Add a Hermite interpolator for the Path code. It would be sort of nice to bring Animations and Paths under a common umbrella, by the way.

git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@326 ed5b42cb-e716-0410-a449-f6a68f950b19

src/as/com/threerings/flash/path/HermiteFunc.as

@@ -0,0 +1,54 @@
+//
+// $Id$
+//
+// Nenya library - tools for developing networked games
+// Copyright (C) 2002-2007 Three Rings Design, Inc., All Rights Reserved
+// http://www.threerings.net/code/nenya/
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.threerings.flash.path {
+
+/**
+ * Interpolates cubically between two values, with beginning and end derivates set
+ * to zero. TODO: Add support for specifying derivate values as well.
+ */
+public class HermiteFunc extends InterpFunc
+{
+    public function HermiteFunc (start :int, end :int)
+    {
+        _start = start;
+        _end = end;
+    }
+
+    // from InterpFunc
+    override public function getValue (t :Number) :int
+    {
+        if (t >= 1) {
+            return _end;
+        } else if (t < 0) { // cope with a funny startOffset
+            return _start;
+        } else {
+            var h00 :Number = 2*t*t*t - 3*t*t + 1;
+            var h01 :Number = -2*t*t*t + 3*t*t;
+
+            return int(_start * h00 + _end * h01);
+        }
+    }
+
+    protected var _start :int;
+    protected var _end :int;
+}
+}

src/as/com/threerings/flash/path/LinePath.as

@@ -6,7 +6,7 @@ package com.threerings.flash.path {
 import flash.display.DisplayObject;
 
 /**
- * Moves a display object along a straight line path in a specified amount of time.
+ * Moves a display object along a line path in a specified amount of time.
  */
 public class LinePath extends Path
 {