My code running a Lua script
Well, this is a bit fun! One of the main points of my game environment is that I should be able to easily modify entity behaviour without having to hard code anything into the environment itself. After a bit of thought, the programming language Lua seemed to be the best idea.
I was completely amazed at how easy it was to add this to my own software. After compiling it up, a surprisingly small amount of code is required to get the basics working. It was harder working out how to extract the Lua script from the zipfile I am using.
The screenshot illustrates a very simple Lua script that does nothing more than contain a function called “think” which looks like this
– Basic test
function think(xpos, ypos)print (“xpos = ” .. xpos .. ” ypos = ” .. ypos)
x = xpos
y = ypos
return x, y
end
So it takes in two parameters, prints them out, then returns them back to the host C++ application. So my C++ application calls the function in Lua, that prints out the values it received, and then returns them. If you look in the debugger you can see it all works 
Now to work out how to expose data and functions in the C++ application so that Lua can use them. I need things like “getPlayerPosition” and so on.
Lua is great stuff. I’ve been adding it to a couple of things we’re doing for work as it’s so much easier adding modules using a scripting engine, than hard coding it and then compiling it in afterwards. And the performance using it isn’t that bad either..
I was thinking to myself “Would it be great to have Lua Scripting on a phone, and lo..it happens. Check this out:
http://code.google.com/p/android-scripting/