From 1c105193e20558c8814c3ddab7697a785518d2e0 Mon Sep 17 00:00:00 2001
From: Humza Shahid <humzasaur@gmail.com>
Date: Sat, 8 Feb 2025 08:39:04 +0000
Subject: [PATCH] extract a couple of collision functions to a separate module
 for reuse

---
 fcore/collision.sml             | 15 +++++++++++++++
 fcore/enemy/enemy-behaviour.sml | 28 ++++++++++------------------
 oms.mlb                         |  1 +
 3 files changed, 26 insertions(+), 18 deletions(-)
 create mode 100644 fcore/collision.sml

diff --git a/fcore/collision.sml b/fcore/collision.sml
new file mode 100644
index 0000000..204546c
--- /dev/null
+++ b/fcore/collision.sml
@@ -0,0 +1,15 @@
+structure Collision =
+struct
+  fun isColliding (ix, iy, ifx, ify, cx, cy, cfx, cfy) =
+    ix < cfx andalso ifx > cx andalso iy < cfy andalso ify > cy
+
+  fun isCollidingPlus (ix, iy, iw, ih, cx, cy, cw, ch) =
+    let
+      val ifx = ix + iw
+      val ify = iy + ih
+      val cfx = cx + cw
+      val cfy = cy + ch
+    in
+      isColliding (ix, iy, ifx, ify, cx, cy, cfx, cfy)
+    end
+end
diff --git a/fcore/enemy/enemy-behaviour.sml b/fcore/enemy/enemy-behaviour.sml
index f49cba3..e348277 100644
--- a/fcore/enemy/enemy-behaviour.sml
+++ b/fcore/enemy/enemy-behaviour.sml
@@ -1,20 +1,6 @@
 structure EnemyBehaviour =
 struct
   open GameType
-
-  fun isColliding (ix, iy, ifx, ify, cx, cy, cfx, cfy) =
-    ix < cfx andalso ifx > cx andalso iy < cfy andalso ify > cy
-
-  fun isCollidingPlus (ix, iy, iw, ih, cx, cy, cw, ch) =
-    let
-      val ifx = ix + iw
-      val ify = iy + ih
-      val cfx = cx + cw
-      val cfy = cy + ch
-    in
-      isColliding (ix, iy, ifx, ify, cx, cy, cfx, cfy)
-    end
-
   (* if player is attacking, does enemy collide with attack? *)
   fun isCollidingWithPlayerAttack (player: player, enemy: enemy) =
     let
@@ -28,12 +14,18 @@ struct
         MAIN_ATTACKING {length, ...} =>
           (case facing of
              FACING_RIGHT =>
-               let val px = px + pSize
-               in isCollidingPlus (px, py, length, pSize, ex, ey, eSize, eSize)
+               let
+                 val px = px + pSize
+               in
+                 Collision.isCollidingPlus
+                   (px, py, length, pSize, ex, ey, eSize, eSize)
                end
            | FACING_LEFT =>
-               let val px = px - length
-               in isCollidingPlus (px, py, length, pSize, ex, ey, eSize, eSize)
+               let
+                 val px = px - length
+               in
+                 Collision.isCollidingPlus
+                   (px, py, length, pSize, ex, ey, eSize, eSize)
                end)
       | _ => false
     end
diff --git a/oms.mlb b/oms.mlb
index 4322209..5857ff3 100644
--- a/oms.mlb
+++ b/oms.mlb
@@ -2,6 +2,7 @@ $(SML_LIB)/basis/basis.mlb
 
 (* fcore *)
 fcore/constants.sml
+fcore/collision.sml
 
 fcore/quad-tree-type.sml
 fcore/quad-tree-fold.sml