diff --git a/ref/gl/gl_local.h b/ref/gl/gl_local.h
index 315312a2..8570bdbf 100644
--- a/ref/gl/gl_local.h
+++ b/ref/gl/gl_local.h
@@ -34,6 +34,7 @@ GNU General Public License for more details.
 #include "common/cvar.h"
 #include "gl_export.h"
 #include "wadfile.h"
+#include "common/mod_local.h"
 
 #if XASH_PSVITA
 int VGL_ShimInit( void );
@@ -252,10 +253,8 @@ typedef struct
 	// cull info
 	vec3_t		modelorg;		// relative to viewpoint
 
-	qboolean fCustomSkybox;
-
 	// get from engine
-	struct world_static_s *world;
+	world_static_t *world;
 	cl_entity_t *entities;
 	movevars_t *movevars;
 	color24 *palette;
diff --git a/ref/gl/gl_rsurf.c b/ref/gl/gl_rsurf.c
index 93cb5a35..e237c659 100644
--- a/ref/gl/gl_rsurf.c
+++ b/ref/gl/gl_rsurf.c
@@ -1300,7 +1300,7 @@ void R_DrawTextureChains( void )
 	RI.currententity = CL_GetEntityByIndex( 0 );
 	RI.currentmodel = RI.currententity->model;
 
-	if( ENGINE_GET_PARM( PARM_SKY_SPHERE ) )
+	if( FBitSet( tr.world->flags, FWORLD_SKYSPHERE ) && !FBitSet( tr.world->flags, FWORLD_CUSTOM_SKYBOX ))
 	{
 		pglDisable( GL_TEXTURE_2D );
 		pglColor3f( 1.0f, 1.0f, 1.0f );
@@ -1310,7 +1310,7 @@ void R_DrawTextureChains( void )
 	for( s = skychain; s != NULL; s = s->texturechain )
 		R_AddSkyBoxSurface( s );
 
-	if( ENGINE_GET_PARM( PARM_SKY_SPHERE ) )
+	if( FBitSet( tr.world->flags, FWORLD_SKYSPHERE ) && !FBitSet( tr.world->flags, FWORLD_CUSTOM_SKYBOX ))
 	{
 		pglEnable( GL_TEXTURE_2D );
 		if( skychain )
diff --git a/ref/gl/gl_warp.c b/ref/gl/gl_warp.c
index 62517cf1..30bdf06c 100644
--- a/ref/gl/gl_warp.c
+++ b/ref/gl/gl_warp.c
@@ -332,7 +332,7 @@ void R_AddSkyBoxSurface( msurface_t *fa )
 	float	*v;
 	int	i;
 
-	if( ENGINE_GET_PARM( PARM_SKY_SPHERE ) && fa->polys && !tr.fCustomSkybox )
+	if( FBitSet( tr.world->flags, FWORLD_SKYSPHERE ) && fa->polys && !FBitSet( tr.world->flags, FWORLD_CUSTOM_SKYBOX ))
 	{
 		glpoly_t	*p = fa->polys;
 
@@ -376,7 +376,7 @@ void R_UnloadSkybox( void )
 	tr.skyboxbasenum = SKYBOX_BASE_NUM;	// set skybox base (to let some mods load hi-res skyboxes)
 
 	memset( tr.skyboxTextures, 0, sizeof( tr.skyboxTextures ));
-	tr.fCustomSkybox = false;
+	ClearBits( tr.world->flags, FWORLD_CUSTOM_SKYBOX );
 }
 
 /*
@@ -478,7 +478,7 @@ void R_SetupSky( const char *skyboxname )
 
 	if( i == 6 )
 	{
-		tr.fCustomSkybox = true;
+		SetBits( tr.world->flags, FWORLD_CUSTOM_SKYBOX );
 		gEngfuncs.Con_DPrintf( "done\n" );
 		return; // loaded
 	}