Basically, before drawing X-Rays, we now bind a second depth buffer.
After drawing XRays, we do an extra resolve pass where we overwrite the
non-XRay depth buffer in pixels where the depth is not maximum (which
means background pixel, since depth is cleared before drawing X-Ray
objects).
This ensures both scene and X-Rays keep their depth values and are ready
for compositing. Well, the odd effect due to depth discontinuities can be
expected, and X-Rays are a bit more expensive (extra buffer + resolve pass)
but at least X-Rays won't invalidate depth values anymore. Whee!
This commit introduces a few ready made effects for the 3D viewport
and OpenGL rendering.
Included effects are Depth of Field, accessible from camera view
and screen space ambient occlusion. Those effects can be turned on and
tweaked from the shading panel in the 3D viewport.
Off screen rendering will use the settings of the current camera.
WIP documentation can be found here:
http://wiki.blender.org/index.php/User:Psy-Fi/Framebuffer_Post-processing
