question about HashMaps

[dapper rivet]

the issue is that front_face is declared const, and so taking an addr-of (&) of it results in a const pointer, which cannot coerce into a mutable slice.

declare front_face as var instead

btw, is the key type an enum? if it is and you're not using any special hashing function (and don't need to preserve insertion order), consider using a std.EnumMap instead of a general-purpose hash map - because the maximal number of keys is statically known and indexes can be computed easily, std.EnumMap does not need an allocator, and is much faster

[dapper rivet]

var vertices_map = std.EnumMap(types.faces, []Vec3).init(.{
    .BACK = …,
    .LEFT = …,
    .RIGHT = …,
})

replace the …s with the values