From 55c5c8eace4d69deac87bd81734991509c54af14 Mon Sep 17 00:00:00 2001
From: Andrei Drexler <makro@rq3.com>
Date: Tue, 10 Sep 2024 01:11:11 +0200
Subject: [PATCH] Clamp gamma to 0.1

---
 Quake/gl_vidsdl.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Quake/gl_vidsdl.c b/Quake/gl_vidsdl.c
index 3898e6848..6731e6155 100644
--- a/Quake/gl_vidsdl.c
+++ b/Quake/gl_vidsdl.c
@@ -221,8 +221,24 @@ void VID_SetMouseCursor (mousecursor_t cursor)
 //
 //==========================================================================
 
+#define MIN_GAMMA		0.1f
+
 static int fsaa;
 
+/*
+================
+VID_Gamma_f -- called when gamma changes
+================
+*/
+static void VID_Gamma_f (cvar_t *var)
+{
+	if (var->value < MIN_GAMMA)
+	{
+		Con_SafePrintf ("%s %g is too low, clamping to %g\n", var->name, var->value, MIN_GAMMA);
+		Cvar_SetValueQuick (var, MIN_GAMMA);
+	}
+}
+
 /*
 ================
 VID_Gamma_Init -- call on init
@@ -231,6 +247,7 @@ VID_Gamma_Init -- call on init
 static void VID_Gamma_Init (void)
 {
 	Cvar_RegisterVariable (&vid_gamma);
+	Cvar_SetCallback (&vid_gamma, VID_Gamma_f);
 	Cvar_RegisterVariable (&vid_contrast);
 }