Time.deltaTime problem?

Unity Engine
1

Hey, I’m trying to make a counter for a grenade. I use this script

var Timer = 0;
var explosion : GameObject;
function Update ()
{
	Timer += Time.deltaTime * 1;
	
	if(Timer >= 3)
	{
		Instantiate (explosion, transform.position, transform.rotation);
		Destroy(gameObject);
	}
	
}

but the timer won’t count upwards. i tried with Timer -= 1 * Time.deltaTime and that counted down each frame and not each second like it should. how can I make it count seconds so the grenade wont blast earlier the faster computer you have.

2

you do know multiplying 1 * x = x. It’s the identity theorem. So that’s just a superfluous operation.

as for the rest, your code looks like it should work. The grenade (gameObject) should only last for 3 seconds before being destroyed and replaced by an explosion.

The only problem I see is that Timer is probably defaulting to ‘int’ (I’m not certain as I don’t write UnityScript). Try saying:

var Timer:float = 0.0f;

where you declare your var.

If it’s just an int though. An integer X plus a very small number like 1/60th (the average deltaTime) will result in just X. Because integers can’t represent fractions, and a fractional value will just be rounded.

3

yeah, it was a problem because it wasnt a float. thanks for the help man :smile:

4

It would be simpler to use Invoke anyway instead of manually making a counter like this.

–Eric

5

Yeah, always avoid having code like this in your Update if not REALLY needed. First price will be to make your own little timer script, attach it to the game object and let it destroy itself after doing it’s work. as it is at the mement, that timer will keep on running and add un needed performance bottleneck. It might not be much, but at the end every bit counts.

6

Invoke should take delegates instead of just string names of functions… grrr ugh.

7

That would be nice, yes.

–Eric

8

You mean it should be extended to support this…

I find the use of strings nice and simple :wink:

9

More error-prone, however. Not using a string doesn’t really make it any less simple anyway; think of StartCoroutine for example.

–Eric

10

Why extend it, delegates give all the functionality necessary.

String’s are not “simple”, it’s expensive to have to look up the function by its name.

this is just as simple, actually it’s 2 less characters.

void Bar()
{
    Invoke(Foo, 3);
}

void Foo()
{
    *do stuff*
}

furthermore I could use anonymous functions in it as well

Invoke( delegate() { *do stuff* }, 3 );

I actually forego Invoke all together, and have my own version of it that takes delegates for this very reason.

11

For some reason I thought you needed to declare the delegates…

In that case, yes you’re right… much betterer to do it that way…

12

I avoid string at all costs except for when representing actual text.

For instance when it comes to animations. I create an enum of the animation names and pass those around. It just requires writing a couple extension methods for Animation that retrieve the string name based on the enum and passes through via that. This way the only area prone to error is this set of functions that convert from enum to string.

13

Is your reasoning for performance or code standards?

Magic strings/numbers are always frowned upon, but that’s generally a coding standard thing…

14

standard

as I said, “This way the only area prone to error is this set of functions that convert from enum to string”. That’s not a speed thing, that’s a standards thing.