Flickering Candle

Good Morning all,

I am a newbie to scripting and would like some assistance on a script idea. I would like to create a flickering light to go with some torch/candle models that I have made.

a) does it sound possible?

b) would random number generator be the best way to create the light levels? I would think it would look more strobe light than flickering as the light levels rise and fall - not jump directly to the next light level.

Thanks for your time,

Maldoror Damone
bauhaus design group

I know it can be done. if you want an example of this, seek out Roc Manderblot (sp) in game. He can normally be found at TeaZers University in the lobby (he is a TeaZer instructor), but he just showed me a new flame type particle system he wrote that is probably as close to the real thing as you are going to get in Second Life.

I am going to try and add hardware light flickering also to my lights as they are all flames and i think a simple timer on off with do it although i dont know what may happen to the cpu usage as it turns on and off.

I was thinking about this myself: Using the new local lighting to create a 'flicker' effect on my torches.

Thing is, I can't think of a way to accomplish this without inadvertantly creating a lag machine/resource hog.

I could easily use a timer(), and rapidly 'flicker' between, say, red/orange/yellow on the light glow: but wouldn't that suck for the Sim?

I saw in another thread that Moopf is doing something like this, but not sure if its the obvious (timer) way, or some other innovative way that isn't so resource intensive.

Inquiring minds want to know

hehe, the little camp fire I've done uses a timer to trigger llSetPrimitiveParams to change the color of the light. A single timer isn't that resource intensive either, for what it's worth, and I doubt any other way of doing this would be any less resource intensive

In response to the original poster:

a. Yup, it's do-able.

b. I'm using two colors (one orange, one yellow). I'm then getting the difference between the components of each and passing that through llFrand to get a random variation between the two colors. You could also use random numbers to change the timer speed, so it's not the same time difference between each change in the light.

It's not hugely resource intensive, although llSetPrimitiveParams gives you a 0.2s delay to the script which is worth remembering too.

It might be friendly to your customers to make the flickering optional - one or two flickering torches fine, special occasions 3 dozen also fine, but every day with 3 dozen isn't that friendly to any neighbours I suspect.

As with anything in SL, it's a case of "everything in moderation"

I just put a
llSetPrimitiveParams([PRIM_POINT_LIGHT, on_off, <1, llFrand(1), 0>, 1.0, 10.0, 0.75]);
inside a while loop, just using the inherent 0.2 sec delay.

It gave a fairly pretty flicker between red and yellow, but you could still see the transitions a _lot_, although I guess I was looking for them.


I didn't see any porformance hit, but then, it is a fairly empty sim, and it was only the one light...

Now I just need to work out how to stop / start an infinite loop from the outside *g*. Hmmm, are scripts multi-threaded? could an event trigger and change a global var while another user function was running? *goes off to play*

You will see the transitions, there isn't much you can do about that, unless you gradually change the light color a little each time from the starting color to the ending color.

Beware infinite loops btw You can't stop it once it's started, scripts aren't multi-threaded.

Thanks for the replies all. My god its refreshing at request help and actually get it without rudeness - one of the things that puts SL above the rest as far as community goes.

I think I will stick with just a constant light source - the majority of the lights in the Gorean section of the sim I am working on are candles and they really dont flicker that much in reality unless there is wind or its sputtering.

Thanks again for being a wall to bounce ideas off of.

Maldoror Damone

I have been playing with cycling between colors to give a flickering effect with my "Fire Pit's". Now, the code below is still being worked on. It needs a lot of refinement, but it might give you a starting place.

I originally had the colors cycling between RED - ORANGE - YELLOW, but the color change was too much and created harsh lighting changes.

I ended up going with color values that were closer to each other and, so far, the effect is nice.

  // Colors to cycle through
  list colors = [ "<1, 0.375, 0>", "<1, 0.5, 0>", "<1, 0.625, 0>" ];
  // Time interval to flicker light at
  float flicker = 0.05;
  
  state on {
  	state_entry() {
  		ParticlesOn();
  		llSetTimerEvent(flicker);
  	}
  
  	timer() {
  		integer random = llFloor(llFrand(llGetListLength(colors)));
  		llSetPrimitiveParams([PRIM_POINT_LIGHT, TRUE, (vector)llList2String(colors, random), 1.0, 10.0, 0.75]);
  	}
  		
  }
  

I hope this helps you out.

can i ask why the above script has particles on in it? looking for reference to it in the script or as a function and ddont see it anywhere

Looking at the script, it is only a fragment of a larger whole.

If you remove the ParticlesOn() call, it will do thi lighing effect.

The particles could be used to appear as a flame, or possibly smoke, but they wouldn't be necessary to make the lighting work.

I was going to ask you how you achieved that effect, because I just came back from your place and noticed the flickering effect on the ceiling and surroundings... AWSOME!!! I'll have to experiment the effect on lag, but since we are limited to see only 6 light sources max, I guess it wont affect it much.

During preview I was experimenting with creating such effects client-side using the TargetOmega thing. I just created a group of three invisible prims in a triangle formation (or there abouts) each with a different light colour set on it, then make that entire group spin around a center point. To make it look a little more interesting, you can put more than one of these spinning light things together at different speeds, making it appear more random.

If you play with the turn speed (which does need to be quite high) and the formation of your invisible light prims you can create some interesting effects in the right circumstances, and it's all done client-side so it won't create any lag on the server.

I was, however, doing this before the six light limitation was added in. I noticed once it was restricted that the effect didn't work so well, but that might be partially due to the large number of light prims that were around at the time.

The Script Above Gives An Error Is There A Working Version Of This Script?