XXX hack sleep(1) before exit

Work around a crash at exit of weston in pvr kernel driver..
XXX add flip time / fps logging
compositor: add support for OES_EGL_image_external

In cases where the GPU can natively handle certain YUV formats,
eglQueryWaylandBufferWL() can return the value EGL_TEXTURE_EXTERNAL_WL
and the compositor will treat the buffer as a single egl-image-external.

See:
http://www.khronos.org/registry/gles/extensions/OES/OES_EGL_image_external.txt

v1: original
v2: rename EGL_TEXTURE_EXTERNAL_OES -> EGL_TEXTURE_EXTERNAL_WL and query
    for the extension
v3: fix build without updated mesa headers, if EGL_TEXTURE_EXTERNAL_WL
    #define is missing from older mesa headers.

Signed-off-by: Rob Clark <rob@ti.com>
compositor: simplify shaders

Re-work how the shaders and emitted vertices work.  Rather than always
rendering clip-rect sized quads and doing transformation in tex coords
(and requiring the corresponding clipping in frag shader), instead
emit transformed vertices, clipped wrt. dirty region, and use simpler
frag shaders.  Also, split the rendering, so blended surfaces with an
opaque region have the opaque region drawn with blend disabled.  The
result is considerably fewer pixels drawn with blend enabled, and much
fewer cycles in the frag shader.

This requires having some more complex logic to figure out the vertices
of the shape which forms the intersection of the clip rect and the
transformed surface.  Which has perhaps got a few bugs or missing cases,
still (visual glitches in some cases) but at this point more or less is
starting to work.  I think it is at least far enough along to get some
initial review.

The result, on small SoC GPU (omap4/pandaboard) on 1920x1080 display,
for simple stuff like moving windows around, I get 60fps (before 30fps
or less), and pushing YUV buffers for hw decoded 1080p video goes from
~6fps to 30fps, with no drop in framerate for transformed/rotated video
surface.

v1: original
v2: check that perpendicular intersect vertex falls within bounds of
    transformed surface
v3: update w/ comments and fixes from Pekka Paalanen
v4: fix for full surface alpha from Pekka Paalanen, fix compositor-
    wayland build

Signed-off-by: Rob Clark <rob@ti.com>
compositor: specialised fragment shader for RGBX

Remove the weston_surface::blend attribute, which really meant that the
texture produced valid alpha values. This was used to override the opaque
region for RGBX surfaces, which produce undefined values for alpha.

Instead, compile a new shader especially for RGBX surfaces, that
hardcodes the sampled alpha as 1.0.

Before "compositor: optimize/simplify shaders" there was a 'vec4 opaque'
in the shaders, that would cause part of the texture to be forced to
alpha=1.0. Now that is gone, and we need this replacement.

To test: launch simple-shm, and use the super+alt+mousewheel combination
to make it transparent. It should not show a light cross over the window.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
compositor: fix blending for full-surface alpha

We can use and render the opaque region only, if we are not applying a
full-surface alpha.

Test case: weston-terminal; use super+alt+mousewheel to adjust the
window transparency. Before it went black, now it blends correctly.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
compositor debug: disable untransformed special case

The untransformed special case was hiding bugs in the other cases.

Probably shouldn't be permanently disabled but it is good for now
to be sure we debug all the transformed cases properly.
compositor: triangle fan debug

Draw the borders of all the triangles.

v1: original
v2: add keybinding to enable/disable fan debug (super-alt-space),
    cycle colors to make it easier to see individual draws, and
    redraw undamaged region to clean up previous frames debug
    lines

Signed-off-by: Rob Clark <rob@ti.com>