implement left jump/left drop tracing in trace-jump.sml, and verified that it works

fcore/enemy-behaviour.sml

@@ -249,9 +249,8 @@ 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_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
@@ -261,79 +260,16 @@ struct
       EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
 
   fun getMoveLeftPatches (nextPlatform, enemy, platformTree, acc) =
-    let
-      val {x = platX, y = platY, width = platWidth, ...} = nextPlatform
-      val platFinishX = platX + platWidth
-
-      val {x = ex, y = ey, yAxis = eyAxis, ...} = enemy
-
-      val xDiff = ex - platX
-    in
-      if ey > platY then
-        (* enemy is lower than next platform so needs to jump *)
-        let
-          val jumpAmt =
-            case eyAxis of
-              JUMPING amt => amt
-            | _ => 0
-          val apexY = ey - (Constants.jumpLimit - jumpAmt)
-
-          val yDiff = platY - apexY
-        in
-          if yDiff <= xDiff then
-            (* enemy can reach platform by jumping *)
-            let
-              val acc =
-                if standingOnArea (enemy, platformTree) then
-                  EnemyPatch.W_Y_AXIS (JUMPING 0) :: acc
-                else
-                  acc
-            in
-              EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
-            end
-          else
-            EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
-        end
+    if TraceJump.traceLeftDrop (enemy, #id nextPlatform, platformTree) then
+      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
       else
-        (* platform is below or at same y coordinat as enemy 
-         * so might possibly require dropping below rather than jumping. *)
-        let
-          (* check if we can get to next platform without jumping.
-           * If we can, then simply move rightwards 
-           * and possibly drop below platform. 
-           * Else, jump and move rightwards *)
-          val yDiff = platY - ey
-        in
-          if yDiff >= xDiff then
-            (* can reach next platform by simply dropping and moving left *)
-            EnemyPatch.W_Y_AXIS DROP_BELOW_PLATFORM
-            :: EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
-          else
-            let
-              val jumpAmt =
-                case eyAxis of
-                  JUMPING amt => amt
-                | _ => 0
-              val apexY = ey - (Constants.jumpLimit - jumpAmt)
-              val yDiff = platY - apexY
-            in
-              if yDiff <= xDiff then
-                (* can reach if we jump and move left *)
-                let
-                  val acc =
-                    if standingOnArea (enemy, platformTree) then
-                      EnemyPatch.W_Y_AXIS (JUMPING 0) :: acc
-                    else
-                      acc
-                in
-                  EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
-                end
-              else
-                (* cannot reach yet so move left until we can *)
-                EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
-            end
-        end
-    end
+        EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
+    else
+      EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
 
   (* get patches to help enemy move to nextPlatformID *)
   fun getPathToNextPlatform
@@ -368,27 +304,26 @@ struct
    * then move enemy left/right to make them fully overlap with platform *)
   fun getHorizontalLandingPatches (enemy, nextPlatform, acc) =
     case #xAxis enemy of
-      STAY_STILL =>
-        acc
+      STAY_STILL => acc
     | _ =>
-      let
-        val {x = px, width = pw, ...} = nextPlatform
-        val pfx = px + pw
+        let
+          val {x = px, width = pw, ...} = nextPlatform
+          val pfx = px + pw
 
-        val {x = ex, ...} = enemy
-        val efx = ex + Constants.enemySize
-      in
-        if isBetween (px, ex, pfx) andalso isBetween (px, efx, pfx) then
-          acc
-        else
-          let
-            val startDiff = abs (px - ex)
-            val endDiff = abs (pfx - efx)
-          in
-            if startDiff > endDiff then EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
-            else EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
-          end
-      end
+          val {x = ex, ...} = enemy
+          val efx = ex + Constants.enemySize
+        in
+          if isBetween (px, ex, pfx) andalso isBetween (px, efx, pfx) then
+            acc
+          else
+            let
+              val startDiff = abs (px - ex)
+              val endDiff = abs (pfx - efx)
+            in
+              if startDiff > endDiff then EnemyPatch.W_X_AXIS MOVE_LEFT :: acc
+              else EnemyPatch.W_X_AXIS MOVE_RIGHT :: acc
+            end
+        end
 
   fun getFallingPatches (enemy, newPlatformID, platforms, acc) =
     let
@@ -426,16 +361,13 @@ struct
     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
+          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
-    | _ =>
-        getPatrollPatches (enemy, wallTree, platformTree, acc)
+    | _ => getPatrollPatches (enemy, wallTree, platformTree, acc)
 
   fun getFollowPatches
     (player: player, enemy, wallTree, platformTree, platforms, acc) =
@@ -466,8 +398,7 @@ struct
             nextPlatformID :: _ =>
               let
                 val acc = EnemyPatch.W_NEXT_PLAT_ID nextPlatformID :: acc
-                val acc =
-                getPathToNextPlatform
+                val acc = getPathToNextPlatform
                   ( nextPlatformID
                   , platforms
                   , platformTree
@@ -479,7 +410,8 @@ struct
               in
                 EnemyPatch.W_X_AXIS STAY_STILL :: acc
               end
-          | [] => startPatrolPatches (player, enemy, wallTree, platformTree, acc)
+          | [] =>
+              startPatrolPatches (player, enemy, wallTree, platformTree, acc)
         end
     end
 

fcore/game-type.sml

@@ -168,13 +168,13 @@ struct
       val walls = Vector.fromList [wall1, wall2, wall3]
       val wallTree = Wall.generateTree walls
 
-      val plat1 = {id = 1, x = 155, y = 911, width = 199}
+      val plat1 = {id = 1, x = 111, y = 711, width = 199}
       val plat2 = {id = 2, x = 355, y = 759, width = 555}
-      val plat3 = {id = 3, x = 355, y = 659, width = 111}
-      val plat4 = {id = 4, x = 155, y = 855, width = 99}
-      val plat5 = {id = 5, x = 155, y = 811, width = 199}
-      val plat6 = {id = 6, x = 155, y = 710, width = 199}
-      val plat7 = {id = 7, x = 301, y = 855, width = 99}
+      val plat3 = {id = 3, x = 955, y = 659, width = 111}
+      val plat4 = {id = 4, x = 455, y = 855, width = 99}
+      val plat5 = {id = 5, x = 555, y = 811, width = 199}
+      val plat6 = {id = 6, x = 655, y = 710, width = 199}
+      val plat7 = {id = 7, x = 701, y = 855, width = 99}
       val plat8 = {id = 8, x = 970, y = 815, width = 303}
       val plat9 = {id = 9, x = 959, y = 705, width = 303}
       val plat10 = {id = 10, x = 970, y = 759, width = 303}
@@ -184,9 +184,9 @@ struct
       val plat14 = {id = 14, x = 1000, y = 415, width = 303}
       val plat15 = {id = 15, x = 1000, y = 335, width = 303}
       val plat16 = {id = 16, x = 1000, y = 295, width = 303}
-      val plat17 = {id = 17, x = 155, y = 599, width = 199}
-      val plat18 = {id = 18, x = 155, y = 499, width = 199}
-      val plat19 = {id = 19, x = 155, y = 399, width = 199}
+      val plat17 = {id = 17, x = 855, y = 599, width = 199}
+      val plat18 = {id = 18, x = 755, y = 499, width = 199}
+      val plat19 = {id = 19, x = 655, y = 399, width = 199}
       val platforms = Vector.fromList
         [ plat1
         , plat2
@@ -212,8 +212,8 @@ struct
 
       val enemy1 =
         { id = 1
-        , x = 251
-        , y = 855
+        , x = 751
+        , y = 555
         , health = 1
         , xAxis = STAY_STILL
         , yAxis = FALLING

fcore/trace-jump.sml

@@ -1,14 +1,16 @@
 structure TraceJump =
 struct
-  structure Trace = MakeQuadTreeFold (struct
-    type env = int
-    type state = bool
+  structure Trace =
+    MakeQuadTreeFold
+      (struct
+         type env = int
+         type state = bool
 
-    fun fold (foldPlatID, nextPlatID, hasFoundNextPlatID) =
-      hasFoundNextPlatID orelse foldPlatID = nextPlatID
-  end)
+         fun fold (foldPlatID, nextPlatID, hasFoundNextPlatID) =
+           hasFoundNextPlatID orelse foldPlatID = nextPlatID
+       end)
 
-  fun traceRightJumpDescent (x, y, nextPlatID, platTree) =
+  fun traceRightDescent (x, y, nextPlatID, platTree) =
     if x >= Constants.worldWidth orelse y >= Constants.worldHeight then
       (* we hit bounds of screen and saw that there was 
        * no way to jump to next nextPlatID *)
@@ -17,62 +19,120 @@ struct
       let
         val width = Constants.moveEnemyBy
         val height = Constants.worldHeight - y
-        val shouldJumpRight =
-          Trace.foldRegion (x, y, width, height, nextPlatID, false, platTree)
+        val shouldJumpRight = Trace.foldRegion
+          (x, y, width, height, nextPlatID, false, platTree)
 
         val nextX = x + Constants.moveEnemyBy
         val nextY = y + Constants.moveEnemyBy
       in
-        shouldJumpRight orelse 
-        traceRightJumpDescent (nextX, nextY, nextPlatID, platTree)
+        shouldJumpRight
+        orelse traceRightDescent (nextX, nextY, nextPlatID, platTree)
       end
 
-  fun traceRightDrop (enemy, nextPlatID, platTree) =
+  fun traceRightDrop (enemy: GameType.enemy, nextPlatID, platTree) =
     let
-      open GameType
-      val {x, y, ...}: enemy = enemy
+      val {x, y, ...} = enemy
       val x = x - Constants.enemySize
     in
-      traceRightJumpDescent (x, y, nextPlatID, platTree)
+      traceRightDescent (x, y, nextPlatID, platTree)
     end
 
   fun traceRightJumpAscent (x, y, remainingJump, nextPlatID, platTree) =
     if remainingJump >= Constants.jumpLimit then
-      traceRightJumpDescent (x, y, nextPlatID, platTree)
+      traceRightDescent (x, y, nextPlatID, platTree)
     else
       let
         val width = Constants.moveEnemyBy
         val height = Constants.worldHeight - y
-        val shouldJumpRight =
-          Trace.foldRegion (x, y, width, height, nextPlatID, false, platTree)
+        val shouldJumpRight = Trace.foldRegion
+          (x, y, width, height, nextPlatID, false, platTree)
 
         val nextX = x + Constants.moveEnemyBy
         val nextY = y - Constants.moveEnemyBy
         val nextJump = remainingJump + Constants.moveEnemyBy
       in
-        shouldJumpRight orelse
+        shouldJumpRight
+        orelse
         traceRightJumpAscent (nextX, nextY, nextJump, nextPlatID, platTree)
       end
 
-  fun traceRightJump (enemy, nextPlatID, platTree) =
+  fun traceRightJump (enemy: GameType.enemy, nextPlatID, platTree) =
     let
-      open GameType
-      val {x, y, ...}: enemy = enemy
+      val {x, y, ...} = enemy
       val x = x - Constants.enemySize
+
+      open GameType
     in
       if EnemyPhysics.standingOnArea (x, y, platTree) then
         traceRightJumpAscent (x, y, 0, nextPlatID, platTree)
       else
         case #yAxis enemy of
-          JUMPING amt =>
-            traceRightJumpAscent (x, y, amt, nextPlatID, platTree)
-        | ON_GROUND =>
-            traceRightJumpAscent (x, y, 0, nextPlatID, platTree)
-        | FALLING =>
-            traceRightJumpDescent (x, y, nextPlatID, platTree)
-        | DROP_BELOW_PLATFORM =>
-            traceRightJumpDescent (x, y, nextPlatID, platTree)
-        | FLOATING _ =>
-            traceRightJumpDescent (x, y, nextPlatID, platTree)
+          JUMPING amt => traceRightJumpAscent (x, y, amt, nextPlatID, platTree)
+        | ON_GROUND => traceRightJumpAscent (x, y, 0, nextPlatID, platTree)
+        | FALLING => traceRightDescent (x, y, nextPlatID, platTree)
+        | DROP_BELOW_PLATFORM => traceRightDescent (x, y, nextPlatID, platTree)
+        | FLOATING _ => traceRightDescent (x, y, nextPlatID, platTree)
+    end
+
+  fun traceLeftDescent (x, y, nextPlatID, platTree) =
+    if x <= 0 orelse y >= Constants.worldHeight then
+      false
+    else
+      let
+        val width = Constants.moveEnemyBy
+        val height = Constants.worldHeight - y
+        val shouldJumpLeft = Trace.foldRegion
+          (x, y, width, height, nextPlatID, false, platTree)
+
+        val nextX = x - Constants.moveEnemyBy
+        val nextY = y + Constants.moveEnemyBy
+      in
+        shouldJumpLeft
+        orelse traceRightDescent (nextX, nextY, nextPlatID, platTree)
+      end
+
+  fun traceLeftDrop (enemy: GameType.enemy, nextPlatID, platTree) =
+    let
+      val {x, y, ...} = enemy
+      val x = x + Constants.enemySize
+    in
+      traceLeftDescent (x, y, nextPlatID, platTree)
+    end
+
+  fun traceLeftJumpAscent (x, y, remainingJump, nextPlatID, platTree) =
+    if remainingJump >= Constants.jumpLimit then
+      traceLeftDescent (x, y, nextPlatID, platTree)
+    else
+      let
+        val width = Constants.moveEnemyBy
+        val height = Constants.worldHeight - y
+        val shouldJumpLeft = Trace.foldRegion
+          (x, y, width, height, nextPlatID, false, platTree)
+
+        val nextX = x - Constants.moveEnemyBy
+        val nextY = y - Constants.moveEnemyBy
+        val nextJump = remainingJump + Constants.moveEnemyBy
+      in
+        shouldJumpLeft
+        orelse
+        traceLeftJumpAscent (nextX, nextY, nextJump, nextPlatID, platTree)
+      end
+
+  fun traceLeftJump (enemy: GameType.enemy, nextPlatID, platTree) =
+    let
+      val {x, y, ...} = enemy
+      val x = x + Constants.enemySize
+
+      open GameType
+    in
+      if EnemyPhysics.standingOnArea (x, y, platTree) then
+        traceLeftJumpAscent (x, y, 0, nextPlatID, platTree)
+      else
+        case #yAxis enemy of
+          JUMPING amt => traceLeftJumpAscent (x, y, amt, nextPlatID, platTree)
+        | ON_GROUND => traceLeftJumpAscent (x, y, 0, nextPlatID, platTree)
+        | FALLING => traceLeftDescent (x, y, nextPlatID, platTree)
+        | DROP_BELOW_PLATFORM => traceLeftDescent (x, y, nextPlatID, platTree)
+        | FLOATING _ => traceLeftDescent (x, y, nextPlatID, platTree)
     end
 end