[Mesa-dev] [RFC PATCH] ARB_vp/ARB_fp: accept duplicate precision options

[Ian Romanick]

On 05/18/2013 11:18 PM, Chris Forbes wrote:
> Relaxes the validation of
>
>     OPTION ARB_precision_hint_{nicest,fastest};
>
> to allow duplicate options. The spec says that both /nicest/ and
> /fastest/ cannot be specified together, but could be interpreted
> either way for respecification of the same option.
>
> Other drivers (NVIDIA etc) accept this, and at least one Unity3D game
> expects it to succeed (Kerbal Space Program).

NOTE: This is a candidate for stable release branches.

> Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
> ---
>   src/mesa/program/program_parse_extra.c | 16 +++++++---------
>   1 file changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/src/mesa/program/program_parse_extra.c b/src/mesa/program/program_parse_extra.c
> index 4d92848..eb1fccc 100644
> --- a/src/mesa/program/program_parse_extra.c
> +++ b/src/mesa/program/program_parse_extra.c
> @@ -194,15 +194,13 @@ _mesa_ARBfp_parse_option(struct asm_parser_state *state, const char *option)
>         } else if (strncmp(option, "precision_hint_", 15) == 0) {
>   	 option += 15;
>
> -	 if (state->option.PrecisionHint == OPTION_NONE) {
> -	    if (strcmp(option, "nicest") == 0) {
> -	       state->option.PrecisionHint = OPTION_NICEST;
> -	       return 1;
> -	    } else if (strcmp(option, "fastest") == 0) {
> -	       state->option.PrecisionHint = OPTION_FASTEST;
> -	       return 1;
> -	    }
> -	 }

I think it's worth quoting the bit of spec that Eric mentioned in a 
comment here.  With or without that change, this patch is

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

> +         if (strcmp(option, "nicest") == 0 && state->option.PrecisionHint != OPTION_FASTEST) {
> +            state->option.PrecisionHint = OPTION_NICEST;
> +            return 1;
> +         } else if (strcmp(option, "fastest") == 0 && state->option.PrecisionHint != OPTION_NICEST) {
> +            state->option.PrecisionHint = OPTION_FASTEST;
> +            return 1;
> +         }
>
>   	 return 0;
>         } else if (strcmp(option, "draw_buffers") == 0) {
>