add 'facing' field to enemy, and update that field when enemy starts moving in different direction (with regards to x_axis)

fcore/enemy/enemy-behaviour.sml

@@ -95,13 +95,15 @@ struct
               (searchStartX, y, searchWidth, searchHeight, ~1, wallTree)
           in
             if hasWallAhead then
-              EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
+              EnemyPatch.W_FACING FACING_RIGHT :: EnemyPatch.W_X_AXIS MOVE_RIGHT
+              :: acc
             else if canWalkAhead (searchStartX, y, wallTree, platformTree) then
               (* invert direction if moving further left 
                * will result in falling down  *)
               acc
             else
-              EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
+              EnemyPatch.W_FACING FACING_RIGHT :: EnemyPatch.W_X_AXIS MOVE_RIGHT
+              :: acc
           end
       | MOVE_RIGHT =>
           let
@@ -116,13 +118,15 @@ struct
               (searchStartX, y, searchWidth, searchHeight, ~1, wallTree)
           in
             if hasWallAhead then
-              EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
+              EnemyPatch.W_FACING FACING_LEFT :: EnemyPatch.W_X_AXIS MOVE_LEFT
+              :: acc
             else if canWalkAhead (searchStartX, y, wallTree, platformTree) then
               (* invert direction if moving further right
                * will result in falling down  *)
               acc
             else
-              EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
+              EnemyPatch.W_FACING FACING_LEFT :: EnemyPatch.W_X_AXIS MOVE_LEFT
+              :: acc
           end
       | STAY_STILL => acc
     end
@@ -202,9 +206,11 @@ struct
         else (* have to travel either left or right before jumping *) if
           ecx < platX
         then
-          EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
+          EnemyPatch.W_FACING FACING_RIGHT :: EnemyPatch.W_X_AXIS MOVE_RIGHT
+          :: acc
         else
-          EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
+          EnemyPatch.W_FACING FACING_LEFT :: EnemyPatch.W_X_AXIS MOVE_LEFT
+          :: acc
       else
         acc
     end
@@ -247,9 +253,11 @@ struct
         else (* have to travel either left or right before jumping *) if
           ecx < platX
         then
-          EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
+          EnemyPatch.W_FACING FACING_RIGHT :: EnemyPatch.W_X_AXIS MOVE_RIGHT
+          :: acc
         else
-          EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
+          EnemyPatch.W_FACING FACING_LEFT :: EnemyPatch.W_X_AXIS MOVE_LEFT
+          :: acc
       else
         acc
     end
@@ -260,27 +268,31 @@ struct
      * So, if we check for jump first, we would always jump before dropping
      * even if jumping is not necessary. *)
     if TraceJump.traceRightDrop (enemy, #id nextPlatform, platformTree) then
-      EnemyPatch.W_Y_AXIS DROP_BELOW_PLATFORM :: EnemyPatch.W_X_AXIS MOVE_RIGHT
-      :: acc
+      EnemyPatch.W_FACING FACING_RIGHT
+      :: EnemyPatch.W_Y_AXIS DROP_BELOW_PLATFORM
+      :: EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
     else if TraceJump.traceRightJump (enemy, #id nextPlatform, platformTree) then
       if standingOnArea (enemy, platformTree) then
-        EnemyPatch.W_Y_AXIS (JUMPING 0) :: EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
+        EnemyPatch.W_FACING FACING_RIGHT :: EnemyPatch.W_Y_AXIS (JUMPING 0)
+        :: EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
       else
-        EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
+        EnemyPatch.W_FACING FACING_RIGHT :: EnemyPatch.W_X_AXIS MOVE_RIGHT
+        :: acc
     else
-      EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
+      EnemyPatch.W_FACING FACING_RIGHT :: EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
 
   fun getMoveLeftPatches (nextPlatform, enemy, platformTree, acc) =
     if TraceJump.traceLeftDrop (enemy, #id nextPlatform, platformTree) then
-      EnemyPatch.W_Y_AXIS DROP_BELOW_PLATFORM :: EnemyPatch.W_X_AXIS MOVE_LEFT
-      :: acc
+      EnemyPatch.W_FACING FACING_LEFT :: EnemyPatch.W_Y_AXIS DROP_BELOW_PLATFORM
+      :: EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
     else if TraceJump.traceLeftJump (enemy, #id nextPlatform, platformTree) then
       if standingOnArea (enemy, platformTree) then
-        EnemyPatch.W_Y_AXIS (JUMPING 0) :: EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
+        EnemyPatch.W_FACING FACING_LEFT :: EnemyPatch.W_Y_AXIS (JUMPING 0)
+        :: EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
       else
-        EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
+        EnemyPatch.W_FACING FACING_LEFT :: EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
     else
-      EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
+      EnemyPatch.W_FACING FACING_LEFT :: EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
 
   (* get patches to help enemy move to nextPlatformID *)
   fun getPathToNextPlatform
@@ -331,13 +343,9 @@ struct
   fun startPatrolPatches (player, enemy, wallTree, platformTree, acc) =
     case #xAxis enemy of
       STAY_STILL =>
-        let
-          val acc =
-            if #x player <= #x enemy then EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
-            else EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
-        in
-          acc
-        end
+        (case #facing enemy of
+           FACING_RIGHT => EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
+         | FACING_LEFT => EnemyPatch.W_X_AXIS MOVE_LEFT :: acc)
     | _ => getPatrolPatches (enemy, wallTree, platformTree, acc)
 
   fun isInFollowRange (player, enemy) =
@@ -484,10 +492,11 @@ struct
             (* make enemy move in opposite direction *)
             case xAxis of
               MOVE_RIGHT =>
-                EnemyPatch.W_X_AXIS MOVE_LEFT :: EnemyPatch.W_X (x - 1)
-                :: patches
+                EnemyPatch.W_FACING FACING_LEFT :: EnemyPatch.W_X_AXIS MOVE_LEFT
+                :: EnemyPatch.W_X (x - 1) :: patches
             | MOVE_LEFT =>
-                EnemyPatch.W_X_AXIS MOVE_RIGHT :: EnemyPatch.W_X (x + 1)
+                EnemyPatch.W_FACING FACING_RIGHT
+                :: EnemyPatch.W_X_AXIS MOVE_RIGHT :: EnemyPatch.W_X (x + 1)
                 :: patches
             | _ => patches
           else

fcore/enemy/enemy-patch.sml

@@ -12,6 +12,7 @@ sig
   | W_BAT_MAX_Y of int
   | W_BAT_MIN_Y of int
   | W_BAT_DIR_Y of EnemyType.bat_dir_y
+  | W_FACING of EntityType.facing
 
   val withPatch: EnemyType.enemy * enemy_patch -> EnemyType.enemy
 
@@ -32,6 +33,7 @@ struct
   | W_BAT_MAX_Y of int
   | W_BAT_MIN_Y of int
   | W_BAT_DIR_Y of EnemyType.bat_dir_y
+  | W_FACING of EntityType.facing
 
   fun mkEnemy
     ( id
@@ -47,6 +49,7 @@ struct
     , batDirY
     , batMaxY
     , batMinY
+    , facing
     ) =
     { id = id
     , health = health
@@ -61,6 +64,7 @@ struct
     , batDirY = batDirY
     , batMaxY = batMaxY
     , batMinY = batMinY
+    , facing = facing
     }
 
   fun withPatch (enemy, patch) =
@@ -79,6 +83,7 @@ struct
         , batDirY
         , batMaxY
         , batMinY
+        , facing
         } = enemy
     in
       case patch of
@@ -97,6 +102,7 @@ struct
             , batDirY
             , batMaxY
             , batMinY
+            , facing
             )
       | W_X x =>
           mkEnemy
@@ -113,6 +119,7 @@ struct
             , batDirY
             , batMaxY
             , batMinY
+            , facing
             )
       | W_X_AXIS xAxis =>
           mkEnemy
@@ -129,6 +136,7 @@ struct
             , batDirY
             , batMaxY
             , batMinY
+            , facing
             )
       | W_Y y =>
           mkEnemy
@@ -145,6 +153,7 @@ struct
             , batDirY
             , batMaxY
             , batMinY
+            , facing
             )
       | W_Y_AXIS yAxis =>
           mkEnemy
@@ -161,6 +170,7 @@ struct
             , batDirY
             , batMaxY
             , batMinY
+            , facing
             )
       | W_PLAT_ID platID =>
           mkEnemy
@@ -177,6 +187,7 @@ struct
             , batDirY
             , batMaxY
             , batMinY
+            , facing
             )
       | W_NEXT_PLAT_ID nextPlatID =>
           mkEnemy
@@ -193,6 +204,7 @@ struct
             , batDirY
             , batMaxY
             , batMinY
+            , facing
             )
       | W_BAT_REST batRest =>
           mkEnemy
@@ -209,6 +221,7 @@ struct
             , batDirY
             , batMaxY
             , batMinY
+            , facing
             )
       | W_BAT_MAX_Y batMaxY =>
           mkEnemy
@@ -225,6 +238,7 @@ struct
             , batDirY
             , batMaxY
             , batMinY
+            , facing
             )
       | W_BAT_MIN_Y batMinY =>
           mkEnemy
@@ -241,6 +255,7 @@ struct
             , batDirY
             , batMaxY
             , batMinY
+            , facing
             )
       | W_BAT_DIR_Y batDirY =>
           mkEnemy
@@ -257,6 +272,24 @@ struct
             , batDirY
             , batMaxY
             , batMinY
+            , facing
+            )
+      | W_FACING facing =>
+          mkEnemy
+            ( id
+            , health
+            , x
+            , y
+            , xAxis
+            , yAxis
+            , variant
+            , platID
+            , nextPlatID
+            , batRest
+            , batDirY
+            , batMaxY
+            , batMinY
+            , facing
             )
     end
 

fcore/enemy/enemy-type.sml

@@ -18,6 +18,7 @@ sig
     , batDirY: bat_dir_y
     , batMaxY: int
     , batMinY: int
+    , facing: EntityType.facing
     }
 
   type falling_enemy = {x: int, y: int, variant: variant}
@@ -43,6 +44,7 @@ struct
     , batDirY: bat_dir_y
     , batMaxY: int
     , batMinY: int
+    , facing: EntityType.facing
     }
 
   type falling_enemy = {x: int, y: int, variant: variant}

fcore/game-type.sml

@@ -109,6 +109,7 @@ struct
         , batRest = 0
         , batMaxY = 485
         , batMinY = 625
+        , facing = EntityType.FACING_RIGHT
         }
       val enemy2 =
         { id = 2
@@ -124,6 +125,7 @@ struct
         , batRest = 0
         , batMaxY = 485
         , batMinY = 625
+        , facing = EntityType.FACING_RIGHT
         }
       val enemies = enemyMapFromList ([enemy1, enemy2], EnemyMap.empty)
       val graph = Graph.fromPlatforms (platforms, platformTree)