Make fog-of-war darker and make that value changeable (#166)

* Make fog-of-war darker and make that value changeable

habitat/utils/visualizations/maps.py

@@ -327,11 +327,10 @@ def get_topdown_map(
     return top_down_map
 
 
-FOG_OF_WAR_COLOR_DESAT = np.array([[0.7], [1.0]])
-
-
 def colorize_topdown_map(
-    top_down_map: np.ndarray, fog_of_war_mask: Optional[np.ndarray] = None
+    top_down_map: np.ndarray,
+    fog_of_war_mask: Optional[np.ndarray] = None,
+    fog_of_war_desat_amount: float = 0.5,
 ) -> np.ndarray:
     r"""Convert the top down map to RGB based on the indicator values.
         Args:
@@ -339,17 +338,21 @@ def colorize_topdown_map(
             fog_of_war_mask: A mask used to determine which parts of the 
                 top_down_map are visible
                 Non-visible parts will be desaturated
+            fog_of_war_desat_amount: Amount to desaturate the color of unexplored areas
+                Decreasing this value will make unexplored areas darker
+                Default: 0.5
         Returns:
             A colored version of the top-down map.
     """
     _map = TOP_DOWN_MAP_COLORS[top_down_map]
 
     if fog_of_war_mask is not None:
+        fog_of_war_desat_values = np.array([[fog_of_war_desat_amount], [1.0]])
         # Only desaturate things that are valid points as only valid points get revealed
         desat_mask = top_down_map != MAP_INVALID_POINT
 
         _map[desat_mask] = (
-            _map * FOG_OF_WAR_COLOR_DESAT[fog_of_war_mask]
+            _map * fog_of_war_desat_values[fog_of_war_mask]
         ).astype(np.uint8)[desat_mask]
 
     return _map