Is vector4 intended to be = to clojure persistent vector?

[joinr]

Messing with some pixel operations, scanning to eliminate blank pixels (naively), I want to filter out
[255.0 255.0 255.0 255.0] and record [x y] coords that are non-blank...

(defn extract-outline [pixels]
  (let [blank [255.0 255.0 255.0 255.0]
        [w h] ((juxt c2d/width c2d/height)  pixels)]
    (->> (for  [x (range w)
                y (range h)]
           (let [p (p/get-color pixels x y)]
             (when (not= p blank)
               [x y])))
         (filter identity)
         vec)))

Input pixels is a result of to-pixels from an image. I believe a vector4 buffer.

The problem is, = between the vec4 that's stored in pixels and the literal 4-element vector I denoted is not considered structurally equal. So, every pixel is returned. I'm guessing the simple way out is to to use vec4 explicitly instead of clojure's vector. Is this intentional?

[genmeblog]

Thanks for spotting it out. Probably I have to think again about equality (https://github.com/generateme/fastmath/blob/master/src/fastmath/vector.clj#L632)

For your case you can convert blank to color (which is vec4): c/to-color [255.0 255.0 255.0 255.0]) or just set blank to white (c/color 255.0 255.0 255.0 255.0) or c/to-color :white.

[genmeblog]

Considering your example, from efficiency point of view, it's good to have the same types (color ie. vec4). But in fastmath I see that it's crucial to follow Clojure perception of identity vs equality. It should refactored for sure.

[joinr]

Can maybe mitigate perf hit with a specific instance check for vector. Or force callers to use vec4 equality somehow. Not a huge deal, just something counterintuitive I ran across. I would be okay if an exception was raised too, telling me to use vec4.