More glam constants for accessing neighbors

[ChristopherBiscardi]

What problem does this solve or what need does it fill?

Grids often have x,y positions. I'll use IVec2 here as an example.

When trying to access neighbor cells, a pattern I use is the IVec2 constants:

A "cross" set of neighbors then, is:

const cross: [IVec2;4] = [IVec2::X, IVec2::Y, IVec2::NEG_X, IVEC2::NEG_Y];

but you can imagine similar for diagonals and 3x3 neighbors including both cross and diagonals.

getting say, the entities from some grid that have valid positions (ie: aren't outside of a grid) can be done with a filter_map.

let valid_positions = cross.iter().filter_map(|offset| {
    grid.get(current_position + offset)
}.collect()

What solution would you like?

A collection of additional constants for these sets of neighbors (feel free to bikeshed names or suggest additional common patterns).

• CROSS (or CARDINALS, or NSEW, etc)
• DIAGONALS
• ALL_NEIGHBORS (ie: not the current position in a 3x3 grid around the current tile)

AXES is an example of a combination that already exists.

What alternative(s) have you considered?

• Just do it manually, which is what I've been doing. But this means every Grid API tends to recreate these access patterns.