android 游戏 碰撞检测

矩形碰撞 原理: 两个矩形位置 的四种情况 不是这四中情况 则碰撞



圆形碰撞 原理: 利用两个圆心之间的距离进行判定.当两个圆心的距离小于半径之和则碰撞.

像素碰撞 :不适用 遍历所有像素 检测 太多了

多矩形碰撞: 设置多个矩形碰撞检测区域 检测碰撞矩形数组 与另一碰撞矩形数组之间的位置关系.

矩形碰撞 代码:

public class MySurfaceView extends SurfaceView implements Callback, Runnable {
private SurfaceHolder sfh;
private Paint paint;
private Thread th;
private boolean flag;
private Canvas canvas;
private int screenW, screenH;
//定义两个矩形的宽高坐标
private int x1 = 10, y1 = 110, w1 = 40, h1 = 40;
private int x2 = 100, y2 = 110, w2 = 40, h2 = 40;
//便于观察是否发生了碰撞设置一个标识位
private boolean isCollsion;

/**
* SurfaceView初始化函数
*/
public MySurfaceView(Context context) {
super(context);
sfh = this.getHolder();
sfh.addCallback(this);
paint = new Paint();
paint.setColor(Color.WHITE);
paint.setAntiAlias(true);
setFocusable(true);
}

/**
* SurfaceView视图创建，响应此函数
*/
@Override
public void surfaceCreated(SurfaceHolder holder) {
screenW = this.getWidth();
screenH = this.getHeight();
flag = true;
//实例线程
th = new Thread(this);
//启动线程
th.start();
}

/**
* 游戏绘图
*/
public void myDraw() {
try {
canvas = sfh.lockCanvas();
if (canvas != null) {
canvas.drawColor(Color.BLACK);
if (isCollsion) {
paint.setColor(Color.RED);
paint.setTextSize(20);
canvas.drawText("Collision！", 0, 30, paint);
} else {
paint.setColor(Color.WHITE);
}
//绘制两个矩形
canvas.drawRect(x1, y1, x1 + w1, y1 + h1, paint);
canvas.drawRect(x2, y2, x2 + w2, y2 + h2, paint);
}
} catch (Exception e) {
// TODO: handle exception
} finally {
if (canvas != null)
sfh.unlockCanvasAndPost(canvas);
}
}

/**
* 触屏事件监听
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
//让矩形1随着触屏位置移动
x1 = (int) event.getX() - w1 / 2;
y1 = (int) event.getY() - h1 / 2;
if (isCollsionWithRect(x1, y1, w1, h1, x2, y2, w2, h2)) {
isCollsion = true;
} else {
isCollsion = false;
}
return true;
}

/**
* 按键事件监听
*/
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
return super.onKeyDown(keyCode, event);
}

/**
* 游戏逻辑
*/
private void logic() {

}

public boolean isCollsionWithRect(int x1, int y1, int w1, int h1, int x2, int y2, int w2, int h2) {
if (x1 >= x2 && x1 >= x2 + w2) {
return false;
} else if (x1 <= x2 && x1 + w1 <= x2) {
return false;
} else if (y1 >= y2 && y1 >= y2 + h2) {
return false;
} else if (y1 <= y2 && y1 + h1 <= y2) {
return false;
}
return true;
}

@Override
public void run() {
while (flag) {
long start = System.currentTimeMillis();
myDraw();
logic();
long end = System.currentTimeMillis();
try {
if (end - start < 50) {
Thread.sleep(50 - (end - start));
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}

/**
* SurfaceView视图状态发生改变，响应此函数
*/
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}

/**
* SurfaceView视图消亡时，响应此函数
*/
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
flag = false;
}
}

圆形碰撞 代码:

public class MySurfaceView extends SurfaceView implements Callback, Runnable {
private SurfaceHolder sfh;
private Paint paint;
private Thread th;
private boolean flag;
private Canvas canvas;
private int screenW, screenH;
//定义两个圆形的半径与坐标
private int r1 = 20, r2 = 20;
private int x1 = 50, y1 = 100, x2 = 150, y2 = 100;
//定义一个碰撞标识位
private boolean isCollision;

/**
* SurfaceView初始化函数
*/
public MySurfaceView(Context context) {
super(context);
sfh = this.getHolder();
sfh.addCallback(this);
paint = new Paint();
paint.setColor(Color.WHITE);
paint.setAntiAlias(true);
setFocusable(true);
}

/**
* SurfaceView视图创建，响应此函数
*/
@Override
public void surfaceCreated(SurfaceHolder holder) {
screenW = this.getWidth();
screenH = this.getHeight();
flag = true;
//实例线程
th = new Thread(this);
//启动线程
th.start();
}

/**
* 游戏绘图
*/
public void myDraw() {
try {
canvas = sfh.lockCanvas();
if (canvas != null) {
canvas.drawColor(Color.BLACK);
if (isCollision) {
paint.setColor(Color.RED);
paint.setTextSize(20);
canvas.drawText("Collision!", 0, 30, paint);
} else {
paint.setColor(Color.WHITE);
}
canvas.drawCircle(x1, y1, r1, paint);
canvas.drawCircle(x2, y2, r2, paint);
}
} catch (Exception e) {
// TODO: handle exception
} finally {
if (canvas != null)
sfh.unlockCanvasAndPost(canvas);
}
}

/**
* 触屏事件监听
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
x1 = (int) event.getX();
y1 = (int) event.getY();
if (isCollisionWithCircle(x1, y1, x2, y2, r1, r2)) {
isCollision = true;
} else {
isCollision = false;
}
return true;
}
/**
* 圆形碰撞
* @param x1    圆形1的圆心X坐标
* @param y1    圆形2的圆心X坐标
* @param x2    圆形1的圆心Y坐标
* @param y2    圆形2的圆心Y坐标
* @param r1    圆形1的半径
* @param r2    圆形2的半径
* @return
*/
private boolean isCollisionWithCircle(int x1, int y1, int x2, int y2, int r1, int r2) {
//Math.sqrt:开平方
//Math.pow(double x, double y): X的Y次方
if (Math.sqrt(Math.pow(x1 - x2, 2) + Math.pow(y1 - y2, 2)) <= r1 + r2) {
//如果两圆的圆心距小于或等于两圆半径则认为发生碰撞
return true;
}
return false;
}

/**
* 按键事件监听
*/
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
return super.onKeyDown(keyCode, event);
}

/**
* 游戏逻辑
*/
private void logic() {
}

@Override
public void run() {
while (flag) {
long start = System.currentTimeMillis();
myDraw();
logic();
long end = System.currentTimeMillis();
try {
if (end - start < 50) {
Thread.sleep(50 - (end - start));
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}

/**
* SurfaceView视图状态发生改变，响应此函数
*/
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}

/**
* SurfaceView视图消亡时，响应此函数
*/
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
flag = false;
}
}

多矩形碰撞 代码

public class MySurfaceView extends SurfaceView implements Callback, Runnable {
private SurfaceHolder sfh;
private Paint paint;
private Thread th;
private boolean flag;
private Canvas canvas;
private int screenW, screenH;
//定义两个矩形图形的宽高坐标
private int rectX1 = 10, rectY1 = 10, rectW1 = 40, rectH1 = 40;
private int rectX2 = 100, rectY2 = 110, rectW2 = 40, rectH2 = 40;
//便于观察是否发生了碰撞设置一个标识位
private boolean isCollsion;
//定义第一个矩形的矩形碰撞数组
private Rect clipRect1 = new Rect(0, 0, 15, 15);
private Rect clipRect2 = new Rect(rectW1 - 15, rectH1 - 15, rectW1, rectH1);
private Rect[] arrayRect1 = new Rect[] { clipRect1, clipRect2 };
//定义第二个矩形的矩形碰撞数组
private Rect clipRect3 = new Rect(0, 0, 15, 15);
private Rect clipRect4 = new Rect(rectW2 - 15, rectH2 - 15, rectW2, rectH2);
private Rect[] arrayRect2 = new Rect[] { clipRect3, clipRect4 };

/**
* SurfaceView初始化函数
*/
public MySurfaceView(Context context) {
super(context);
sfh = this.getHolder();
sfh.addCallback(this);
paint = new Paint();
paint.setColor(Color.WHITE);
paint.setAntiAlias(true);
setFocusable(true);
}

/**
* SurfaceView视图创建，响应此函数
*/
@Override
public void surfaceCreated(SurfaceHolder holder) {
screenW = this.getWidth();
screenH = this.getHeight();
flag = true;
//实例线程
th = new Thread(this);
//启动线程
th.start();
}

/**
* 游戏绘图
*/
public void myDraw() {
try {
canvas = sfh.lockCanvas();
if (canvas != null) {
canvas.drawColor(Color.BLACK);
paint.setColor(Color.WHITE);
paint.setStyle(Style.FILL);
if (isCollsion) {
paint.setTextSize(20);
canvas.drawText("Collision！", 0, 30, paint);
}
//绘制两个矩形
canvas.drawRect(rectX1, rectY1, rectX1 + rectW1, rectY1 + rectH1, paint);
canvas.drawRect(rectX2, rectY2, rectX2 + rectW2, rectY2 + rectH2, paint);
//---绘制碰撞区域使用非填充，并设置画笔颜色白色
paint.setStyle(Style.STROKE);
paint.setColor(Color.RED);
//绘制第一个矩形的所有矩形碰撞区域
for (int i = 0; i < arrayRect1.length; i++) {
canvas.drawRect(arrayRect1[i].left + this.rectX1, arrayRect1[i].top + this.rectY1, arrayRect1[i].right + this.rectX1, arrayRect1[i].bottom
+ this.rectY1, paint);
}
//绘制第二个矩形的所有矩形碰撞区域
for (int i = 0; i < arrayRect2.length; i++) {
canvas.drawRect(arrayRect2[i].left + this.rectX2, arrayRect2[i].top + this.rectY2, arrayRect2[i].right + this.rectX2, arrayRect2[i].bottom
+ rectY2, paint);
}
}
} catch (Exception e) {
// TODO: handle exception
} finally {
if (canvas != null)
sfh.unlockCanvasAndPost(canvas);
}
}

/**
* 触屏事件监听
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
//让矩形1随着触屏位置移动
rectX1 = (int) event.getX() - rectW1 / 2;
rectY1 = (int) event.getY() - rectH1 / 2;
if (isCollsionWithRect(arrayRect1, arrayRect2)) {
isCollsion = true;
} else {
isCollsion = false;
}
return true;
}

/**
* 按键事件监听
*/
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
return super.onKeyDown(keyCode, event);
}

/**
* 游戏逻辑
*/
private void logic() {

}

//Rect 类中的四个属性  top bottom left right
//分别表示这个矩形的         上       下            左          右
public boolean isCollsionWithRect(Rect[] rectArray, Rect[] rect2Array) {
Rect rect = null;
Rect rect2 = null;
for (int i = 0; i < rectArray.length; i++) {
//依次取出第一个矩形数组的每个矩形实例
rect = rectArray[i];
//获取到第一个矩形数组中每个矩形元素的属性值
int x1 = rect.left + this.rectX1;
int y1 = rect.top + this.rectY1;
int w1 = rect.right - rect.left;
int h1 = rect.bottom - rect.top;
for (int j = 0; j < rect2Array.length; j++) {
//依次取出第二个矩形数组的每个矩形实例
rect2 = rect2Array[j];
//获取到第二个矩形数组中每个矩形元素的属性值
int x2 = rect2.left + this.rectX2;
int y2 = rect2.top + this.rectY2;
int w2 = rect2.right - rect2.left;
int h2 = rect2.bottom - rect2.top;
//进行循环遍历两个矩形碰撞数组所有元素之间的位置关系
if (x1 >= x2 && x1 >= x2 + w2) {
} else if (x1 <= x2 && x1 + w1 <= x2) {
} else if (y1 >= y2 && y1 >= y2 + h2) {
} else if (y1 <= y2 && y1 + h1 <= y2) {
} else {
//只要有一个碰撞矩形数组与另一碰撞矩形数组发生碰撞则认为碰撞
return true;
}
}
}
return false;
}

@Override
public void run() {
while (flag) {
long start = System.currentTimeMillis();
myDraw();
logic();
long end = System.currentTimeMillis();
try {
if (end - start < 50) {
Thread.sleep(50 - (end - start));
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}

/**
* SurfaceView视图状态发生改变，响应此函数
*/
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}

/**
* SurfaceView视图消亡时，响应此函数
*/
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
flag = false;
}
}