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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.

Originally published at Error_Success. Please leave any comments there.

I’m working away on my un-named project, which is starting to take shape nicely. When it’s eventually finished it’ll be some sort of game engine-thing for making 2D style sprite based games – shooters, platformers, and so on. I have no idea what to call it though – a framework seems to be something like XNA where you have a collection of classes and libraries that can be bolted together and compiled up to make a program. An engine seems to be something similar, or the part of a game you get when all the assets and levels are stripped out – imagine Doom without its WAD files.

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Originally published at Error_Success. Please leave any comments there.