Side Projects: Xibalba

This is actually the project around which this blog formed, a turn based roguelike-like game of procedural dungeons, faint mesoamerican stylings, dice rolls, and general geekery.

So far it's seen more use as a rendering playpen than an actual game, although messing around with various representations of immutable game state has been fun.

Oh, and for the curious, I did indeed mis-spell the name for a goodly portion of the project. This is what happens when you start naming things at dark o'clock one night and don't check them for ages.

On the graphics side:

• Deferred shading forms the core of the pipeline. I wanted lots of light sources, and wanted an excuse to mess around with deferred rendering. It's been fun.
• A single main light uses a conventional forward-rendering technique with exponential shadow maps. This forms the focal point, being centred on the player character, and also serves to illustrate line of sight.
• Transparent objects are forward-rendered after the deferred pass, although I don't like this approach at all. Planning on doing some stuff with screen-door transparency for water at least, essentially stealing the work done by Media Molecule for LBP.
• Zeroth order particle systems! I've a minor obsession with these, entirely deterministic effects with all particle motion calculated in the vertex shader for a given time.
• Star-shaped bloom. This is just a very boring post-process, but it's summed over many increasingly downsampled versions of the final image so has quite a large effect considering the main blur kernel is rather small.
• SSAO. Actually, this is no longer a 'proper' SSAO implementation. After messing around with a few different approaches, I eventually settled on a very crude approximation of the depth Laplacian using difference of gaussians, plus some falloff over large distance deltas. This gives a rather stylized effect that I really like. It only works well for quite compressed scenes due to fixed kernel size - perfect for a top-down view though!

First working implementation of the deferred render targets:


Prototyping water, note that only the main (forward rendered, shadowed) light affects the water surface:


The 'notSSAO' post process, dialled up to 11. This also shows a chunk of the map lit almost entirely by deferred lights cenred on the glowing mushrooms:


And last repeat screenshot for this post, the basic particles with a simple lit and shadowed alpha-tested rendering mode:


I'll try to get this running on my partner's PC and get some new screenshots of this for a later post. Have to admit, it was nice going over the early screenshots and see it evolve.