Feature Request: Cross-Map Tag Patch

[jadrvel]

I am a new player in the Halo series. While playing the campaigns, I found some numerical design choices unsatisfactory (e.g., the ammunition capacity of certain weapons). Since I couldn't find an existing mod on Nexus that makes the exact modifications I wanted, I came across this fantastic project and found it more than capable of achieving my goals.

However, after learning about the structure of Halo's map files, I realized that I have to manually apply the same modifications to each map, which is quite tedious. The existing map patch feature seemed relevant, but after reviewing the code, I noticed that it relies on the specific binary layout of each map file, preventing it from being applied across multiple maps.

While it is true that different maps within the same game have their tags stored at different offsets, tags within the same group share the same structure, and many tags (e.g., weapon tags) are logically identical across all maps. Therefore, I believe a cross-map tag patch feature could be a valuable addition to Assembly, making modifications more convenient.

[jadrvel]

Since I'm a .NET developer myself, I've actually been working on this feature over the past few days and am close to completing it. I'd appreciate it if you could let me know whether your team is interested in this idea. If so, I'd be happy to refine my implementation and submit a pull request.

[Lord-Zedd]

Depends how its implemented but I'm open to it.

[jadrvel]

Great! Thanks for your interest in this feature.

My implementation introduces a new structure called TagChange, which records modifications made to a tag. Each TagChange includes the tag's name, group magic, and base size as identifiers. The data changes are categorized into three sections:

• Top-Level Changes: Modifications to the root structure, excluding data references and tag blocks (since they act as pointers).
• Data Reference Changes: Modifications to the actual contents of data references.
• Tag Block Changes: Modifications to the actual contents of tag blocks. These changes are recorded recursively using a structure similar to TagChange, as tag blocks can be nested.

To build and apply these changes, I implemented a specialized IPluginVisitor that tracks the offsets of data references and tag blocks. By following their addresses, I ensure accurate change detection and application. For handling the actual binary modifications, I reused DataChange, DataComparer, and DataPatcher.

I haven't explored the poking functionality yet, but I assume there isn't a significant difference between applying a patch to the cache file and to memory. Given that TagPatch is designed for cross-map modifications, it seems reasonable for this format not to support poking.

Regarding the UI, I plan to modify the PatchControl page to support this new format. Since much of the information is shared, most controls will remain the same, except for an additional button in the tag-building tab to differentiate between Patch and TagPatch. Alternatively, I could create a dedicated page, TagPatchControl, specifically for this format—whichever approach you prefer.

Additionally, I have refactored a few source files related to my implementation to improve readability and maintainability.