package com.tb;
import org.jbox2d.collision.AABB;
import org.jbox2d.collision.PolygonDef;
import org.jbox2d.common.Vec2;
import org.jbox2d.dynamics.Body;
import org.jbox2d.dynamics.BodyDef;
import org.jbox2d.dynamics.World;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.SurfaceHolder.Callback;
public class MySurfaceView extends SurfaceView implements Callback, Runnable {
private Thread th;
private SurfaceHolder sfh;
private Canvas canvas;
private Paint paint;
private boolean flag;
// ----添加一个物理世界---->>
final float RATE = 30;// 屏幕到现实世界的比例 30px:1m;
World world;// 声明一个物理世界对象
AABB aabb;// 声明一个物理世界的范围对象
Vec2 gravity;// 声明一个重力向量对象
float timeStep = 1f / 60f;// 物理世界模拟的的频率
int iterations = 10;// 迭代值,迭代越大模拟越精确,但性能越低
//-----矩形的宽高
float rectW=10,rectH=10;
public MySurfaceView(Context context) {
super(context);
this.setKeepScreenOn(true);
sfh = this.getHolder();
sfh.addCallback(this);
paint = new Paint();
paint.setAntiAlias(true);
paint.setStyle(Style.STROKE);
this.setFocusable(true);
// --添加一个物理世界--->>
aabb = new AABB();// 实例化物理世界的范围对象
gravity = new Vec2(0, 10);// 实例化物理世界重力向量对象
aabb.lowerBound.set(-100, -100);// 设置物理世界范围的左上角坐标
aabb.upperBound.set(100, 100);// 设置物理世界范围的右下角坐标
world = new World(aabb, gravity, true);// 实例化物理世界对象
// ----在物理世界中添加多个矩形Body
for (int i = 0; i < 5; i++) {
createPolygon(35, 10 + i * 17, rectW, rectH, false);
}
for (int i = 0; i < 2; i++) {
createPolygon(22 + i * 20, 100, rectW, rectH, true);
}
}
public void surfaceCreated(SurfaceHolder holder) {
flag = true;
th = new Thread(this);
th.start();
}
public Body createPolygon(float x, float y, float width, float height,
boolean isStatic) {
// ---创建多边形皮肤
PolygonDef pd = new PolygonDef(); // 实例一个多边形的皮肤
if (isStatic) {
pd.density = 0; // 设置多边形为静态
} else {
pd.density = 1; // 设置多边形的质量
}
pd.friction = 0.8f; // 设置多边形的摩擦力
pd.restitution = 0.3f; // 设置多边形的恢复力
// 设置多边形快捷成盒子(矩形)
// 两个参数为多边形宽高的一半
pd.setAsBox(width / 2 / RATE, height / 2 / RATE);
// ---创建刚体
BodyDef bd = new BodyDef(); // 实例一个刚体对象
bd.position.set((x + width / 2) / RATE, (y + height / 2) / RATE);// 设置刚体的坐标
// ---创建Body(物体)
Body body = world.createBody(bd); // 物理世界创建物体
body.createShape(pd); // 为Body添加皮肤
body.setMassFromShapes(); // 将整个物体计算打包
return body;
}
public void myDraw() {
try {
canvas = sfh.lockCanvas();
if (canvas != null) {
canvas.drawColor(Color.WHITE);
/*
//得到Body链表的表头
Body body = world.getBodyList();
//通过world.getBodyCount()得到循环遍历Body的次数
for (int i = 1; i < world.getBodyCount(); i++) {
//得到当前body的角度
float angele = (float) (body.getAngle() * 180 / Math.PI);
//得到当前body的质点X坐标
float bodyX = body.getPosition().x*RATE-rectW/2;
//得到当前body的质点Y坐标
float bodyY = body.getPosition().y*RATE-rectH/2;
//链表指向下一个body
body = body.m_next;
}
*/
Body body = world.getBodyList();
for (int i = 1; i < world.getBodyCount(); i++) {
canvas.save();
canvas.rotate((float) (body.getAngle() * 180 / Math.PI),
body.getPosition().x * RATE ,
body.getPosition().y * RATE);
canvas.drawRect(
body.getPosition().x*RATE-rectW/2,
body.getPosition().y*RATE-rectH/2,
body.getPosition().x*RATE-rectW/2+rectW,
body.getPosition().y*RATE-rectH/2+rectH,
paint);
body = body.m_next;
canvas.restore();
}
}
} catch (Exception e) {
Log.e("Himi", "myDraw is Error!");
} finally {
if (canvas != null)
sfh.unlockCanvasAndPost(canvas);
}
}
public void Logic() {
// --开始模拟物理世界--->>
world.step(timeStep, iterations);// 物理世界进行模拟
}
public void run() {
while (flag) {
myDraw();
Logic();
try {
Thread.sleep((long) timeStep * 1000);
} catch (Exception ex) {
Log.e("Himi", "Thread is Error!");
}
}
}
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
public void surfaceDestroyed(SurfaceHolder holder) {
flag = false;
}
}