[Piglit] [PATCH] glsl-1.20: Verify GLSL rules about when a new name comes into scope

[Kenneth Graunke]

On 03/02/2012 10:35 AM, Ian Romanick wrote:
> From: Ian Romanick<ian.d.romanick at intel.com>
>
> Signed-off-by: Ian Romanick<ian.d.romanick at intel.com>
> Cc: Kenneth Graunke<kenneth at whitecape.org>
> ---
> This issue came up in some ARB discussions.  The GLSL rules are
> different from C, and this surprised a couple people.  It doesn't
> appear that we have any tests for this, so I decided to add one.

Hrm, you're right...I don't see any tests for this either.

>   ...n-nested-scope-hides-parameter-frag.shader_test |   35 +++++++++++++++++++
>   ...n-nested-scope-hides-parameter-vert.shader_test |   36 ++++++++++++++++++++
>   2 files changed, 71 insertions(+), 0 deletions(-)
>   create mode 100644 tests/spec/glsl-1.20/execution/function-nested-scope-hides-parameter-frag.shader_test
>   create mode 100644 tests/spec/glsl-1.20/execution/function-nested-scope-hides-parameter-vert.shader_test
>
> diff --git a/tests/spec/glsl-1.20/execution/function-nested-scope-hides-parameter-frag.shader_test b/tests/spec/glsl-1.20/execution/function-nested-scope-hides-parameter-frag.shader_test
> new file mode 100644
> index 0000000..c954339
> --- /dev/null
> +++ b/tests/spec/glsl-1.20/execution/function-nested-scope-hides-parameter-frag.shader_test
> @@ -0,0 +1,35 @@
> +[require]
> +GLSL>= 1.10
> +
> +[fragment shader]

Erp. :( Your test prefix is "glsl-1.20" and your spec quotes are from 
the GLSL 1.20 spec...but your shaders are 1.10, which has different 
scoping rules!  That sends up red flags.

That said, the 1.10 spec doesn't seem to say -anything- on this, so 
presumably this was the intended behavior all along...

Otherwise, I agree with these tests.  I would be happy with one of two 
options:
- Move them to spec/glsl-1.10, change subject line appropriately, and 
add a comment as to why you think they apply to GLSL 1.10 as well.
- Add #version 120 and change config block to GLSL >= 1.20

With one of those changes, these are:
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

> +float f(float p)
> +{
> +	/* Page 27 of the GLSL 1.20 spec says:
> +	 *
> +	 *     "Within a declaration, the scope of a name starts immediately
> +	 *     after the initializer if present or immediately after the name
> +	 *     being declared if not."
> +	 *
> +	 * This means the use of 'p' in the first initializer below should
> +	 * have the value of the function parameter 'p' and the use of 'p' in
> +	 * the second initializer shoudl have the value of the function

                                   ^^^ should.

> +	 * parameter 'p' + 0.5.
> +	 */
> +	{
> +		float p = p + 0.5, q = p;
> +		return q;
> +	}
> +}
> +
> +void main()
> +{
> +	gl_FragColor = vec4(f(0.25));
> +}
> +
> +[test]
> +clear color 0.1 0.1 0.1 1.0
> +clear
> +
> +draw rect -1 -1 2 2
> +probe all rgb 0.75 0.75 0.75
> diff --git a/tests/spec/glsl-1.20/execution/function-nested-scope-hides-parameter-vert.shader_test b/tests/spec/glsl-1.20/execution/function-nested-scope-hides-parameter-vert.shader_test
> new file mode 100644
> index 0000000..ec438d3
> --- /dev/null
> +++ b/tests/spec/glsl-1.20/execution/function-nested-scope-hides-parameter-vert.shader_test
> @@ -0,0 +1,36 @@
> +[require]
> +GLSL>= 1.10
> +
> +[vertex shader]
> +
> +float f(float p)
> +{
> +	/* Page 27 of the GLSL 1.20 spec says:
> +	 *
> +	 *     "Within a declaration, the scope of a name starts immediately
> +	 *     after the initializer if present or immediately after the name
> +	 *     being declared if not."
> +	 *
> +	 * This means the use of 'p' in the first initializer below should
> +	 * have the value of the function parameter 'p' and the use of 'p' in
> +	 * the second initializer shoudl have the value of the function

                                   ^^^ should.

> +	 * parameter 'p' + 0.5.
> +	 */
> +	{
> +		float p = p + 0.5, q = p;
> +		return q;
> +	}
> +}
> +
> +void main()
> +{
> +	gl_Position = gl_Vertex;
> +	gl_FrontColor = vec4(f(0.25));
> +}
> +
> +[test]
> +clear color 0.1 0.1 0.1 1.0
> +clear
> +
> +draw rect -1 -1 2 2
> +probe all rgb 0.75 0.75 0.75