WIP: wayland: add basic support for non-RGBA textureswip/nielsdg/add-yuv-support-gnome-3-32

Up until now, we didn't support sending YUV textures to the Wayland
server. This was for several reasons:

* We draw onto an RGBA framebuffer, so any other color format needs to
be converted to that color space. Since we don't want to lose a lot of
performance, this is ideally done on the GPU (using shaders).
* YUV formats can consist of several planes (for example NV12, a common
format in decoded video frames consists of a Y-plane and a subsampled
UV-plane). Mutter always assumed that any texture it got was
representable by a `CoglTexture`, which does not have this kind of
concept.

To deal with this, we introduce a new "texture": a
`CoglMultiPlaneTexture` which consists of multiple CoglTextures, each
representing a plane in the texture we got. It also provides support
for CoglSnippets which can convert the colorspace if necessary.

What changes are in this commit:
* Introduce a new CoglMultiPlaneTexture object. Right now it is not
implemented as a CoglTexture to prevent any confusion (but it is
somewhat related to CoglMetaTexture)
* Added some extra values to the CoglPixelFormat enum that deal with YUV
* Make the necessary changes in MetaWaylandBuffer, so that it knows how
to deal with incoming buffers (for example EGLImages and shm buffers)
* This also introduces some changes in MetaDmaBuf, as that is also a
different kind of buffer we can receive from wayland.

Acknowledgements
* There was a lot of prior art already done by the authors of Weston,
CoglGstVideoSink and ClutterGstSink
* My employer Barco for allowing me to work on this

1 files changed, 4 insertions, 0 deletions

diff --git a/cogl/cogl/driver/gl/cogl-texture-2d-gl.c b/cogl/cogl/driver/gl/cogl-texture-2d-gl.c
index e36c3523e..cc23f1161 100644
--- a/cogl/cogl/driver/gl/cogl-texture-2d-gl.c
+++ b/cogl/cogl/driver/gl/cogl-texture-2d-gl.c
@@ -209,6 +209,8 @@ allocate_from_bitmap (CoglTexture2D *tex_2d,
   GLenum gl_format;
   GLenum gl_type;
 
+  g_warning ("allocate_from_bitmap()");
+
   internal_format =
     _cogl_texture_determine_internal_format (tex, cogl_bitmap_get_format (bmp));
 
@@ -349,6 +351,8 @@ allocate_from_gl_foreign (CoglTexture2D *tex_2d,
   GLint gl_compressed = GL_FALSE;
   GLenum gl_int_format = 0;
 
+  g_warning ("allocate_from_egl_image_foreign()");
+
   if (!ctx->texture_driver->allows_foreign_gl_target (ctx, GL_TEXTURE_2D))
     {
       _cogl_set_error (error,