JME Mouse Movement #10

In this post I am going to show you how to move the camera with the mouse. I only want to allow the user to move the camera from left to right, and not up and down. I am going to use the FirstPersonHandler class. This class contains a class called MouseLookHandler and with this class you are suppose to be able to lock the axis. However, this doesn't let me lock the axis in the y direction. When I look at the code, I only see the the rotateLeft and the rotateRight lockable.

rotateLeft.setLockAxis(lockAxis);
rotateRight.setLockAxis(lockAxis);

Therefore, I modified the code so the camera won't rotate in the y direction.

This is the modified FirstPersonHandler class. The only difference is that I changed the MouseLookHandler to be my modified MouseLookHandler.

NewFirstPersonHandler.java

/*
* Copyright (c) 2003-2006 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.guid.asteroid3D;

import com.jme.input.InputHandler;
import com.jme.input.KeyboardLookHandler;
import com.jme.input.MouseLookHandler;
import com.jme.renderer.Camera;

/**
* <code>FirsPersonController</code> defines an InputHandler that sets
* input to be controlled similar to First Person Shooting games. By default the
* commands are, WSAD moves the camera forward, backward and strafes. The
* arrow keys rotate and tilt the camera and the mouse also rotates and tilts
* the camera. <br>
* This is a handler that is composed from {@link KeyboardLookHandler} and {@link MouseLookHandler}.
* @author Mark Powell
* @version $Id: FirstPersonHandler.java,v 1.17 2007/08/26 08:44:20 irrisor Exp $
*/
public class NewFirstPersonHandler extends InputHandler {
private NewMouseLookHandler mouseLookHandler;
private KeyboardLookHandler keyboardLookHandler;

/**
* @return handler for keyboard controls
*/
public KeyboardLookHandler getKeyboardLookHandler() {
return keyboardLookHandler;
}

/**
* @return handler for mouse controls
*/
public NewMouseLookHandler getMouseLookHandler() {
return mouseLookHandler;
}

public void setButtonPressRequired(boolean value) {
mouseLookHandler.requireButtonPress(value);
}

/**
* Creates a first person handler.
* @param cam The camera to move by this handler.
*/
public NewFirstPersonHandler( Camera cam ) {
mouseLookHandler = new NewMouseLookHandler( cam, 1 );
addToAttachedHandlers( mouseLookHandler );
keyboardLookHandler = new KeyboardLookHandler( cam, 0.5f, 0.01f );
addToAttachedHandlers( keyboardLookHandler );
}

/**
* Creates a first person handler.
* @param cam The camera to move by this handler.
* @param moveSpeed action speed for move actions
* @param turnSpeed action speed for rotating actions
*/
public NewFirstPersonHandler(Camera cam, float moveSpeed, float turnSpeed ) {
mouseLookHandler = new NewMouseLookHandler( cam, turnSpeed );
addToAttachedHandlers( mouseLookHandler );
keyboardLookHandler = new KeyboardLookHandler( cam, moveSpeed, turnSpeed );
addToAttachedHandlers( keyboardLookHandler );
}
}

In the NewMouseLookHandler class, the only thing I changed was the MouseLook. I am using my modified MouseLook class.

NewMouseLookHandler.java

package com.guid.asteroid3D;

/*
* Copyright (c) 2003-2006 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.
*/



import com.jme.input.InputHandler;
import com.jme.input.RelativeMouse;
import com.jme.input.action.MouseLook;
import com.jme.math.Vector3f;
import com.jme.renderer.Camera;

/**
* <code>MouseLookHandler</code> defines an InputHandler that allows to rotate the camera via the mouse.
*/
public class NewMouseLookHandler extends InputHandler {

private NewMouseLook mouseLook;

public NewMouseLookHandler( Camera cam, float speed ) {
RelativeMouse mouse = new RelativeMouse("Mouse Input");
mouse.registerWithInputHandler( this );

mouseLook = new NewMouseLook(mouse, cam, speed );
mouseLook.setLockAxis(new Vector3f(cam.getUp()));
addAction(mouseLook);
}

public void requireButtonPress(boolean value) {
mouseLook.setButtonPressRequired(value);
}

public void setLockAxis(Vector3f lock) {
mouseLook.setLockAxis(new Vector3f(lock));
}

public MouseLook getMouseLook() {
return mouseLook;
}
}

This is the class that I modified. The only thing I changed was to set the mouse y axis to 0 so the user can't move the mouse in the y direction.

NewMouseLook.java

package com.guid.asteroid3D;

import com.jme.input.Mouse;
import com.jme.input.action.InputActionEvent;
import com.jme.input.action.MouseLook;
import com.jme.renderer.Camera;

public class NewMouseLook extends MouseLook{

public NewMouseLook(Mouse mouse, Camera camera, float speed) {
super(mouse, camera, speed);

}

public void performAction(InputActionEvent evt) {
super.mouse.getLocalTranslation().y=0;
super.performAction(evt);

}

}

In your Asteroid3DGame.java class, add this global variable: private InputHandler handler=null;

In the initGame method in your Asteroid3DGame.java class, you should add this coded.

NewFirstPersonHandler fpHandler = new NewFirstPersonHandler( cam, 50, 1 );
fpHandler.getKeyboardLookHandler().setEnabled( false );
fpHandler.getMouseLookHandler().setEnabled( true);
fpHandler.getMouseLookHandler().requireButtonPress(true);
handler = fpHandler;

This code will create the FirstPerson camera that will allow the scene to move with the mouse only in the x direction.

In your update method, you should also add this code to update your handler.
handler.update(interpolation);

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