GhostObject.java

/*
 * Java port of Bullet (c) 2008 Martin Dvorak <jezek2@advel.cz>
 *
 * Bullet Continuous Collision Detection and Physics Library
 * Copyright (c) 2003-2008 Erwin Coumans  http://www.bulletphysics.com/
 *
 * This software is provided 'as-is', without any express or implied warranty.
 * In no event will the authors be held liable for any damages arising from
 * the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */

package com.bulletphysics.collision.dispatch;

import com.bulletphysics.collision.broadphase.BroadphaseProxy;
import com.bulletphysics.collision.broadphase.Dispatcher;
import com.bulletphysics.collision.shapes.ConvexShape;
import com.bulletphysics.linearmath.AabbUtil2;
import com.bulletphysics.linearmath.Transform;
import com.bulletphysics.linearmath.TransformUtil;
import com.bulletphysics.util.ObjectArrayList;
import com.bulletphysics.util.Stack;

import javax.vecmath.Quat4f;
import javax.vecmath.Vector3f;

/**
 * GhostObject can keep track of all objects that are overlapping. By default, this
 * overlap is based on the AABB. This is useful for creating a character controller,
 * collision sensors/triggers, explosions etc.
 *
 * @author tomrbryn
 */
public class GhostObject extends CollisionObject {

	protected ObjectArrayList<CollisionObject> overlappingObjects = new ObjectArrayList<CollisionObject>();

	public GhostObject() {
		this.internalType = CollisionObjectType.GHOST_OBJECT;
	}

	/**
	 * This method is mainly for expert/internal use only.
	 */
	public void addOverlappingObjectInternal(BroadphaseProxy otherProxy, BroadphaseProxy thisProxy) {
		CollisionObject otherObject = (CollisionObject)otherProxy.clientObject;
		assert(otherObject != null);
		
		// if this linearSearch becomes too slow (too many overlapping objects) we should add a more appropriate data structure
		int index = overlappingObjects.indexOf(otherObject);
		if (index == -1) {
			// not found
			overlappingObjects.add(otherObject);
		}
	}

	/**
	 * This method is mainly for expert/internal use only.
	 */
	public void removeOverlappingObjectInternal(BroadphaseProxy otherProxy, Dispatcher dispatcher, BroadphaseProxy thisProxy) {
		CollisionObject otherObject = (CollisionObject) otherProxy.clientObject;
		assert(otherObject != null);
		
		int index = overlappingObjects.indexOf(otherObject);
		if (index != -1) {
			overlappingObjects.set(index, overlappingObjects.getQuick(overlappingObjects.size()-1));
			overlappingObjects.removeQuick(overlappingObjects.size()-1);
		}
	}

	public void convexSweepTest(ConvexShape castShape, Transform convexFromWorld, Transform convexToWorld, CollisionWorld.ConvexResultCallback resultCallback, float allowedCcdPenetration) {
		Stack stack = Stack.enter();
	    Transform convexFromTrans = stack.allocTransform();
		Transform convexToTrans = stack.allocTransform();

		convexFromTrans.set(convexFromWorld);
		convexToTrans.set(convexToWorld);

		Vector3f castShapeAabbMin = stack.allocVector3f();
		Vector3f castShapeAabbMax = stack.allocVector3f();

		// compute AABB that encompasses angular movement
		{
			Vector3f linVel = stack.allocVector3f();
			Vector3f angVel = stack.allocVector3f();
			TransformUtil.calculateVelocity(convexFromTrans, convexToTrans, 1f, linVel, angVel);
			Transform R = stack.allocTransform();
			R.setIdentity();
			R.setRotation(convexFromTrans.getRotation(stack.allocQuat4f()));
			castShape.calculateTemporalAabb(R, linVel, angVel, 1f, castShapeAabbMin, castShapeAabbMax);
		}

		Transform tmpTrans = stack.allocTransform();

		// go over all objects, and if the ray intersects their aabb + cast shape aabb,
		// do a ray-shape query using convexCaster (CCD)
		for (int i=0; i<overlappingObjects.size(); i++) {
			CollisionObject collisionObject = overlappingObjects.getQuick(i);

			// only perform raycast if filterMask matches
			if (resultCallback.needsCollision(collisionObject.getBroadphaseHandle())) {
				//RigidcollisionObject* collisionObject = ctrl->GetRigidcollisionObject();
				Vector3f collisionObjectAabbMin = stack.allocVector3f();
				Vector3f collisionObjectAabbMax = stack.allocVector3f();
				collisionObject.getCollisionShape().getAabb(collisionObject.getWorldTransform(tmpTrans), collisionObjectAabbMin, collisionObjectAabbMax);
				AabbUtil2.aabbExpand(collisionObjectAabbMin, collisionObjectAabbMax, castShapeAabbMin, castShapeAabbMax);
				float[] hitLambda = new float[]{1f}; // could use resultCallback.closestHitFraction, but needs testing
				Vector3f hitNormal = stack.allocVector3f();
				if (AabbUtil2.rayAabb(convexFromWorld.origin, convexToWorld.origin, collisionObjectAabbMin, collisionObjectAabbMax, hitLambda, hitNormal)) {
					CollisionWorld.objectQuerySingle(castShape, convexFromTrans, convexToTrans,
					                                 collisionObject,
					                                 collisionObject.getCollisionShape(),
					                                 collisionObject.getWorldTransform(tmpTrans),
					                                 resultCallback,
					                                 allowedCcdPenetration);
				}
			}
		}
		stack.leave();
	}

	public void rayTest(Vector3f rayFromWorld, Vector3f rayToWorld, CollisionWorld.RayResultCallback resultCallback) {
	    Stack stack = Stack.enter();
		Transform rayFromTrans = stack.allocTransform();
		rayFromTrans.setIdentity();
		rayFromTrans.origin.set(rayFromWorld);
		Transform rayToTrans = stack.allocTransform();
		rayToTrans.setIdentity();
		rayToTrans.origin.set(rayToWorld);

		Transform tmpTrans = stack.allocTransform();

		for (int i=0; i<overlappingObjects.size(); i++) {
			CollisionObject collisionObject = overlappingObjects.getQuick(i);
			
			// only perform raycast if filterMask matches
			if (resultCallback.needsCollision(collisionObject.getBroadphaseHandle())) {
				CollisionWorld.rayTestSingle(rayFromTrans, rayToTrans,
				                             collisionObject,
				                             collisionObject.getCollisionShape(),
				                             collisionObject.getWorldTransform(tmpTrans),
				                             resultCallback);
			}
		}
		stack.leave();
	}

	public int getNumOverlappingObjects() {
		return overlappingObjects.size();
	}

	public CollisionObject getOverlappingObject(int index) {
		return overlappingObjects.getQuick(index);
	}

	public ObjectArrayList<CollisionObject> getOverlappingPairs() {
		return overlappingObjects;
	}

	//
	// internal cast
	//

	public static GhostObject upcast(CollisionObject colObj) {
		if (colObj.getInternalType() == CollisionObjectType.GHOST_OBJECT) {
			return (GhostObject)colObj;
		}
		
		return null;
	}
	
}