[Piglit] [PATCH] s3tc-errors: Use -4, not -3 as an invalid x offset

[Brian Paul]

On 03/09/2015 06:10 PM, James Jones wrote:
> The code in question passes "-3" for the X offset
> of a TexSubImage2D operation.  TexSubImage2D is
> defined to generate INVALID_VALUE for offsets that
> are less than the negative border width, and
> that is what the test expects.  However,
> TexSubImage2D is also defined to generate
> INVALID_OPERATION for offsets that are not
> multiples of 4 when using S3TC textures, as this
> test does.  Therefore, implementations can
> legitimately generate either error here.  To avoid
> ambiguity, use -4 instead.
>
> Passes on GeForce GTX 680 (binary driver 346.47)
>
> Signed-off-by: James Jones <jajones at nvidia.com>
> ---
>   tests/texturing/s3tc-errors.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tests/texturing/s3tc-errors.c b/tests/texturing/s3tc-errors.c
> index 0ed1279..659cfe1 100644
> --- a/tests/texturing/s3tc-errors.c
> +++ b/tests/texturing/s3tc-errors.c
> @@ -267,7 +267,7 @@ test_format(int width, int height, GLfloat *image, GLenum requested_format)
>   	pass = check_gl_error2(GL_INVALID_OPERATION, GL_INVALID_VALUE) && pass;
>
>   	/* Try compressed subimage with invalid offset - should not work */
> -	x = -3;
> +	x = -4;
>   	y = 8;
>   	w = 4;
>   	h = 4;
>

Reviewed-by: Brian Paul <brianp at vmware.com>