[Mesa-dev] [PATCH 0/3] gl_SampleMaskIn[] support

[Chris Forbes]

This adds another tiny piece of ARB_gpu_shader5.

>From the ARB_gpu_shader5 specification:

The variable gl_SampleMaskIn is an array of integers, each holding a
bitfield indicating the set of samples covered by the primitive generating
the fragment during multisample rasterization.  The array has ceil(<s>/32)
elements, where <s> is the maximum number of color samples supported by
the implementation.  Bit <n> or word <w> in the bitfield is set if and
only if the sample numbered <w>*32+<n> is considered covered for this
fragment shader invocation.

At this stage we statically set the size of the array to be 1, same as
we do for ARB_sample_shading's gl_SampleMask[] output, since none of our
supported hardware can do >32x MSAA.

-- Chris