0

我有一个在屏幕上绘制位图的应用程序。我想避免重叠，但似乎我做错了什么。从图中可以看出，位图 52 和 53 重叠。

从日志中我们可以看到：
ID:52 X START:974.0 X FINISH:1166.0 Y START:1044.0 Y END:1236.0
ID:53 X START:833.0 X FINISH:1025.0 Y START:898.0 Y END:1090.0

我试图弄清楚是否应该发生碰撞或什么，这是结果。半径 = (1166 - 974)/2 = 95
dx = (974 + 96) - (833 + 96) = 1070 - 929 = 141
dy = (1044 + 96) + (898 + 96) = 1140 - 994 = 146
距离= 141*141 + 146*146 = 19881 + 21316 = 41197
布尔 = 41197 < (96 +96) * (96+96) ? ----- 41197 < 36864 ?
不，没有碰撞。它们没有重叠......
为什么它们在屏幕上重叠？

//this function makes sure that balls are not overlapping themselves
public void setBalls() {
    for (int bubu=0;bubu <12;bubu++) {// creates 12 blue balls
        ball = new Ball(BitmapFactory.decodeResource(getResources(),R.drawable.circle));
        boolean ok = false;
        while (!ok) {
            ball.realx =  (random.nextInt(canvasWidth) - ball.getRadius());
            ball.realy =  (random.nextInt(canvasHeight) - ball.getRadius());
            Log.d("ball","ID:"+ball.id+" X START:"+ball.realx+ " X FINISH:"+ (ball.realx + (ball.getRadius())*2) + " Y START:"+ball.realy+" Y END:"+(ball.realy+ (ball.getRadius())*2));
            ok = canStartHere(ball);
            }
            ballContainer.add(ball);
        }
    }

//helper function of setBalls() 
public boolean canStartHere(Ball ball) {
    boolean conditionClear = true;
    for (Ball balll: ballContainer) {
    if (hitTest(ball, balll)){
            conditionClear = false;
        }   
    }
        return conditionClear;
    }

// return whether ball intersects ball2 or not 
public boolean hitTest(Ball ball, Ball ball2) {
    boolean hit = false;
    float dx = (ball.realx + ball.radius) - (ball2.realx + ball2.radius);
    float dy = (ball.realy + ball.radius) - (ball2.realy + ball2.radius);
    float dist = (dx * dx) + (dy * dy);
    if (dist <= (ball.getRadius() + ball2.getRadius()) * (ball.getRadius() + ball2.getRadius())) {
        // THERE IS AN INTERSECTION
        hit = true;
    } else {
        // no intersection
    }
    return hit;
}

这是 Ball 类

public class Ball {

Bitmap bitmap;

int  radius, speed, angle, mass,id;
float posx, posy,realx,realy;
double velX;
double velY;
static int totalID = 0;
Random random = new Random();


public Ball(Bitmap image) {
    this.bitmap = image;
    this.id = totalID;
    totalID ++;
    double tempAngle = random.nextInt(361);
    double tempRadians = tempAngle * (Math.PI/180);
    //velX = Math.cos(tempRadians)*4; commented out so they are still
    //velY = Math.sin(tempRadians)*4;
    Log.d("tag", "created a ball with ID " + this.id);
    this.radius = (bitmap.getWidth() / 2);
    this.mass = radius;

}

public int getRadius() {
    return radius;
}

在此处输入图像描述

4

0 回答 0