[Piglit] [PATCH v2 4/4] GL_MESA_pack_invert: make it endian-safe

[Ilia Mirkin]

On Tue, Mar 29, 2016 at 5:06 AM, Oded Gabbay <oded.gabbay at gmail.com> wrote:
> In this test we use GL_BGRA + GL_UNSIGNED_BYTE. However, the test
> function constructs the expected colors array as 32-bit values, which is
> a wrong way to build expected results values when testing array_of_bytes
> (GL_UNSIGNED_BYTE) in an endian-safe way.
>
> This patch fixes this bug by building the expected colors using array of
> array_of_bytes.
>
> This fixes the test in llvmpipe, softpipe and r600g in big-endian machine.
>
> Signed-off-by: Oded Gabbay <oded.gabbay at gmail.com>
> ---
>  tests/spec/mesa_pack_invert/readpixels.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/tests/spec/mesa_pack_invert/readpixels.c b/tests/spec/mesa_pack_invert/readpixels.c
> index f8fbebe..af508a3 100644
> --- a/tests/spec/mesa_pack_invert/readpixels.c
> +++ b/tests/spec/mesa_pack_invert/readpixels.c
> @@ -47,18 +47,18 @@ PIGLIT_GL_TEST_CONFIG_END
>  static bool
>  check_unorm(const uint32_t *data, const char *name)
>  {
> -       static const uint32_t colors[] = {
> -               0x000000ff,
> -               0xffffffff,
> -               0x00ff0000,
> -               0x0000ff00
> +       static const uint8_t colors[4][4] = {
> +               {0xff, 0x00, 0x00, 0x00},
> +               {0xff, 0xff, 0xff, 0xff},
> +               {0x00, 0x00, 0xff, 0x00},
> +               {0x00, 0xff, 0x00, 0x00}
>         };
>         int x, y;
>
>         for (y = 0; y < H; y++) {
>                 for (x = 0; x < W; x++) {
>                         int i = (y >= H / 2) * 2 + (x >= W / 2);
> -                       uint32_t expected = colors[i];
> +                       uint32_t expected = *((uint32_t *) ((uint8_t *) &colors[i][0]));

Is the double-cast really necessary here? You can't just do

*(uint32_t *)&colors[i][0]

?

>
>                         if (data[y * W + x] != expected) {
>                                 fprintf(stderr,
> --
> 2.5.5
>
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