/*
* Phys2D - a 2D physics engine based on the work of Erin Catto.
*
* This source is provided under the terms of the BSD License.
*
* Copyright (c) 2006, Phys2D
* 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 the Phys2D/New Dawn Software 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 net.phys2d.raw.collide;
import net.phys2d.math.MathUtil;
import net.phys2d.math.Vector2f;
import net.phys2d.raw.Body;
import net.phys2d.raw.Contact;
import net.phys2d.raw.shapes.Circle;
/**
* A collider for circle 2 circle collisions
*
* The create() method is used as a factory just in case this
* class becomes stateful eventually.
*
* @author Kevin Glass
*/
public strictfp class CircleCircleCollider implements Collider {
/**
* @see net.phys2d.raw.collide.Collider#collide(net.phys2d.raw.Contact[], net.phys2d.raw.Body, net.phys2d.raw.Body)
*/
public int collide(Contact[] contacts, Body bodyA, Body bodyB) {
float x1 = bodyA.getPosition().getX();
float y1 = bodyA.getPosition().getY();
float x2 = bodyB.getPosition().getX();
float y2 = bodyB.getPosition().getY();
boolean touches = bodyA.getShape().getBounds().touches(x1,y1,bodyB.getShape().getBounds(),x2,y2);
if (!touches) {
return 0;
}
Circle circleA = (Circle) bodyA.getShape();
Circle circleB = (Circle) bodyB.getShape();
touches = circleA.touches(x1,y1,circleB,x2,y2);
if (!touches) {
return 0;
}
Vector2f normal = MathUtil.sub(bodyB.getPosition(),bodyA.getPosition());
float sep = (circleA.getRadius() + circleB.getRadius()) - normal.length();
normal.normalise();
Vector2f pt = MathUtil.scale(normal, circleA.getRadius());
pt.add(bodyA.getPosition());
contacts[0].setSeparation(-sep);
contacts[0].setPosition(pt);
contacts[0].setNormal(normal);
FeaturePair fp = new FeaturePair();
contacts[0].setFeature(fp);
return 1;
}
}