From 9244bdc7dbf9e754be48e3351e6fbbc642904f11 Mon Sep 17 00:00:00 2001
From: SNMetamorph <snmetamorph.adc@gmail.com>
Date: Thu, 21 Nov 2024 23:17:30 +0400
Subject: [PATCH] ref: gl: added gl_fog cvar for better GoldSrc compatibility

---
 ref/gl/gl_local.h  | 1 +
 ref/gl/gl_opengl.c | 2 ++
 ref/gl/gl_rmain.c  | 5 +++--
 ref/gl/gl_triapi.c | 2 +-
 4 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/ref/gl/gl_local.h b/ref/gl/gl_local.h
index 6ca3a7e9a..c999c20e8 100644
--- a/ref/gl/gl_local.h
+++ b/ref/gl/gl_local.h
@@ -783,6 +783,7 @@ extern convar_t	gl_test;		// cvar to testify new effects
 extern convar_t	gl_msaa;
 extern convar_t	gl_stencilbits;
 extern convar_t	gl_overbright;
+extern convar_t gl_fog;
 
 extern convar_t	r_lighting_extended;
 extern convar_t	r_lighting_ambient;
diff --git a/ref/gl/gl_opengl.c b/ref/gl/gl_opengl.c
index a632364ba..fa9a1a807 100644
--- a/ref/gl/gl_opengl.c
+++ b/ref/gl/gl_opengl.c
@@ -20,6 +20,7 @@ CVAR_DEFINE_AUTO( gl_test, "0", 0, "engine developer cvar for quick testing new
 CVAR_DEFINE_AUTO( gl_msaa, "1", FCVAR_GLCONFIG, "enable or disable multisample anti-aliasing" );
 CVAR_DEFINE_AUTO( gl_stencilbits, "8", FCVAR_GLCONFIG|FCVAR_READ_ONLY, "pixelformat stencil bits (0 - auto)" );
 CVAR_DEFINE_AUTO( gl_overbright, "1", FCVAR_GLCONFIG, "overbrights" );
+CVAR_DEFINE_AUTO( gl_fog, "1", FCVAR_GLCONFIG, "allow for rendering fog using built-in OpenGL fog implementation" );
 CVAR_DEFINE_AUTO( r_lighting_extended, "1", FCVAR_GLCONFIG, "allow to get lighting from world and bmodels" );
 CVAR_DEFINE_AUTO( r_lighting_ambient, "0.3", FCVAR_GLCONFIG, "map ambient lighting scale" );
 CVAR_DEFINE_AUTO( r_detailtextures, "1", FCVAR_GLCONFIG, "enable detail textures support" );
@@ -1208,6 +1209,7 @@ static void GL_InitCommands( void )
 	gEngfuncs.Cvar_RegisterVariable( &gl_stencilbits );
 	gEngfuncs.Cvar_RegisterVariable( &gl_round_down );
 	gEngfuncs.Cvar_RegisterVariable( &gl_overbright );
+	gEngfuncs.Cvar_RegisterVariable( &gl_fog );
 
 	// these cvar not used by engine but some mods requires this
 	gEngfuncs.Cvar_RegisterVariable( &gl_polyoffset );
diff --git a/ref/gl/gl_rmain.c b/ref/gl/gl_rmain.c
index 69a63dfa1..1a307233a 100644
--- a/ref/gl/gl_rmain.c
+++ b/ref/gl/gl_rmain.c
@@ -44,7 +44,7 @@ void R_AllowFog( qboolean allowed )
 {
 	if( allowed )
 	{
-		if( glState.isFogEnabled )
+		if( glState.isFogEnabled && gl_fog.value )
 			pglEnable( GL_FOG );
 	}
 	else
@@ -800,7 +800,8 @@ R_DrawFog
 */
 void R_DrawFog( void )
 {
-	if( !RI.fogEnabled ) return;
+	if( !RI.fogEnabled || !gl_fog.value )
+		return;
 
 	pglEnable( GL_FOG );
 	if( ENGINE_GET_PARM( PARM_QUAKE_COMPATIBLE ))
diff --git a/ref/gl/gl_triapi.c b/ref/gl/gl_triapi.c
index 2c23c2f6b..db05e5184 100644
--- a/ref/gl/gl_triapi.c
+++ b/ref/gl/gl_triapi.c
@@ -263,7 +263,7 @@ enables global fog on the level
 void TriFog( float flFogColor[3], float flStart, float flEnd, int bOn )
 {
 	// overrided by internal fog
-	if( RI.fogEnabled ) return;
+	if( RI.fogEnabled || !gl_fog.value ) return;
 	RI.fogCustom = bOn;
 
 	// check for invalid parms