From 2eb11ded520cca80712d5a608b759859695794de Mon Sep 17 00:00:00 2001
From: lightningterror <18107717+lightningterror@users.noreply.github.com>
Date: Tue, 21 Feb 2023 17:37:44 +0100
Subject: [PATCH] GS-metal: Check each channel individually if it overflows and
 do corrections.

---
 pcsx2/GS/Renderers/Metal/tfx.metal | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/pcsx2/GS/Renderers/Metal/tfx.metal b/pcsx2/GS/Renderers/Metal/tfx.metal
index 9a616b3fa1..4c104ff35e 100644
--- a/pcsx2/GS/Renderers/Metal/tfx.metal
+++ b/pcsx2/GS/Renderers/Metal/tfx.metal
@@ -825,8 +825,10 @@ struct PSMain
 		return selector == 0 ? zero : selector == 1 ? one : two;
 	}
 
-	void ps_blend(thread float4& Color, thread float& As)
+	void ps_blend(thread float4& Color, thread float4& As_rgba)
 	{
+		float As = As_rgba.a;
+		
 		if (SW_BLEND)
 		{
 			// PABE
@@ -873,15 +875,14 @@ struct PSMain
 			{
 				// Replace Af with As so we can do proper compensation for Alpha.
 				if (PS_BLEND_C == 2)
-					As = cb.alpha_fix;
+					As_rgba = float4(cb.alpha_fix);
 				// Subtract 1 for alpha to compensate for the changed equation,
 				// if c.rgb > 255.0f then we further need to adjust alpha accordingly,
 				// we pick the lowest overflow from all colors because it's the safest,
 				// we divide by 255 the color because we don't know Cd value,
 				// changed alpha should only be done for hw blend.
-				float min_color = min(min(Color.r, Color.g), Color.b);
-				float alpha_compensate = max(1.f, min_color / 255.f);
-				As -= alpha_compensate;
+				float3 alpha_compensate = max(float3(1.f), Color.rgb / float3(255.f));
+				As_rgba.rgb -= alpha_compensate;
 			}
 			else if (PS_CLR_HW == 2)
 			{
@@ -977,7 +978,7 @@ struct PSMain
 			C.a = 128.0f;
 		}
 
-		float alpha_blend = SW_AD_TO_HW ? (trunc(current_color.a * 255.5f) / 128.f) : (C.a / 128.f);
+		float4 alpha_blend = SW_AD_TO_HW ? float4(trunc(current_color.a * 255.5f) / 128.f) : float4(C.a / 128.f);
 
 		if (PS_DFMT == FMT_16)
 		{