[Mesa-dev] non-16byte-aligned constant buffers in gallium?

[Roland Scheidegger]

Hi,

when looking at a regression (piglit
ext_transform_feedback-immediate-reuse-uniform-buffer, bug 90081) I
realized that behavior wrt non-size-aligned constant buffers doesn't
seem to be all that clear cut. In particular I'm wondering if what the
test (or rather the state tracker) does is actually ok?
Constant buffers were always really considered to have been consisting
of vec4 of floats (they are accessed with xyzw semantics after all),
hence having a constant buffer with a size not a multiple of 16 bytes
seems rather odd. I wonder though if they need to be handled gracefully
somehow (of course, in usual GL fashion, nobody has any idea that this
spiffy 4-byte transform feedback or whatever different bind point buffer
is going to be used as a constant buffer later), or if this is something
which should be addressed elsewhere.

Roland