MiniGame1: GrandPrix Monaco

You will:

How to find information

Manage Input

Control a car by translation/rotation

Snap vertex

Create a chase camera

Build a track

End the race using a finish line

How to search

Suppose you want to know how to rotate an object, here are some of the simplest and most efficient methods:

Indication

If you do not know the name of the function, ask for how to rotate in unity
If you already know the function name: ask for Unity Rotate

With IntelliSense - Autocomplete
Type: Rotate(
Use up/down arrows to see the different options

Please ask for how to do it, not just to do it
Fore example: Rotate in unity using c#

Outside of a specific topic, watching a 15-minute video to find an answer that only takes 10 seconds to explain is quite time-consuming.

Refresher

How to manage your view:

F key: center an object.

Right-click: look around.

ALT + Left-click: rotate camera while focusing on the selected object.

ALT + Right-click: zoom in & out.

Mouse wheel: zoom in & out.

Hold mouse wheel + mouse move: pan.

Car Controls

Scene Layout

In the Assets folder, create a new folder named MiniGames

Inside this folder, create a new Scene named: Ultimate Race

Using 3D Cubes:

Create a road of 50mx10m

Create a car 4mx2mx1m

Adjust your camera so the entire scene is visible in Play mode.

Input.GetAxis()

Unity combines both keyboard and joystick inputs through the Input utility class. By using the function GetAxis(« Horizontal »), we retrieve information about horizontal movement from either the arrow keys or/and the joystick.

Create a new script and attach it to the car

Set its name to CarControler

Paste the following code
using UnityEngine;

public class carControler : MonoBehaviour
{
        void Start() { }

        void Update()
        {
                float v = Input.GetAxis("Horizontal");
                Debug.Log(v);
        }
}
Enter Play mode

Use the left and right arrow keys and observe the values returned by the GetAxis function.

Note

Unity seems to simulate joystick behavior through keyboard keys. For example, when we press the right arrow key, Unity smooths the return values from 0 to 1.

Physic’s law

In unity, rotations use degrees. We recall the formula that gives the rotation angle based on the rotation speed and the time interval:

\[angle = dT \times Rot_{speed}\]

Let’s turn

We want to make our vehicle rotate at a maximum speed of 30°/sec.

Add a public float variable turnSpeed in your script

In the update() function, add these lines:

float dt =  Time.deltaTime;
float hInput = Input.GetAxis("Horizontal");
transform.Rotate( ... );

Check the documentation of the Rotate function
Using a simple operation, make it so that:
- When input is 0, nothing happens
- When input is 1, the vehicle turns at the speed turnSpeed

Go forward

We want our vehicle to drive at a maximum speed of 30m/s.

Add a public float variable maxSpeed in your script

When the player press the up arrow key, the vehicle must go forward at the speed maxSpeed

Buid a track

Select the piece of road in the scene

Duplicate it and move it away

In the Inspector, change its Y-value for 30°

Snap it to the end of the road

Add multiple pieces to build a small track

Chase camera

We want the camera to follow the vehicle

In the Hierarchy, drag and drop the camera into the car GameObject

The camera becomes a child object of the car in the Hierarchy

This way, when the car moves, the camera automatically follows

Reset the camera transform node

Activate camera preview

Select translate tool

Move the camera to position it above the car’s roof with a downward view

Finish line

Create a finish line

Create a collider with a script to detect when the car passes between the two poles

Change the color of the banner from red to green

Add more fun

As you may have noticed, the car doesn’t fall when it goes off the track. To make things more fun and a bit more challenging, we’re going to simulate gravity. We’ll give a brief overview of the process here, as it will be covered in more detail in an upcoming chapter.

Select the Car GameObject

In the Inspector, click the Add Component button

Add a Rigidbody component

In the Rigidbody settings, make sure the Use Gravity option is enabled

Enter Play mode and have fun !