st/mesa: use roundf instead of floorf for lod-bias rounding

There's no good reason not to use a symmetric rounding mode here. This
fixes the following GL CTS case for me:

GTF-GL33.gtf21.GL3Tests.texture_lod_bias.texture_lod_bias_all

Fixes: 132b69c4edb ("st/mesa: round lod_bias to a multiple of 1/256")
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6892>

diff --git a/src/mesa/state_tracker/st_atom_sampler.c b/src/mesa/state_tracker/st_atom_sampler.c
index 0c188c1..0d99eae 100644 (file)
--- a/src/mesa/state_tracker/st_atom_sampler.c
+++ b/src/mesa/state_tracker/st_atom_sampler.c
@@ -132,7 +132,7 @@ st_convert_sampler(const struct st_context *st,
     * levels.
     */
    sampler->lod_bias = CLAMP(sampler->lod_bias, -16, 16);
-   sampler->lod_bias = floorf(sampler->lod_bias * 256) / 256;
+   sampler->lod_bias = roundf(sampler->lod_bias * 256) / 256;
 
    sampler->min_lod = MAX2(msamp->MinLod, 0.0f);
    sampler->max_lod = msamp->MaxLod;