EI S14 - Indicate uncleared swamp hexes with "swap reed" images

EI's S14 involves traversing a swamp with hidden undead. To make it easier for the player to remember which hexes they've cleared, mark the uncleared hexes.

data/campaigns/Eastern_Invasion/scenarios/14_The_Drowned_Plains.cfg

@@ -344,6 +344,40 @@
     [event]
         name=prestart
 
+        #---------------------------
+        # MARK UNTOUCHED HEXES
+        #---------------------------
+        # make it easier for the player to know which hexes they've cleared of undead by marking the untouched ones
+#define PLACE_REEDS TERRAIN IPF
+    [store_locations]
+        x,y=1-99,1-99
+        terrain={TERRAIN}
+        variable=swamp_hexes
+    [/store_locations]
+    [foreach]
+        array=swamp_hexes
+        [do]
+            {VARIABLE_OP variant rand 1..5}
+            {PLACE_IMAGE scenery/swamp-reeds$variant|.png{IPF} $this_item.x $this_item.y}
+            {CLEAR_VARIABLE variant}
+            [event]
+                name=enter hex
+                delayed_variable_substitution=no
+                [filter]
+                    side=1
+                    [filter_location]
+                        x,y=$this_item.x,$this_item.y
+                        radius=1
+                    [/filter_location]
+                [/filter]
+                {REMOVE_IMAGE $this_item.x $this_item.y}
+            [/event]
+        [/do]
+    [/foreach]
+#enddef
+        {PLACE_REEDS Ss,Ss^Qhu "~CS(25,25,25)"}
+        {PLACE_REEDS Sm,Sm^Qhu "~CS(-15,-35,0)"}
+
         #---------------------------
         # SPAWN AMBUSHERS
         #---------------------------