userdata:dot(other): value

Overview

Calculates the dot product of the vectors on the first row of two float typed userdatas. The resulting value is the cosine of the angle between the two first-row vectors multiplied by the magnitude of both.

Arguments

`other`: userdata

The other userdata to perform a dot product with.

Returns

`value`: number|nil

The dot product of the vectors in the first row of self and other, or nil if either is not float typed, or they are not the same width.

Example

-- Each of these vectors is normalized. This means fully parallel vectors will result in 1.
local a = vec(-0.47942554, 0.87758256)
local b = vec(0.87758256, 0.47942554)
local c = vec(0.9004471, 0.43496553)

assert(a:dot(b) == 0) -- a and b are perpendicular.
?a:dot(c) -- -0.04997917382977 - a is almost perpendicular with c, facing slightly away.
?b:dot(c) --  0.99875025526421 - b is almost fully aligned with c.