Java tutorial
/******************************************************************************* * Copyright 2011 See AUTHORS file. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. ******************************************************************************/ package com.badlogic.gdx.physics.box2d.joints; import org.jbox2d.common.Vec2; import com.badlogic.gdx.math.Vector2; import com.badlogic.gdx.physics.box2d.Joint; import com.badlogic.gdx.physics.box2d.World; /** A mouse joint is used to make a point on a body track a specified world point. This a soft constraint with a maximum force. * This allows the constraint to stretch and without applying huge forces. NOTE: this joint is not documented in the manual * because it was developed to be used in the testbed. If you want to learn how to use the mouse joint, look at the testbed. */ public class MouseJoint extends Joint { org.jbox2d.dynamics.joints.MouseJoint joint; final Vec2 tmp = new Vec2(); public MouseJoint(World world, org.jbox2d.dynamics.joints.MouseJoint joint) { super(world, joint); this.joint = joint; } /** Use this to update the target point. */ public void setTarget(Vector2 target) { tmp.set(target.x, target.y); joint.setTarget(tmp); } /** Use this to update the target point. */ private final Vector2 target = new Vector2(); public Vector2 getTarget() { Vec2 t = joint.getTarget(); return target.set(t.x, t.y); } /** Set/get the maximum force in Newtons. */ public void setMaxForce(float force) { joint.setMaxForce(force); } /** Set/get the maximum force in Newtons. */ public float getMaxForce() { return joint.getMaxForce(); } /** Set/get the frequency in Hertz. */ public void setFrequency(float hz) { joint.setFrequency(hz); } /** Set/get the frequency in Hertz. */ public float getFrequency() { return joint.getFrequency(); } /** Set/get the damping ratio (dimensionless). */ public void setDampingRatio(float ratio) { joint.setDampingRatio(ratio); } /** Set/get the damping ratio (dimensionless). */ public float getDampingRatio() { return joint.getDampingRatio(); } }