Added spline path for camera.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@3823 542714f4-19e9-0310-aa3c-eee0fc999fb1
2006-01-28 01:35:08 +00:00
parent 21181e8ba3
commit e81084a588
1 changed files with 109 additions and 0 deletions
@@ -0,0 +1,109 @@
+//
+// $Id$
+//
+// Narya library - tools for developing networked games
+// Copyright (C) 2002-2005 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.camera;
+
+import com.jme.math.Vector3f;
+import com.jme.renderer.Camera;
+
+import com.threerings.jme.Log;
+
+/**
+ * Moves the camera along a cubic Hermite spline path defined by the start and
+ * end locations and directions.  Spline formulas obtained from
+ * <a href="http://en.wikipedia.org/wiki/Cubic_Hermite_spline">Wikipedia</a>.
+ */
+public class SplinePath extends CameraPath
+{
+    /**
+     * Creates a cubic spline path for the camera to follow.
+     *
+     * @param tloc the target location
+     * @param tdir the target direction
+     * @param duration the duration of the path
+     */
+    public SplinePath (CameraHandler camhand, Vector3f tloc,
+        Vector3f tdir, float duration)
+    {
+        super(camhand);
+        
+        // get the spline function coefficients
+        Camera cam = camhand.getCamera();
+        _p0 = new Vector3f(cam.getLocation());
+        _p1 = new Vector3f(tloc);
+        float pdist = _p0.distance(_p1);
+        _m0 = cam.getDirection().mult(pdist*0.5f);
+        _m1 = tdir.mult(pdist*0.5f);
+        
+        _duration = duration;
+    }
+    
+    // documentation inherited
+    public boolean tick (float secondsSince)
+    {
+        _elapsed = Math.min(_elapsed + secondsSince, _duration);
+        float t = _elapsed / _duration, t2 = t*t, t3 = t2*t,
+            h00 = 2*t3 - 3*t2 + 1,
+            h00p = 6*t2 - 6*t,
+            h10 = t3 - 2*t2 + t,
+            h10p = 3*t2 - 4*t + 1,
+            h01 = -2*t3 + 3*t2,
+            h01p = -6*t2 + 6*t,
+            h11 = t3 - t2,
+            h11p = 3*t2 - 2*t;
+    
+        // take the derivative to find the direction and inst. speed
+        _p0.mult(h00p, _dir);
+        _dir.scaleAdd(h10p, _m0, _dir);
+        _dir.scaleAdd(h01p, _p1, _dir);
+        _dir.scaleAdd(h11p, _m1, _dir);
+        float inst = _dir.length();
+        _dir.normalizeLocal();
+        
+        // evaluate the spline function to find the location
+        _p0.mult(h00, _loc);
+        _loc.scaleAdd(h10, _m0, _loc);
+        _loc.scaleAdd(h01, _p1, _loc);
+        _loc.scaleAdd(h11, _m1, _loc);
+        
+        // compute the left and up vectors using the camera's current
+        // up vector
+        Camera cam = _camhand.getCamera();
+        cam.getUp().cross(_dir, _left);
+        _left.normalizeLocal();
+        _dir.cross(_left, _up);
+        
+        // update the camera's location and orientation
+        cam.setFrame(_loc, _left, _up, _dir);
+        
+        return _elapsed >= _duration;
+    }
+ 
+    /** The parameters of the spline. */
+    Vector3f _p0, _m0, _p1, _m1;
+    
+    /** Working vectors. */
+    Vector3f _loc = new Vector3f(), _left = new Vector3f(),
+        _up = new Vector3f(), _dir = new Vector3f();
+    
+    /** The elapsed time and speed parameters. */
+    float _elapsed, _duration;
+}