Remember how many chunk updates there are when the sun sets or rises in Minecraft? In 1.7 there are zero.
I put lighting data in a second texture, u is skylight, v is blocklight. To fade skylight, I just dynamically change the texture data.
Also, this means that skylight and blocklight can have different colors now. Nights are brighter, but tinted blue now. Blocklights are warm.
This is the key to
"infinite" height, I think! When he has a texture of the surface for calculating the sunlight, instead of using the whole chunk to do it, he should be able to split the world into 16x16x16 chunks, instead of 16x128x16.
I am really hoping that we'll get infinite height soon.