[Mesa-dev] [PATCH] mesa/main: Fix unpack_R5G6B5_UNORM.

[Brian Paul]

On 10/07/2014 04:04 AM, Iago Toral Quiroga wrote:
> There is a comment warning about the fact that this is not doing what we
> expect, so fix it. This should be doing the same as unpack_B5G6R5_UNORM
> but swapping B and R.
> ---
>
> Jason started some work to auto-generate the format_pack.c and
> format_unpack.c files which I think has this fixed. I am continuing his
> work on this at the moment, but I guess it might make sense to fix this in
> the current code too while that work is on-going.
>
> No piglit regressions observed.
>
>   src/mesa/main/format_unpack.c | 10 +++-------
>   1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/src/mesa/main/format_unpack.c b/src/mesa/main/format_unpack.c
> index d5628a9..11b028c 100644
> --- a/src/mesa/main/format_unpack.c
> +++ b/src/mesa/main/format_unpack.c
> @@ -207,16 +207,12 @@ unpack_B5G6R5_UNORM(const void *src, GLfloat dst[][4], GLuint n)
>   static void
>   unpack_R5G6B5_UNORM(const void *src, GLfloat dst[][4], GLuint n)
>   {
> -   /* Warning: this function does not match the current Mesa definition
> -    * of MESA_FORMAT_R5G6B5_UNORM.
> -    */
>      const GLushort *s = ((const GLushort *) src);
>      GLuint i;
>      for (i = 0; i < n; i++) {
> -      GLuint t = (s[i] >> 8) | (s[i] << 8); /* byte swap */
> -      dst[i][RCOMP] = UBYTE_TO_FLOAT( ((t >> 8) & 0xf8) | ((t >> 13) & 0x7) );
> -      dst[i][GCOMP] = UBYTE_TO_FLOAT( ((t >> 3) & 0xfc) | ((t >>  9) & 0x3) );
> -      dst[i][BCOMP] = UBYTE_TO_FLOAT( ((t << 3) & 0xf8) | ((t >>  2) & 0x7) );
> +      dst[i][RCOMP] = ((s[i]      ) & 0x1f) * (1.0F / 31.0F);
> +      dst[i][GCOMP] = ((s[i] >> 5 ) & 0x3f) * (1.0F / 63.0F);
> +      dst[i][BCOMP] = ((s[i] >> 11) & 0x1f) * (1.0F / 31.0F);
>         dst[i][ACOMP] = 1.0F;
>      }
>   }
>

Candidate for stable branches?

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