vec3.without(a, b)

[magcius]

Very common in games math, and a function that should probably be more well-known: without(a, b) is a - b*dot(a, b). You can think of it as projecting a onto the plane formed by the normal of b.

[greggman]

I don't mind adding new functions but I'm not seeing this as "very common" unless it goes by another name? It's doesn't appear to be in glm, nor Unreal, nor Unity. It doesn't appear to be in DirectX. Not sure where else to look. It does look liek their are lots of useful functions on some of those that I'd be happy to see added.

[magcius]

Unity calls it ProjectOnPlane

Unreal calls it ProjectOnTo, with a variant (ProjectOnToNormal) that assumes the given vector is normal.

[greggman]

do you want to add it?