Magrathea is an experiment in creating and rendering real-scale procedural planets with 3D terrain. It's a scaled-up adaptation of my quadtree terrain project, with multiple flat adaptive meshes projected onto a sphere. By default, Magrathea renders a planet whose size matches Earth's moon.
When you run the program, it may take a while for the terrain to be built from scratch. When the camera moves, the level of detail changes to match your viewing position. This is constantly happening on a background thread. You can explore the world using the mouse and keyboard. You must press C to attach the mouse to the camera, after which mouse movements will control yaw and pitch. Roll is controlled with the Q and E keys. You can use the WASD keys to fly around. Pressing Up and Down will change the camera's movement speed in powers of 10.
There are also some experimental atmosphere effects which can be cycled with the Space key. The first is the most complex, and uses ray tracing to sample the density of a virtual region surrounding the planet. Samples are weighted with the sun's elevation to create a soft shadow. The second is much simpler, and produces an exponential halo surrounding the globe. The gradient of the falloff varies with altitude. The simpler effect is still convincing, but produces no shadow on the night side.
I think this project has a lot of potential, both as a base for games/simulations with full size solar systems and as an educational tool for anyone wanting a clean and minimalistic example of planet rendering. I believe it could be used to create very immersive virtual worlds when coupled with more complex visuals.
Don't panic, and remember to bring your towel!
