From e644160e380fd0b8be78a21b7e7034ec6ebdd5e4 Mon Sep 17 00:00:00 2001
From: Humza Shahid <humzasaur@gmail.com>
Date: Thu, 23 Jan 2025 01:06:16 +0000
Subject: [PATCH] enemy dropping below platform (without any bugs) is fully
 implemented now

---
 fcore/enemy-behaviour.sml |  3 +-
 fcore/physics.sml         | 77 +++++++++++++++++++++++++++------------
 fcore/platform.sml        |  4 +-
 fcore/quad-tree.sml       |  8 ++--
 4 files changed, 61 insertions(+), 31 deletions(-)

diff --git a/fcore/enemy-behaviour.sml b/fcore/enemy-behaviour.sml
index 6fd3a28..f9e40f7 100644
--- a/fcore/enemy-behaviour.sml
+++ b/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) =
diff --git a/fcore/physics.sml b/fcore/physics.sml
index 3a854d6..90dbd57 100644
--- a/fcore/physics.sml
+++ b/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
-    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 y = y + Fn.entitySize - 1
 
-                 val newY = platY - Fn.entitySize
-                 val acc = Fn.W_Y_AXIS ON_GROUND :: Fn.W_Y newY :: acc
-               in
-                 getPlatformPatches (yAxis, platforms, tl, acc)
-               end)
-      | [] => acc
+      val width = Fn.entitySize
+      val height = Platform.platHeight
+
+      val ww = Constants.worldWidth
+      val wh = Constants.worldHeight
+    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
diff --git a/fcore/platform.sml b/fcore/platform.sml
index 7e1c1a7..10063fb 100644
--- a/fcore/platform.sml
+++ b/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 rPlatHeight = 3.0
+  val platHeight = 5
+  val rPlatHeight = 5.0
 
   fun helpGenerateTree (pos, platVec, acc) =
     if pos = Vector.length platVec then
diff --git a/fcore/quad-tree.sml b/fcore/quad-tree.sml
index 6465d07..820d05b 100644
--- a/fcore/quad-tree.sml
+++ b/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)