Moveable Ball

​

// Mouse Control

​

int swidth, sheight, xc, yc, rad;

int[] fillcol = new int[3];

​

// The setup code below is executed once only.

void setup() {

  // Set up the graphics:

    background(50);

    // Set up the screen size:

    swidth = 0.7*screen.width;

    sheight = 0.7*screen.height;

    size(swidth,sheight);

    // Increase the font size:

    textSize(20);

    // Set the location and intial radius of the circle:

    xc = 0.5*swidth;

    yc = 0.5*sheight;

    rad = 40;

    // Set the initial color of the circle to blue:

    fillcol = {0,255,0};

}

​

// The draw code below is executed over and over again.

void draw() {

    background(255); // Clear the screen.

    fill(fillcol[0],fillcol[1],fillcol[2]); // Set the fill color.

    ellipse(xc,yc,2*rad,2*rad); // Draw a circle.

}

​

​

void mouseDragged() {

// This is a built-in Processing function. It runs any time a mouse button

// is pressed and the mouse cursor dragged around the screen.

​

    // Set the radius of the circle so that the circle passes through the 

    // current mouse location:

    // rad = sqrt(pow(mouseX-xc,2) + pow(mouseY-yc,2));

    // Set the color of the circle to red while the mouse button is pressed:

    fillcol = {0,0,255};

    xc = mouseX;

    yc = mouseY;

}

​

​

void mouseReleased() {

// This is a built-in Processing function. It runs any time a mouse button

// is released.

    // Set the fill color back to blue, now that the mouse button has

    // been released:

    fillcol = {0,255,0};

}