From b1f971aa9b2656878583196b53050f19c92cac5e Mon Sep 17 00:00:00 2001
From: Rachael Alexanderson <madame-rachelle@users.noreply.github.com>
Date: Wed, 16 Mar 2022 13:32:56 -0400
Subject: [PATCH] - add gl_satformula == 2 - an optional 'more accurate'
 desaturation

---
 wadsrc/static/shaders/pp/present.fp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/wadsrc/static/shaders/pp/present.fp b/wadsrc/static/shaders/pp/present.fp
index c10625883..4266757f9 100644
--- a/wadsrc/static/shaders/pp/present.fp
+++ b/wadsrc/static/shaders/pp/present.fp
@@ -12,6 +12,8 @@ vec4 ApplyGamma(vec4 c)
 	vec3 valgray;
 	if (GrayFormula == 0)
 		valgray = vec3(c.r + c.g + c.b) * (1 - Saturation) / 3 + c.rgb * Saturation;
+	else if (GrayFormula == 2)	// new formula
+		valgray = mix(vec3(pow(dot(pow(vec3(c), vec3(2.2)), vec3(0.2126, 0.7152, 0.0722)), 1.0/2.2)), c.rgb, Saturation);
 	else
 		valgray = mix(vec3(dot(c.rgb, vec3(0.3,0.56,0.14))), c.rgb, Saturation);
 	vec3 val = valgray * Contrast - (Contrast - 1.0) * 0.5;