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author | Eric Anholt <[email protected]> | 2010-09-22 11:47:03 -0700 |
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committer | Eric Anholt <[email protected]> | 2010-09-22 13:09:51 -0700 |
commit | b39e6f33b60ef9bbaf81f320aaca6a440d8a6a8f (patch) | |
tree | c3547819e402b729d84a4847aed95b81ec09fdbf /src/mesa/program/program.c | |
parent | 38da5c9cb636387539daaf5688c2a3badee32447 (diff) |
glsl: Rework assignments with write_masks to have LHS chan count match RHS.
It turns out that most people new to this IR are surprised when an
assignment to (say) 3 components on the LHS takes 4 components on the
RHS. It also makes for quite strange IR output:
(assign (constant bool (1)) (x) (var_ref color) (swiz x (var_ref v) ))
(assign (constant bool (1)) (y) (var_ref color) (swiz yy (var_ref v) ))
(assign (constant bool (1)) (z) (var_ref color) (swiz zzz (var_ref v) ))
But even worse, even we get it wrong, as shown by this line of our
current step(float, vec4):
(assign (constant bool (1)) (w)
(var_ref t)
(expression float b2f (expression bool >=
(swiz w (var_ref x))(var_ref edge))))
where we try to assign a float to the writemasked-out x channel and
don't supply anything for the actual w channel we're writing. Drivers
right now just get lucky since ir_to_mesa spams the float value across
all the source channels of a vec4.
Instead, the RHS will now have a number of components equal to the
number of components actually being written. Hopefully this confuses
everyone less, and it also makes codegen for a scalar target simpler.
Reviewed-by: Kenneth Graunke <[email protected]>
Reviewed-by: Ian Romanick <[email protected]>
Diffstat (limited to 'src/mesa/program/program.c')
0 files changed, 0 insertions, 0 deletions