Michael Bayne
c2117ee86d
goodies, both Java 2D and LWJGL/JME 3D. git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@1 ed5b42cb-e716-0410-a449-f6a68f950b19
114 lines
3.9 KiB
Java
114 lines
3.9 KiB
Java
//
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// $Id$
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//
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// Narya library - tools for developing networked games
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// Copyright (C) 2002-2005 Three Rings Design, Inc., All Rights Reserved
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// http://www.threerings.net/code/narya/
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//
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// This library is free software; you can redistribute it and/or modify it
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// under the terms of the GNU Lesser General Public License as published
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// by the Free Software Foundation; either version 2.1 of the License, or
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// (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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package com.threerings.jme.camera;
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import com.jme.math.Vector3f;
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import com.jme.renderer.Camera;
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import com.threerings.jme.Log;
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/**
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* Moves the camera along a cubic Hermite spline path defined by the start and
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* end locations and directions. Spline formulas obtained from
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* <a href="http://en.wikipedia.org/wiki/Cubic_Hermite_spline">Wikipedia</a>.
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*/
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public class SplinePath extends CameraPath
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{
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/**
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* Creates a cubic spline path for the camera to follow.
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*
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* @param tloc the target location
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* @param tdir the target direction
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* @param axis the heading axis (typically {@link Vector3f#UNIT_Z})
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* @param duration the duration of the path
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* @param tension the tension parameter, which can range from zero to one:
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* higher tension values create a more direct path with a sharper turn,
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* lower values create a rounder path with a smoother turn
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*/
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public SplinePath (CameraHandler camhand, Vector3f tloc,
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Vector3f tdir, Vector3f axis, float duration, float tension)
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{
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super(camhand);
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// get the spline function coefficients
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Camera cam = camhand.getCamera();
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_p0 = new Vector3f(cam.getLocation());
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_p1 = new Vector3f(tloc);
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float tscale = (1f - tension) * _p0.distance(_p1);
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_m0 = cam.getDirection().mult(tscale);
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_m1 = tdir.mult(tscale);
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_axis = axis;
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_duration = duration;
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}
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// documentation inherited
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public boolean tick (float secondsSince)
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{
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_elapsed = Math.min(_elapsed + secondsSince, _duration);
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float t = _elapsed / _duration, t2 = t*t, t3 = t2*t,
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h00 = 2*t3 - 3*t2 + 1,
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h00p = 6*t2 - 6*t,
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h10 = t3 - 2*t2 + t,
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h10p = 3*t2 - 4*t + 1,
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h01 = -2*t3 + 3*t2,
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h01p = -6*t2 + 6*t,
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h11 = t3 - t2,
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h11p = 3*t2 - 2*t;
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// take the derivative to find the direction
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_p0.mult(h00p, _dir);
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_dir.scaleAdd(h10p, _m0, _dir);
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_dir.scaleAdd(h01p, _p1, _dir);
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_dir.scaleAdd(h11p, _m1, _dir);
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_dir.normalizeLocal();
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// evaluate the spline function to find the location
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_p0.mult(h00, _loc);
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_loc.scaleAdd(h10, _m0, _loc);
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_loc.scaleAdd(h01, _p1, _loc);
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_loc.scaleAdd(h11, _m1, _loc);
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// compute the left and up vectors using the direction and
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// axis vectors
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Camera cam = _camhand.getCamera();
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_axis.cross(_dir, _left);
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_left.normalizeLocal();
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_dir.cross(_left, _up);
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// update the camera's location and orientation
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cam.setFrame(_loc, _left, _up, _dir);
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return _elapsed >= _duration;
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}
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/** The parameters of the spline. */
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Vector3f _p0, _m0, _p1, _m1, _axis;
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/** Working vectors. */
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Vector3f _loc = new Vector3f(), _left = new Vector3f(),
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_up = new Vector3f(), _dir = new Vector3f();
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/** The elapsed time and total duration. */
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float _elapsed, _duration;
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}
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