keynoderotateleftaction.java

java 3d game jme 工程开发源代码

/*
 * Copyright (c) 2003-2009 jMonkeyEngine
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of 'jMonkeyEngine' nor the names of its contributors 
 *   may be used to endorse or promote products derived from this software 
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.jme.input.action;

import com.jme.math.Matrix3f;
import com.jme.math.Vector3f;
import com.jme.scene.Spatial;

/**
 * <code>KeyNodeRotateLeftAction</code> rotates a node to the left. The axis
 * of rotation is dependant on the setting of the lock axis. If no lock axis is
 * set, the node rotates about it's y-axis. This will allow the node to roll.
 * However, to prevent rolling, setting the lock axis to the world's y-axis (or
 * any desired axis for that matter), will cause the node to rotate about the
 * world. The locking of the axis is particularly useful for control schemes
 * similar to first person shooters.
 * 
 * @author Mark Powell
 * @version $Id: KeyNodeRotateLeftAction.java,v 1.12 2004/08/22 02:00:34 cep21
 *          Exp $
 */
public class KeyNodeRotateLeftAction extends KeyInputAction {
    //temporary variables to handle rotation
    private static final Matrix3f incr = new Matrix3f();

    private static final Matrix3f tempMa = new Matrix3f();

    private static final Matrix3f tempMb = new Matrix3f();

    private static final Vector3f tempVa = new Vector3f();
    //the node to manipulate
    private Spatial node;
    //an optional axis to lock, preventing rolling on this axis.
    private Vector3f lockAxis;

    /**
     * Constructor instantiates a new <code>KeyNodeRotateLeftAction</code>
     * object using the node and speed parameters for it's attributes.
     * 
     * @param node
     *            the node that will be affected by this action.
     * @param speed
     *            the speed at which the node can move.
     */
    public KeyNodeRotateLeftAction(Spatial node, float speed) {
        this.node = node;
        this.speed = speed;
    }

    /**
     * 
     * <code>setLockAxis</code> allows a certain axis to be locked, meaning
     * the camera will always be within the plane of the locked axis. For
     * example, if the node is a first person camera, the user might lock the
     * node's up vector. This will keep the node vertical with the ground.
     * 
     * @param lockAxis
     *            the axis to lock - should be unit length (normalized).
     */
    public void setLockAxis(Vector3f lockAxis) {
        this.lockAxis = lockAxis;
    }

    /**
     * <code>performAction</code> rotates the camera about it's up vector or
     * lock axis at a speed of movement speed * time. Where time is the time
     * between frames and 1 corresponds to 1 second.
     * 
     * @see com.jme.input.action.KeyInputAction#performAction(InputActionEvent)
     */
    public void performAction(InputActionEvent evt) {
        if (lockAxis == null) {
            node.getLocalRotation().getRotationColumn(1, tempVa);
            tempVa.normalizeLocal();
            incr.fromAngleNormalAxis(speed * evt.getTime(), tempVa);
        } else {
            incr.fromAngleNormalAxis(speed * evt.getTime(), lockAxis);
        }
        node.getLocalRotation().fromRotationMatrix(
                incr.mult(node.getLocalRotation().toRotationMatrix(tempMa),
                        tempMb));
        node.getLocalRotation().normalize();
    }
}