enemy dropping below platform (without any bugs) is fully implemented now

fcore/enemy-behaviour.sml

@@ -187,11 +187,12 @@ struct
       val platFinishX = platX + platW
 
       val {x = eX, y = ey, yAxis = eyAxis, ...} = enemy
+      val ey = ey + Constants.enemySize
 
       val standingOnPlat = standingOnArea (enemy, platformTree)
     in
       isBetween (platX, eX, platFinishX) andalso standingOnPlat
-      andalso (ey > platY andalso ey + Constants.jumpLimit >= platY)
+      andalso (ey > platY andalso ey >= platY)
     end
 
   fun canDrop (nextPlatform, platformTree, enemy) =

fcore/physics.sml

@@ -73,31 +73,30 @@ struct
             end
     end
 
-  fun getPlatformPatches (yAxis, platforms: platform vector, lst, acc) =
+  fun standingOnArea (x, y, tree) =
     let
-      open QuadTree
+      val y = y + Fn.entitySize - 1
-    in
-      case lst of
-        platID :: tl =>
-          (case yAxis of
-             DROP_BELOW_PLATFORM =>
-               (* pass through, allowing player to drop below the platform *)
-               getPlatformPatches (yAxis, platforms, tl, acc)
-           | JUMPING _ =>
-               (* pass through, allowing player to jump above the platform *)
-               getPlatformPatches (yAxis, platforms, tl, acc)
-           | _ =>
-               let
-                 (* default case: 
-                  * player will land on platform and stay on the ground there. *)
-                 val {y = platY, ...} = Vector.sub (platforms, platID - 1)
 
-                 val newY = platY - Fn.entitySize
+      val width = Fn.entitySize
-                 val acc = Fn.W_Y_AXIS ON_GROUND :: Fn.W_Y newY :: acc
+      val height = Platform.platHeight
-               in
+
-                 getPlatformPatches (yAxis, platforms, tl, acc)
+      val ww = Constants.worldWidth
-               end)
+      val wh = Constants.worldHeight
-      | [] => acc
+    in
+      QuadTree.hasCollisionAt (x, y, width, height, 0, 0, ww, wh, ~1, tree)
+    end
+
+  fun standingOnAreaID (x, y, tree) =
+    let
+      val y = y + Fn.entitySize - 1
+
+      val width = Fn.entitySize
+      val height = Platform.platHeight
+
+      val ww = Constants.worldWidth
+      val wh = Constants.worldHeight
+    in
+      QuadTree.getItemID (x, y, width, height, 0, 0, ww, wh, tree)
     end
 
   fun getWallPatches (walls: wall vector, lst, acc) =
@@ -151,7 +150,37 @@ struct
 
       val platCollisions = QuadTree.getCollisionsBelow
         (x, y, size, size, 0, 0, ww, wh, 0, platformTree)
-      val acc = getPlatformPatches (yAxis, platforms, platCollisions, [])
+
+      val platID = standingOnAreaID (x, y, platformTree)
+
+      val acc = []
+
+      val acc =
+        if platID <> ~1 then
+          (case yAxis of
+             DROP_BELOW_PLATFORM =>
+               (* pass through, allowing player to drop below the platform *)
+               acc
+           | JUMPING _ =>
+               (* pass through, allowing player to jump above the platform *)
+               acc
+           | FLOATING _ =>
+               (* pass through, allowing player to jump above the platform *)
+               acc
+           | _ =>
+               let
+                 (* default case: 
+                  * player will land on platform and stay on the ground there. *)
+                 val {y = platY, ...}: GameType.platform =
+                   Vector.sub (platforms, platID - 1)
+
+                 val newY = platY - Fn.entitySize
+                 val acc = Fn.W_Y_AXIS ON_GROUND :: Fn.W_Y newY :: acc
+               in
+                 acc
+               end)
+        else
+          acc
 
       val acc =
         case yAxis of

fcore/platform.sml

@@ -2,8 +2,8 @@ structure Platform =
 struct
   (* collision height of a platform.
    * Visual height may (and probably will) be different. *)
-  val platHeight = 3
+  val platHeight = 5
-  val rPlatHeight = 3.0
+  val rPlatHeight = 5.0
 
   fun helpGenerateTree (pos, platVec, acc) =
     if pos = Vector.length platVec then

fcore/quad-tree.sml

@@ -1305,7 +1305,7 @@ struct
                      , quadY
                      , halfWidth
                      , halfHeight
-                     , tree
+                     , topLeft
                      )
                  end
              | TOP_RIGHT =>
@@ -1323,7 +1323,7 @@ struct
                      , quadY
                      , halfWidth
                      , halfHeight
-                     , tree
+                     , topRight
                      )
                  end
              | BOTTOM_LEFT =>
@@ -1341,7 +1341,7 @@ struct
                      , middleY
                      , halfWidth
                      , halfHeight
-                     , tree
+                     , bottomLeft
                      )
                  end
              | BOTTOM_RIGHT =>
@@ -1360,7 +1360,7 @@ struct
                      , middleY
                      , halfWidth
                      , halfHeight
-                     , tree
+                     , bottomRight
                      )
                  end
              | PARENT_QUADRANT => ~1)