[Piglit] [PATCH] copyteximage: Fix the test to eliminate GL_TEXTURE_1D failures on NVIDIA

[Brian Paul]

On Tue, Aug 21, 2012 at 5:32 PM, Anuj Phogat <anuj.phogat at gmail.com> wrote:
> Draw and probe a QUAD (in place of a LINE) in case of GL_TEXTURE_1D. This
> fixes the test failures on NVIDIA's proprietary linux drivers. In case of
> LINE, glReadPixels() misses the relevant pixels by one pixel on NVIDIA.
>
> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
> ---
> Brian, both these patches (including the one I sent earlier today) resolve
> separate issues. So, I'm keeping this fix in a separate patch. Let me know
> if you have any comments on the patches.
>
>  tests/texturing/copyteximage.c |   16 +++++-----------
>  1 files changed, 5 insertions(+), 11 deletions(-)
>
> diff --git a/tests/texturing/copyteximage.c b/tests/texturing/copyteximage.c
> index c8a8492..43bc78b 100644
> --- a/tests/texturing/copyteximage.c
> +++ b/tests/texturing/copyteximage.c
> @@ -442,8 +442,6 @@ piglit_display(void)
>                 for (i = 0; i < ARRAY_SIZE(test_vectors); i++) {
>                         GLint x = IMAGE_SIZE * (i + 1);
>                         GLint y = 0;
> -                       GLfloat vertices_1d[2][2] = { {x, y},
> -                                                     {x + IMAGE_SIZE, y} };
>
>                         format = test_vectors[i].format;
>                         expected = (const float*)test_vectors[i].expected;
> @@ -485,15 +483,11 @@ piglit_display(void)
>                                        && pass;
>
>                                 glEnable(target[j].target);
> -                               glEnableClientState(GL_VERTEX_ARRAY);
> -                               glTexCoordPointer(1, GL_FLOAT, 0, texCoords_1d);
> -                               glVertexPointer(2, GL_FLOAT, 0, vertices_1d);
> -
> -                               glDrawArrays(GL_LINES, 0, 2);
> -                               pass = piglit_probe_pixel_rgba(x, 0, expected)
> -                                      && pass;
> -                               pass = piglit_probe_pixel_rgba(x + IMAGE_SIZE - 1,
> -                                                              0, expected)
> +                               glTexCoordPointer(2, GL_FLOAT, 0, texCoords_2d);
> +                               piglit_draw_rect(x, y, IMAGE_SIZE, 1);

Drawing a quad that's one pixel tall is just about as risky as drawing
a line, in terms of trying to hit specific pixels.  Why not draw a
taller quad?

Otherwise, see the OpenGL docs I mentioned in my reply to Matt.
Basically, I think you need to use a 0.375 x/y translation to hit
specific pixels.

-Brian


> +                               pass = piglit_probe_rect_rgba(x, y, IMAGE_SIZE,
> +                                                             1,
> +                                                             expected)
>                                        && pass;
>                                 break;
>