From 083ba935bcfe9ebdc9996dc621dffa9cfe5c0e83 Mon Sep 17 00:00:00 2001
From: Michael Fabian 'Xaymar' Dirks <info@xaymar.com>
Date: Wed, 14 Apr 2021 11:36:45 +0200
Subject: [PATCH] filters/color-grading: Fix incorrect Lift logic (#515)

Fixes #515
---
 data/effects/color-grade.effect | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/data/effects/color-grade.effect b/data/effects/color-grade.effect
index cbae677..a051644 100644
--- a/data/effects/color-grade.effect
+++ b/data/effects/color-grade.effect
@@ -50,8 +50,10 @@ uniform float4 pCorrection;
 // Functionality
 //------------------------------------------------------------------------------
 
-float3 grade_lift(float3 v) { // same as grade_offset?
-	return (v.rgb + pLift.rgb) + pLift.a;
+float3 grade_lift(float3 v) {
+	float3 multiplier1 = float3(1., 1., 1.) - pLift.rgb;
+	float3 multiplier2 = float3(1., 1., 1.) - pLift.aaa;
+	return float3(1., 1., 1.) - ((float3(1., 1., 1.) - v) * multiplier1 * multiplier2);
 };
 
 float3 grade_gamma(float3 v) {