Halo 4 Sandbox Modding? with Liberty?

Nov 16, 2012 at 7:02 PM

Great job on the tool! I found it via your YouTube video.

But question...

The main thing I'm looking for is a way to Mod the Sandbox Level like in the Halo 3 days...

Are you planning on upgrading the tool to handle Sandbox Levels and if so by when?

Is there a tool where I can manually uncompress/recompress the sandbox levels so I can mod in Hex? I'll take anything I can get at this point ;P

Developer
Nov 17, 2012 at 1:12 AM

There isn't really any tool out right now because nobody knows how to decompress them. Also, Liberty is a campaign save editor, so even if we did figure out how to edit them, the editor would be released as a separate program.

Nov 17, 2012 at 6:39 AM

hmmm... has the ISO been torn down to see if there's a special dll that's used to compress instead of just xcompress.dll?

Nov 17, 2012 at 6:51 AM
Edited Nov 17, 2012 at 10:02 AM

Well.. I should have looked before asking because... the funny thing is... most of the .map files I've extracted seem to be only partially compressed (Just have to figure out what these offsets control).. however the size of the container file compared to the contents seems unusually large... any ideas? I'll try tinkering and report back.

Yea side note Forge is like the only creative side to Halo so why not do a separate editor for it? :)

Edit:

Pretty sure there's checksums in the map files for error checking, I made a thread with examples of comparisons showing it: http://www.purchasemods.com/forums/Thread-Modding-Halo-4-Forge-Maps

If anyone has an idea of which checksums are being used here please share.. looks like the main one returned an int 64 value and zero bytes seem to be removed from the bottom when items are placed on the map so that the file size stays the same...

Developer
Nov 17, 2012 at 2:46 PM

I should probably clarify what I meant by "compression" because I'll admit my word choice was kinda bad. I haven't looked at Halo 4 forge maps yet (maybe this afternoon I will), but Reach maps at least are "compressed" in the sense that values aren't aligned on byte boundaries. Lord Zedd, DeadCanadian, and I have all tried looking at them with no results. See this blog post for an example of what I mean: http://www.xboxchaos.com/blog/11/entry-13-reach-mvar-help-find-the-pattern/

H4 maps could be completely different though, so take that with a grain of salt unless you run into huge issues trying to make any sense of the data.

Developer
Nov 17, 2012 at 2:50 PM

Also, as far as checksums go, Bungie and 343 like to use SHA-1. Usually you'll have to fill the place where the hash is stored (0x14 bytes long) with zeroes or some other number (GPDs use 0x99), take a hash of all or part of the file, and then store it there. It's also possible for the hash to be salted, where the area to be hashed is prepended with EDD43009666D5C4A5C3657FAB40E022F535AC6C9EE471F01F1A44756B7714F1C36EC (this salt is the same in both Reach and H4) before hashing it.