Physics Simulation - 3D Game Development Practical Introduction - page 232

UpdateSteering() function takes a float value in degrees, and adds it to currentSteering . If the
passed value is zero, the function returns the steering to the straight position by using
steeringSpeed . The steering dead zone is set between -3 and 3 degrees, so if the steering
value is within these limits, it is going to be set instantly to zero (straight). After setting the
new value of currentSteering , the function checks the limits by comparing currentSteering
with maxSteeringAngle and -maxSteeringAngle . Finally, the value of cuurentSteering is stored
in steerAngle member of all wheel colliders in frontWheels .
The last function we are going to discuss in this script is KmphToRPM() . This function takes
two parameters: a wheel collider and a speed value expressed in km/h. The first step is to
convert speed from km/h to meter/minute and store the result in mpm variable. The second
step is to convert the speed from meter/minute to RPM. However, this conversion depends
on the circumference of the wheel. The circumference tells us how many meters the wheel
moves during one complete rotation. Therefore, we divide mpm by the circumference to get
the speed in RPM and return it. After adding this script to the root object of the vehicle, we
are ready to move to our next script.
Now we need another script that enables the player to provide his input to control the
vehicle. This script is going to read input from the keyboard and invoke the corresponding
functions from PhysicsCarDriver . Listing 44 shows KeyboardCarController script, which
handles player input.