[Mesa-dev] [PATCH 4/8] glsl: Add new builtins required by GL_ARB_sample_shading

[Kenneth Graunke]

On 10/16/2013 03:49 PM, Ian Romanick wrote:
[snip]
> You are completely correct here.  We should check what other vendors do.
>  I think 5 tests will tell us everything we need to know (then we'll
> probably submit some spec bugs).  I don't have any non-Intel hardware
> that supports either extension, so I can't actually try any of these.

Thanks for the tests, Ian!

I ran them on my Radeon HD 6870 with Catalyst 13.10 by doing:
$ PIGLIT_PLATFORM=glx glslparsertest --check-link 1.frag pass

> 1. Does this compile, link, and run:
> 
> #version 130
> #extension GL_ARB_sample_shading: require
> 
> out vec4 color;
> 
> void main() {
>     color = vec4(gl_SampleMask.length());
>     gl_SampleMask[0] = ~0;
> }

Successfully compiled and linked fragment shader 1.frag: (no compiler output)

> 2. Does this compile and link:
> 
> #version 130
> #extension GL_ARB_sample_shading: require
> 
> out vec4 color;
> 
> void main() {
>     color = vec4(1);
>     gl_SampleMask[0] = ~0;
>     gl_SampleMask[1] = ~0;
> }

Failed to compile fragment shader 2.frag:
Fragment shader failed to compile with the following errors:
ERROR: 0:9: error(#147) "[" array index out of range: '1'
ERROR: error(#273) 1 compilation errors.  No code generated

> 3. Does this compile and link:
> 
> #version 130
> #extension GL_ARB_sample_shading: require
> #extension GL_ARB_gpu_shader5: require
> 
> out vec4 color;
> 
> void main() {
>     color = vec4(1);
>     gl_SampleMask = gl_SampleMaskIn;
> }

Successfully compiled and linked fragment shader 3.frag: (no compiler output)

> 4. Does this compile and link:
> 
> #version 130
> #extension GL_ARB_sample_shading: require
> 
> out vec4 color;
> in int gl_SampleMask[1];
> 
> void main() {
>     color = vec4(1);
>     gl_SampleMask[0] = ~0;
> }

Successfully compiled and linked fragment shader 4.frag:
WARNING: 0:5: warning(#375) Redeclaration of  built-in name: gl_SampleMask
WARNING: 0:9: warning(#398) l-value required: assign "gl_SampleMask" (can't modify an input)

Presumably you meant "out int gl_SampleMask[1];" instead.  With that change,

Successfully compiled and linked fragment shader 4b.frag:
WARNING: 0:5: warning(#375) Redeclaration of  built-in name: gl_SampleMask

> 5. Does this compile and link:
> 
> #version 130
> #extension GL_ARB_sample_shading: require
> 
> out vec4 color;
> in int gl_SampleMask[2];
> 
> void main() {
>     color = vec4(1);
>     gl_SampleMask[0] = ~0;
>     gl_SampleMask[1] = ~0;
> }

Successfully compiled and linked fragment shader 5.frag:
WARNING: 0:5: warning(#375) Redeclaration of  built-in name: gl_SampleMask
WARNING: 0:9: warning(#398) l-value required: assign "gl_SampleMask" (can't modify an input)
WARNING: 0:10: warning(#398) l-value required: assign "gl_SampleMask" (can't modify an input)

Again changing "in" to "out":

Successfully compiled and linked fragment shader 5b.frag:
WARNING: 0:5: warning(#375) Redeclaration of  built-in name: gl_SampleMask

I haven't actually tried drawing with the shaders.

--Ken