From 13e0546f56b0b2090b4bf3476e0f78acc0646515 Mon Sep 17 00:00:00 2001
From: lightningterror <18107717+lightningterror@users.noreply.github.com>
Date: Sun, 22 Sep 2024 13:55:29 +0200
Subject: [PATCH] GS/HW: Make sure it's not a channel shuffle when the alpha of
a target is used as source.
The alpha of a target used a source is meaningless to us,
since it's not really an indexed texture.
---
pcsx2/GS/Renderers/HW/GSRendererHW.cpp | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/pcsx2/GS/Renderers/HW/GSRendererHW.cpp b/pcsx2/GS/Renderers/HW/GSRendererHW.cpp
index 466d42facf..7fbe8ab0db 100644
--- a/pcsx2/GS/Renderers/HW/GSRendererHW.cpp
+++ b/pcsx2/GS/Renderers/HW/GSRendererHW.cpp
@@ -2576,7 +2576,9 @@ void GSRendererHW::Draw()
// We don't know the alpha range of direct sources when we first tried to optimize the alpha test.
// Moving the texture lookup before the ATST optimization complicates things a lot, so instead,
// recompute it, and everything derived from it again if it changes.
- if (src->m_valid_alpha_minmax)
+ // No channel shuffle as the alpha of a target used a source is meaningless to us,
+ // since it's not really an indexed texture.
+ if (!IsPossibleChannelShuffle() && src->m_valid_alpha_minmax)
{
CalcAlphaMinMax(src->m_alpha_minmax.first, src->m_alpha_minmax.second);