Hello! This is a demonstration of M.GRL's new GLSL to GLSL compiler. The editor pane on the left contains shader source code that defines several procedural textures. A second source file (which is not directly exposed for editing) describes the 'main' method for the shader program.
You can define additional procedural textures by adding them into the shader source in the editing box on the left. These functions must be prefaced with 'plugin' and have the same type signature as the other plugin functions. An example of such a function is as follows:
Click compile, and then click on the objects in the demo to cycle through the available textures.
More information about the shader compiler can be found in this blog post.