Digital Lights

Hi,

I want to have a digital light display of 8 lights, representing 8 digital bits, and incrementing from 0 to 255 in the normal digital way, i.e.

00000000
00000001
00000010
00000011
00000100

etc

Now, I thought (as usual, the long way round) I could do this by having a timer increment a variable X every second, from 0 to 255 then back to zero again, followed by 255 'If' statements, i.e

If X = 3 Then (and set the respective TRUE/FALSE values for each of the 8 Light variables L0 to L7)

and I could then define the status of the lights as being FALSE = Black and TRUE = white (or whatever colors or glow level I choose)


Tell me, there must be a better and more efficient way of achieving all this,

Thanks

Rock

This is where you use bit masking.

A quick example to show the idea.

integer counter = 0;

setLight(integer lightNumber, integer lightState)
{
	if(lightState)
	{
		// do stuff to turn light on
	}
	else
	{
		// do stuff to turn light off
	}
}

checkLights(integer toCheck)
{
	integer temp;
	for(temp = 1; temp < 256; temp = temp << 1)
		setLight(temp, toCheck & temp);
}


default
{
	state_entry()
	{
		checkLights(counter);
		llSetTimerEvent(1.0);
	}
	timer()
	{
		++counter;
		if(counter > 255)
			counter = 0;
		checkLights(counter);
	}
}

Many thanks Beverley, that is just the sort of clarity on the problem I was hoping for.

Rock

This is a recursive example where you only need to increment the least-significant bit/lamp and the others are incremented as required. NB: There is no decrement option in this example but it would be trivial to add. I've used linked messages so this could be triggered from an external script with minimal changes. Within the one script a global function would be more efficient.

list LampStates = [FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE];

default{
link_message(integer FromPrim, integer Value, string Message, key Additional){
if (Value < llGetListLength(LampStates)){ // Can adjust for 16-bit, etc.
if (Message == "Increment"{
if (llList2Integer(Value) == FALSE){
// ... TURN LAMP ON HERE ...
} else {
// ... TURN LAMP OFF HERE ...
llMessageLinked(LINK_THIS, ++Value, "Increment", NULL_KEY);}
LampStates = llListReplaceList(LampStates, [!llList2Integer(Value)], Value, Value);}}}

state_entry(){
llSetTimerEvent(1.0);
}

timer(){
llMessageLinked(LINK_THIS, 0, "Increment", NULL_KEY);}
}