legacy_spawn

[Svengali]

legacy_spawn doesn't work similiar to the old legacy-scripting method. If a ship script uses the js-method the spawned thing (cargo,...) will be positioned at the players position. And if the player is slowly travelling he will possibly collide.

The same for legacy_spawnShip. The difference is that the spawned item is sometimes positioned (0,0,0).

The old legacy scripting methods in shipdata.plist are working as expected.

[Eric Walch]

legacy_spawn doesn't work similiar to the old legacy-scripting method. If a ship script uses the js-method the spawned thing (cargo,...) will be positioned at the players position. And if the player is slowly travelling he will possibly collide.

Possibly misuse of the function?? I used it already intensively in my tests and in UPS. it is working as expected in the death actions:

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    player.commsMessage("I'll be back with help for revenge!!", 5);
    system.legacy_spawn("ups-container", 5);
    system.legacy_spawn("textilepod", 15);

The cargo end up in the place........ On better thinking. (memory is getting old) I also found odditys in the placement of the cargo. Because I was close to the ship itself i just didn't realise it but now recollect one occasion were the placement was certainly wrong.

[JensAyton]

Seems like a problem with setting up the legacy scripting target. Worse, fixing it could be problematic. Hmm.

Tracked as bug #013086.

[Commander McLane]

As far as spawnShip: is concerned: Remember that it requires the specification of the desired position in the spawn-directory the entity's shipdata. If this is missing, I guess the entity could easily end up in position (0,0,0).

[Eric Walch]

As far as spawnShip: is concerned: Remember that it requires the specification of the desired position in the spawn-directory the entity's shipdata. If this is missing, I guess the entity could easily end up in position (0,0,0).

spawnShip: is a very unused function. It uses no placements co-ordinates but instead of that it uses the internal spawn directory for placement as Cmdr McLane writes. This function has to be used for very exact placements of objects as it also contains a orientation field. It is used for example to place the racing rings around Lave.

[TGHC]

could it be used to place generation ships further away from the witchpoint, to avoid crashes?

[Commander McLane]

@TGHC: No, it could only be used to give each Generation Ship its own, unique spawning-location. But the same can be achieved by other ways.

@Eric: I would love you to dig deeper into the orientation-key in the spawn-directory. I have no idea why it seems to work with the racing rings (probably it doesn't, but their correct orientation is due to something else?), because I never got it to work with any entity I tried with. No matter what orientation I give it, it is always spawned with its z-axis along the internal (absolute) z-axis. See the Hacker Outposts in Anarchies1.0.oxp as an example (which I am to upload soon).

EDIT: It seems I have run into a problem, that will further delay the release of Anarchies1.0.oxp. Ironically it is related to the very method discussed here.

[Commander McLane]

The same for legacy_spawnShip. The difference is that the spawned item is sometimes positioned (0,0,0).

The old legacy scripting methods in shipdata.plist are working as expected.

No, I have just encountered a case where an object spawned in the old plist style with spawnShip: was created at (0,0,0).

So both the old spawnShip: and the new legacy_spawnShip seem to be broken in the same way in 1.70.

[Svengali]

Ok, after some more testing:

The position of the spawned thing is only sometimes (0,0,0) and sometimes the players position. Or maybe the ones position who has killed the ship. So it is necessary to correct the position after spawning.

Currently I'm using:

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this.shipDied = function()
{
	System.legacy_spawn('harkov_honeypod', 8);
	let posto = this.ship.position.add(3,1,5.6);
	let allpods = System.shipsWithRole('harkov_honeypod');
	allpods.reverse();
	for (let a = 8; a > 0; a--)
	{
		allpods[0].setPosition(posto.add(Math.random(),Math.random(),Math.random()));
		allpods.shift();
	}
}

But it is not always working. The problem is that if the player==killer and if he moves very slow the script will position the cargo to close to the player, so he will collide. And the other problem is that the sorting order is only based on the distance.

Any solutions?

[Kaks]

The solution to spawn is already on svn, as reported here. Hopefully, it won't be too long before the release of Oolite 1.71...

Edit: As far as js is concerned, you could check the distance to the player with

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player.position.distanceTo(posto)

& then move posto accordingly if it's less than the distance desired....

Edit 2: in case player is already dereferenced, you could store a reference to player inside the ship script :

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this.beingAttacked = function(whom)
{
//find the player
if (whom.isPlayer) this.Player=whom;
//other stuff

}

then inside the this.shipDied function:

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if(this.Player && this.Player.position.distanceTo(posto)<20){
//stuff
}

[Svengali]

Sorry Kaks,

maybe the problem was not clear. Just as explanation. My problem was that the moved pods were possibly not the spawned pods, because it is possible that there were already some of them out there. But after a little bit more thinking about it I found the solution. It is not totally safe, but a good workaround for the legacy_spawn problem in V1.70.

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/*
this.name           = "harkov_transporter";
this.author         = "Svengali";
this.copyright      = "Feb2008";
this.description    = "Localhero Part I - V1.03.5";
this.version        = "1.00";
*/
this.shipDied = function() { this.localhero_transport(); }

this.localhero_transport = function()
{
	system.legacy_spawn('harkov_honeypod', 8);
	let posto = this.ship.position.add(3,1,5.6);
	let allpods = system.shipsWithRole('harkov_honeypod');
	allpods.sort().reverse();
	for (let a = Math.min(8, allpods.length); a > 0; a--)
	{
		allpods[0].setPosition(posto.add(Math.random(),Math.random(),Math.random()));
		allpods.shift();
	}
}

sort() does the trick. Ahruman has told us that scooper is a concatenated string. And the other thing is to limit the number of loops, because it is possible that some pods were destroyed. I know that it is a timeintensive solution and maybe there is a better way. But it is a working solution. I have tested it with 3 Transports at the same time and the result was no reference error and they are doing their job.

Cheerio

[Kaks]

Ahruman has told us that scooper is a concatenated string.

Not quite sure what you mean, scooper is an object, and I don't remember Ahruman saying 'scooper is a concatenated string.'

Still, we weren't talking about scooper, and I'm glad you found a solution for the actual problem you had.

Cheers,

Kaks

[Svengali]

Not quite sure what you mean, scooper is an object, and I don't remember Ahruman saying 'scooper is a concatenated string.'

Ok Kaks. You are right . He said

The square brackets don’t indicate an array. The standard behaviour of toString() for general objects is to return “[Object something]”, where “something” is the class of the object. Oolite’s toString() implementations use a variant of that syntax.

That gave me the hint to search for string-handling-methods. And allpods is similiar to scooper. A array with more infos in it (Name, ID, Position,...).

[JensAyton]

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allpods[0].setPosition(posto.add(Math.random(),Math.random(),Math.random()));

This may not really be what you want, since the range of Math.random() is [0, 1). If you want a random offset, you’d be better off with something like:

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this.randomDirection = function()
{
    // Returns vectors distributed reasonably evenly over the unit sphere.
    function myRandom() { return Math.random() * 2 - 1; }
    let v;
    do
    {
        v = new Vector(myRandom(), myRandom(), myRandom());
    } while (v.magnitude() == 0); // Catch the unlikely event of v = (0, 0, 0)
    return v.direction();
}

this.randomVector = function(scale)
{
    // Returns vectors distributed reasonably evenly in a sphere of radius "scale".
    if (scale === undefined)  scale = 1;
    return this.randomDirection(). multiply(scale * Math.random());
}

randomDirection() has a slight bias towards the corners of the co-ordinate cube, but it’s unlikely to be noticeable. Vector should probably have these methods built in.

[Svengali]

Muchas gracias, Ahruman.

This may not really be what you want, since the range of Math.random() is [0, 1).

That's all I wanted. There are 8 pods nearby to that position where the ship died. The explosion could possibly give the spawned cargo pods a momentum. That's what I wanted. The momentum isn't that high ( added(3,1,5.6) before) , so they will be more scattered. And the used AI will stop them. But maybe it would be better to define a variable for that case instead of calling Math.random() 3 times on every loop.

Another case will come to use your snippet. Thanks a lot.