Commit Graph

2 Commits

Author SHA1 Message Date
Chip Davis
f3c0942d10 MSL: Use vectors for the tessellation level builtins in tese shaders.
The tessellation levels in Metal are stored as a densely-packed array of
half-precision floating point values. But, stage-in attributes in Metal
have to have offsets and strides aligned to a multiple of four, so we
can't add them individually. Luckily for us, the arrays have lengths
less than 4. So, let's use vectors for them!

Triangles get a single attribute with a `float4`, where the outer levels
are in `.xyz` and the inner levels are in `.w`. The arrays are unpacked
as though we had added the elements individually. Quads get two: a
`float4` with the outer levels and a `float2` with the inner levels.
Further, since vectors can be indexed as arrays, there's no need to
unpack them in this case.

This also saves on precious vertex attributes. Before, we were using up
to 6 of them. Now we need two at most.
2019-02-22 12:18:51 -06:00
Chip Davis
7a7e210515 MSL: Force unnamed array builtin attributes to have a name.
That way, when we refer to them, they'll have the name that we're
expecting.
2019-02-20 22:16:51 -06:00