Super Racing 2D is a top-down driving game in which you control a racing car with realistic physics. Players can try their skills on various tracks with different terrains that behave differently. Like in real life, you must master accelerating, braking, and steering to complete each one successfully. It’s based in retro – arcade like racing games.

How it works?

The user controls a Car along the tracks. The car is made of four wheels and a chassis. Each wheel manages its own settings (max speed, rotation, drag, acceleration…, etc.), and the chassis manages the steering of the car.

Some important classes

The Wheels

An important fact about the wheels is that they can only “move” forward, and under normal circumstances, they should not be able to move laterally. The only condition that allows this to happen is when they skid (like when you take a curve at a high speed).

To limit the lateral velocity, we project the wheel’s current velocity into the lateral normal vector and then add an impulse in the inverse direction. Since we don’t want to completely kill the lateral velocity, we have a maxLateralImpulse force that allows us to tune how much we want it to skid. The wheels have some additional functions to update the friction, manage acceleration (forward and backward) and revolute joints in the front wheels to control the rotation of the car.

The Chassis

The chassis constructor creates the wheels, one in each corner and their respective (Revolute) Joints. But since we only have front traction, those are the only joints stored in the class.

A trick for the chassis is that it behaves as a box but is actually drawn as a more complex polygon. This will eventually allow different “skins” without changing the logic and dynamics.