Improve compressed point bit manipulation

[braw-lee]

fixes #3111

added some comments on both rust and cpp side
i am not sure about the terminology used in bit manipulation, pls suggest improvements if any
i didn't name the hard-coded constants (1 and 0x7FFF) yet
do we need to name them or the explanation in comments seems enough?
@P-E-P

[P-E-P]

added some comments on both rust and cpp side

Nice, it really lacked some

i am not sure about the terminology used in bit manipulation, pls suggest improvements if any

Looks fine, probably a tiny teensy overly verbose but I still like it like that.

i didn't name the hard-coded constants (1 and 0x7FFF) yet do we need to name them or the explanation in comments seems enough? @P-E-P

It is already clear enough with the comments, I'll put here what I would have written myself but this is meant as an example for you to get a rough idea, not because I want you to change your code. This is a community project, not @P-E-P 's personal project 😄

// probably in a namespace or something so those values don't slip everywhere in the project
constexpr uint32_t BASIC_BLOCK_OFFSET = 16;
constexpr uint32_t BASIC_BLOCK_MASK = 0xFFFF;

constexpr uint32_t STATEMENT_OFFSET = 1;
constexpr uint32_t STATEMENT_MASK = 0x7FFF;

// [...]

return (point >> STATEMENT_OFFSET) & STATEMENT_MASK;

What you've written is fine, that's just a different way of doing it. Some people would probably have written a union over Point and a bitfield struct or something.

[braw-lee]

ah that looks much better, now I feel like copy pasting this 😄