class Box:
    def __init__(self, x, y, s):
        self.x = x
        self.y = y
        self.s = s
    def draw(self, cam):
        rect(self.x * cam['z'] - cam['x'], self.y * cam['z'] - cam['y'], self.s * cam['z'], self.s * cam['z'])

cam = {'x': 0, 'y': 0, 'z': 1}

boxes = []

def setup():
    size(800, 600)

    for i in range(20):
        boxes.append(Box(random(-20,20) * 20, random(-20,20) * 20, random(10,30)))

def draw():
    if mousePressed:
        cam['x'] -= mouseX - pmouseX
        cam['y'] -= mouseY - pmouseY

    background(123)

    wmouseY = (mouseY + cam['y']) / cam['z']
    wmouseX = (mouseX + cam['x']) / cam['z']

    text(str(wmouseX) + ', ' + str(wmouseY), 20, 20)

    for b in boxes:
        b.draw(cam)

def keyPressed():
    if key == 'e':
        cam['z'] += 0.5
    elif key == 'q':
        cam['z'] -= 0.5
    if cam['z'] < 0.5:
        cam['z'] = 0.5