From 7d16a915eda4931c1e2beb5afd921b933e86b2f1 Mon Sep 17 00:00:00 2001
From: lightningterror <18107717+lightningterror@users.noreply.github.com>
Date: Thu, 12 Dec 2024 11:49:25 +0100
Subject: [PATCH] GS/HW: Adjust how we handle dithering on blend mix.

Allow dither adjust regardless of alpha. usually it is clamed to 1 anyway so we can expand it if alpha max is higher than 128.

Expand dither adjust to work in rev subtract conditions.
---
 pcsx2/GS/Renderers/HW/GSRendererHW.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pcsx2/GS/Renderers/HW/GSRendererHW.cpp b/pcsx2/GS/Renderers/HW/GSRendererHW.cpp
index 7fbe8ab0db25c..e593c3be43f3f 100644
--- a/pcsx2/GS/Renderers/HW/GSRendererHW.cpp
+++ b/pcsx2/GS/Renderers/HW/GSRendererHW.cpp
@@ -4553,7 +4553,8 @@ void GSRendererHW::EmulateBlending(int rt_alpha_min, int rt_alpha_max, const boo
 			// Disable dithering on blend mix if needed.
 			if (m_conf.ps.dither)
 			{
-				const bool can_dither = (m_conf.ps.blend_a == 0 && m_conf.ps.blend_b == 1 && alpha_eq_less_one);
+				// TODO: Either exclude BMIX1_ALPHA_HIGH_ONE case or allow alpha > 1.0 on dither adjust, case is currently disabled.
+				const bool can_dither = (m_conf.ps.blend_a == 0 && m_conf.ps.blend_b == 1) || (m_conf.ps.blend_a == 1 && m_conf.ps.blend_b == 0);
 				m_conf.ps.dither = can_dither;
 				m_conf.ps.dither_adjust = can_dither;
 			}