Im praticing my Object-Oriented Programming with a simple program that lets me control a "car" (its actually just a rect()).

So far i have the car being displayed and moving. But i want to make it a bit more "natural" to drive the little square.

At the moment i just have "if key W is pressed, X++ / if key S pressed X-- / if A angle++ / if D angle--" this is a really simple translation and rotation of the shape.

 I'd like to use W / S to move the square always forward and backwards having in mind the front and back of the "car" and A / D would rotate the "car". THis way i could actually control the "car" in a more natural way.

Here's what i've got so far: (Keep in mind this is really basic and primitive stuff :X)

1. Car car;
2. void setup(){
3.   size(400,400);
4.   car = new Car();
5. }
6. void draw(){
7.   background(200,210,200);
8.   //DRAW THE SHAPE
9.   car.display();
10.  
11.   //CONTROL THE CAR WITH KEYBOARD (W,S,D,A)
12.   if(keyPressed) {
13.     if (key == 'w' || key == 'W') {
14.       car.forward();
15.     }
16.   }
17.  
18.   if(keyPressed) {
19.     if (key == 's' || key == 'S') {
20.       car.backward();
21.     }
22.   }
23.  
24.   if(keyPressed) {
25.     if (key == 'a' || key == 'A') {
26.       car.left();
27.     }
28.   }
29.  
30.   if(keyPressed) {
31.     if (key == 'd' || key == 'D') {
32.       car.right();
33.     }
34.   }
35. }

1. class Car{
2.   float speed, posX, posY, w, h, angle;
3.   Car(){
4.    posX = width/2;
5.    posY = width/2; 
6.    w = 30;
7.    h = 10;
8.    speed = 5;
9.    angle = radians(90);
10.   }
11.  
12.   void display(){
13.     rectMode(CENTER);   
14.     translate(posX, posY);
15.     rotate(angle);
16.     rect(0, 0, w, h);
17.   }
18.  
19.   void forward(){
20.     posX += 5;
21.   }
22.  
23.   void backward(){
24.     posX -= 5;
25.   }
26.  
27.   void left(){
28.     angle += radians(15);
29.   }
30.  
31.   void right(){
32.     angle -= radians(15);
33.   }
34. }

Since im going to be doing alot of this kind of programming (much like programing a game) i'd probably be better with reading about this theme.

I'll be needing Gravity , Inertia, Collision and so on to make the controls more fluid and natural.

I've been trying a few keywords on google but not getting where i'd like.
Maybe some of you can suggest a good book or anything at all i can start reading :)