Dynamic block allocation, properties and block groups

[satoshinm]

Statically adding new blocks is showing its limitations, especially as large numbers of new blocks are added (see https://github.com/satoshinm/NetCraft/issues/154). Several parallel arrays have to be updated in src/item.[ch], not to mention functions, all have to be carefully kept in sync.

To fix this, allocate the blocks dynamically. Review changes from the DanielOaks:dynamic_stuff fork https://github.com/satoshinm/NetCraft/issues/25#issuecomment-293212777, too. The interface I envision would be something like calling a function to increment the next available block/item id, while populating:

• const char *item_names[] - human-readable string name
• const int blocks[256][6] - cube textures
• const int plants[256] - plant textures, used instead of blocks if is_plant (do we need two arrays? update: removed in https://github.com/satoshinm/NetCraft/pull/161/commits/6d7c39537f7faa0ccff2e34f03a546361eeb8800)
• bool is_plant(int w) - switch, what about storing in a struct a bool flag and accessing it instead?
• bool is_obstacle(int w)
• bool is_transparent(int w)
• bool is_destructable(int w) - just calls out to is_hardness() now
• int is_illuminated(int w) - light level
• float is_hardness(int w) - this needs to be updated, many are missing; see updated hardness in https://github.com/satoshinm/Glowstone/commit/6ba5dde062d30f11539e267f5085ee5e5df978f1

int register_block(name, textures, properties...) // return allocated id allocate and expand the arrays as needed (not hardcoding 256, up to 16-bit? https://github.com/satoshinm/NetCraft/issues/55)

Also important: registering block "states". Furnace (https://github.com/satoshinm/WebSandboxMC/issues/61) for example should have 4 sub-blocks, one for each orthogonal direction. register_blocks("Furnace", 4, ...), allocating 4 block ids. Then somehow get the "associated data" from a block, 0-3 for the furnace. Different textures per sub-block type, they should be merely regular blocks, but grouped together logically for programmatic convenience. Info text should show type=furnace (id=...) but attached data=0-3.

[satoshinm]

Registering groups of blocks is now possible, and the data values shows in the info text. Example is furnace, it has 4 blocks for each orthogonal rotation, direction the front is facing: