package com.bf;
import org.jbox2d.collision.AABB;
import org.jbox2d.collision.CircleDef;
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.KeyEvent;
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
// --->>给第一个Body赋予力
Body body1;
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动态圆形Body
for (int i = 0; i < 10; i++) {
if (i == 0) {
// 取出第一个body实例
body1 = createCircle(70, 350, 10, false);
} else {
createCircle(200, 100 + i * 17, 10, false);
}
}
// 添加屏幕下方添加多个静态物体
for (int i = 0; i < 20; i++) {
createCircle(0+i*20, 400, 10, true);
}
}
public void surfaceCreated(SurfaceHolder holder) {
flag = true;
th = new Thread(this);
th.start();
}
public Body createCircle(float x, float y, float r, boolean isStatic) {
CircleDef cd = new CircleDef();
if (isStatic) {
cd.density = 0;
} else {
cd.density = 1;
}
cd.friction = 0.8f;
cd.restitution = 0.3f;
cd.radius = r / RATE;
BodyDef bd = new BodyDef();
bd.position.set((x + r) / RATE, (y + r) / RATE);
Body body = world.createBody(bd);
body.m_userData = new MyCircle(x, y, r);
body.createShape(cd);
body.setMassFromShapes();
return body;
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
Vec2 vForce = new Vec2(150,-150);
body1.applyForce(vForce, body1.getWorldCenter());
return super.onKeyDown(keyCode, event);
}
public void myDraw() {
try {
canvas = sfh.lockCanvas();
if (canvas != null) {
canvas.drawColor(Color.WHITE);
Body body = world.getBodyList();
for (int i = 1; i < world.getBodyCount(); i++) {
((MyCircle) body.m_userData).draw(canvas, paint);
body = body.m_next;
}
}
} 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
// 取出body链表表头
Body body = world.getBodyList();
for (int i = 1; i < world.getBodyCount(); i++) {
// 设置MyCircle的X,Y坐标
MyCircle mc = (MyCircle) body.m_userData;
mc.setX(body.getPosition().x * RATE - mc.r);
mc.setY(body.getPosition().y * RATE - mc.r);
// 将链表指针指向下一个body元素
body = body.m_next;
}
}
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;
}
}