This is annoying and it requires that the server must match this precisely to not cause bugs. Additionally, this code shits its pants when the client hits a spot of network lag.
This can be implemented easily as a plugin. There is no reason whatsoever for this to be in the core.
Survival reach distance is 6, but that's only a measure of how far the player must reach to hit any part of the target block. Measured from the centre, this again provides a possible corner reach which is too far away from the centre of the block by sqrt(3) / 2 blocks.
Simple fix - allow an extra block's distance.
Since chunks are unloaded before changed blocks are processed, there is a small chance that a block might get changed in a chunk, and then get unloaded due to not being in use, before the updates are broadcasted.
This is unlikely to ever happen since chunks usually don't get unloaded unless they don't have loaders anyway, but it could happen (?) if a chunk is forcefully unloaded.
This is needed because players can break blocks that are outside of their field of view. A player can be inside a block and be able to break that block, while looking up, which places its centre (which is where the interact check is done from) actually behind the player's field of view. This causes anti-cheat to be triggered and makes it impossible to break blocks one is inside.
This commit changes the max negative diff to be half of the distance between a block's centre and its corners (M_SQRT_3 / 2).
This now removes the need for recursing around for structures comprised of multiple blocks. Instead, override getAffectedBlocks() to return all blocks that need to be deleted when the current block is deleted, and make sure that only one half of the block drops something. When a player breaks one of the blocks, all the blocks affected by that block will also be destroyed, creating particles and sounds where appropriate.
This fixes creative drops for double plants and beds.
This may be invalid in some cases, such as:
- chunk is not loaded
- entity is not fully constructed
- entity is a Player who has not yet completed the login sequence.
Level providers are now cut back to just an interface to a world's data. They don't keep their own chunk registries or any stupid shit like that because the Level already does that.
This furthers the goal of being able to move level I/O off the main thread, and also drastically decreases the complication of implementing level providers.
