More work on object tiles. Revamped isometric scene rendering to

gather dirty sprites and objects and render after base and fringe tile
layers.  Add shadow tiles in the footprint of objects to make them
impassable.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@460 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/miso/client/util/IsoUtil.java

@@ -1,11 +1,13 @@
 //
-// $Id: IsoUtil.java,v 1.7 2001/10/12 00:42:08 shaper Exp $
+// $Id: IsoUtil.java,v 1.8 2001/10/13 01:08:59 shaper Exp $
 
 package com.threerings.miso.scene.util;
 
 import java.awt.*;
+import java.util.Comparator;
 
 import com.threerings.media.sprite.Sprite;
+import com.threerings.media.sprite.DirtyItemList;
 import com.threerings.media.tile.ObjectTile;
 import com.threerings.media.util.MathUtil;
 
@@ -18,6 +20,20 @@ import com.threerings.miso.scene.*;
  */
 public class IsoUtil
 {
+    /** The comparator used to sort dirty items in ascending render order. */
+    public static final Comparator DIRTY_COMP = new DirtyItemComparator();
+
+    /**
+     * Returns a polygon bounding the given object tile display image,
+     * with the bottom of the polygon shaped to conform to the known
+     * object dimensions.
+     *
+     * @param model the scene view model.
+     * @param root the root tile at which the object is located.
+     * @param tile the object tile.
+     *
+     * @return the bounding polygon.
+     */
     public static Polygon getObjectBounds (
         IsoSceneViewModel model, Polygon root, ObjectTile tile)
     {
@@ -55,7 +71,7 @@ public class IsoUtil
         return boundsPoly;
     }
 
- /**
+    /**
      * Given two points in screen pixel coordinates, return the
      * compass direction that point B lies in from point A from an
      * isometric perspective.
@@ -327,4 +343,29 @@ public class IsoUtil
 
     /** Multiplication factor to embed tile coords in full coords. */
     protected static final int FULL_TILE_FACTOR = 100;
+
+    /**
+     * A comparator class to facilitate sorting the dirty items in
+     * ascending x- and y-coordinate order suitable for rendering in
+     * the isometric view with proper visual results.
+     */
+    protected static class DirtyItemComparator implements Comparator
+    {
+        public int compare (Object a, Object b)
+        {
+            DirtyItemList.DirtyItem da = (DirtyItemList.DirtyItem)a;
+            DirtyItemList.DirtyItem db = (DirtyItemList.DirtyItem)b;
+
+            if (da.y <= db.y && da.x <= db.x) {
+                return -1;
+            }
+
+            return 1;
+        }
+
+        public boolean equals (Object obj)
+        {
+	    return (obj == this);
+        }
+    }
 }