Hi everyone.

I've done a very small amount of Lua coding before. For my current mod project I'll need to do a fair amount. Before I dive into it, I'd like to clarify one thing that I've wondered about for a while.

In the Lua Callback Reference list HERE, there's a whole list of functions that the game accepts. I understand how to use a lot of them but there's one way of using certain ones that I've seen a lot that I really don't get. Here's an example from the teleport sample code (not Zerted's): Just to be clear, I'm not trying to make a teleporter - I only used that example because it was one of the first I could find. My understanding is that MoveEntityToNode allows the Lua code to access information that is inside of the C code the game engine is using, and that entIn, pathIn, and nodeIn are variables. What I don't understand is how I/we know the names of those variables, and in what order they need to be called. Here's another example, something I was helping JazzMaster with: How do we know that these variables are called object and killer, and how do we know that they aren't supposed to be called in the reverse order (i.e. function(killer, object))?

Thanks in advance. I know there's probably an obvious answer I'm missing.

jedimoose32 wrote:My understanding is that MoveEntityToNode allows the Lua code to access information that is inside of the C code the game engine is using, and that entIn, pathIn, and nodeIn are variables. What I don't understand is how I/we know the names of those variables, and in what order they need to be called.

I think those names are mere placeholders to describe the nature of the value that goes there. Their order was figured out by trial and error I'd guess.

jedimoose32 wrote:

Code: Select all

onvehkill = OnObjectKill(
        function(object, killer)
            if IsCharacterHuman(killer) and GetEntityClass(object) == GetEntityClassPtr("imp_hover_speederbike") then
            counted_points = counted_points + 1
            end
        end)

How do we know that these variables are called object and killer, and how do we know that they aren't supposed to be called in the reverse order (i.e. function(killer, object))?

The document battlefront2_scripting_system shows what the names and orders are for a bunch of functions. I believe that's where we learned these orders and names. You should probably read it if your going to go into scripting.

You're right, that doc is pretty helpful. Thanks!

I can't believe I fell victim to the classic "didn't check the documentation first" blunder...

The parameter/argument/variable names mean nothing. You can name them anything and it'll still work as long as you're consistent. It's the positions that matter. First parameter, second parameter, etc... It's a very common mistake people make when new to programming.

As for determining what they are, you read it in the documentation or look how the retail code uses the functions. If there are no example, then it can be very difficult to figure out how to use them. I think there are examples for almost every function. But developers normally follow a convention. Such as all the Set/Get functions behaving in a similar way and all Is**** functions are boolean checks that return true or false. You can use hints like that to guess at their parameters. You could also use a hex editor and try to locate where the function is defined within the exe.

Here's an almost complete listing of all available ingame functions:

That makes sense. I'm assuming the best way to check for the retail usage of certain functions is to... use a hex editor?

Thanks for that list by the way!

No, use a tool to search through all of the asset and documentation files at the same time. Something like grep, my example finder, Window's indexing service, etc... Unless you really want to learn hex editing.

I've done everything I did without hexes, curses, or charms

Oh, by the way, Zerted, your Example Finder no longer works since Java 1.8 was released.

[RDH]Zerted wrote:I've done everything I did without hexes, curses, or charms

I notice you didn't say anything about spells...

And yeah I have had trouble with the example finder since the update as well.

Strange. I also have the latest version of Java, yet I don't have any trouble with Example Finder.

Mine works sometimes, and other times it doesn't. Like for example I'll try to use it and when I try to press the buttons they don't do anything.

You guys probably have both versions installed.

If you mean both 32-bit and 64-bit then yes. Otherwise... I'm not sure and I'd have to check yo see whether I have somehow managed to get a redundant Java installation on my machine.

I mean 1.7 and 1.8.

Nope. I just had a look and I actually only have 1.8, as far as I can tell.

I don't have enough HDD space available right now to install Java 8 and test it. Though I don't have a clue as to why it would stop working. Thanks for letting me know about it.