Explicitly set OpenGL profile to core (X11, Windows).

Enable GLES2 on Windows.

platform/windows/context_gl_win.cpp

@@ -38,6 +38,8 @@
 #define WGL_CONTEXT_MINOR_VERSION_ARB 0x2092
 #define WGL_CONTEXT_FLAGS_ARB 0x2094
 #define WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB 0x00000002
+#define WGL_CONTEXT_PROFILE_MASK_ARB 0x9126
+#define WGL_CONTEXT_CORE_PROFILE_BIT_ARB 0x00000001
 
 typedef HGLRC(APIENTRY *PFNWGLCREATECONTEXTATTRIBSARBPROC)(HDC, HGLRC, const int *);
 
@@ -153,6 +155,7 @@ Error ContextGL_Win::initialize() {
 			WGL_CONTEXT_MAJOR_VERSION_ARB, 3, //we want a 3.3 context
 			WGL_CONTEXT_MINOR_VERSION_ARB, 3,
 			//and it shall be forward compatible so that we can only use up to date functionality
+			WGL_CONTEXT_PROFILE_MASK_ARB, WGL_CONTEXT_CORE_PROFILE_BIT_ARB,
 			WGL_CONTEXT_FLAGS_ARB, WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB /*| _WGL_CONTEXT_DEBUG_BIT_ARB*/,
 			0
 		}; //zero indicates the end of the array

platform/windows/os_windows.cpp

@@ -30,6 +30,7 @@
 
 #include "os_windows.h"
 
+#include "drivers/gles2/rasterizer_gles2.h"
 #include "drivers/gles3/rasterizer_gles3.h"
 #include "drivers/windows/dir_access_windows.h"
 #include "drivers/windows/file_access_windows.h"
@@ -1069,12 +1070,19 @@ Error OS_Windows::initialize(const VideoMode &p_desired, int p_video_driver, int
 	}
 
 #if defined(OPENGL_ENABLED)
-	gl_context = memnew(ContextGL_Win(hWnd, true));
-	gl_context->initialize();
+	if (p_video_driver == VIDEO_DRIVER_GLES2) {
+		gl_context = memnew(ContextGL_Win(hWnd, false));
+		gl_context->initialize();
 
-	RasterizerGLES3::register_config();
+		RasterizerGLES2::register_config();
+		RasterizerGLES2::make_current();
+	} else {
+		gl_context = memnew(ContextGL_Win(hWnd, true));
+		gl_context->initialize();
 
-	RasterizerGLES3::make_current();
+		RasterizerGLES3::register_config();
+		RasterizerGLES3::make_current();
+	}
 
 	gl_context->set_use_vsync(video_mode.use_vsync);
 #endif

platform/x11/context_gl_x11.cpp

@@ -170,6 +170,7 @@ Error ContextGL_X11::initialize() {
 			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
 			};