pointlight on/off like in horror games

Question

Hey guy's. I was looking for a JS were the pointlight goes on/off like in horror movies/games.

By example; 2 seconds light and then it's off for a half second and then half second on, and then 1 second off and then again 2 seconds on.

2 seconds: on -> 0.5 second: off -> 0.5 second: on -> 1 second: off -> Then again and over again.

I was looking but i couldn't find anything.

I thought something like this;

     function Update() {
     light.range += 5.0 * 0.0;
     light.range +=-5.0 * 2.0;
     light.range += 5.0 * 2.5;
     light.range +=-5.0 * 3.5;
 }

But i know it's wrong :(

Someone help me please.

Thanks in advance.

Answer 1

Best Answer

Answer by syclamoth · Nov 27, 2011 at 01:33 AM

Why not do it with a coroutine?

var minOnTime : float = 1; var maxOnTime : float = 2.5; var minOffTime : float = 0.2; var maxOffTime : float = 0.6;

// set this in the inspector- drag the actual mesh onto it!
var lampRenderer : MeshRenderer;

private var lightIntensity;
private var glowyTexture : Texture2D;
private var blackTexture : Texture2D;

function Start()
{
    lightIntensity = light.intensity;
    blackTexture = new Texture2D(2, 2);
    var cols : Color[] = new Color[4];
    for( var i = 0; i < cols.Length; ++i ) {
        cols[i] = Color.clear;
    }
    blackTexture.SetPixels(cols);
    blackTexture.Apply();

 glowyTexture = lampRenderer.material.GetTexture("_Illum") as Texture2D;
 StartCoroutine(FlickerLoop());

function FlickerLoop()
{
    while(true)
    {
        yield WaitForSeconds(Random.Range(minOnTime, maxOnTime));
        light.intensity = 0;
        lampRenderer.material.SetTexture("_Illum", blackTexture);
        yield WaitForSeconds(Random.Range(minOffTime, maxOffTime));
        light.intensity = lightIntensity;
        lampRenderer.material.SetTexture("_Illum", glowyTexture);
    }
}

This will make the light randomly flicker by the four values you can change in the inspector. You can also adapt this script to make the light jump around a bit, or make it change colour!

(I'm not too hot with JS, since I'm usually a C# man, so tell me if this has any errors since it's not tested!)

EDIT: There was one other issue- it should have been Color.clear, not Color.black where I set the 'black' texture! Sorry again (forgot how illum textures worked)

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Donilias · Nov 27, 2011 at 01:45 AM 0

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were should i draw this JS? Because i drawed this in the pointlight and nothing happend.

syclamoth · Nov 27, 2011 at 01:47 AM 0

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Oh whoops! I forgot one important line! Fixing it now. It was the one in Start() under the lightIntensity thing. Sorry!

Donilias · Nov 27, 2011 at 01:55 AM 0

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It's working and i think this looks perfect. But only one question. I have a lamp with this pointlight in it. So the lamp-texture is self-illumn. Can i remove the self-illumn when the light turns off, and the texture receives his self-illumn back when the light turns on. And so over again?

syclamoth · Nov 27, 2011 at 02:11 AM 0

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Oh! Yes. But since the builtin self-illu$$anonymous$$ating shader does not have a slider for 'illu$$anonymous$$ation', you'll have to provide a 'black' texture to put in the illu$$anonymous$$ation slot when it's not turned on. So, at the top of the script, put

 var blackTexture : Texture2D;
 var glowyTexture : Texture2D;

Then, having assigned them in the inspector the normal way, you can use

 renderer.material.SetTexture("_Illum", blackTexture);

and

 renderer.material.SetTexture("_Illum", glowyTexture);

next to the lines where you turn the light on and off.

(sorry this took so long, I had to do some research!)

Donilias · Nov 27, 2011 at 02:16 AM 0

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And what if i don't use textures, but only colors? like white:color.white and black:color.black

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Answer 2

Answer by Kilometers · Nov 27, 2011 at 12:53 AM

One of your problems is that you would be making all of these changes in a single frame. That is what the Update() function amounts to each time it is called: a single frame. There are different approaches to spacing out a timed event, but one way might be this:

         float lastTime = 0; // Keeps track of the last time the light was changed
         bool lastState = false; // Keeps track of the last state the light was set to, on (true) or off (false)
 

 void Update () {
     if (lastTime + Random.Range(0.5f, 2f) < Time.realtimeSinceStartup)
     {
         if (lastState == false) // If the light was off...
         {
             light.range = 5; // Turn it on.
             lastState = true;
         }
         else // If the light was on...
         {
             light.range = 0; //Turn it off.
             lastState = false;
         }

         lastTime = Time.realtimeSinceStartup; // And update the last time the light was set
     }
 }

Note the Random.Range() function. It will generate a value between 0.5 and 2, which correspond to .5 seconds and 2 seconds. It serves as the interval for the flicker. This ought to be an easier way to get a random stutter to the light.

EDIT: I just realized that you were looking for javascript. Sorry about that. Still the concept applies, and aside from the way the variables are declared, I don't think too much of the code is different.

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Donilias · Nov 27, 2011 at 01:14 AM 0

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I don't have any knowledge with C#. So i don't know what to do.

syclamoth · Nov 27, 2011 at 01:35 AM 1

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I don't think you should be calling 'Random.Range' every frame like that. Because the value gets reset every time, it's much more likely to fall on the '0.5' side than the '2' side, since it checks every time.

Kilometers · Nov 27, 2011 at 01:55 AM 0

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Ah I didn't know that. Thanks!

Answer 3

Answer by Geko_X · Nov 27, 2011 at 01:30 AM

I converted the code for you:

     private var lastTime : float = 0; // Keeps track of the last time the light was changed
     private var lastState : boolean = false; // Keeps track of the last state the light was set to, on (true) or off (false)
     
     
     function Update () {
         if (lastTime + Random.Range(0.5f, 2f) < Time.realtimeSinceStartup)
         {
             if (lastState == false) // If the light was off...
             {
                 light.range = 5; // Turn it on.
                 lastState = true;
             }
             else // If the light was on...
             {
                 light.range = 0; //Turn it off.
                 lastState = false;
             }
     
             lastTime = Time.realtimeSinceStartup; // And update the last time the light was set
             }
      }

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Donilias · Nov 27, 2011 at 01:46 AM 0

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This is working Thnx. But i'm still waiting for the best choice. Yours or syclamoth :)

pointlight on/off like in horror games

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