The problem ist that if BaseLevel + MinLod is bigger than MaxLevel, min_lod
becomes bigger than max_lod, so the code below swaps min_lod and max_lod and
we send a max_lod to the driver that is bigger than MaxLevel.
This could also be fixed by adding a condition like
if (sampler->min_lod > texobj->MaxLevel)
sampler->min_lod = texobj->MaxLevel;
But clamping is a little bit cleaner imho.
Fabian
From 3e21ca559b9c49f86a768db849f6fa0497055706 Mon Sep 17 00:00:00 2001
From: Fabian Bieler <der.f...@gmx.net>
Date: Tue, 29 Mar 2011 11:56:31 +0200
Subject: [PATCH 3/4] st/mesa: Clamp min_lod and max_lod to BaseLevel and MaxLevel
This works correctly if BaseLevel + MinLod > MaxLevel.
Note: This also changes the behaviour if MaxLevel < BaseLevel.
---
src/mesa/state_tracker/st_atom_sampler.c | 9 ++++-----
1 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/src/mesa/state_tracker/st_atom_sampler.c b/src/mesa/state_tracker/st_atom_sampler.c
index 5f1849d..2025720 100644
--- a/src/mesa/state_tracker/st_atom_sampler.c
+++ b/src/mesa/state_tracker/st_atom_sampler.c
@@ -166,12 +166,11 @@ update_samplers(struct st_context *st)
sampler->lod_bias = st->ctx->Texture.Unit[texUnit].LodBias +
texobj->LodBias;
- sampler->min_lod = texobj->BaseLevel + texobj->MinLod;
- if (sampler->min_lod < texobj->BaseLevel)
- sampler->min_lod = texobj->BaseLevel;
+ sampler->min_lod = CLAMP(texobj->BaseLevel + texobj->MinLod,
+ texobj->BaseLevel, texobj->MaxLevel);
+ sampler->max_lod = CLAMP(texobj->BaseLevel + texobj->MaxLod,
+ texobj->BaseLevel, texobj->MaxLevel);
- sampler->max_lod = MIN2((GLfloat) texobj->MaxLevel,
- (texobj->MaxLod + texobj->BaseLevel));
if (sampler->max_lod < sampler->min_lod) {
/* The GL spec doesn't seem to specify what to do in this case.
* Swap the values.
--
1.7.4.1
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-dev
