DecodeShaderStages accepted only clockwise triangle patches and no HOS
level clamp narrower than [1, 63], so terrain drawn as TRI_CCW quad
patches with VGT_HOS_MAX_TESS_LEVEL 9 aborted. Quad domains and TRI_CCW
now decode and emit Quads and VertexOrderCcw; isolines, other
partitionings and point or line output still throw.
VGT_HOS_MIN/MAX_TESS_LEVEL are read per draw and pushed in the last 8
bytes of the pre-rasterization push constant slot, where the hull reads
them to clamp its factors; they stay out of every key and the recompile
request, so one hull serves every level. Zero, negative and NaN outer
factors still cull; clamps outside 0 <= min <= 63, max >= 1,
min <= max throw. Quad hulls write four outer and two inner factors at
a 24-byte stride, the layout Mesa's TF ring store uses.
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