Added optional target orientation to PanPath.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@3840 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/jme/camera/PanPath.java

@@ -21,7 +21,9 @@
 
 package com.threerings.jme.camera;
 
+import com.jme.math.Quaternion;
 import com.jme.math.Vector3f;
+import com.jme.renderer.Camera;
 
 /**
  * Pans the camera to the specified location in the specified amount of time.
@@ -29,30 +31,57 @@ import com.jme.math.Vector3f;
 public class PanPath extends CameraPath
 {
     /**
-     * Creates a panning path for the specified camera.
+     * Creates a panning path for the specified camera that will retain the
+     * camera's current orientation.
      *
      * @param target the target position for the camera.
      * @param duration the number of seconds in which to pan the camera.
      */
     public PanPath (CameraHandler camhand, Vector3f target, float duration)
     {
-        super(camhand);
-
-        _start = new Vector3f(camhand.getCamera().getLocation());
-        _velocity = target.subtract(_start);
-        _velocity.divideLocal(duration);
-        _duration = duration;
+        this(camhand, target, null, duration);
     }
 
+    /**
+     * Creates a panning path for the specified camera.
+     *
+     * @param target the target position for the camera.
+     * @param trot the target rotation for the camera (or <code>null</code> to
+     * keep its current orientation)
+     * @param duration the number of seconds in which to pan the camera.
+     */
+    public PanPath (CameraHandler camhand, Vector3f target, Quaternion trot,
+        float duration)
+    {
+        super(camhand);
+
+        Camera cam = camhand.getCamera();
+        _start = new Vector3f(cam.getLocation());
+        _velocity = target.subtract(_start);
+        _velocity.divideLocal(duration);
+        if (trot != null) {
+            _irot = new Quaternion();
+            _irot.fromAxes(cam.getLeft(), cam.getUp(), cam.getDirection());
+            _trot = trot;
+        }
+        
+        _duration = duration;
+    }
+    
     // documentation inherited
     public boolean tick (float secondsSince)
     {
-        _elapsed += secondsSince;
-        _camloc.scaleAdd(Math.min(_elapsed, _duration), _velocity, _start);
+        _elapsed = Math.min(_elapsed + secondsSince, _duration);
+        _camloc.scaleAdd(_elapsed, _velocity, _start);
         _camhand.setLocation(_camloc);
+        if (_irot != null) {
+            _camhand.getCamera().setAxes(_axes.slerp(_irot, _trot,
+                _elapsed / _duration));
+        }
         return (_elapsed >= _duration);
     }
 
     protected Vector3f _start, _velocity, _camloc = new Vector3f();
+    protected Quaternion _irot, _trot, _axes = new Quaternion();
     protected float _elapsed, _duration;
 }