Question

处理代码如下，一个简单的问题：为什么当我的鼠标正在播放时，圆圈会从屏幕上消失？我已经添加边界检查，但它似乎不起作用。为什么???

int maxCircle = 200;
float minDistance=30;
float distance1;
float distance2;
Circle [] circles= new Circle[maxCircle];


void setup() {
  size(800,800);
  smooth();
  for(int i=0;i<maxCircle;i++){
    circles[i] = new Circle(random(width),random(height),random(2,20));
  }
}


void draw() {
  background(255,255);
  for(int i=0;i<maxCircle;i++) {
    circles[i].update(width,height);

    for (int j=0; j<maxCircle; j++) {
      distance1 = dist(circles[i].x,circles[i].y,circles[j].x,circles[j].y);
      if ( distance1 < minDistance ) {
        stroke(0,10);
        noFill();
        line(circles[i].x,circles[i].y,circles[j].x,circles[j].y);
       }
    }
    circles[i].display();
  }
}

void mouseMoved() {
  for(int i = 0; i<maxCircle;i++) {
    distance2 = dist(mouseX,mouseY,circles[i].x,circles[i].y);

    circles[i].x-=(mouseX-circles[i].x)/distance2;
    circles[i].y-=(mouseX-circles[i].y)/distance2;

    if(circles[i].x<circles[i].r || circles[i].x>width-circles[i].r) {
      circles[i].vx*=-1;
    };
    if(circles[i].y<circles[i].r || circles[i].y> height-circles[i].r) {
      circles[i].vy*=-1;
    }
  }
}    

class Circle {
  float x,y,vx,vy,r,speed;

  Circle(float tempx, float tempy, float tempr) {  
    x=tempx;
    y=tempy;
    vx=random(-1,1);
    vy=random(-1,1);
    r=tempr;
   }

  void update(int w,int h) {
    x+=vx;
    y+=vy;

    if(x<r || x>w-r) {
      vx*=-1;
    }
    if(y<r || y>h-r) {
      vy*=-1;
    }
   }

  void display() {
    fill(0,50);
    noStroke();
    ellipse(x,y,r,r);
  }
}

Answer 1

哦，我找到了解决方案：

   int maxCircle = 200;
   float minDistance = 20;
     Circle [] circles = new Circle[maxCircle];

void setup() {
size(800, 800);
smooth();
for (int i = 0; i < maxCircle; i++) {
  circles[i] = new Circle();
 }
}

  void draw() {
  background(255, 255);
     for (int i = 0; i < maxCircle; i++) {
circles[i].update(); 

noFill();
for (int j = 0; j < maxCircle; j++) {
  if (i == j)
    continue;


  float distance = dist(circles[i].x, circles[i].y, circles[j].x, circles[j].y);
  if (distance < minDistance) {
    stroke(0, 20);
    line(circles[i].x, circles[i].y, circles[j].x, circles[j].y);
  }
}

         circles[i].display();
    }
      }

 void mouseMoved() {
  for (int i = 0; i < maxCircle; i++) {
 float distance = dist(mouseX, mouseY, circles[i].x, circles[i].y);

circles[i].x -= (mouseX - circles[i].x) / distance;
circles[i].y -= (mouseX - circles[i].y) / distance;

circles[i].checkBounds();
      }
    }
     class Circle {
   float x, y, vx, vy, r, speed;

       Circle() {  
        vx = random(-1, 1);
         vy = random(-1, 1);
         r = random(1, 10); // See below
         x = random(r, width - r);
         y = random(r, height - r);  
     }

        void checkBounds() {
         if (x < r || x > width - r) {
           vx *= -1;
          if (x < r) {
           x = r;
           } else {
             x = width - r;
           }
           }
           if (y <= r || y >= height - r) {
           vy *= -1;
              if (y < r) {
                y = r;
             } else {
              y = width - r;
               }
            }
              }

        void update() {
x += vx;
y += vy;
checkBounds();
 }

   void display() {
     fill(0, 50);
      noStroke();

       ellipse(x, y, r * 2, r * 2);
      }
        }

Answer 2

在update（）方法中，当您使用向量计算新坐标时，可能会在屏幕外设置坐标。我添加了4个条件语句，如果超过它，则将值重置为屏幕边界。

  void update(int w,int h) {
    x+=vx;
    y+=vy;

    if(x<r || x>w-r) {
      vx*=-1;
      if (x>w-r) x = w-r;
      if (x<r) x = r;
    }
    if(y<r || y>h-r) {
      vy*=-1;
      if (y>h-r) y = h-r;
      if (y<r) y = r;
    }
   }

为什么圈子会从屏幕上消失？

2 个答案: