Startline User Manual
From SecondSailing
This is work in progress. Please excuse the incomplete state of the article.
Contents |
Introduction to the start line
The start line has the role to detect boats crossing it and taking a time for them. This time is stored and - after a second crossing - compared to the finish time.
This is done for several boats controlled by chat commands, so that a typical race scenario is easily supported. lag A typical race scenario starts with preparations that st parameters special to the next race. Then the race is started. After boats have finished the race a result is queried from the start line for further processing (e.g. publishing on a web page)
Operating the start line
One important thing to know is that the line will switch of it's listener when you start a race. This is done to reduce as much as possible. To activate the listener again you need to "touch" the start line.
The line will give you a short text after you clicked. If it's not doing, you probably wear a wrong group tag.
After that you can give commands in open chat to the line. Try "+help" to test, if things work.
Preparating commands
A group of commands deals with the preparation of a race.
they are
| +time x | set the countdown time to x seconds. That means from the moment you start until the line allows crossings of boats, a time of x seconds must pass.
A typical time is 120 seconds, i.e. 2 minutes. But you can change that value to anything you like. This value will be recognized until the line is reset |
| +numlaps n | set number of race laps. Setting this to a value larger than 1 requires sailors to cross the line multiple times (usually at the end of each lap :-) ) before the lines announces a finish. |
| +minlaptime x | set minimum possible lap time. Time is given in seconds. Any crossing after the start and before this time is elapsed will be ignored. |
Starting the line
+start will start the countdown. Note that you can restart the line at any time even when a countdown is in progress.
The line will go to the typical start sequence meaning colour changes, shouted announcements of the time left until the races starts and horn sounds. if enabled (see XXX) below, the line will get locked, so that only the originator of the +start command can operate the line for some time.
obtaining results
Each time a crossing is seen, the line will comment that with a line shouted out loud. To get a comprehensive output of all crossings seen since the last start command you can use the "+results" command.
miscellanious commands
+unlock - unlock a locked line. This is the only command that can be given to a locked line. It will remove any lock so that the line can be operated by anyone again. Before you unlock a line you should think why it is locked. Just that nobody can be seen near the line doesn't mean it's not in use. Chances are good someone is running a hot lap or the race director participates in the race.
+reset ´resets the line. That includes stopping the race timer and setting various parameters back to defaults.
+help - displays a short list of possible commands.
Configuring the start line
!! This is only true for newer lines, older lines don't have this feature !!
The start line can be configured by editing the description field of the line.
Configuration settings are given here in the form of parameter <-> value pairs. Each such a pair is separated by colons.
The parameter and the value are separated by an equal ("=") sign
A typical description line would look like this: dbg=0, ways=1, locktime=10
The following parameters are known:
| dbg | Setting this parameter to 1 will enable a lot of debug output. You don't really want to do that :-) |
| ways | possible values are 1 or 2. This controls whether the line acts as a one way or a two way line. |
| group | possible values are 0 and 1. If 0 is set, the line is open to everybody. If 1 is set, the line can only be operated by group members
that are in the same group as the line |
| locktime | any value equal or larger than 0. 0 means, the locking is disabled. any other number means, the line is locked for X minutes after the start command was given. See above for details of locking. |
How the start line detects boats
The line uses the LSL command llVolumeDetect and the events derived from that. Each time a boat (more exact, a prim of a boat. Yes, that happens several times per boat) starts intersecting with the start line a piece of code (an event handler) is triggered. Indeed that doesn't only happen with boats but with every object. Even avatars trigger that mechanism!
As there is no genuine way to tell whether an object is a boat or another kind of object the line reads out the name of the object. If the name contains a "#" sign, it is treated as a boat. All boats that support ID's follow that scheme and add the ID at the end of the name field, separated by a "#" sign.
Boats that don't officially support ID's (like most of the Trudeau boats) usually can be ID'ed by editing the name line manually.
Older lines now took the text following the #-sign and treated that as a number. When it was not a number, the number 0 was taken instead. That lead to the well known duplicate ID problem.
A somewhat newer version treated the text as text, meaning that more than numbers could be used. But the most famous boat, the tako, still only supported two digits with it's ID scheme. Not much won.
Newer lines take the ID of the owner instead. That has the advantage that the ID's are not important to the line (note, they still must be set to have the #-sign in the name).
It has the disadvantage that boats sailed not by their owner are registered by the owners name. Due to that there is still a slight chance that two boats are registered under the same ID. But since that scheme is active there have been no complains about that, so it seems to be a very rare event.
Developer information
See Technical Background for Developers and Designers for more information.
Where to purchase the line
The line is sold at the NYC loft. If you are interested to have your own vendor at your location IM Cynthia Centaur in world.
