On 04/28/2012 12:24 PM, Vadim Girlin wrote:
On Sat, 2012-04-28 at 11:42 -0700, Kenneth Graunke wrote:
On 04/28/2012 11:20 AM, Vadim Girlin wrote:
According to GLSL 1.30 specification, initial value for all uniforms
without initializer is 0. Some applications rely on this behaviour,
e.g. google's MapGL doesn't set all sampler uniforms.
(see https://bugs.freedesktop.org/show_bug.cgi?id=49088 )
Signed-off-by: Vadim Girlin<vadimgir...@gmail.com>
---
Tested with r600g only - no regressions.
Awesome find! I was at a complete loss here. :)
It turns out this is in the 1.20 spec too; it looks like 1.10 doesn't
say (but that isn't too surprising). I might add a comment:
/* From the GLSL 1.20 specification, page 24, section 4.3.5 "Uniform":
* "The link time initial value is either the value of the variable's
* initializer, or 0 if no initializer present. Sampler types cannot
* have initializers."
*/
Also, do you really need the memsets in ir_to_mesa and st_glsl_to_tgsi?
Everything should go through the linker, so that seems somewhat
redundant. I tested with just the link_uniforms change and that was
enough to fix MapsGL on i965/Sandybridge.
Without the memset in the st_glsl_to_tgsi firefox crashed with MapGL.
Probably some code in the state tracker relies on the synchronized
values of the SamplerUnits arrays in the gl_program and
gl_shader_program. Also, _mesa_uniform function compares these arrays to
check for update, and some piglit test failed due to the following
problem:
First array is initialized: 0, 0, 0, ...
Second (without memset) : 0, 1, 2, ...
The app calls Uniform1i to set sampler[1] to 1, so we do first[1]=1, but
then it's equal with second[1] and update is not detected.
Vadim
Ah, okay...I missed that one was operating on the gl_shader_program
while the other was setting the parallel structure in the gl_program.
I can believe that you'd need that, then.
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