return "GLES3";
 		case VIDEO_DRIVER_GLES2:
 			return "GLES2";
 	}
@@ -123,44 +120,21 @@ int OS_Android::get_current_video_driver() const {
 
 Error OS_Android::initialize(const VideoMode &p_desired, int p_video_driver, int p_audio_driver) {
 
-	bool use_gl3 = godot_java->get_gles_version_code() >= 0x00030000;
-	use_gl3 = use_gl3 && (GLOBAL_GET("rendering/quality/driver/driver_name") == "GLES3");
 	bool gl_initialization_error = false;
 
-	while (true) {
-		if (use_gl3) {
-			if (RasterizerGLES3::is_viable() == OK) {
-				godot_java->gfx_init(false);
-				RasterizerGLES3::register_config();
-				RasterizerGLES3::make_current();
-				break;
-			} else {
-				if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2")) {
-					p_video_driver = VIDEO_DRIVER_GLES2;
-					use_gl3 = false;
-					continue;
-				} else {
-					gl_initialization_error = true;
-					break;
-				}
-			}
-		} else {
-			if (RasterizerGLES2::is_viable() == OK) {
-				godot_java->gfx_init(true);
-				RasterizerGLES2::register_config();
-				RasterizerGLES2::make_current();
-				break;
-			} else {
-				gl_initialization_error = true;
-				break;
-			}
-		}
+	// FIXME: Add Vulkan support. Readd fallback code from Vulkan to GLES2?
+
+	if (RasterizerGLES2::is_viable() == OK) {
+		RasterizerGLES2::register_config();
+		RasterizerGLES2::make_current();
+	} else {
+		gl_initialization_error = true;
 	}
 
 	if (gl_initialization_error) {
 		OS::get_singleton()->alert("Your device does not support any of the supported OpenGL versions.\n"
 								   "Please try updating your Android version.",
-				"Unable to initialize Video driver");
+				"Unable to initialize video driver");
 		return ERR_UNAVAILABLE;
 	}
 
@@ -750,7 +724,6 @@ void OS_Android::vibrate_handheld(int p_duration_ms) {
 
 bool OS_Android::_check_internal_feature_support(const String &p_feature) {
 	if (p_feature == "mobile") {
-		//TODO support etc2 only if GLES3 driver is selected
 		return true;
 	}
 #if defined(__aarch64__)
diff --git a/platform/haiku/os_haiku.cpp b/platform/haiku/os_haiku.cpp
index 80ab9c6aa1..2e4bb2ff26 100644
--- a/platform/haiku/os_haiku.cpp
+++ b/platform/haiku/os_haiku.cpp
@@ -28,10 +28,9 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-#include "drivers/gles3/rasterizer_gles3.h"
-
 #include "os_haiku.h"
 
+#include "drivers/gles2/rasterizer_gles2.h"
 #include "main/main.h"
 #include "servers/physics/physics_server_sw.h"
 #include "servers/visual/visual_server_raster.h"
@@ -78,7 +77,7 @@ int OS_Haiku::get_video_driver_count() const {
 }
 
 const char *OS_Haiku::get_video_driver_name(int p_driver) const {
-	return "GLES3";
+	return "GLES2";
 }
 
 int OS_Haiku::get_current_video_driver() const {
@@ -112,9 +111,9 @@ Error OS_Haiku::initialize(const VideoMode &p_desired, int p_video_driver, int p
 	context_gl->initialize();
 	context_gl->make_current();
 	context_gl->set_use_vsync(current_video_mode.use_vsync);
-	RasterizerGLES3::register_config();
-	RasterizerGLES3::make_current();
-
+	// FIXME: That's not how the rasterizer setup should happen.
+	RasterizerGLES2::register_config();
+	RasterizerGLES2::make_current();
 #endif
 
 	visual_server = memnew(VisualServerRaster);
diff --git a/platform/haiku/platform_config.h b/platform/haiku/platform_config.h
index 2df3c05f36..f2d5418adf 100644
--- a/platform/haiku/platform_config.h
+++ b/platform/haiku/platform_config.h
@@ -33,5 +33,4 @@
 // for ifaddrs.h needed in drivers/unix/ip_unix.cpp
 #define _BSD_SOURCE 1
 
-#define GLES3_INCLUDE_H "thirdparty/glad/glad/glad.h"
 #define GLES2_INCLUDE_H "thirdparty/glad/glad/glad.h"
diff --git a/platform/iphone/export/export.cpp b/platform/iphone/export/export.cpp
index f9276c16b5..0767ce7638 100644
--- a/platform/iphone/export/export.cpp
+++ b/platform/iphone/export/export.cpp
@@ -167,11 +167,9 @@ void EditorExportPlatformIOS::get_preset_features(const Ref<EditorExportPreset>
 	String driver = ProjectSettings::get_singleton()->get("rendering/quality/driver/driver_name");
 	if (driver == "GLES2") {
 		r_features->push_back("etc");
-	} else if (driver == "GLES3") {
+	} else if (driver == "Vulkan") {
+		// FIXME: Review if this is correct.
 		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/gl_view.mm b/platform/iphone/gl_view.mm
index e8d737d9c3..ede60a502d 100644
--- a/platform/iphone/gl_view.mm
+++ b/platform/iphone/gl_view.mm
@@ -47,7 +47,6 @@
 @end
 */
 
-bool gles3_available = true;
 int gl_view_base_fb;
 static String keyboard_text;
 static GLView *_instance = NULL;
@@ -284,20 +283,11 @@ static void clear_touches() {
 			kEAGLColorFormatRGBA8,
 			kEAGLDrawablePropertyColorFormat,
 			nil];
-	bool fallback_gl2 = false;
-	// Create a GL ES 3 context based on the gl driver from project settings
-	if (GLOBAL_GET("rendering/quality/driver/driver_name") == "GLES3") {
-		context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES3];
-		NSLog(@"Setting up an OpenGL ES 3.0 context. Based on Project Settings \"rendering/quality/driver/driver_name\"");
-		if (!context && GLOBAL_GET("rendering/quality/driver/fallback_to_gles2")) {
-			gles3_available = false;
-			fallback_gl2 = true;
-			NSLog(@"Failed to create OpenGL ES 3.0 context. Falling back to OpenGL ES 2.0");
-		}
-	}
+
+	// FIXME: Add Vulkan support via MoltenVK. Add fallback code back?
 
 	// Create GL ES 2 context
-	if (GLOBAL_GET("rendering/quality/driver/driver_name") == "GLES2" || fallback_gl2) {
+	if (GLOBAL_GET("rendering/quality/driver/driver_name") == "GLES2") {
 		context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
 		NSLog(@"Setting up an OpenGL ES 2.0 context.");
 		if (!context) {
diff --git a/platform/iphone/os_iphone.cpp b/platform/iphone/os_iphone.cpp
index 7a699f9b50..634062f46b 100644
--- a/platform/iphone/os_iphone.cpp
+++ b/platform/iphone/os_iphone.cpp
@@ -33,7 +33,6 @@
 #include "os_iphone.h"
 
 #include "drivers/gles2/rasterizer_gles2.h"
-#include "drivers/gles3/rasterizer_gles3.h"
 #include "servers/visual/visual_server_raster.h"
 #include "servers/visual/visual_server_wrap_mt.h"
 
@@ -57,8 +56,6 @@ int OSIPhone::get_video_driver_count() const {
 const char *OSIPhone::get_video_driver_name(int p_driver) const {
 
 	switch (p_driver) {
-		case VIDEO_DRIVER_GLES3:
-			return "GLES3";
 		case VIDEO_DRIVER_GLES2:
 			return "GLES2";
 	}
@@ -103,44 +100,22 @@ int OSIPhone::get_current_video_driver() const {
 	return video_driver_index;
 }
 
-extern bool gles3_available; // from gl_view.mm
-
 Error OSIPhone::initialize(const VideoMode &p_desired, int p_video_driver, int p_audio_driver) {
 
-	bool use_gl3 = GLOBAL_GET("rendering/quality/driver/driver_name") == "GLES3";
 	bool gl_initialization_error = false;
 
-	while (true) {
-		if (use_gl3) {
-			if (RasterizerGLES3::is_viable() == OK && gles3_available) {
-				RasterizerGLES3::register_config();
-				RasterizerGLES3::make_current();
-				break;
-			} else {
-				if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2")) {
-					p_video_driver = VIDEO_DRIVER_GLES2;
-					use_gl3 = false;
-					continue;
-				} else {
-					gl_initialization_error = true;
-					break;
-				}
-			}
-		} else {
-			if (RasterizerGLES2::is_viable() == OK) {
-				RasterizerGLES2::register_config();
-				RasterizerGLES2::make_current();
-				break;
-			} else {
-				gl_initialization_error = true;
-				break;
-			}
-		}
+	// FIXME: Add Vulkan support via MoltenVK. Add fallback code back?
+
+	if (RasterizerGLES2::is_viable() == OK) {
+		RasterizerGLES2::register_config();
+		RasterizerGLES2::make_current();
+	} else {
+		gl_initialization_error = true;
 	}
 
 	if (gl_initialization_error) {
 		OS::get_singleton()->alert("Your device does not support any of the supported OpenGL versions.",
-				"Unable to initialize Video driver");
+				"Unable to initialize video driver");
 		return ERR_UNAVAILABLE;
 	}
 
@@ -155,10 +130,7 @@ Error OSIPhone::initialize(const VideoMode &p_desired, int p_video_driver, int p
 	//visual_server->cursor_set_visible(false, 0);
 
 	// reset this to what it should be, it will have been set to 0 after visual_server->init() is called
-	if (use_gl3)
-		RasterizerStorageGLES3::system_fbo = gl_view_base_fb;
-	else
-		RasterizerStorageGLES2::system_fbo = gl_view_base_fb;
+	RasterizerStorageGLES2::system_fbo = gl_view_base_fb;
 
 	AudioDriverManager::initialize(p_audio_driver);
 
@@ -467,7 +439,7 @@ bool OSIPhone::can_draw() const {
 int OSIPhone::set_base_framebuffer(int p_fb) {
 
 	// gl_view_base_fb has not been updated yet
-	RasterizerStorageGLES3::system_fbo = p_fb;
+	RasterizerStorageGLES2::system_fbo = p_fb;
 
 	return 0;
 };
diff --git a/platform/iphone/platform_config.h b/platform/iphone/platform_config.h
index d39c64eed6..bc190ba956 100644
--- a/platform/iphone/platform_config.h
+++ b/platform/iphone/platform_config.h
@@ -31,7 +31,6 @@
 #include <alloca.h>
 
 #define GLES2_INCLUDE_H <ES2/gl.h>
-#define GLES3_INCLUDE_H <ES3/gl.h>
 
 #define PLATFORM_REFCOUNT
 
diff --git a/platform/javascript/export/export.cpp b/platform/javascript/export/export.cpp
index 6e1f7d749b..c44a0270ab 100644
--- a/platform/javascript/export/export.cpp
+++ b/platform/javascript/export/export.cpp
@@ -271,11 +271,9 @@ void EditorExportPlatformJavaScript::get_preset_features(const Ref<EditorExportP
 		String driver = ProjectSettings::get_singleton()->get("rendering/quality/driver/driver_name");
 		if (driver == "GLES2") {
 			r_features->push_back("etc");
-		} else if (driver == "GLES3") {
+		} else if (driver == "Vulkan") {
+			// FIXME: Review if this is correct.
 			r_features->push_back("etc2");
-			if (ProjectSettings::get_singleton()->get("rendering/quality/driver/fallback_to_gles2")) {
-				r_features->push_back("etc");
-			}
 		}
 	}
 }
diff --git a/platform/javascript/os_javascript.cpp b/platform/javascript/os_javascript.cpp
index f657ef483e..d22e53e7ea 100644
--- a/platform/javascript/os_javascript.cpp
+++ b/platform/javascript/os_javascript.cpp
@@ -32,7 +32,6 @@
 
 #include "core/io/file_access_buffered_fa.h"
 #include "drivers/gles2/rasterizer_gles2.h"
-#include "drivers/gles3/rasterizer_gles3.h"
 #include "drivers/unix/dir_access_unix.h"
 #include "drivers/unix/file_access_unix.h"
 #include "main/main.h"
@@ -825,8 +824,6 @@ int OS_JavaScript::get_video_driver_count() const {
 const char *OS_JavaScript::get_video_driver_name(int p_driver) const {
 
 	switch (p_driver) {
-		case VIDEO_DRIVER_GLES3:
-			return "GLES3";
 		case VIDEO_DRIVER_GLES2:
 			return "GLES2";
 	}
@@ -908,41 +905,14 @@ Error OS_JavaScript::initialize(const VideoMode &p_desired, int p_video_driver,
 		set_window_per_pixel_transparency_enabled(true);
 	}
 
-	bool gles3 = true;
-	if (p_video_driver == VIDEO_DRIVER_GLES2) {
-		gles3 = false;
-	}
-
 	bool gl_initialization_error = false;
 
-	while (true) {
-		if (gles3) {
-			if (RasterizerGLES3::is_viable() == OK) {
-				attributes.majorVersion = 2;
-				RasterizerGLES3::register_config();
-				RasterizerGLES3::make_current();
-				break;
-			} else {
-				if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2")) {
-					p_video_driver = VIDEO_DRIVER_GLES2;
-					gles3 = false;
-					continue;
-				} else {
-					gl_initialization_error = true;
-					break;
-				}
-			}
-		} else {
-			if (RasterizerGLES2::is_viable() == OK) {
-				attributes.majorVersion = 1;
-				RasterizerGLES2::register_config();
-				RasterizerGLES2::make_current();
-				break;
-			} else {
-				gl_initialization_error = true;
-				break;
-			}
-		}
+	if (RasterizerGLES2::is_viable() == OK) {
+		attributes.majorVersion = 1;
+		RasterizerGLES2::register_config();
+		RasterizerGLES2::make_current();
+	} else {
+		gl_initialization_error = true;
 	}
 
 	EMSCRIPTEN_WEBGL_CONTEXT_HANDLE ctx = emscripten_webgl_create_context(GODOT_CANVAS_SELECTOR, &attributes);
@@ -951,9 +921,8 @@ Error OS_JavaScript::initialize(const VideoMode &p_desired, int p_video_driver,
 	}
 
 	if (gl_initialization_error) {
-		OS::get_singleton()->alert("Your browser does not support any of the supported WebGL versions.\n"
-								   "Please update your browser version.",
-				"Unable to initialize Video driver");
+		OS::get_singleton()->alert("Your browser does not seem to support WebGL. Please update your browser version.",
+				"Unable to initialize video driver");
 		return ERR_UNAVAILABLE;
 	}
 
diff --git a/platform/osx/os_osx.h b/platform/osx/os_osx.h
index 00fc56def6..bfd13be43a 100644
--- a/platform/osx/os_osx.h
+++ b/platform/osx/os_osx.h
@@ -78,8 +78,6 @@ public:
 	int key_event_pos;
 
 	bool force_quit;
-	//  rasterizer seems to no longer be given to visual server, its using GLES3 directly?
-	//Rasterizer *rasterizer;
 	VisualServer *visual_server;
 
 	List<String> args;
diff --git a/platform/osx/platform_config.h b/platform/osx/platform_config.h
index 046512ae84..155f37ed55 100644
--- a/platform/osx/platform_config.h
+++ b/platform/osx/platform_config.h
@@ -30,6 +30,5 @@
 
 #include <alloca.h>
 
-#define GLES3_INCLUDE_H "thirdparty/glad/glad/glad.h"
 #define GLES2_INCLUDE_H "thirdparty/glad/glad/glad.h"
 #define PTHREAD_RENAME_SELF
diff --git a/platform/uwp/app.h b/platform/uwp/app.h
index 302d9759b3..b7265ad086 100644
--- a/platform/uwp/app.h
+++ b/platform/uwp/app.h
@@ -34,7 +34,6 @@
 
 #include <wrl.h>
 
-// ANGLE doesn't provide a specific lib for GLES3, so we keep using GLES2
 #include "GLES2/gl2.h"
 #include "os_uwp.h"
 
diff --git a/platform/uwp/context_egl_uwp.h b/platform/uwp/context_egl_uwp.h
index 7a41685867..fa61cf50c6 100644
--- a/platform/uwp/context_egl_uwp.h
+++ b/platform/uwp/context_egl_uwp.h
@@ -45,7 +45,7 @@ class ContextEGL_UWP {
 public:
 	enum Driver {
 		GLES_2_0,
-		GLES_3_0,
+		VULKAN, // FIXME: Add Vulkan support.
 	};
 
 private:
diff --git a/platform/uwp/os_uwp.cpp b/platform/uwp/os_uwp.cpp
index d5047b53ab..9748c1ef9f 100644
--- a/platform/uwp/os_uwp.cpp
+++ b/platform/uwp/os_uwp.cpp
@@ -36,7 +36,6 @@
 #include "core/io/marshalls.h"
 #include "core/project_settings.h"
 #include "drivers/gles2/rasterizer_gles2.h"
-#include "drivers/gles3/rasterizer_gles3.h"
 #include "drivers/unix/ip_unix.h"
 #include "drivers/windows/dir_access_windows.h"
 #include "drivers/windows/file_access_windows.h"
@@ -186,71 +185,33 @@ Error OS_UWP::initialize(const VideoMode &p_desired, int p_video_driver, int p_a
 	main_loop = NULL;
 	outside = true;
 
+	// FIXME: Hardcoded for now, add Vulkan support.
+	p_video_driver = VIDEO_DRIVER_GLES2;
 	ContextEGL_UWP::Driver opengl_api_type = ContextEGL_UWP::GLES_2_0;
 
-	if (p_video_driver == VIDEO_DRIVER_GLES2) {
-		opengl_api_type = ContextEGL_UWP::GLES_2_0;
-	}
-
 	bool gl_initialization_error = false;
 
-	gl_context = NULL;
-	while (!gl_context) {
-		gl_context = memnew(ContextEGL_UWP(window, opengl_api_type));
-
-		if (gl_context->initialize() != OK) {
-			memdelete(gl_context);
-			gl_context = NULL;
-
-			if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2")) {
-				if (p_video_driver == VIDEO_DRIVER_GLES2) {
-					gl_initialization_error = true;
-					break;
-				}
-
-				p_video_driver = VIDEO_DRIVER_GLES2;
-				opengl_api_type = ContextEGL_UWP::GLES_2_0;
-			} else {
-				gl_initialization_error = true;
-				break;
-			}
-		}
-	}
+	gl_context = memnew(ContextEGL_UWP(window, opengl_api_type));
 
-	while (true) {
-		if (opengl_api_type == ContextEGL_UWP::GLES_3_0) {
-			if (RasterizerGLES3::is_viable() == OK) {
-				RasterizerGLES3::register_config();
-				RasterizerGLES3::make_current();
-				break;
-			} else {
-				if (GLOBAL_GET("rendering/quality/driver/fallback_to_gles2")) {
-					p_video_driver = VIDEO_DRIVER_GLES2;
-					opengl_api_type = ContextEGL_UWP::GLES_2_0;
-					continue;
-				} else {
-					gl_initialization_error = true;
-					break;
-				}
-			}
-		}
+	if (gl_context->initialize() != OK) {
+		memdelete(gl_context);
+		gl_context = NULL;
+		gl_initialization_error = true;
+	}
 
-		if (opengl_api_type == ContextEGL_UWP::GLES_2_0) {
-			if (RasterizerGLES2::is_viable() == OK) {
-				RasterizerGLES2::register_config();
-				RasterizerGLES2::make_current();
-				break;
-			} else {
-				gl_initialization_error = true;
-				break;
-			}
+	if (opengl_api_type == ContextEGL_UWP::GLES_2_0) {
+		if (RasterizerGLES2::is_viable() == OK) {
+			RasterizerGLES2::register_config();
+			RasterizerGLES2::make_current();
+		} else {
+			gl_initialization_error = true;
 		}
 	}
 
 	if (gl_initialization_error) {
 		OS::get_singleton()->alert("Your video card driver does not support any of the supported OpenGL versions.\n"
 								   "Please update your drivers or if you have a very old or integrated GPU upgrade it.",
-				"Unable to initialize Video driver");
+				"Unable to initialize video driver");
 		return ERR_UNAVAILABLE;
 	}
 
diff --git a/platform/windows/platform_config.h b/platform/windows/platform_config.h
index 04653ee56c..290decac5f 100644
--- a/platform/windows/platform_config.h
+++ b/platform/windows/platform_config.h
@@ -29,8 +29,5 @@
 /*************************************************************************/
 
 #include <malloc.h>
-//#else
-//#include <alloca.h>
-//#endif
-#define GLES3_INCLUDE_H "thirdparty/glad/glad/glad.h"
+
 #define GLES2_INCLUDE_H "thirdparty/glad/glad/glad.h"
diff --git a/platform/x11/context_gl_x11.cpp b/platform/x11/context_gl_x11.cpp
index 3b88af28e4..5442af3bef 100644
--- a/platform/x11/context_gl_x11.cpp
+++ b/platform/x11/context_gl_x11.cpp
@@ -166,29 +166,11 @@ Error ContextGL_X11::initialize() {
 	int (*oldHandler)(Display *, XErrorEvent *) = XSetErrorHandler(&ctxErrorHandler);
 
 	switch (context_type) {
-		case OLDSTYLE: {
-
-			p->glx_context = glXCreateContext(x11_display, vi, 0, GL_TRUE);
-			ERR_FAIL_COND_V(!p->glx_context, ERR_UNCONFIGURED);
-		} break;
 		case GLES_2_0_COMPATIBLE: {
 
 			p->glx_context = glXCreateNewContext(x11_display, fbconfig, GLX_RGBA_TYPE, 0, true);
 			ERR_FAIL_COND_V(!p->glx_context, ERR_UNCONFIGURED);
 		} break;
-		case GLES_3_0_COMPATIBLE: {
-
-			static int context_attribs[] = {
-				GLX_CONTEXT_MAJOR_VERSION_ARB, 3,
-				GLX_CONTEXT_MINOR_VERSION_ARB, 3,
-				GLX_CONTEXT_PROFILE_MASK_ARB, GLX_CONTEXT_CORE_PROFILE_BIT_ARB,
-				GLX_CONTEXT_FLAGS_ARB, GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB /*|GLX_CONTEXT_DEBUG_BIT_ARB*/,
-				None
-			};
-
-			p->glx_context = glXCreateContextAttribsARB(x11_display, fbconfig, NULL, true, context_attribs);
-			ERR_FAIL_COND_V(ctxErrorOccurred || !p->glx_context, ERR_UNCONFIGURED);
-		} break;
 	}
 
 	swa.colormap = XCreateColormap(x11_display, RootWindow(x11_display, vi->screen), vi->visual, AllocNone);
diff --git a/platform/x11/context_gl_x11.h b/platform/x11/context_gl_x11.h
index 5e5ccc5c86..2c0643c95a 100644
--- a/platform/x11/context_gl_x11.h
+++ b/platform/x11/context_gl_x11.h
@@ -45,15 +45,12 @@ class ContextGL_X11 {
 
 public:
 	enum ContextType {
-		OLDSTYLE,
 		GLES_2_0_COMPATIBLE,
-		GLES_3_0_COMPATIBLE
 	};
 
 private:
 	ContextGL_X11_Private *p;
 	OS::VideoMode default_video_mode;
-	//::Colormap x11_colormap;
 	::Display *x11_display;
 	::Window &x11_window;
 	bool double_buffer;
diff --git a/platform/x11/platform_config.h b/platform/x11/platform_config.h
index c905ddb236..ac30519132 100644
--- a/platform/x11/platform_config.h
+++ b/platform/x11/platform_config.h
@@ -36,5 +36,4 @@
 #define PTHREAD_BSD_SET_NAME
 #endif
 
-#define GLES3_INCLUDE_H "thirdparty/glad/glad/glad.h"
 #define GLES2_INCLUDE_H "thirdparty/glad/glad/glad.h"