Setup processing

A typical running structure

Here is a typical way to use Processing library:

from processing import *

healthPoint = 3

def setup():
    size(500, 400)

def draw():
    background(0, 0, 0)
    # do other drawings and logic

    # here if you want to end the drawing, call exitp()
    if healthPoint == 0:
        exitp()


run()

Notice the run() function at bottom, it will call setup() once, and will iteratively call draw() function again and again and again, until you call exitp() function.

In setup() function, we setup the canvas size for drawing, which is 500px in width and 400px in height. In the draw() function, we make the canvas's background as black (RGB color (0, 0, 0) is black).

Get input from user

If you want to make a game with Processing, one important part will be detecting if player pressed keyboard or clicked mouse, which is:

from processing import *

healthPoint = 3

def setup():
    size(500, 400)

def draw():
    background(0, 0, 0)
    # do other drawings and logic
    # here if you want to end the drawing, call exitp()
    if healthPoint == 0:
        exitp()

def keyPressed():
    if keyboard.keyCode == 37:
        # left arrow key pressed
        # do something ...
    elif keyboard.keyCode == 39:
        # right arrow key
        # do something ...

def mousePressed():
    print "Mouse pressed at", mouse.x, mouse.y


run()

3D drawing

Processing also support 3D drawing, to use 3D, you need to setup canvas to "3D" model by passing P3D as the 3rd parameter in size function:

from processing import *

rotating = 0.01

def setup():
    size(400, 400, P3D)

def draw():
    global rotating
    background(0, 0, 0)
    translate(200, 100, 0)
    rotateY(rotating)
    rotating += 0.01
    if rotating >= PI:
        rotating = 0.01
    fill(255, 0, 0)
    box(40)

run()

To check more functions about Processing library, check all functions under Processing Graphic on the left.