[Piglit] [PATCH] Fix piglit_probe_pixel_rgb on GLES2

[Brian Paul]

On 03/25/2018 01:49 PM, Rhys Perry wrote:
> GLES2 requires GL_RGBA to be used with GL_UNSIGNED_BYTE in glReadPixels
> ---
>   tests/util/piglit-util-gl.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/tests/util/piglit-util-gl.c b/tests/util/piglit-util-gl.c
> index df39c1c87..be060aae5 100644
> --- a/tests/util/piglit-util-gl.c
> +++ b/tests/util/piglit-util-gl.c
> @@ -1017,7 +1017,7 @@ static GLfloat *
>   read_pixels_float(GLint x, GLint y, GLsizei width, GLsizei height,
>   		  GLenum format, GLfloat *pixels)
>   {
> -	GLubyte *pixels_b;
> +	uint8_t pixels_b[4];
>   	unsigned i, ncomponents;
>   
>   	ncomponents = width * height * piglit_num_components(format);
> @@ -1029,11 +1029,9 @@ read_pixels_float(GLint x, GLint y, GLsizei width, GLsizei height,
>   		return pixels;
>   	}
>   
> -	pixels_b = malloc(ncomponents * sizeof(GLubyte));
> -	glReadPixels(x, y, width, height, format, GL_UNSIGNED_BYTE, pixels_b);
> +	glReadPixels(x, y, width, height, GL_RGBA, GL_UNSIGNED_BYTE, pixels_b);
>   	for (i = 0; i < ncomponents; i++)
>   		pixels[i] = pixels_b[i] / 255.0;
> -	free(pixels_b);
>   	return pixels;
>   }
>   
> 

This doesn't look right.  The pixels_b buffer must be large enough to 
hold 'ncomponents' values, not 4.

Also, I'd prefer to keep read GL_RGB on non-ES.  Reading GL_RGB vs. 
GL_RGBA probably hits different code paths in the driver, which is a 
good thing.

-Brian