[Mesa-dev] [PATCH] mesa: Return 8 bits for GL_TEXTURE_RED_SIZE on RGTC formats.

[Brian Paul]

On 06/06/2012 12:57 AM, Kenneth Graunke wrote:
>  From the issues section of the GL_ARB_texture_compression_rgtc extension:
>
> 15) What should glGetTexLevelParameter return for
>      GL_TEXTURE_GREEN_SIZE and GL_TEXTURE_BLUE_SIZE for the RGTC1
>      formats?  What should glGetTexLevelParameter return for
>      GL_TEXTURE_BLUE_SIZE for the RGTC2 formats?
>
>      RESOLVED:  Zero bits.
>
>      These formats always return 0.0 for these respective components
>      and have no bits devoted to these components.
>
>      Returning 8 bits for red size of RGTC1 and the red and green
>      sizes of RGTC2 makes sense because that's the maximum potential
>      precision for the uncompressed texels.
>
> Thus, we need to return 8 bits for GL_TEXTURE_RED_SIZE on all RGTC formats
> and 8 bits for GL_TEXTURE_GREEN_SIZE on RGTC2 formats.  BLUE should be 0.
>
> Fixes oglconform/rgtc/advanced.texture_fetch.tex_param.
>
> Signed-off-by: Kenneth Graunke<kenneth at whitecape.org>
> ---
>   src/mesa/main/formats.c |    8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/src/mesa/main/formats.c b/src/mesa/main/formats.c
> index cecb70c..ccc0b17 100644
> --- a/src/mesa/main/formats.c
> +++ b/src/mesa/main/formats.c
> @@ -1319,7 +1319,7 @@ static struct gl_format_info format_info[MESA_FORMAT_COUNT] =
>        "MESA_FORMAT_RED_RGTC1",
>        GL_RED,
>        GL_UNSIGNED_NORMALIZED,
> -     4, 0, 0, 0,
> +     8, 0, 0, 0,
>        0, 0, 0, 0, 0,
>        4, 4, 8                     /* 8 bytes per 4x4 block */
>      },
> @@ -1328,7 +1328,7 @@ static struct gl_format_info format_info[MESA_FORMAT_COUNT] =
>        "MESA_FORMAT_SIGNED_RED_RGTC1",
>        GL_RED,
>        GL_SIGNED_NORMALIZED,
> -     4, 0, 0, 0,
> +     8, 0, 0, 0,
>        0, 0, 0, 0, 0,
>        4, 4, 8                     /* 8 bytes per 4x4 block */
>      },
> @@ -1337,7 +1337,7 @@ static struct gl_format_info format_info[MESA_FORMAT_COUNT] =
>        "MESA_FORMAT_RG_RGTC2",
>        GL_RG,
>        GL_UNSIGNED_NORMALIZED,
> -     4, 4, 0, 0,
> +     8, 8, 0, 0,
>        0, 0, 0, 0, 0,
>        4, 4, 16                     /* 16 bytes per 4x4 block */
>      },
> @@ -1346,7 +1346,7 @@ static struct gl_format_info format_info[MESA_FORMAT_COUNT] =
>        "MESA_FORMAT_SIGNED_RG_RGTC2",
>        GL_RG,
>        GL_SIGNED_NORMALIZED,
> -     4, 4, 0, 0,
> +     8, 8, 0, 0,
>        0, 0, 0, 0, 0,
>        4, 4, 16                     /* 16 bytes per 4x4 block */
>      },

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

We should also check the DXT formats too...

-Brian