Add fallback in case mod does not set cg.cgameClientLerpOrigin

This is normally set in etmain so most mods should probably have it, but in case it's not, fallback to client origin

src/client/cl_tc_vis.c

@@ -480,10 +480,17 @@ static qboolean CullFace(const visFace_t *face) {
 }
 
 static void draw(visBrushNode_t *brush, qhandle_t shader) {
-	vec3_t clientOrigin;
+	vec3_t clientOrigin = { 0.0f, 0.0f, 0.0f };
 	frustum = re.GetFrustum();
 
-	VectorCopy(cl.cgameClientLerpOrigin, clientOrigin);
+	// this should be set to cg.refdef.vieworg in cgame,
+	// but fallback to player origin in case a mod has removed the syscall that sets it
+	if (!VectorCompare(cl.cgameClientLerpOrigin, vec3_origin)) {
+		VectorCopy(cl.cgameClientLerpOrigin, clientOrigin);
+	} else if (cl.snap.valid) {
+		VectorCopy(cl.snap.ps.origin, clientOrigin);
+		clientOrigin[2] += (float)cl.snap.ps.viewheight;
+	}
 
 	while (brush) {
 		int i;