[Mesa-dev] [PATCH] util/u_format: add _is_alpha()

[Marek Olšák]

Reviewed-by: Marek Olšák <marek.olsak at amd.com>

Marek

On Fri, Sep 12, 2014 at 2:47 PM, Rob Clark <robdclark at gmail.com> wrote:
> From: Rob Clark <robclark at freedesktop.org>
>
> Because of render-to-alpha (000x) shenanigans, freedreno needs to do
> some special handling when rendering to alpha-only formats.  And I
> noticed that while we had _is_luminance(), _is_intensity(), etc, an
> _is_alpha() helper was missing.  So fix that.
>
> Signed-off-by: Rob Clark <robclark at freedesktop.org>
> ---
>  src/gallium/auxiliary/util/u_format.c | 17 +++++++++++++++++
>  src/gallium/auxiliary/util/u_format.h |  2 ++
>  2 files changed, 19 insertions(+)
>
> diff --git a/src/gallium/auxiliary/util/u_format.c b/src/gallium/auxiliary/util/u_format.c
> index d53dd78..c1ce408 100644
> --- a/src/gallium/auxiliary/util/u_format.c
> +++ b/src/gallium/auxiliary/util/u_format.c
> @@ -92,6 +92,23 @@ util_format_is_luminance(enum pipe_format format)
>  }
>
>  boolean
> +util_format_is_alpha(enum pipe_format format)
> +{
> +   const struct util_format_description *desc =
> +      util_format_description(format);
> +
> +   if ((desc->colorspace == UTIL_FORMAT_COLORSPACE_RGB ||
> +        desc->colorspace == UTIL_FORMAT_COLORSPACE_SRGB) &&
> +       desc->swizzle[0] == UTIL_FORMAT_SWIZZLE_0 &&
> +       desc->swizzle[1] == UTIL_FORMAT_SWIZZLE_0 &&
> +       desc->swizzle[2] == UTIL_FORMAT_SWIZZLE_0 &&
> +       desc->swizzle[3] == UTIL_FORMAT_SWIZZLE_X) {
> +      return TRUE;
> +   }
> +   return FALSE;
> +}
> +
> +boolean
>  util_format_is_pure_integer(enum pipe_format format)
>  {
>     const struct util_format_description *desc = util_format_description(format);
> diff --git a/src/gallium/auxiliary/util/u_format.h b/src/gallium/auxiliary/util/u_format.h
> index df31400..621574c 100644
> --- a/src/gallium/auxiliary/util/u_format.h
> +++ b/src/gallium/auxiliary/util/u_format.h
> @@ -661,6 +661,8 @@ util_format_has_alpha(enum pipe_format format);
>  boolean
>  util_format_is_luminance(enum pipe_format format);
>
> +boolean
> +util_format_is_alpha(enum pipe_format format);
>
>  boolean
>  util_format_is_luminance_alpha(enum pipe_format format);
> --
> 1.9.3
>
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