GameMonkey Script

What is GameMonkey Script?

GameMonkey is a embedded scripting language that is intended for use in game and tool applications. GameMonkey is however suitable for use in any project requiring simple scripting support. GameMonkey borrows concepts from Lua (www.lua.org), but uses syntax similar to C, making it more accessible to game programmers. GameMonkey also natively supports multithreading and the concept of states.

Can I use GameMonkey freely in my hobby or work project?

Yes, GameMonkey is distributed under the MIT license and is free for any use including commercial products. Please read the full license included in the download package.

What are the key features of GM?

  • Small code base. Compiled code may use about 50kb of RAM. Less when tweaking or sharing with application.
  • Compile source code at run time, or link to precompiled libs.
  • Lightweight, native threading.
  • Soft real-time incremental garbage collection. Controllable memory footprint. No painful reference counting.
  • Easy to bind C\C++ functions and call script from C\C++.
  • Runtime debugging and reflexion support.
  • C style syntax.
  • Competitive performance when compared to other scripting languages for both CPU and Memory usage. Speed is a trade off for flexibility and simplicity.
  • Easily modifiable as it is written in C++ and uses Flex and Bison.

What does the script code look like?

Here is some script code that calls functions bound in C:

OnDoorTriggerEnter = function(door, objEntering)
{
  if(objEntering == player && !door.IsOpen())
  {
    door.Open();
    return true;
  }
  return false;
};

How do I bind a new script function in C?

Here is an example of binding a script function in C:

// Use in script as: DebugText(int x, int y, string text)
int GM_CDECL DebugText(gmThread *a_thread)
{
  GM_CHECK_NUM_PARAMS(1);
  GM_CHECK_STRING_PARAM(text, 2);
  GM_INT_PARAM(x, 0, 10);
  GM_INT_PARAM(y, 1, 10);
  
  Font::Text(text, (float) x, (float) y);
  
  return GM_OK;
}

How easy is it to call script from C?

Here is some C code calling a script function:

#include "gmMachine.h"
#include "gmCall.h"   // Header contains helper class

extern gmMachine machine;   // Virtual Machine instance

// Attempts to call a function int Add(int, int) in script
int AddTwoIntegers(int valueA, int valueB)
{
  int resultInt = 0;

  gmCall call;

  if(call.BeginGlobalFunction(&machine, "Add"))
  {
    call.AddParamInt(valueA);
    call.AddParamInt(valueB);
    call.End();
    call.GetReturnedInt(resultInt);
  }

  return resultInt;
}

What platforms does GameMonkey run on?

Written entirely in C++, it should run on any platform with at most minor modification or configuration. It has been successfully compiled and run on: Windows PC, Apple Mac, Microsoft XBox, Sony PlayStation2, Sony PSP and Nintendo GameCube.

What is coming in the future?

  • A new virtual machine that is a register stack machine and should be up to two times faster than the current VM.
  • An IDE with Debugger.
  • More bindings for useful tools and applications.
  • Possibly native support for enums or constants.

What can I do to help?

  • Use GM in your projects.
  • Create bindings for GM and share them.
  • Tell others about GM.
  • Make improvements to GM or its related materials such as debugger, documents, samples, etc. and share them.
  • Visit the GM website regularly for updates and discuss it in the forum.
  • There may be other things such as server space or download mirrors your could provide, so contact us if you think you can help.

What should I do right now?

  1. Download the latest file package.
  2. Read the FAQ and Script Reference.
  3. Write your first script program.
  4. Look at the samples.
  5. Think of the possibilities and get coding!

What is in the download package?

gmsrc\bin			Compiled binaries
     \doc			Documents
     \EditorHighlighters	Editor syntax highlighters
     \scripts			Sample programs
     \src\binds			Sample bindings
         \examples		Sample applications
         \gm			GameMonkey Script source code
         \gmd			Sample Debugger
         \gme			Sample script executable
         \gml			GameMonkey librarian
         \platform		Platform configuration headers
The source code folders contain project and workspace files for MS Visual Studio 6.

Where can I download GameMonkey?

You can download the latest files from the GameMonkey download section here.

Is there is a forum for GameMonkey?

The forums for GameMonkey site can be found here.