org.dyn4j.collision.Fixture Maven / Gradle / Ivy
/*
* Copyright (c) 2010-2016 William Bittle http://www.dyn4j.org/
* 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 dyn4j 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 org.dyn4j.collision;
import java.util.UUID;
import org.dyn4j.DataContainer;
import org.dyn4j.geometry.Convex;
import org.dyn4j.geometry.Shape;
import org.dyn4j.resources.Messages;
/**
* Represents a geometric piece of a {@link Collidable}.
*
* A {@link Fixture} has a one-to-one relationship with a {@link Convex} {@link Shape}, storing
* additional collision specific information.
*
* A {@link Collidable} is composed of many {@link Fixture}s to represent its physical shape. While
* the only shapes supported by the collision detection system are {@link Convex} shapes, the composition
* of multiple {@link Fixture}s in a {@link Collidable} allows the collidables to be non-convex.
*
* The {@link Fixture}'s {@link Shape} should be translated and rotated using the {@link Shape}'s methods
* to move the shape relative to the containing {@link Collidable}. Other modifications to the shape is
* not recommended after adding it to a {@link Fixture}. To change the shape of a fixture, remove the existing
* {@link Fixture} from the {@link Collidable} and add a new {@link Fixture} with an updated shape instead.
*
* There's no restriction on reusing {@link Shape}s and {@link Fixture}s between {@link Collidable}s, but
* this is also discouraged to reduce confusion and unexpected behavior (primarily local translations and
* rotations).
*
* A {@link Fixture} can have a {@link Filter} assigned to enable filtering of collisions between it
* and other fixtures.
*
* A {@link Fixture} can be flagged as a sensor fixture to enable standard collision detection, but disable
* collision resolution (response).
* @author William Bittle
* @version 3.2.0
* @since 2.0.0
*/
public class Fixture implements DataContainer {
/** The id for the fixture */
protected final UUID id;
/** The convex shape for this fixture */
protected final Convex shape;
/** The collision filter */
protected Filter filter;
/** Whether the fixture only senses contact */
protected boolean sensor;
/** The user data */
protected Object userData;
/**
* Minimal constructor.
* @param shape the {@link Convex} {@link Shape} for this fixture
* @throws NullPointerException if shape is null
*/
public Fixture(Convex shape) {
if (shape == null) throw new NullPointerException(Messages.getString("collision.fixture.nullShape"));
this.id = UUID.randomUUID();
this.shape = shape;
this.filter = Filter.DEFAULT_FILTER;
this.sensor = false;
}
/* (non-Javadoc)
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals(Object obj) {
if (obj == null) return false;
if (obj == this) return true;
if (obj instanceof Fixture) {
return this.id.equals(((Fixture)obj).id);
}
return false;
}
/* (non-Javadoc)
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
return this.id.hashCode();
}
/* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("Fixture[Id=").append(this.id)
.append("|Shape=").append(this.shape)
.append("|Filter=").append(this.filter)
.append("|IsSensor=").append(this.sensor)
.append("]");
return sb.toString();
}
/**
* Returns the id for this fixture.
*
* This identifier is constant for the life of this {@link Fixture}.
* @return UUID
*/
public UUID getId() {
return this.id;
}
/**
* The {@link Convex} {@link Shape} representing the geometry of this fixture.
* @return {@link Convex}
*/
public Convex getShape() {
return this.shape;
}
/**
* Returns the collision filter for this fixture.
* @return {@link Filter}
*/
public Filter getFilter() {
return this.filter;
}
/**
* Sets the collision filter for this fixture.
* @param filter the collision filter
* @throws NullPointerException if filter is null; Use {@link Filter#DEFAULT_FILTER} instead
*/
public void setFilter(Filter filter) {
// check if the given filter is null
if (filter == null) throw new NullPointerException(Messages.getString("collision.fixture.nullFilter"));
// use the given filter
this.filter = filter;
}
/**
* Returns true if this fixture is a sensor.
*
* A sensor fixture is a fixture that participates in collision detection but does not
* participate in collision resolution (response).
* @return boolean
*/
public boolean isSensor() {
return this.sensor;
}
/**
* Toggles this fixture as a sensor fixture.
*
* A sensor fixture is a fixture that participates in collision detection but does not
* participate in collision resolution (response).
* @param flag true if this fixture should only sense contacts
*/
public void setSensor(boolean flag) {
this.sensor = flag;
}
/* (non-Javadoc)
* @see org.dyn4j.DataContainer#getUserData()
*/
public Object getUserData() {
return this.userData;
}
/* (non-Javadoc)
* @see org.dyn4j.DataContainer#setUserData(java.lang.Object)
*/
public void setUserData(Object userData) {
this.userData = userData;
}
}