/*******************************************************************************
 * 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.tests.bullet;

import com.badlogic.gdx.graphics.g3d.Model;
import com.badlogic.gdx.graphics.g3d.ModelInstance;
import com.badlogic.gdx.math.Matrix4;
import com.badlogic.gdx.math.Vector3;
import com.badlogic.gdx.math.collision.BoundingBox;
import com.badlogic.gdx.physics.bullet.collision.btCollisionObject;
import com.badlogic.gdx.physics.bullet.dynamics.btRigidBody;
import com.badlogic.gdx.physics.bullet.dynamics.btRigidBody.btRigidBodyConstructionInfo;
import com.badlogic.gdx.physics.bullet.linearmath.btMotionState;

/** @author xoppa Renderable BaseEntity with a bullet physics body. */
public class BulletEntity extends BaseEntity {
	private final static Matrix4 tmpM = new Matrix4();
	public BulletEntity.MotionState motionState;
	public btCollisionObject body;

	public final BoundingBox boundingBox = new BoundingBox();
	public final float boundingBoxRadius;

	public BulletEntity (final Model model, final btRigidBodyConstructionInfo bodyInfo, final float x, final float y, final float z) {
		this(model, bodyInfo == null ? null : new btRigidBody(bodyInfo), x, y, z);
	}

	public BulletEntity (final Model model, final btRigidBodyConstructionInfo bodyInfo, final Matrix4 transform) {
		this(model, bodyInfo == null ? null : new btRigidBody(bodyInfo), transform);
	}

	public BulletEntity (final Model model, final btCollisionObject body, final float x, final float y, final float z) {
		this(model, body, tmpM.setToTranslation(x, y, z));
	}

	public BulletEntity (final Model model, final btCollisionObject body, final Matrix4 transform) {
		this(new ModelInstance(model, transform.cpy()), body);
	}

	public BulletEntity (final ModelInstance modelInstance, final btCollisionObject body) {
		this.modelInstance = modelInstance;
		this.transform = this.modelInstance.transform;
		this.body = body;

		modelInstance.calculateBoundingBox(boundingBox);
		boundingBoxRadius = boundingBox.getDimensions(new Vector3()).len() * 0.5f;

		if (body != null) {
			body.userData = this;
			if (body instanceof btRigidBody) {
				this.motionState = new MotionState(this.modelInstance.transform);
				((btRigidBody)this.body).setMotionState(motionState);
			} else
				body.setWorldTransform(transform);
		}
	}

	@Override
	public void dispose () {
		// Don't rely on the GC
		if (motionState != null) motionState.dispose();
		if (body != null) body.dispose();
		// And remove the reference
		motionState = null;
		body = null;
	}

	static class MotionState extends btMotionState {
		private final Matrix4 transform;

		public MotionState (final Matrix4 transform) {
			this.transform = transform;
		}

		/** For dynamic and static bodies this method is called by bullet once to get the initial state of the body. For kinematic
		 * bodies this method is called on every update, unless the body is deactivated. */
		@Override
		public void getWorldTransform (final Matrix4 worldTrans) {
			worldTrans.set(transform);
		}

		/** For dynamic bodies this method is called by bullet every update to inform about the new position and rotation. */
		@Override
		public void setWorldTransform (final Matrix4 worldTrans) {
			transform.set(worldTrans);
		}
	}
}