Update state with if on Quil - clojure

Question

I am trying to make 10 PRINT code with Quil. I try to transform this code from the twitter post https://twitter.com/ACharLuk/status/913094845505445890 which is using luna
This is my code for it
(ns tenprint.core
(:require [quil.core :as q]
[quil.middleware :as m]))
(defn setup []
(q/frame-rate 30)
(q/color-mode :hsb)
{:x 0
:y 0
:scale 20
}
)
(defn update-state [state]
(let [x (:x state) y (:y state) s (:scale state)]
{
:x (do (+ x s) ((if (>= x q/width) 0)))
:y (do (if (>= x q/width) (+ y s)) (if (>= x q/height) (+ y s)))
:scale (+ s 0)
}
)
)
(defn draw-state [state]
(q/background 0)
(q/stroke 255)
;(q/line 0 10 10 0)
(let [x (:x state) y (:y state) s (:scale state)]
(if (> (rand) 0.5)
(q/line x y (+ x s) (+ y s))
(q/line x (+ y s) (+ x s) y)
)
)
)
(q/defsketch tenprint
:title "10PRINT"
:size [500 500]
:setup setup
:update update-state
:draw draw-state
:settings #(q/smooth 2)
:features [:keep-on-top]
:middleware [m/fun-mode]
)
And it just appears like this. I was trying to split the update of states, but it says that you must not have duplicated variables to be updated
Thank you.

Answer 1

Your code is in the right direction and you managed to draw the first line. It crashed when update-state was called. To fix the code I did the following things:
Clojure works with pure functions where you cannot "set" values as you seem to wanted to do in update-state (with do only the last expression is returned, not two values). To update-state you need to return a whole new state.
q/height and q/widths are functions that return the height and width, so call them (surround them by parentheses) to get the number out.
When you redraw the background in update-state the older lines are gone, so put (q/background 0) in setup.
Move (q/no-loop) from update-state to the draw-state entry-point of the program.
And stylistically I changed this:
Use associative destructuring in function parameter instead of getting values of keys in let.
Place trailing parentheses on the same line (see Clojure style guide).
Below the working version:
(ns tenprint.core
(:require [quil.core :as q]
[quil.middleware :as m]))
(defn setup []
(q/background 0) ; move setting background to setup, otherwise the state is overwritten
(q/frame-rate 30)
(q/stroke 255)
(q/color-mode :hsb)
{:x 0
:y 0
:scale 20})
(defn update-state [{:keys [x y scale] :as state}] ; destructure
;; height and width are functions you need to `(call)` to get the value
{:x (if (>= x (q/width)) 0 (+ x scale)) ; fix if-statements
:y (if (>= x (q/width)) (+ y scale) y) ; 'do' does something different than you think
:scale scale}) ; no need to add 0
(defn draw-state [{:keys [x y scale] :as state}] ; destructure
(if (>= y (q/height))
(q/no-loop)
(if (> (rand) 0.5)
(q/line x y (+ x scale) (+ y scale))
(q/line x (+ y scale) (+ x scale) y))))
(q/defsketch tenprint
:title "10 PRINT"
:size [500 500]
:setup setup
:draw draw-state
:update update-state
:features [:keep-on-top]
:middleware [m/fun-mode])