[Mesa-dev] [PATCH 25/53] st/nine: Handle NRM with input of null norm

[Ilia Mirkin]

On Wed, Jan 7, 2015 at 11:36 AM, Axel Davy <axel.davy at ens.fr> wrote:
> When the input's xyz are 0.0, the output
> should be 0.0. This is due to the fact that
> Inf * 0 = 0 for dx9. To handle this case,
> cap the result of RSQ to FLT_MAX. We have
> FLT_MAX * 0 = 0.
>
> Reviewed-by: David Heidelberg <david at ixit.cz>
> Signed-off-by: Axel Davy <axel.davy at ens.fr>
>
> Cc: "10.4" <mesa-stable at lists.freedesktop.org>
> ---
>  src/gallium/state_trackers/nine/nine_shader.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/src/gallium/state_trackers/nine/nine_shader.c b/src/gallium/state_trackers/nine/nine_shader.c
> index 4dee5f5..48492b4 100644
> --- a/src/gallium/state_trackers/nine/nine_shader.c
> +++ b/src/gallium/state_trackers/nine/nine_shader.c
> @@ -1973,10 +1973,12 @@ DECL_SPECIAL(NRM)
>      struct ureg_program *ureg = tx->ureg;
>      struct ureg_dst tmp = tx_scratch_scalar(tx);
>      struct ureg_src nrm = tx_src_scalar(tmp);
> +    struct ureg_dst dst = tx_dst_param(tx, &tx->insn.dst[0]);
>      struct ureg_src src = tx_src_param(tx, &tx->insn.src[0]);
>      ureg_DP3(ureg, tmp, src, src);
>      ureg_RSQ(ureg, tmp, nrm);
> -    ureg_MUL(ureg, tx_dst_param(tx, &tx->insn.dst[0]), src, nrm);
> +    ureg_MIN(ureg, tmp, ureg_imm1f(ureg, FLT_MAX), nrm);
> +    ureg_MUL(ureg, dst, src, nrm);

Was this supposed to use tmp instead of nrm? Otherwise tmp is
unused... Also, same question as before wrt the MIN.

  -ilia