## 29 Dec, 2019 - 3 minutes

By

Matthew Deig

Tags:

I got inspire by my visit up to the Vintage Computer Festival Midwest with their talk on the computer that made the Death Star plans graphics. Then later on this year I saw this post Functional Christmas Article on Generative Art and I recently was picking up Clojure and was thinking that I could use this to do something like I saw at the Festival. Turns out it wasn’t too bad to try to get something like it, because I found this video of retro computer graphics so I dug in.

### First Attempt

I started out doing circles to get some polar coordinates down and some other functions but I ended up switching to lines and came up with this

Unfortunately I don’t have the code that made that video.

### My other experiments

A few more of my experiments.

### My Final Experiment of the Day

While I was working on the lines I decided to add more lines to the animation. When I was doing that it started to look like a ship scanning something so I ended up creating what I was seeing.

I do have the code for that

``````(defn polar-conv-x [r x]
(* r (q/cos x)))
(defn polar-conv-y [r y]
(* r (q/sin y)))

(defn parametic-fun-x [x]
(+ (q/sin (/ x 10.5)) (q/cos (/ x 5.5))))

(defn parametic-fun-y [y]
(+ (q/cos (/ y 2)) (q/sin (/ y 4))))

(defn setup []
; Set frame rate to 30 frames per second.
(q/frame-rate 30)
; Set color mode to HSB (HSV) instead of default RGB.
(q/color-mode :hsb)
(q/background 0)
; setup function returns initial state. It contains
; circle color and position.
{:color 0
:t 0})

(defn update-state [state]
; Update sketch state by changing circle color and position.
{:color (mod (+ (:color state) 0.7) 255)
:t (+ (:t state) 0.1)})

(defn draw-state [state]
; Clear the sketch by filling it with light-grey color.
(q/background 0)
; Set circle color.
(q/stroke (:color state) 255 255)
; Calculate x and y coordinates of the circle.
(let [t (:t state)
x (polar-conv-x (* t 2) (parametic-fun-x t))
y (polar-conv-y (* t 2) (parametic-fun-y t))]
; Move origin point to the center of the sketch.
(q/with-translation [(/ (q/width) 2)
(/ (q/height) 2)]
; Draw the circle.
(q/line x y (* -1 y) (* -1 x))
(q/line (* -1 x) (* -1 y) (* -1 y) (* -1 x))
(q/line x (* -1 y) (* -1 y) (* -1 x))
(q/line (* -1 x) y (* -1 y) (* -1 x))
(q/line x (* -1 y) (* -1 x) (* -1 y))
(q/line x y (* -1 x) y)
(q/line x (* -1 y) x y)
(q/line (* -1 x) y (* -1 x) (* -1 y))
)))
``````