Question of the Week

[RPC]

Anyways, to stimulate some activity on the forums and clear up some ambiguities I (and maybe may others) have about code, I will ask some questions about some vaguely documented parts of Transcendence.

On dockscreens:
What kinds of dockscreens are there? What are they used for?
What are the necessary components of a dockscreen? (Like ListEntries need a name, ImageDesc, and something else)
What is the advantage of using a global dockscreen?

[Atarlost]

Is there any good way to pass variables in and out of a dockscreen called from inside a script using (scrShowScreen)?

[shanejfilomena]

Is there any good way to pass variables in and out of a dockscreen called from inside a script using (scrShowScreen)?

do you mean :

Code: Select all

; Aliases for backwards compatibility ------------------------------
			(setq comShowBuyScreen scrShowBuyScreen)
			(setq comShowSellScreen scrShowSellScreen)
			(setq intMassString strMassString)
			(setq intTranslate objTranslate)

?
I really do not know what you mean by variables : I have hunted the player's cargo, shield and weapon level, combat level....
I think the database has about 99% of most of what we would need : not exactly in the form we want to use them, but I think find many examples to interesting things.

[george moromisato]

Is there any good way to pass variables in and out of a dockscreen called from inside a script using (scrShowScreen)?

I'm glad you brought this up (and thanks, RPC, for kicking it off). I'd like to come up with a good method. Today, as you know, the game uses global variables to pass info to a dock screen--something that won't scale very well.

For dockscreens that are designed to be reusable, I've been slowly moving to a pattern of wrapping the call to scrShowScreen in another function which sets the global variables--that way, when the time comes, we can change it.

Meanwhile, maybe we can brainstorm on some better methods. Some ideas:

1. For dock screens with an UNID, you can always use (typSetGlobalData ...) and (typGetGlobalData ...). This is just as much of a hack, but at least it is scoped to the dock screen instead of the global variable pool.

2. My preferred method is to pass an extra argument to scrShowScreen and have that be accessible from inside the dock screen. The arg could be accessible via a new function (scrGetArgs, or something). [One arg is enough since you can always pass a structure.]

Does anyone have other ideas?

[Atarlost]

A list of key value pairs in one singular global variable maybe?

At the moment I need to pass a list of atoms into and back out of a custom dockscreen.

[RPC]

@Atarlost: I don't know it this will work, but try placing the list of atoms as data on a SpaceObject (using ObjSetData), then use the dockscreen to call them up again when needed.

[alterecco]

In DSF i use a state object that is available to the screens until they exit. That is, i can set a variable in the state, change screen, and retrieve the same variable again (by key). When the player exits a screen completely the state is cleared. We could change that so that a state object could be accessed before and after entering and exiting a screen?

[Mike]

"1. For dock screens with an UNID, you can always use (typSetGlobalData ...) and (typGetGlobalData ...). This is just as much of a hack, but at least it is scoped to the dock screen instead of the global variable pool.

2. My preferred method is to pass an extra argument to scrShowScreen and have that be accessible from inside the dock screen. The arg could be accessible via a new function (scrGetArgs, or something). [One arg is enough since you can always pass a structure.]"

I think I did the quote thing the wrong way but...

Passing Structs = good plan.
Indexing ALL the things would be an alternative, if it weren't impractical, less robust and just plain painful to do. ...segfaults are evil...

[Prophet]

What kinds of dockscreens are there? What are they used for?

• Text - The standard DS.
  ItemPicker - Used for buy/sell can also use a custom list of 'items'
  Canvas - shows pics primarily. underused IMHO

What are the necessary components of a dockscreen? (Like ListEntries need a name, ImageDesc, and something else)

Your question focuses on an itempicker screen which requires an image, Title, description and can take more arguments as needed.

What is the advantage of using a global dockscreen?

A global dockscreen is not tied to any spaceobject or item and can be called from anywhere, even pure script. You could have multiple stations/items call the same global screen.



As for scoping variables, I like the method DSF uses for handling (variables are valid during the entire 'session') and would love that funtionality to be incorporated into the engine.

[RPC]

Thanks Prophet. So is the canvas DS the one used in the neurohacking minigame?

[alterecco]

So is the canvas DS the one used in the neurohacking minigame?

Yes.

We also have a CustomPicker screen type... My personal favorite and the one G.O.D uses almost exclusively :)

[RPC]

Ok, this will be a huge task, (unless it's already documented) but can I get a tutorial for making each dockscreen? If would also be placed in the wiki for future reference.

[alterecco]

Man... i should really really do this... there are just so many games to play, so many projects to play with and so much work to be done... :/ I hope i will find the time and the inspiration. You might be interested in the DSF documentation. It has a little bit of info about screens in general. If there were more people than me using it I guess it would be worth it expanding the DSF docs... :)

[RPC]

Yeah, you should do the tutorial alterecco.
Also closures isn't on the DSF documentation. D:

[Ttech]

Yeah, you should do the tutorial alterecco.
Also closures isn't on the DSF documentation. D:

I don't think closures are specifically dock screen framework though.