Android下2d物理引擎Box2d用法簡單實例
本文實例講述了Android下2d物理引擎Box2d用法。分享給大家供大家參考。具體如下:
程序運行的時候需要加載Jbox2d的庫,可到以下地址下載(使用的是不帶渲染部分的庫jbox2d-2.0.1-library-only.jar):
http://sourceforge.net/projects/jbox2d/
package com.test; 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.app.Activity; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.os.Bundle; import android.os.Handler; import android.view.View; import android.view.Window; import android.view.WindowManager; public class MyBox2d extends Activity { private final static int RATE = 10;//屏幕到現(xiàn)實世界的比例 10px:1m; private AABB worldAABB; //創(chuàng)建 一個管理碰撞的世界 private World world; private float timeStep = 1/60;//模擬的的頻率 private int iterations = 10;//迭代越大,模擬約精確,但性能越低 private Body body,body2,body3; private MyView myView; private Handler mHandler; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); getWindow().setFlags(WindowManager.LayoutParams. FLAG_FULLSCREEN , WindowManager.LayoutParams. FLAG_FULLSCREEN); worldAABB = new AABB(); //上下界,以屏幕的左上方為 原點,如果創(chuàng)建的剛體到達(dá)屏幕的邊緣的話,會停止模擬 worldAABB.lowerBound.set(-100.0f,-100.0f); worldAABB.upperBound.set(100.0f, 100.0f); //注意這里使用的是現(xiàn)實世界的單位 Vec2 gravity = new Vec2(0.0f,10.0f); boolean doSleep = true; world = new World(worldAABB, gravity, doSleep);//創(chuàng)建世界 createBox(160, 470, 160, 10, true); createBox1(160, 150, 160, 10, false); createCircle(160, 100, 10); createCircle1(150, 60, 10); timeStep = 1.0f/60.0f; iterations = 10; myView = new MyView(this); setContentView(myView); mHandler = new Handler(); mHandler.post(update); } private Runnable update = new Runnable() { public void run() { world.step(timeStep, iterations);//開始模擬 Vec2 position = body.getPosition(); Vec2 position1 = body2.getPosition(); Vec2 position2 = body3.getPosition(); myView.x=position.x*RATE; myView.y=position.y*RATE; myView.x1=position1.x*RATE; myView.y1=position1.y*RATE; myView.x2=position2.x*RATE; myView.y2=position2.y*RATE; myView.update(); mHandler.postDelayed(update, (long)timeStep*1000); } }; public void createBox(float x,float y,float half_width,float half_height,boolean isStatic){ PolygonDef shape = new PolygonDef(); if(isStatic){shape.density = 0;} else{shape.density = 2.0f;} shape.friction = 0.8f; shape.restitution = 0.3f; shape.setAsBox(half_width/RATE, half_height/RATE); BodyDef bodyDef = new BodyDef(); bodyDef.position.set(x/RATE, y/RATE); Body body1= world.createBody(bodyDef); body1.createShape(shape); body1.setMassFromShapes(); } public void createCircle(float x,float y,float radius){ CircleDef shape = new CircleDef(); shape.density = 7; shape.friction = 0.2f; shape.radius = radius/RATE; BodyDef bodyDef = new BodyDef(); bodyDef.position.set(x/RATE, y/RATE); body2 = world.createBody(bodyDef); body2.createShape(shape); body2.setMassFromShapes(); } public void createCircle1(float x,float y,float radius){ CircleDef shape = new CircleDef(); shape.density = 7; shape.friction = 0.2f; shape.radius = radius/RATE; BodyDef bodyDef = new BodyDef(); bodyDef.position.set(x/RATE, y/RATE); body3 = world.createBody(bodyDef); body3.createShape(shape); body3.setMassFromShapes(); } public void createBox1(float x,float y,float half_width,float half_height,boolean isStatic){ PolygonDef shape = new PolygonDef(); if(isStatic){shape.density = 0;} else{shape.density = 2.0f;} shape.friction = 0.3f; shape.setAsBox(half_width/RATE, half_height/RATE); BodyDef bodyDef = new BodyDef(); bodyDef.position.set(x/RATE, y/RATE); body= world.createBody(bodyDef); body.createShape(shape); body.setMassFromShapes(); } class MyView extends View{ Canvas canvas; public float x=160,y=150; public float x1=160,y1=100; public float x2=150,y2=60; public MyView(Context context) { super(context); } public void drawBox(float x,float y){ Paint mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setColor(Color.RED); canvas.drawRect(x-160, y-10, x+160, y+10, mPaint); } public void drawGround(){ Paint mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setColor(Color.BLUE); canvas.drawRect(0, 460, 320, 480, mPaint); } public void drawCircle(float x1,float y1){ Paint mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setColor(Color.GREEN); canvas.drawCircle(x1, y1, 10, mPaint); } public void update(){ postInvalidate(); } protected void onDraw(Canvas canvas) { super.onDraw(canvas); this.canvas = canvas; drawGround(); drawBox(x, y); drawCircle(x1, y1); drawCircle(x2, y2); } } }
希望本文所述對大家的Android程序設(shè)計有所幫助。
相關(guān)文章
解析Android開發(fā)中多點觸摸的實現(xiàn)方法
多點觸摸(MultiTouch),指的是允許計算機用戶同時通過多個手指來控制圖形界面的一種技術(shù)。與多點觸摸技術(shù)相對應(yīng)的就是單點觸摸,單點觸摸的設(shè)備已經(jīng)有很多年了,小尺寸的有觸摸式的手機,大尺寸的最常見的就是銀行里的ATM機和排隊查詢機等等2013-05-05Android Build Variants 為項目設(shè)置變種版本的方法
下面小編就為大家分享一篇Android Build Variants 為項目設(shè)置變種版本的方法,具有很好的參考價值,希望對大家有所幫助。一起跟隨小編過來看看吧2018-01-01詳解Android中Intent對象與Intent Filter過濾匹配過程
這篇文章主要介紹了Android中Intent對象與Intent Filter過濾匹配過程,感興趣的小伙伴們可以參考一下2015-12-12Android Content Provider詳解及示例代碼
本文主要講解Android Content Provider,這里提供相關(guān)文檔資料,并附有實現(xiàn)代碼和實現(xiàn)效果圖,有需要的小伙伴可以參考下2016-08-08Android ViewPager制作新手導(dǎo)航頁(動態(tài)加載)
這篇文章主要為大家詳細(xì)介紹了Android ViewPager制作新手導(dǎo)航頁,了解什么是動態(tài)加載指示器,感興趣的小伙伴們可以參考一下2016-05-05