[mutter] shaped-texture: Draw external textures via offscreen

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 012691bebf31affc98288aa1490e0abc15efcb92
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Dec 20 17:37:48 2018 +0100

    shaped-texture: Draw external textures via offscreen
    
    EGLStream textures are imported as GL_TEXTURE_EXTERNAL_OES and reading
    pixels directly from them is not supported. To make it possible to get
    pixels, create an offscreen framebuffer and paint the actor to it, then
    read pixels from the framebuffer instead of the texture directly.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/362

 src/compositor/meta-shaped-texture.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/src/compositor/meta-shaped-texture.c b/src/compositor/meta-shaped-texture.c
index 955375995..bf204bc5b 100644
--- a/src/compositor/meta-shaped-texture.c
+++ b/src/compositor/meta-shaped-texture.c
@@ -1042,6 +1042,9 @@ meta_shaped_texture_set_transform (MetaShapedTexture    *stex,
 static gboolean
 should_get_via_offscreen (MetaShapedTexture *stex)
 {
+  if (!cogl_texture_is_get_data_supported (stex->texture))
+    return TRUE;
+
   switch (stex->transform)
     {
     case META_MONITOR_TRANSFORM_90: