Apologies if this has been covered before, but I can''t seem to find any tutorials or threads that cover what I can''t figure out. Noone seems to cover the initial stuff. I''m trying to work out how to integrate a scripting system into my engine. At the moment the actual language used isn''t important (although FYI I''m considering python or lua). What I want to know is how the actual integration works. Here''s an example: I have a GUI system in the engine. I want to be able to create windows and menus using a config file (like xml or something, it doesn''t really matter what). I need to have the event functions for things like buttons execute user-defined (where user = game designer, not engine developer) code, and for that code to be executed when said button is clicked. The code would need to play with things in the engine (eg pop up a new (already defined in another config file) window, or change a graphics setting, or something like that) which means it needs to be able to change engine settings and interact with other objects in the system. Let''s say I have a window for configuring the video options. I would need the scripting code to be capable of populating certain parts of the window like list boxes (for resolution changes) and sliders and so forth. I would also need the code for the OnClick event of the OK button to be able to get the values of the list boxes, sliders, etc from them and update game settings with them. Another example would be when the user does something in the game world, like "use" an object. I would need to be able to run a block of code that would alter the game world in the way desired for when said object is used, which means the scripting system needs to be able to affect these objects in some way. So my question is (after that rather long winded paragraph) how does all this work? How exactly do I expose the required functionality in my (C++) engine? How do I run a block of code taken from a config file that says "when the object defined by this config file does this or is interacted with do this"? Links to tutorials/threads that I missed explaining this are welcome. Thanks in advance for any help. -------------------- Never eat anything bigger than your own head.

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I''m not interested in writing my own scripting language. I''ve written compilers before, and I know that it''s far too much work to be worth doing when there are existing solutions around. What I want to know is how to integrate an existing language into my system such that I can call user defined code when necessary and have it work with existing objects in the engine like windows and entities in the game world.

--------------------
Never eat anything bigger than your own head.

Biggles,

On the same search as you''re on about half an hour ago, I came across the following, and it looks like just the ticket

Download the "lua scripting" link on http://www.gametutorials.com/CodeDump/CodeDump_Pg1.htm.

Cheers,
I.

www.coldcity.com
code, pics, life

Boost.Python + Python or Lua + Luabind

I prefer the former

quote:Original post by Biggles
What I want to know is how to integrate an existing language into my system such that I can call user defined code when necessary and have it work with existing objects in the engine like windows and entities in the game world.

Many existing scripting languages can do that for you. In
particular, Tcl is very suitable for GUI controls, especially
when used with Tk. But you can use Tcl with your own GUI stuff.


Kami no Itte ga ore ni zettai naru!

That link was quite helpful, IainC. Thanks.

Now, let me see if I''ve got this right. Working from the example of the GUI component:

I would create some functions in C++ that could be called from the script to retrieve a pointer to a GUI object (like a label or a button). Then, in the script, I would call the function necessary to get the object I want. Once I have a pointer to it in the script, I can do things like set and retrieve values on it as long as I also provide functions to do that in the class for that object.
For handling something like user defined code when a button is clicked, I would store the code with the button and then the OnClick function for the button (in C++) would feed that code into the script VM where it is run.

I''m still a little confused about how object scoping would work in the script, and the functions that are accessed by the script. It looks like these functions will have to be C functions, but they also need to be able to access the instances of classes in my engine (for example, a C function used by the script to draw a rectangle on the screen would need to be able to access the display object, eg Display::DrawRect), which have been encapsulated inside the main engine class. How do I get around this problem without breaking encapsulation? Is it even possible?