quiltools

Functional geometry wrapper for quil

Usage

Leiningen/Boot

[org.clojars.fergalbyrne/quiltools "0.1.2"]

Clojure CLI/deps.edn

org.clojars.fergalbyrne/quiltools {:mvn/version "0.1.2"}

Example:

(ns quilplayground
  (:require [quiltools.core :refer :all]
            [quil.core :as q]
            [quil.middleware :as m]))

(defn wheel []
  "draws an inverted semicircle in the top half of its box"
  (q/arc 0.5 0 1 1 0 q/PI))

(defn car []
  "draws a car"
  (let [h 0.3
        y (- 1 h)
        x 0.05]
    (q/rect 0 0.4 1 (- y 0.4))
    ((->> wheel (in h h) (at x y)))
    ((->> wheel (in h h) (at (- 1 h x) y)))))

(defn envelope []
  "draws an envelope"
  (q/rect 0 0 1 1)
  (q/arc 0.5 0 1 1 0 q/PI))

(defn setup []
  (q/frame-rate 50)
  (q/color-mode :hsb)
  {:color 0
   :angle 0
   :direction 1})

(defn update-state [state]
  (let [{:keys [color angle direction]} state]
    {:color (mod (+ color 0.7) 255)
     :angle (mod (+ angle 0.02) q/TWO-PI)
     :direction (if (n-ticks? 120)
                    (- direction)
                    direction)}))

(defn draw-state [state]
  (q/background 240)
  (q/fill (:color state) 255 255)
  (let [{angle :angle direction :direction} state)
        x (* 150 (q/cos angle))
        y (* 150 (q/sin angle))]
    (q/with-translation [(/ (q/width) 2)
                         (/ (q/height) 2)]
      ((->> envelope (in 100 100) (spin (- q/QUARTER-PI angle))))
      ((->> car (in 50 50) (spin (* direction angle 2)) (at x y))))))
;
(q/defsketch quil-playground
  :title "You spin my circle right round"
  :size [500 500]
  :setup setup
  :update update-state
  :draw draw-state
  :features [:keep-on-top]
  :middleware [m/fun-mode])

The functions wheel, car and envelope draw their graphics in a box with origin [0 0] and size [1 1]. quiltools provides the functions at, in and spin which each take a drawing-function as last argument, returning a drawing function which draws at a location, in a box of given size, and with a given spin angle.

To draw a car in a given sized box, at a given point, with a given spin, pipe the car function and call the result:

((->> car (in 50 50) (spin (* angle 2)) (at x y)))

Note: the ordering is important, as scaling, translation and rotation do not generally commute. The order given above (in -> spin -> at) will yield expected results.

License

Copyright © 2020 Fergal Byrne & Louise Klodt

This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0 which is available at http://www.eclipse.org/legal/epl-2.0.

This Source Code may also be made available under the following Secondary Licenses when the conditions for such availability set forth in the Eclipse Public License, v. 2.0 are satisfied: GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version, with the GNU Classpath Exception which is available at https://www.gnu.org/software/classpath/license.html.