小程序源码 (在物理世界中添加圆形).rar

package com.cc; import org.jbox2d.collision.AABB; import org.jbox2d.collision.CircleDef; 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.RectF; 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; // ---添加物理世界----->> final float RATE = 30; World world; AABB aabb; Vec2 gravity; float timeStep = 1f / 60f; final int iterations = 10; // ----在物理世界中添加一个圆形--->> Body body;// 声明物体对象 float circleX = 0;// 声明圆形X坐标 float circleY = 0;// 声明圆形Y坐标 float circleR = 20;// 声明圆形半径 // ----在物理世界中添加一个多边形--->> Body body2;// 声明物体对象 float polygonX = 5;// 声明矩形X坐标 float polygonY = 110;// 声明矩形Y坐标 float polygonWidth = 150;// 声明矩形宽度 float polygonHeight = 50;// 声明矩形高度 public MySurfaceView(Context context) { super(context); this.setKeepScreenOn(true); sfh = this.getHolder(); sfh.addCallback(this); paint = new Paint(); paint.setStyle(Style.STROKE); paint.setAntiAlias(true); setFocusable(true); // ---添加物理世界-->> aabb = new AABB(); gravity = new Vec2(0f, 10f); aabb.lowerBound.set(-100f, -100f); aabb.upperBound.set(100f, 100f); world = new World(aabb, gravity, true); // ----在物理世界中添加一个圆形--->> body = createCircle(circleX, circleY, circleR, false);// 创建一个圆形 // ----在物理世界中添加一个多边形--->> body2 = createPolygon(polygonX, polygonY, polygonWidth, polygonHeight,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) { // ---创建圆形皮肤 CircleDef cd = new CircleDef(); // 实例一个圆形的皮肤 if (isStatic) { cd.density = 0; // 设置圆形为静态 } else { cd.density = 1; // 设置圆形的质量 } cd.friction = 0.8f; // 设置圆形的摩擦力 cd.restitution = 0.3f; // 设置圆形的恢复力 cd.radius = r / RATE; // 设置圆形的半径 // ---创建刚体 BodyDef bd = new BodyDef(); // 实例一个刚体对象 bd.position.set((x + r) / RATE, (y + r) / 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(cd); // 为Body添加皮肤 body.setMassFromShapes(); // 将整个物体计算打包 return body; } 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); RectF rect = new RectF(circleX, circleY, circleX + circleR * 2, circleY + circleR * 2); canvas.drawArc(rect, 0, 360, true, paint);// 绘画圆形 canvas.drawRect(polygonX, polygonY, polygonX + polygonWidth, polygonY + polygonHeight, paint); } } catch (Exception e) { Log.e("Himi", "myDraw is Error!"); } finally { if (canvas != null) sfh.unlockCanvasAndPost(canvas); } } public void Logic() { // ----物理世界进行模拟 world.step(timeStep, iterations); Vec2 position = body.getPosition(); circleX = position.x * RATE - circleR; circleY = position.y * RATE - circleR; Vec2 position2 = body2.getPosition(); polygonX = position2.x * RATE - polygonWidth / 2; polygonY = position2.y * RATE - polygonHeight / 2; } 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; } }