Building a Second Life Checkers Game

I (SL: Wood Wheels) have been working on a checkers game in Second Life. This is just a learning experience and a chance to really dig into a new language. I've found that the best way to learn a new language is to build something and keep increasing the complexity. I've built a bunch of houses, doors, lamps and a soccer ball, but this is definitely the next step in the evolution of my understanding.

There are a bunch of lessons learned so far and I thought this would be a good opportunity to pass some of those on beyond a couple of updates to the lslwiki and slwiki.

The first lesson was where I started out giving each game piece it's own script and sending messages back to a larger script attached to the board. This was using Link Messages (llMessageLinked). It was good that I figured out early that this was the wrong way after reading the section on Script Effeciency. #1 in efficient design: If you need to have a bunch of buttons, don't put a script in each prim, use llDetectedLink number.

I now have only one script in the board. By default, each linked prim has a link number and you can traverse the list of linked prims using something like this:

integer count = llGetNumberOfPrims();
integer i = 2;
for (;i<=count;++i)
{
  string stName = llGetLinkName(i);
  list namelist = llCSV2List(stName);
  string stType = llLink2String(0);
  string stPieceNum = llLink2String(1);
  if ((stType=="r") || (stType=="b"))
  {
    llOwnerSay("have a "+stType+" piece numbered "+(string)stPieceNum);   

    // I also save the link number, color and piece number 
    // in a list which I'll show later
  }
}

I gave each piece on the board an object name of "r,1" or "r,2" which allows me to identify which piece is touched during the move. I then convert this name to a list (llCSV2List()) to separate out the color and piece number. You might note that i started with 2. The board, which is the root prim (the one selected last when linking), is number 1 and I don't include it in the lookup. I don't have the move mechanic completed, but the early design of it is working and I'm refining the movement code now.

There is probably a lot more to talk about and lists are a big part of the design. I'll try and write more on that tomorrow.