Racing Game Lap

Unity Engine
1

Hi.
How do I lap system? please help.

2

One way would be to use triggers. Just place a trigger at the appropriate location, and whenever a player enters the trigger, increase the lap counter for that player.

If the player can back up or turn around, you may need to take extra steps to keep the player from backtracking and then crossing the trigger again.

For a full-fledged system, you’d probably want to track the vehicles’ progression along the track using a spline, which would allow you to prevent backtracking and to determine placing, and also to render a minimap if desired. (I haven’t implemented a racing game myself, but I would imagine that most racing games use some kind of spline-based system.)

3

Is there a code example?

4

The way I’ve seen it done easily is to have 3 collision zones. One at the start line, one at each of 2 split time points.

Once you go through one zone, check for if the player has entered the next. When the player gets around to going through the start line, lapCount++

To get the lap time, as the player starts the lap, set lapStart = Time.time then at the end lapTime = Time.time - lapStart

5

Which part do you need help with?

6

Check out the Unity Scripting Reference - ‘OnTriggerEnter’, ‘OnTriggerExit’ ‘OnTriggerStay’. There will be code examples there.

If you add an empty GO to your scene and add a box collider to cover the area you want to register the lap increase, you can then change the collider to be a trigger in its settings.

Create a script using OnTriggerEnter, which increments your lap counter, and you should be good to go. The player will need the script and a rigidbody.

Have a go and if you get very stuck reply with what you have done, including code etc, and someone will help out. It’s best to have a go rather than just ask for the answer - you’ll learn so much more.

Best Regards,
Matt.

7

I’m trying to add a lap timer to the CarDemoTutorial, but with no success. Also, I can’t add the CarController without causing an Array Exception. Why does it happen?

8

I’ve been working on a Lap timer and I’m nearly there but I’ve got one minor fault in the code that I’d like help with.
I’ve got a trigger on the start finish line and it’s all working as it should be expect for the fact that the “Best Lap” time is being updated to match the “Last lap” time if the car is taking longer than the recorded “Best”.
To try and illustrate:
Lap 1 time = 1:00
Lap 2 time = 0.50
upto this point it’s working well (I think)
Lap 3 time = 0.70
Lap 4 > 0.70
when the current lap time is greater than the best recorded so far it changes the best to equal the last lap time.

I’m really quite new to coding and so any help would be much appreciated.

private var startTimer;
private var Timer : int;
private var roundedTimer : int;
private var Current;
private var displaySeconds : int;
private var displayMinutes : int;
private var Last;
private var LastMinutes : int;
private var LastSeconds : int;
private var Best;
private var BestMinutes : int;
private var BestSeconds : int;
private var Lastlap;

var font : Font;


function OnTriggerExit(car : Collider)  
	{
    startTimer = Time.time;
	}

function OnTriggerEnter(car : Collider)
	{
	LastMinutes = displayMinutes;
	LastSeconds = displaySeconds;
	Lastlap = ((LastMinutes*60) + LastSeconds);
	}
	
function OnGUI () 
{

//make sure that your time is based on when this script was first called
    //instead of when your game started
var currentTime = Time.time - startTimer;

    Timer = currentTime;

	//display the timer
    roundedTimer = Mathf.CeilToInt(Timer);
    displaySeconds = roundedTimer % 60;
    displayMinutes = roundedTimer / 60; 

Current = String.Format ("{0:00}:{1:00}", displayMinutes, displaySeconds);

	GUI.BeginGroup (Rect (540,10,200,200));
		GUI.skin.font = font;
		GUI.contentColor = Color.black;
		GUI.Label (Rect (0, 0, 150, 50), "Current Lap:" +(Current));
	GUI.EndGroup ();
	
Last = String.Format("{0:00}:{1:00}", LastMinutes, LastSeconds);
	
	GUI.BeginGroup (Rect (540,10,200,200));
		GUI.skin.font = font;
		GUI.contentColor = Color.black;
		GUI.Label (Rect (0, 20, 150, 50), "Last Lap:" +(Last));
	GUI.EndGroup ();
	
	if (Lastlap < roundedTimer)
	{
	BestMinutes = LastMinutes;
	BestSeconds = LastSeconds;
	}
	else if (Lastlap > roundedTimer)
	{
	BestMinutes = BestMinutes;
	BestSeconds = BestSeconds;
	}
	
Best = String.Format("{0:00}:{1:00}", BestMinutes, BestSeconds);
	
	GUI.BeginGroup (Rect (540,10,200,200));
		GUI.skin.font = font;
		GUI.contentColor = Color.black;
		GUI.Label (Rect (0, 40, 150, 50), "Best Lap:" +(Best));
	GUI.EndGroup ();
}

You’ll notice I’ve got a bit saying else if (X > Y) B = B; I’m trying to say leave B as it is i.e. do nothing but when I changed the code to use what I say someone else was using as s ‘do nothing’ command i.e. return; it seemed to do nothing but actually scrapped it. As I said, I learning as I go along here and so please excuse any noob mistakes.

Thanks in advance.