Fix the missing world on map reload.

If the map got reloaded but the current leaf didn't change the world (and
most entities) didn't get drawn. Forcing a vis update by first setting
r_viewleaf to null and marking surfaces does the trick :)

libs/video/renderer/gl/gl_rmisc.c

@@ -192,7 +192,10 @@ R_NewMap (model_t *worldmodel, struct model_s **models, int num_models)
 	for (i = 0; i < r_worldentity.model->numleafs; i++)
 		r_worldentity.model->leafs[i].efrags = NULL;
 
+	// Force a vis update
 	r_viewleaf = NULL;
+	R_MarkLeaves ();
+
 	R_ClearParticles ();
 
 	GL_BuildLightmaps (models, num_models);

libs/video/renderer/glsl/glsl_main.c

@@ -274,6 +274,10 @@ R_NewMap (model_t *worldmodel, struct model_s **models, int num_models)
 	memset (&r_worldentity, 0, sizeof (r_worldentity));
 	r_worldentity.model = worldmodel;
 
+	// Force a vis update
+	r_viewleaf = NULL;
+	R_MarkLeaves ();
+
 	R_FreeAllEntities ();
 	R_ClearParticles ();
 	R_RegisterTextures (models, num_models);

libs/video/renderer/r_bsp.c

@@ -63,6 +63,8 @@ R_MarkLeaves (void)
 
 	r_visframecount++;
 	r_oldviewleaf = r_viewleaf;
+	if (!r_viewleaf)
+		return;
 
 	if (r_novis->int_val) {
 		r_oldviewleaf = 0;	// so vis will be recalcualted when novis gets

libs/video/renderer/sw/sw_rmain.c

@@ -199,7 +199,10 @@ R_NewMap (model_t *worldmodel, struct model_s **models, int num_models)
 	if (worldmodel->skytexture)
 		R_InitSky (worldmodel->skytexture);
 
+	// Force a vis update
 	r_viewleaf = NULL;
+	R_MarkLeaves ();
+
 	R_ClearParticles ();
 
 	r_cnumsurfs = r_maxsurfs->int_val;

libs/video/renderer/sw32/sw32_rmain.c

@@ -227,7 +227,10 @@ R_NewMap (model_t *worldmodel, struct model_s **models, int num_models)
 	if (worldmodel->skytexture)
 		R_InitSky (worldmodel->skytexture);
 
+	// Force a vis update
 	r_viewleaf = NULL;
+	R_MarkLeaves ();
+
 	R_ClearParticles ();
 
 	r_cnumsurfs = r_maxsurfs->int_val;