[Piglit] [PATCH] glsl-fs-main-return-conditional: Test for using return in main

[Ian Romanick]

On 03/22/2013 03:28 PM, sroland at vmware.com wrote:
> From: Roland Scheidegger <sroland at vmware.com>
>
> Similar to glsl-fs-main-return (and glsl-vs-main-return), this is testing
> using return in main. Contrary to the these other tests, this hits both
> the cases where the return path is and is NOT taken (the gallivm code
> got it wrong and always did an early exit which got unnoticed by the
> existing tests, see https://bugs.freedesktop.org/show_bug.cgi?id=62357).
> It also needs glsl 1.30 (even though this is not specific to what's tested
> here).

Are there any drivers in Mesa that don't expose GLSL 1.30 but would 
benefit from this test?

> ---
>   .../glsl-fs-main-return-conditional.shader_test    |   34 ++++++++++++++++++++
>   1 file changed, 34 insertions(+)
>   create mode 100644 tests/shaders/glsl-fs-main-return-conditional.shader_test
>
> diff --git a/tests/shaders/glsl-fs-main-return-conditional.shader_test b/tests/shaders/glsl-fs-main-return-conditional.shader_test
> new file mode 100644
> index 0000000..124a4cd
> --- /dev/null
> +++ b/tests/shaders/glsl-fs-main-return-conditional.shader_test
> @@ -0,0 +1,34 @@
> +[require]
> +GLSL >= 1.30
> +
> +[vertex shader]
> +#version 130
> +void main()
> +{
> +	gl_Position = gl_Vertex;
> +}
> +
> +[fragment shader]
> +#version 130
> +uniform vec4 v;

This could just be

const vec4 v = vec4(0., 1., 0., 1.);

and delete the uniform setting in the [test] section.

> +
> +void main()
> +{
> +	uint posintx = uint(gl_FragCoord.x);
> +	uint one = uint(1);
> +	gl_FragColor = v;
> +	if ((posintx & one) == one) {
> +		return;  // return for every second pixel
> +	}
> +	gl_FragColor = vec4(1.0) - v;
> +}

It seems like this could be done as:

void main()
{
     floor x = floor(gl_FragCoord.x - 0.5);

     gl_FragCoord = v;
     if (mod(x, 2.0) > epsilon)
         return;

     gl_FragColor = vec4(1.0) - v;
}

> +
> +[test]
> +uniform vec4 v 0 1 0 1
> +
> +draw rect -1 -1 2 2
> +probe rgb 0 0 1 0 1
> +probe rgb 1 0 0 1 0
> +probe rgb 2 0 1 0 1
> +probe rgb 3 0 0 1 0
> +
>