1 files changed, 53 insertions, 0 deletions
diff --git a/java/gjt/animation/EdgeCollisionDetector.java b/java/gjt/animation/EdgeCollisionDetector.java
new file mode 100644
index 00000000000..8624b7c2f28
--- /dev/null
+++ b/java/gjt/animation/EdgeCollisionDetector.java
@@ -0,0 +1,53 @@
+package gjt.animation;
+
+import java.awt.*;
+import java.util.Enumeration;
+import java.util.Vector;
+import gjt.Orientation;
+
+/**
+ * A CollisionDetector that detects collisions between Sprites
+ * and the edges of the CollisionArena in which they reside.<p>
+ *
+ * @version 1.0, Apr 1 1996
+ * @author  David Geary
+ * @see     CollisionDetector
+ * @see     Sprite
+ * @see     gjt.test.SimpleAnimationTest
+ * @see     gjt.test.BumpAnimationTest
+ * @see     gjt.test.TwoDrinkersAnimationTest
+ */
+public class EdgeCollisionDetector extends CollisionDetector {
+    public EdgeCollisionDetector(CollisionArena arena) {
+        super(arena);
+    }
+    public void detectCollisions() {
+        Enumeration sprites     = arena.getSprites().elements();
+        Dimension   arenaSize   = arena.getSize();
+        Insets      arenaInsets = arena.getInsets();
+        Sprite      sprite;
+
+        while(sprites.hasMoreElements()) {
+            sprite = (Sprite)sprites.nextElement();
+            
+            Point nl = sprite.nextLocation ();
+            Point mv = sprite.getMoveVector();
+            int   nextRightEdge   = nl.x + sprite.width();
+            int   nextBottomEdge  = nl.y + sprite.height();
+            int   arenaBottomEdge = arenaSize.height - 
+                                    arenaInsets.bottom;
+            int   arenaRightEdge  = arenaSize.width - 
+                                    arenaInsets.right;
+
+            if(nextRightEdge > arenaRightEdge) 
+                arena.edgeCollision(sprite, Orientation.LEFT);
+            else if(nl.x < arenaInsets.left)
+                arena.edgeCollision(sprite, Orientation.RIGHT);
+
+            if(nextBottomEdge > arenaBottomEdge) 
+                arena.edgeCollision(sprite, Orientation.BOTTOM);
+            else if(nl.y < arenaInsets.top)
+                arena.edgeCollision(sprite, Orientation.TOP);
+        }
+    }
+}