Transparency in FRAK (2014-08-22)

Recently we introduced improved transparency handling to FRAK engine. It can now be configured between
three transparency rendering modes: sorted, blended and stochastic.

The sorted mode is what used to be the default earlier and is there mainly for backwards compatibility
and fallback reasons. This can be used for decent transparency, but the geometry has to be modelled
while keeping in mind that transparent meshes are compared by their centers.


Failure case for the old algorithm:




The first of the new modes is blended and it uses the weighted blended order-independent transparency
algorithm with a few modifications related to handling alpha-mapped surfaces. This mode is the new
default for the engine, since floating point textures seem to be supported by most browsers these days.


Weighted Blended Order-independent Transparency:




The second new mode is stochastic. It is still a work in progress, but a viable alternative for certain situations.
Stochastic transparency works by using random noise to give each transparent surface a proportional probability of
getting through to the camera. This provides slightly more physically correct results, but currently is a bit too noisy.


Stochastic Transparency:



FRAK Engine