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Kavawuvi

Invader (MCC updates)

Tiddy-bits:

1 minute ago, Vaporeon said:
Spoiler

20200226065749_1.jpg

Scenery now works. turns out there is a value in scenario tags for the BSP index scenery is in that the gearbox version of the game does not care about while MCC however does.

Looks like we won't be having any trouble porting Snowgulch over.

ST34MF0X and Sunstriker7 like this

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Invader is dropping direct support for Halo: Combat Evolved Anniversary (MCC) maps.

 

This means that Invader, itself, will not natively support building CEA maps or extracting tags anymore. There are a few reasons for this, but it mainly boils down to the fact that supporting both CEA and Gearbox Halo PC maps at the same time would be insane for a project developed by one person (me) while trying to add new features. I don't know how many times I've added a feature, only to break MCC or break Gearbox Halo PC maps and having to take time to fix that, too.

 

I am planning on writing a couple tools that use Invader and build/extract MCC maps, but they will not be a direct part of Invader by themselves.

 

Anyway, let's talk about why this change is being made.

 

It is impossible to identify a compressed CEA map without decompressing part of it, unlike every other type of map file.

Because CEA maps compress the header, it is impossible to determine what kind of map it is without decompressing it. This is a pretty big deal, because I can't be sure if, say, bitmaps.map, sounds.map, or loc.map files are actually MCC maps, so I have to attempt to decompress it. This makes things like map loading less efficient, as a result, and it also makes it prone to being broken by feature additions.

 

It is impossible to rationally tell the difference between a CEA map and a retail Halo PC map, and this is an IMPORTANT distinction.

Halo: CEA changes up the rules for map parsing in its format, yet for some reason, they decided to continue using engine version 0x00000007, the same as retail Halo PC. These are different formats, though! Here's a list of what they did:

  • CEA maps no longer use a fixed base memory address. Instead, they can have any base memory address, and this address is derived from the tag array address. It just so happens that there's a tool that does the EXACT same thing: Eschaton. This means that MCC maps cannot have their tag array moved, but Halo PC maps can.
  • CEA maps (that are stock) use a different base memory address than Halo PC (0x40448000 instead of 0x40440000).
  • CEA maps' BSP data can overlap the base tag data by address. Just going by the map alone, the tag space would appear to have been reduced to 16 MiB (in actuality it was increased). However, BSPs are loaded in separate buffers, and this 16 MiB window provides a high chance for an overlap. Halo PC maps cannot do this, thus Invader's map parser accounts for this when it comes to potential BSP data being placed in tag data (Invader's -O does this).
  • CEA maps can have BSP data located outside of the BSP tag, itself.

Maps are limited in what custom assets can be used.

Someone (likely Saber) changed the way bitmaps and sounds are loaded to a way that completely bypasses tag data. Basically, all of the bitmap data is located in the inplace1.ipak file and referenced in .imeta files, and the sound data is located in .fmod files. For whatever reason, CEA does NOT use tag data for determining the location or format of bitmap and sound data, even if that data were internal to the map, itself. This means custom lightmaps, textures, sounds, etc. are impossible by map file alone. You can use custom assets, but to do so, you'd need to replace the inplace1.ipak file, the fmod files, and the .imeta files of all maps. The inplace1.ipak file is a massive file, containing both CEA and classic CE assets. Unless you're okay with all of your other maps not working, you need to include that, too. Most CEA custom maps work around this massive limitation by deleting the lightmaps (so everything is fullbright - better than not being able to see anything I guess) and swapping textures with stock CE textures until it resembles the original.

 

What tag data is even used?

It appears that the way 343 Industries prefers to fix issues is through code. A quick look at the game executable confirms that they use a large number of hardcoded tag paths, thus some tags are directly referenced for some reason. From reading discussions from 343 Industries developers, this somewhat implies this. For modding, this limits us even further. This quote basically sums tag data in CEA up:

 

Getting custom maps to work on MCC is an error-prone process.

As seen in Storm's video, even correctly installing a map can fail, resulting in even 2v2s failing to work in some custom games.

 

Correctly installing a map requires replacing an existing map while modifying a file in a completely separate file. This is a far cry from Halo: Custom Edition (or Halo Trial / retail Halo PC with a mod like Chimera) simply letting you copy the map into the maps folder. Speaking of which, the game, by popular demand, has anticheat. Guess what anticheat does NOT like you doing? Replacing or modifying files. This limits how you can even play the game. Even a theoretical "Refined Anniversary" would have to be played with anticheat turned off, and you're only limited to singleplayer and custom games.

 

We don't know how modding support will work, assuming CEA will even support custom maps.

We don't even know how 343 Industries plans on supporting custom maps in the future, if at all. We assume that, if they wanted to, they would want to support Halo: Custom Edition maps, and if they do, Invader supports generating Halo: Custom Edition maps, anyway.

 

--

 

tl;dr:

 

It's difficult to support a game that is actively and openly hostile towards custom content being loaded. Invader is developed by two people, with me being the only person who actually writes code. I do this in my spare time, and I do it for free. Maybe it'd be different if I was actually getting paid for this, but I'm not. Also, Invader's scope is tag data and maps that reference or have tags. Traditionally, a Halo map file is an archive of tags. However, this game actively disregards tag data, and its assets are stored in ipak/fmod files which do NOT use tag data to reference.

 

Supporting something that falls within the scope of Invader (Halo PC) and something that is well out of scope (CEA ipaks, etc.) at the same time in one project is insane, so this was the path we both agreed on.

Zatarita and (SBB) Storm like this

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Posted (edited)

On 6/28/2020 at 2:39 PM, Kavawuvi said:

...

Supporting something that falls within the scope of Invader (Halo PC) and something that is well out of scope (CEA ipaks, etc.) at the same time in one project is insane, so this was the path we both agreed on.


I think this part alone should be enough for everyone tbh. If the original intention was to create an open source hek, supporting mcc falls outside that scope, and would cause bloat reducing the options for optimizing for its original intention.

 

 Besides, with the niche design of mcc, it requires a bit more finesse to keep everything working smoother. If someone REALLY wants it they can fork it and do it; however, I’m certain there will be someone who comes along and can dedicate the appropriate amount of time to their own project and do it right instead of just adding partial support to an existing project.

 

Plus managing expectations is important for project management. When working with something as ambitious as an open source hek, from a programmers perspective it can become overwhelming to add things while you’re going. Almost managing two separate projects at once.

 

i respect your decision. I appreciate the work you put in. Thank you for trying

Edited by Zatarita
WaeV and Kavawuvi like this

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