[Piglit] [PATCH v2 2/4] fbo-pbo-readpixels-small: make it endian-safe

[Ilia Mirkin]

Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>

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 probe
> function receives two 4-byte values to compare, expected and observed.
> This is wrong as the correct way to compare array_of_bytes
> (GL_UNSIGNED_BYTE) in an endian-safe way is by comparing memory (and not
> values).
>
> This patch fixes this bug by changing the function to receive two
> pointers instead of values. It also corrects the way the expected values
> are constructed to be in endian-safe way for array-of-bytes
>
> This fixes the test in llvmpipe, softpipe and r600g in big-endian machine.
>
> v2: Changed initialization of expected results to be more clear
>
> Signed-off-by: Oded Gabbay <oded.gabbay at gmail.com>
> ---
>  tests/fbo/fbo-pbo-readpixels-small.c | 27 +++++++++++++++++----------
>  1 file changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/tests/fbo/fbo-pbo-readpixels-small.c b/tests/fbo/fbo-pbo-readpixels-small.c
> index c7730b2..e088cf8 100644
> --- a/tests/fbo/fbo-pbo-readpixels-small.c
> +++ b/tests/fbo/fbo-pbo-readpixels-small.c
> @@ -80,12 +80,16 @@ make_fbo(GLuint *fbo, GLuint *tex)
>  }
>
>  static GLboolean
> -probe(int x, int y, uint32_t expected, uint32_t observed)
> +probe(int x, int y, uint8_t *expected, uint32_t *observed)
>  {
> -       if ((expected & 0xffffff) != (observed & 0xffffff)) {
> +       uint8_t *p_obs = (uint8_t *) observed;
> +
> +       if (expected[0] != p_obs[0] ||
> +                expected[1] != p_obs[1] ||
> +                expected[2] != p_obs[2]) {
>                 printf("Probe color at (%i,%i)\n", x, y);
> -               printf("  Expected: 0x%08x\n", expected);
> -               printf("  Observed: 0x%08x\n", observed);
> +               printf("  Expected: 0x%08x\n", *((uint32_t *) expected));
> +               printf("  Observed: 0x%08x\n", *observed);
>
>                 return GL_FALSE;
>         } else {
> @@ -99,6 +103,8 @@ piglit_display(void)
>         GLboolean pass = GL_TRUE;
>         GLuint fbo, tex, pbo;
>         uint32_t *addr;
> +       static uint8_t green[] = {0x00, 0xFF, 0x00, 0x00};
> +       static uint8_t blue[]  = {0xFF, 0x00, 0x00, 0x00};
>
>         make_fbo(&fbo, &tex);
>
> @@ -122,24 +128,25 @@ piglit_display(void)
>         glReadPixels(0, 0, 2, 2,
>                      GL_BGRA, GL_UNSIGNED_BYTE, (void *)(uintptr_t)0);
>         addr = glMapBufferARB(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY_ARB);
> -       pass &= probe(0, 0, 0x0000ff00, addr[0]);
> -       pass &= probe(1, 0, 0x0000ff00, addr[1]);
> -       pass &= probe(0, 1, 0x000000ff, addr[2]);
> -       pass &= probe(1, 1, 0x000000ff, addr[3]);
> +
> +       pass &= probe(0, 0, green, &addr[0]);
> +       pass &= probe(1, 0, green, &addr[1]);
> +       pass &= probe(0, 1, blue, &addr[2]);
> +       pass &= probe(1, 1, blue, &addr[3]);
>         glUnmapBufferARB(GL_PIXEL_PACK_BUFFER);
>
>         /* Read with an offset. */
>         glReadPixels(1, 0, 1, 1,
>                      GL_BGRA, GL_UNSIGNED_BYTE, (void *)(uintptr_t)4);
>         addr = glMapBufferARB(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY_ARB);
> -       pass &= probe(1, 0, 0x0000ff00, addr[1]);
> +       pass &= probe(1, 0, green, &addr[1]);
>         glUnmapBufferARB(GL_PIXEL_PACK_BUFFER);
>
>         /* Read with an offset. */
>         glReadPixels(1, 1, 1, 1,
>                      GL_BGRA, GL_UNSIGNED_BYTE, (void *)(uintptr_t)4);
>         addr = glMapBufferARB(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY_ARB);
> -       pass &= probe(1, 1, 0x000000ff, addr[1]);
> +       pass &= probe(1, 1, blue, &addr[1]);
>         glUnmapBufferARB(GL_PIXEL_PACK_BUFFER);
>
>         glDeleteBuffersARB(1, &pbo);
> --
> 2.5.5
>
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