Processing: Creative Coding and Computational Art

PROCESSING: CREATIVE CODING AND COMPUTATIONAL ART
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First, I need to create the Door object; in OOP this is called instantiation. Then I optionally
set its knob position. Notice how I used the static variable LFT, preceded by the class name
and a dot. Finally, the door is drawn. Look carefully at the syntax—the door object door1
is attached directly to its method with a dot. If you eventually wanted to change the value
of one of the properties, you’d target it the same way. For example, to change the x property
to 194, you’d write: door1.x = 194. Of course, this command would have to come
after the Door object has been instantiated: door1 = new Door(100, 250);. Before you
move on to the Window class, I strongly recommend you review the Door class a few times,
as well as my description. I also suggest trying to make some more doors on your own. This
little sketch covers a lot of important issues that will be built upon.
Window class
A window shares certain characteristics with a door. Both have an x and y position, as well
as width and height. If this example were more detailed, both objects might also have
color, material, price, and inventory number characteristics. There is a way of minimizing
this redundancy between classes in OOP, called inheritance (covered extensively in
Chapter 8), in which classes can inherit properties and methods from other classes.
However, inheritance adds another level of abstraction and complexity, so for this example
I’ll redundantly create the same properties in the different classes. Later on in the book,
when you’re an advanced object-oriented programmer, you’ll apply inheritance. Here’s a
sketch that draws three windows using the new Window class (see Figure 9-32):
// Drawing Some Windows
void setup(){
size(450, 250);
background(200);
smooth();
Window window1 = new Window(100, 150);
window1.drawWindow(50, 50);
Window window2 = new Window(100, 150, true, Window.DOUBLE);
window2.drawWindow(175, 50);
Window window3 = new Window(100, 150, true, Window.QUAD);
window3.drawWindow(300, 50);
}
class Window{
//window properties
int x;
int y;
int w;
int h;
// customized features
boolean hasSash = false;