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

[Jason Ekstrand]

On Oct 7, 2014 12:04 PM, "Iago Toral Quiroga" <itoral at igalia.com> 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.

Not much time to reply right now, but I seem to recall there being a bit
more to fix here.  What about packing and swrast's texel fetch
implementation.  Are those OK for this format?

> No piglit regressions observed.

On what drivers?  It might be good to test on swrast and llvmpipe.  I'm not
super-concerned there but we should at least try not to break it.
--Jason

>
>  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;
>     }
>  }
> --
> 1.9.1
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/mesa-dev/attachments/20141007/ea7f7964/attachment.html>