Mesa (staging/20.1): st/mesa: use roundf instead of floorf for lod-bias rounding

[GitLab Mirror]

Module: Mesa
Branch: staging/20.1
Commit: 30b256c21e08d6193da534b4b700cdfeb47a506f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=30b256c21e08d6193da534b4b700cdfeb47a506f

Author: Erik Faye-Lund <erik.faye-lund at collabora.com>
Date:   Mon Sep 28 16:11:38 2020 +0200

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 at amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6892>
(cherry picked from commit 7685c37bf47104497d70c4580abb9e050ea8100f)

---

 .pick_status.json                        | 2 +-
 src/mesa/state_tracker/st_atom_sampler.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/.pick_status.json b/.pick_status.json
index a734fabb12d..57d4ab82da8 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -310,7 +310,7 @@
         "description": "st/mesa: use roundf instead of floorf for lod-bias rounding",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "master_sha": null,
         "because_sha": "132b69c4edb824c70c98f8937c63e49b04f3adff"
     },
diff --git a/src/mesa/state_tracker/st_atom_sampler.c b/src/mesa/state_tracker/st_atom_sampler.c
index 7ae981b71b4..3efbdc2c827 100644
--- 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;