可以拉的線

下面兩張圖是這個程式可以讓被拉的線放開滑鼠後會彈回來。

被拉的時候

放開彈回去的樣子

void setup()

{

  size(300,300);

}

float x=100,y=150;

void draw(){

  background(#002966);

  stroke(#b7efff);

  line(x,y,200,150);

  

  fill(#b7efff);

  ellipse(x,y,13,13);

  ellipse(200,150,13,13);

  if(!mousePressed){

    float dx=x-200;

    float dy=y-150;

    float len=sqrt(dx*dx+dy*dy);

    x-=dx*(len-100)/len;

    y-=dy*(len-100)/len;

  }

}

void mouseDragged(){

  x=mouseX; y=mouseY;

}

彈回來會減速

void setup()

{

  size(300,300);

}

float x=100,y=150;

void draw(){

  background(#002966);

  stroke(#b7efff);

  line(x,y,200,150);

  

  fill(#b7efff);

  ellipse(x,y,13,13);

  ellipse(200,150,13,13);

  if(!mousePressed){

    float dx=x-200;

    float dy=y-150;

    float len=sqrt(dx*dx+dy*dy);

    x-=dx*(len-100)/len*0.1;

    y-=dy*(len-100)/len*0.1;

  }

}

void mouseDragged(){

  x=mouseX; y=mouseY;

}

新的東西~~~

這個圈圈會跟著滑鼠移動。

void setup(){

  size(400,300);

}

float x=100,y=150;

void draw(){

  background(#002966);

  ellipse(x,y,50,50);

  

  float dx=x-mouseX;

  float dy=y-mouseY;

  float len=sqrt(dx*dx+dy*dy);

  x-=dx*0.1;

  y-=dy*0.1;

}

讓圈圈跟滑鼠距離相隔100。

void setup(){

  size(400,300);

}

float x=100,y=150;

void draw(){

  background(#002966);

  ellipse(x,y,50,50);

  

  float dx=x-mouseX;

  float dy=y-mouseY;

  float len=sqrt(dx*dx+dy*dy);

  x-=dx*(len-100)/len*0.1;

  y-=dy*(len-100)/len*0.1;

}

void setup()

{

  size(300,300);

}

float x=100,y=150,vx,vy;

void draw(){

  background(#002966);

  stroke(#b7efff);

  line(x,y,200,150);

  

  fill(#b7efff);

  ellipse(x,y,13,13);

   ellipse(200,150,13,13);

  if(!mousePressed){

    float dx=x-200;

    float dy=y-150;

    float len=sqrt(dx*dx+dy*dy);

    float f=(len-100);

    dx/=len;

    dy/=len;

    vx-=f*dx*0.0001;

    vy-=f*dy*0.0001;

    x+=vx;

    y+=vy;

    //x-=dx*(len-100)/len*0.1;

    //y-=dy*(len-100)/len*0.1;

  }

}

void mouseDragged(){

  x=mouseX; y=mouseY;

}