What's the deal with CourseMap? Is it a course? Is it a map? Who knows!

[vabold]

Note

The goal of this discussion is to decide on logistical problems early, to avoid complications later on. Names used are subject to change.

Intro

CourseMap is responsible for parsing and storing information about the KMP files found in course archives. Its static pointer is located at 0x809bd6e8 PAL. In the Ghidra server, it is mostly named KmpHolder, with some exceptions. Its structure consists of only pointers to classes classes called Accessors, labeled in the Ghidra as KartpointHolder, EnemypathHolder, etc. The only exception is the header structure at offset 0x4, which consists of the raw file and some parsed header data such as the version.

Accessor Structure

Each class responsible for a KMP section has a base Accessor class. The structure is as follows:

class Accessor {
protected:
    // The object the accessor class handles
    // Instead of using "void**", we will use a template
    void** obj;
    // Decides how many objects will be in the pointer array
    u16 count;
    // Pointer to the beginning of the KMP section
    void* raw;
};

From there, each created class' pointers are set in CourseMap::init.

File Structure

Due to multiple Accessor functions existing between CourseMap functions, we know they must exist in the same TU. This complicates things, as we cannot have each Accessor class in their own file. Instead, we must decide how the classes will be laid out.

One idea is to structure them similarly to RaceConfig and its subsidiary classes. As an example, CheckpointAccessor would exist as CourseMap::CheckpointAccessor, and the Checkpoint object would exist as CourseMap::CheckpointAccessor::Checkpoint.

Additional Topics

During the discussion, new topics and new viewpoints will inevitably come up. This discussion post will be updated to reflect that.

[vabold]

riidefi: Holder does not have ownership of the objects, Accessor is a better descriptor

riidefi is right - Checkpoint holds a pointer to the object directly in the KMP file, as does the Holder/Accessor. If necessary, the base class for an object should be called Proxy. I will update the discussion accordingly.

[em-eight]

CourseMap boundaries

rodata:
start >= 0x8088f8e8 (do not duplicate float conversion constant)
start <= 0x8088fa24 (many data here is referenced in CourseMap constructor)
end >= 0x8088fa90 (string referenced in constructor)
end <= 0x8088faa4 (start of DvdArchive data)
I suggest splitting the smallest amount and we can always extend later
data:
start == 0x808b2c20 (things before that are Channelnstaller related and here is where CourseMap data start)
end == 0x808b2c78 (after that it's DvdArchive data and before that are KMP object vtables)
text:
start == 0x80512694 (CourseMap static instance creation, previous function references float conversion constant that would be duplicated if in CourseMap data)
end == 0x80518cc0 (after that it is DvdArchive text and before that it EnemyPoint destructor)
.bss
start == 0x809bd6e8 (CourseMap static instance)
end == 0x809bd6f8 (GameScene related stuff start)

[vabold]

start == 0x80512694

0x80510d7c and forward is part of CourseMap as well.

[Thodoris1999]

It seems that raw is only used to access the section info (section name, count and additional value), so I think it is a pointer to such struct. It also makes sense because obj (suggesting to just call it data) can access the rest of the section data anyway.