Updated standard source header. Created a time function mechanism that can be

used to easily plug in different methods of smoothly varying a value over time.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@3834 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/jme/util/LinearTimeFunction.java

@@ -0,0 +1,42 @@
+//
+// $Id: LinearTimeFunction.java 3122 2004-09-18 22:57:08Z mdb $
+//
+// Narya library - tools for developing networked games
+// Copyright (C) 2002-2006 Three Rings Design, Inc., All Rights Reserved
+// http://www.threerings.net/code/narya/
+//
+// 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.jme.util;
+
+/**
+ * Varies a value linearly with time.
+ */
+public class LinearTimeFunction extends TimeFunction
+{
+    public LinearTimeFunction (float start, float end, float duration)
+    {
+        super(start, end, duration);
+        _range = (end - start);
+    }
+
+    // documentation inherited
+    protected float computeValue ()
+    {
+        return (_elapsed * _range / _duration) + _start;
+    }
+
+    protected float _range;
+}