The immediate benefits:
•Minecraft worlds become as virtually infinite vertically as they are horizontally: The absolute limit being Y = ±30,000,000.
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A large FPS increase:
Alpha testers report an FPS increase of 100~200%.
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Increase in running capability: Computers running Minecraft on Tiny render distance will handle only 30% the blocks they do now.
The possible features:
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Spherical render/load distance: Reduce handled blocks by up to 30% by cutting corners made of unneeded chunks.
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Server chunk occlusion/exclusion: Reduce bandwidth usage and defeat hackers by only sending data for visible chunks.
•Three-dimensional biomes: Save biome data per chunk rather than per block column, create volcanoes with magma chambers, underground rivers, tropical skylands floating over icy taigas, and more.
The disadvantages:
•Unloaded gravity-pause: Falling non-player entities and fluids will be forced to pause their fall if they reach unloaded chunks, but will resume falling when those chunks are loaded.
•Slow falling-pause: Players with slower computers and smaller render distances will have falling occasionally paused as they fall into unloaded chunks, until new chunks can be loaded.
The problems:
•Current sunlight and rain calculation methods cannot work with infinite vertical space:
The solution to this is described here.
•Current BiomeDecorator cannot work with multiple vertical chunks simultaneously: The BiomeDecorator code must be altered to function correctly with this, or removed.
•Current cave generation method is executed an extra time for each vertical chunk created simultaneously, leading to lag spikes on world generation: Cave generation's method must be altered to suit this system more.
•Current grass/dirt generation algorithm forces additional chunk requests when chunks are loaded, causing chunks to load slower than they should: This algorithm must be replaced with something else.
http://www.minecraftforum.net/topic...ver-two-thousand-supportersupdated-1015/#data
How worlds will be stored:
How the current storage works, and what changes:
Interestingly enough, the current method of storage, the Anvil format, is derived from the storage method that the original Cubic Chunks mod used. The Anvil format stores individual chunk as a series of 163 quasi-cubic chunks. These 'fake' cubic chunks allow for easier reference of specific data, but they still can't be separated from each other, meaning that it fails to reap the full benefits of this system. Even so, the change allowed Mojang to double the maximum height with no performance hit. Chunks are stored in groups of 322, inside 'MCRegion' files, for a total of 1024 chunks.
By nature, cubic chunks does away with the 'quasi-cubic' nonsense. In terms of chunk grouping, instead of using groups of 323 chunks, new "3DRegion" files would contain groups of 163. This means each 3DRegion file contains 4096 chunks, four times as many as MCRegion files. However, each 3DRegion contains only one fourth the amount of blocks. For per-chunk positional metadata, 3DRegion files would use the same number of bits as MCRegion files, after compression. Calculations show that the same area encompassed by a single MCRegion file would consume 64 kilobytes of extra space with 4 3DRegion files, which is nothing.
Converting existing worlds:
Most people are probably wondering something like "But won't this totally destroy all existing worlds?". Absolutely not; conversion could not be simpler. When a non-cubic world is loaded after the implementation of this system, a conversion process will begin and convert the entire world at once(To avoid making chunk loading take longer during play). First, all existing MCRegion files will be divided into quarters to create 3DRegion files. Then, all existing chunks are divided into sixteenths using the quasi-cubic properties to identify boundaries. After that, conversion is done.
The "isEmpty" flag optimization:
A 1-bit flag is added to each chunk, named "isEmpty". If the chunk consists of 100% air blocks, this bit is 1, any other case makes it 0. When the bit is 1, all data for the chunk besides the isEmpty flag is deleted and ignored, which reduces filesize. Empty chunks are never loaded, and locations where they occur are merely simulated as entities reside in them. The chunk will only load when something requires saving inside it.
Render/Load distance alterations:
After the implementation of Cubic Chunks, view distances' radii will apply to the vertical axis too. This reduces handled blocks in the cases of tiny and short render distances, and increases them in the cases of normal and far render distances. This can be optimized by utilizing a spherical render distance instead of a cubic one, which would reduce handled blocks in all distances except Far.
