Ensures that the layout transition happens at the right time, and
otherwise relaxes the barrier since it is assumed that the backend
will emit barriers with the appropriate as necessary.
While this doesn't support vertex stages yet, it should be faster
when the pipeline writes to storage resources from the fragment
shader.
We should analyze the vertex stage shaders for SSBO writes in
order to determine whether to spill the render pass.
Begins transform feedback when rendering with an xfb-enabled
pipeline bound, and ends transform feedback as needed, while
writing back the counters supplied by the app. This does not
yet support transform feedback queries or the draw command.
Apparently we need those to make sure that the initial layout
transition itself is valid. We don't need to add shader access
though, since we cannot access attachments inside shaders.
Fixes validation errors and some unnecessary cruft. We don't need
visibility operations in the external-to-renderpass dependency
because that part is handled by regular barriers, an execution
dependency is enough (but still required to handle write-after-read.
Spilling the render pass should make shader storage buffer/image writes
visible due to how external subpass dependencies are defined. For UAV
rendering, we need to do this when changing the UAVs, even if the render
targets themselves do not change.
Instead, the color format and layout will now be set in
the render pass description. This slows down render pass
lookups but may improve efficiency and work around driver
bugs.
Fixes a few bottlenecks that were encountered in the Cascading Shadow
Maps demo from the Microsoft SDK. Performance is now slightly better
than wined3d with CSMT, MESA_NO_ERROR and mesa_glthread enabled.
