[Piglit] [PATCH 4/4] ext_shader_samples_identical: Simple fragment shader rendering test

[Neil Roberts]

Ian Romanick <idr at freedesktop.org> writes:

> +# Group EXT_shader_samples_identical
> +with profile.group_manager(
> +        PiglitGLTest,
> +        grouptools.join('spec', 'EXT_shader_samples_identical')) as g:
> +    g(['ext_shader_samples_identical', '2'])
> +    g(['ext_shader_samples_identical', '4'])
> +    g(['ext_shader_samples_identical', '8'])
> +    g(['ext_shader_samples_identical', '16'])

It might be nice to iterate over MSAA_SAMPLE_COUNTS instead of
hardcoding the sample counts.

> +	glUseProgram(draw_prog);
> +	glVertexAttribPointer(PIGLIT_ATTRIB_POS, 2, GL_FLOAT,
> +			      GL_FALSE, 0, tri_verts);
> +	glEnableVertexAttribArray(PIGLIT_ATTRIB_POS);
> +	glDrawArrays(GL_TRIANGLES, 0, 3);
> +	glDisableVertexAttribArray(PIGLIT_ATTRIB_POS);

It could be good to use piglit_draw_rect_from_arrays here and maybe draw
a diamond shape or something instead of a triangle. That way it would be
less code and it would be easier to port to a core profile because it
wouldn't rely on being able to skip using a VBO and VAO. It should just
work because you are using the standard Piglit names for your
attributes.

> +	glVertexAttribPointer(PIGLIT_ATTRIB_POS, 2, GL_FLOAT,
> +			      GL_FALSE, 0, quad_verts);
> +	glVertexAttribPointer(PIGLIT_ATTRIB_TEX, 2, GL_FLOAT,
> +			      GL_FALSE, 0, quad_texcoords);
> +	glEnableVertexAttribArray(PIGLIT_ATTRIB_POS);
> +	glEnableVertexAttribArray(PIGLIT_ATTRIB_TEX);
> +	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
> +	glDisableVertexAttribArray(PIGLIT_ATTRIB_POS);
> +	glDisableVertexAttribArray(PIGLIT_ATTRIB_TEX);

Same here, I think it could be good to use piglit_draw_rect_tex.

Otherwise seems like a neat test.

Regards,
- Neil