GeeXLab

GLSL (short for OpenGL Shading Language) is an extensive C-based shading language that comes with support for the most popular operating systems to date and can create shaders compatible with most graphics cards.
GeeXLab is a powerful piece of software that empowers you to use everything that GLSL has to offer in order to get a feel of what the 3D programming world is all about. In other words, it is a real-time 3D prototyping and coding tool.
The GLSL-, Python- and Lua-based utility makes it possible for you to design demos, interactive applications, and games. Even simpler, just imagine GeeXLab as being your private testing ground for 3D experimenting.

User-friendly coding app – at least from a programmer's point of view

The fact that this app was designed especially for programmers becomes evident once you launch it for the first time. Forget all about user-friendly toolbars and self-explanatory features, as you are greeted by a stripped-down interface with just a menu bar at your disposal.
Despite its apparent complicated nature, the principle behind GeeXLab is quite simple. You need to simply load a source code file (a scene) or drag and drop it onto the main window, and the app simply displays its content in real-time 3D form.

Helps you tweak GLSL scenes and makes live coding more interactive

Not only this, but the tool can also help you modify the source code. Since live programming is its basic feature, GeeXLab enables you to fiddle about with the code and change the parameters, all while viewing the changes in real-time.
To really get your hands dirty and start tweaking a GLSL scene, considering you have already loaded the XML file, you need to start the network live coding interface from the Tools menu. Enter the address of the server and the port number, and then click the designated button for connecting.
After you choose the GSLS program from the GPU list and the shaders that form it from the edit boxes, you are ready to start the live-coding process. Once finished, reverse the process and close the live coding session by disconnecting from the server.

Useful GSLS 3D programming tool

It may not seem as much, but programmers out there surely appreciate even the most basic interfaces, and this is exactly the case with this app.
All in all, GeeXLab is a straightforward coding and prototyping tool that manages to make live-coding seem a tad bit easier and far more interactive.