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

[James Jones]

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;
-- 
1.9.1