[mutter/wip/carlosg/away-with-swizzling: 1/2] Revert "Revert "cogl: Pick glReadPixels format by target, not source""

[Carlos Garnacho <carlosg src gnome org>]

commit d83a325f98c8a6fa346a924192e65cf7a3c87c81
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Mar 7 22:56:35 2019 +0100

    Revert "Revert "cogl: Pick glReadPixels format by target, not source""
    
    This reverts commit 4f72099023bc5bb142a782a1924797729329cc9a.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/486

 cogl/cogl/driver/gl/cogl-framebuffer-gl.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/cogl/cogl/driver/gl/cogl-framebuffer-gl.c b/cogl/cogl/driver/gl/cogl-framebuffer-gl.c
index 84c2f314a..c2bf92882 100644
--- a/cogl/cogl/driver/gl/cogl-framebuffer-gl.c
+++ b/cogl/cogl/driver/gl/cogl-framebuffer-gl.c
@@ -4,6 +4,7 @@
  * A Low Level GPU Graphics and Utilities API
  *
  * Copyright (C) 2007,2008,2009,2012 Intel Corporation.
+ * Copyright (C) 2018 DisplayLink (UK) Ltd.
  *
  * Permission is hereby granted, free of charge, to any person
  * obtaining a copy of this software and associated documentation
@@ -1273,9 +1274,12 @@ _cogl_framebuffer_gl_read_pixels_into_bitmap (CoglFramebuffer *framebuffer,
   if (!cogl_is_offscreen (framebuffer))
     y = framebuffer_height - y - height;
 
+  /* Use target format ANY, because GL texture_swizzle extension cannot
+   * ever apply for glReadPixels.
+   */
   required_format = ctx->driver_vtable->pixel_format_to_gl_with_target (ctx,
-                                                                        framebuffer->internal_format,
                                                                         format,
+                                                                        COGL_PIXEL_FORMAT_ANY,
                                                                         &gl_intformat,
                                                                         &gl_format,
                                                                         &gl_type);