[Mesa-dev] [PATCH 2/2] mesa: Add fall-back formats for unsupported snorm formats

[Kenneth Graunke]

On 04/02/2011 07:18 PM, Ian Romanick wrote:
> From: Ian Romanick<ian.d.romanick at intel.com>
>
> This is always the way the real hardware and desktop OpenGL.  Some

Err...what?

> hardware can't do some formats natively.  The alpha-only, luminance,
> and intensity formats are usually the most problematic.  Some sized
> formats can also be problematic.  This patch provides fall-back
> formats for those that are not natively supported.
>
> At some point it would be interesting to try providing
> device-independent conversions using EXT_texture_swizzle.  The drivers
> that support EXT_texture_swizzle could, for example, see
> GL_LUMINANCE16_SNORM as MESA_FORMAT_SIGNED_R16 with a { r, r, r, 1 }
> swizzle.  Care would need to be taken to prevent issues with using
> those textures for FBO rendering.
>
> This is the rest of the fix for glean's pixelFormats test on i965.
>
> Cc: Marek Ol ák<maraeo at gmail.com>

's' please!  ^^^

> ---
>   src/mesa/main/texformat.c |   26 +++++++++++++++++++++++---
>   1 files changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/src/mesa/main/texformat.c b/src/mesa/main/texformat.c
> index 8b7b4ff..da90745 100644
> --- a/src/mesa/main/texformat.c
> +++ b/src/mesa/main/texformat.c
> @@ -402,7 +402,7 @@ _mesa_choose_tex_format( struct gl_context *ctx, GLint internalFormat,
>            case GL_RGB_SNORM:
>            case GL_RGB8_SNORM:
>   	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBX8888);
> -	    break;
> +	    /* FALLTHROUGH */
>            case GL_RGBA_SNORM:
>            case GL_RGBA8_SNORM:
>   	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888);
> @@ -411,18 +411,27 @@ _mesa_choose_tex_format( struct gl_context *ctx, GLint internalFormat,
>            case GL_ALPHA_SNORM:
>            case GL_ALPHA8_SNORM:
>               RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_A8);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888_REV);

I'm probably being dense here, but if RGBA8888 works as a fallback, 
couldn't R8 work as well?

>               break;
>            case GL_LUMINANCE_SNORM:
>            case GL_LUMINANCE8_SNORM:
>               RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_L8);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBX8888);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888_REV);

ditto

>               break;
>            case GL_LUMINANCE_ALPHA_SNORM:
>            case GL_LUMINANCE8_ALPHA8_SNORM:
>               RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_AL88);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888_REV);

ditto, but RG88

>               break;
>            case GL_INTENSITY_SNORM:
>            case GL_INTENSITY8_SNORM:
>               RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_I8);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888_REV);
>               break;

ditto

>            case GL_R16_SNORM:
>   	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_R16);
> @@ -432,21 +441,32 @@ _mesa_choose_tex_format( struct gl_context *ctx, GLint internalFormat,
>   	    break;
>            case GL_RGB16_SNORM:
>   	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGB_16);
> -	    break;
> +	    /* FALLTHROUGH */
>            case GL_RGBA16_SNORM:
>   	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA_16);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888_REV);
>   	    break;
>            case GL_ALPHA16_SNORM:
>               RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_A16);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA_16);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888_REV);
>               break;
>            case GL_LUMINANCE16_SNORM:
>               RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_L16);
> -            break;
> +	    /* FALLTHROUGH */
>            case GL_LUMINANCE16_ALPHA16_SNORM:
>               RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_AL1616);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA_16);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888_REV);
>               break;
>            case GL_INTENSITY16_SNORM:
>               RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_I16);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA_16);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888);
> +	    RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_RGBA8888_REV);
>               break;
>            default:
>               ; /* fall-through */