Am 16.03.19 um 02:28 schrieb Qiang Yu:
> Signed-off-by: Qiang Yu <yuq...@gmail.com>
> ---
> src/util/u_math.h | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/src/util/u_math.h b/src/util/u_math.h
> index e7dbbe5ca22..ffadfb47282 100644
> --- a/src/util/u_math.h
> +++ b/src/util/u_math.h
> @@ -389,6 +389,37 @@ float_to_ubyte(float f)
> }
> }
>
> +/**
> + * Convert ushort to float in [0, 1].
> + */
> +static inline float
> +ushort_to_float(ushort us)
> +{
> + return (float) us * (1.0f / 65535.0f);
> +}
> +
> +
> +/**
> + * Convert float in [0,1] to ushort in [0,65535] with clamping.
> + */
> +static inline ushort
> +float_to_ushort(float f)
> +{
> + union fi tmp;
> +
> + tmp.f = f;
> + if (tmp.i < 0) {
> + return (ushort) 0;
> + }
> + else if (tmp.i >= 0x3f800000 /* 1.0f */) {
> + return (ushort) 65535;
> + }
This will convert NaNs to either 0 or 65535, depending on their sign.
I think generally it's better to convert this consistently to 0 (gl
usually doesn't require this, however d3d10 does).
Roland
> + else {
> + tmp.f = tmp.f * (65535.0f/65536.0f) + 128.0f;
> + return (ushort) tmp.i;
> + }
> +}
> +
> static inline float
> byte_to_float_tex(int8_t b)
> {
>
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