Basic mobs support

[nictuku]

I'd like to add basic mobs support - that is, have the ability to spawn mobs, but initially without any strong AI, which of course we should also add later.

If anybody else wants to work on this, please contact me via github so we can sync up and avoid duplicating work.

[huin]

Sounds awesome, will bring the server to life a bit.

[nictuku]

As a sub-product of this, I want to make a http://wiki.vg page to document all 'metadata' transformations that can be applied to a mob spawn packet, by cataloging all mobtype+metadata combinations seen in a notchian server.

Whenever "intercept" shows an unknown combination coming from a notchian server, I'll record that and make a similar mob appear in our own server in front of my player, so we can document them via screenshot.

[huin]

Sounds like a good plan to me, and has good community benefits. I've gained a lot from that wiki.

[huin]

http://www.minecraftwiki.net/wiki/Alpha_Level_Format/Chunk_File_Format <- there's some information on this other wiki that should be useful here.

[huin]

I've found that test case that failed and mysteriously stopped failing (I thought at the time it was a dirty tree). Turns out that it's an architecture difference causing it. I modified the tests to output with %x instead of %q to make the hex dump easier to read:

--- FAIL: mob.TestMobSpawn (0.00 seconds)
    Resulting raw data mismatch for creeper spawn, wanted:
        1800001e6132000000000000000000000000008d000110ff11017f1c00001e61000000000000
        but got: 
        1800001e6132000000000000000000000000008d0001110110ff7f1c00001e61000000000000
FAIL
make: *** [test] Error 1

Or with added spaces around each metadata section:

1800001e6132000000000000000000000000008d 0001 10ff 1101 7f 1c00001e61000000000000
but got:
1800001e6132000000000000000000000000008d 0001 1101 10ff 7f 1c00001e61000000000000

It looks like the maps of entity metadata are iterating in different orders on different architectures (x86 vs x86_64) - which is causing the tests to fail - although functionally the code is still doing the right thing, but the tests are a little fragile and map-order dependent.