The RGBX version isn't supported as a vertex input type, but since we
force the last channel's value anyway, this should be fine. The only
potential risk I see is in the limiter on VBO reads past the end of
the buffer forcing the whole vertex to 0 when the A channel lands past
the end.
Fixes piglit draw-vertices-half-float.
0,
BRW_SURFACEFORMAT_R16_FLOAT,
BRW_SURFACEFORMAT_R16G16_FLOAT,
- 0, /* can't seem to render this one */
+ BRW_SURFACEFORMAT_R16G16B16A16_FLOAT,
BRW_SURFACEFORMAT_R16G16B16A16_FLOAT
};