While traditionnal 3D rendering uses discrete geometry as a unit, programming on OpenGL's fragment shaders provides a truly mathematical and generative way to represent depth. Instead of projecting polygons on the screen, the image is the result of multiple rays of light travelling through the scene. This actually allows us to consider a much more complex idea of geometry ; instead of simply creating multiple distinct objects, we can now produce a continuous and open world, in which light phenomenons can be controlled by physical parameters.
The general concept of creating fully generative scene if actually very powerful ; it allows us to work for more than just a result, and to experiment with the idea of variation. When recreating the behaviours of nature, the ability to control the rules themselves then becomes very interesting.