Tapani Pälli <tapani.pa...@intel.com> writes: > On 04/07/2015 01:22 PM, Francisco Jerez wrote: >> Tapani Pälli <tapani.pa...@intel.com> writes: >> >>> From: Kalyan Kondapally <kalyan.kondapa...@intel.com> >>> >>> Dynamic indexing of sampler arrays is prohibited by GLSL ES 3.00. >>> Earlier versions allow 'constant-index-expression' indexing, where >>> index can contain a loop induction variable. >>> >>> Patch allows dynamic indexing for sampler arrays when GLSL ES < 3.00. >>> This change makes 'sampler-array-index.frag' parser test in Piglit >>> pass + fishgl.com works when running Chrome on OpenGL ES 2.0 backend. >>> >>> v2: small change and some more commit message (Tapani) >>> >>> Signed-off-by: Kalyan Kondapally <kalyan.kondapa...@intel.com> >>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=84225 >> >> Looks good, but did you check what happens now if the shader uses actual >> variable indexing (i.e. which lowering cannot turn into a constant) on >> an implementation that doesn't support it? Hopefully no crashes or >> hangs? > > I could test something like this, can you throw example of a good victim > platform and some ugly corner case? I have a shader_test that has > expression with a uniform in it as index as a starter. > I guess SNB would be "bad" enough. The hardware actually supports dynamically uniform indexing of surfaces but we don't implement it and it would likely violate some assumptions in the back-end if it gets that far.
> As a plan B, I think loop analysis could store some information which
> can be then used for additional validation of array index in a later
> step (skip it in AST and check only later for ES 1.00).
>
Yeah, well. It seems rather annoying to get right at the GLSL IR level
too, because you'd have to traverse variable defs and built-in function
calls, except maybe after optimization (after loop unrolling and
constant folding at least). At that point a valid ESSL 1.0 program
should only have sampler arrays indexed by constants, what will probably
make your job easier.
>>> ---
>>> src/glsl/ast_array_index.cpp | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/src/glsl/ast_array_index.cpp b/src/glsl/ast_array_index.cpp
>>> index ecef651..b2609b6 100644
>>> --- a/src/glsl/ast_array_index.cpp
>>> +++ b/src/glsl/ast_array_index.cpp
>>> @@ -226,7 +226,7 @@ _mesa_ast_array_index_to_hir(void *mem_ctx,
>>> * dynamically uniform expression is undefined.
>>> */
>>> if (array->type->element_type()->is_sampler()) {
>>> - if (!state->is_version(130, 100)) {
>>> + if (!state->is_version(130, 300)) {
>>> if (state->es_shader) {
>>> _mesa_glsl_warning(&loc, state,
>>> "sampler arrays indexed with non-constant "
>>> --
>>> 2.1.0
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