Start scribbling around again

src/aphorisms/fourty_one.clj

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+(ns aphorisms.fourty-one
+  (:require [thi.ng.geom.core :as g]
+            [thi.ng.geom.vector :as v]
+            [quil.core :as q]
+            [quil.middleware :as qm]
+            [thi.ng.geom.rect :as r]
+            [aphorisms.utils.middleware :refer [screenshottable]]
+
+            [thi.ng.geom.line :as l]
+            [thi.ng.math.core :as m]
+            [thi.ng.geom.utils.intersect :as isec]))
+
+;; More practice to get a feeling for the `thi.ng` API again
+;; Resizing cells in the grid, generating random lines and playing with intersections
+
+(def height 500 #_(int (* width (Math/sqrt 2))))
+(def width #_500 (int (* height (Math/sqrt 2))))
+(def padding (* height 0.1))
+(def canvas (r/rect width height))
+
+(defn center-in
+  "Centers `r2` in or around `r1`."
+  [r1 r2]
+  (g/translate (assoc r2 :p (:p r1))
+               (v/vec2 (* 0.5 (- (g/width r1) (g/width r2)))
+                       (* 0.5 (- (g/height r1) (g/height r2))))))
+
+(def bounds (center-in canvas (r/rect (- width (* 2 padding)) (- height (* 2 padding)))))
+
+(defn as-grid [rect cell-size]
+  (let [n-x (int (/ (g/width rect) cell-size))
+        n-y (int (/ (g/height rect) cell-size))
+        t (v/vec2 (* (mod (g/width rect) n-x) 0.5)
+                  (* (mod (g/height rect) n-x) 0.5))]
+    (for [x (range n-x)
+          y (range n-y)]
+      (-> (r/rect (* x cell-size) (* y cell-size) cell-size)
+          (g/translate (:p rect))
+          (g/translate t )))))
+
+(def grid (map #(g/scale-size % 0.92) (as-grid bounds 50)))
+
+(defn line-inside [rect]
+  (l/line2 (g/random-point-inside rect) (g/random-point-inside rect)))
+
+;; below is the rendering logic
+
+(defn setup []
+  (q/frame-rate 30)
+  (q/color-mode :hsb 360 100 100)
+  (q/rect-mode :center)
+  (q/ellipse-mode :center)
+  (q/background 350)
+  {:lines (repeatedly 5 #(line-inside bounds))})
+
+(defn update-state [state]
+  state)
+
+(defn mouse-pressed [state _]
+  (assoc state :lines (repeatedly 20 #(line-inside bounds))))
+
+(let [l (l/line2 50 50 200 210)]
+  (g/intersect-line l (first (g/edges (first grid)))))
+
+(defn draw-state [state]
+  (q/translate -0.5 -0.5)
+  (q/background 180 0 98)
+  (q/stroke-weight 0.5)
+  (q/no-fill)
+  (q/stroke 320 100 70)
+  (doseq [line (:lines state)
+          :let [[a b] (g/vertices line)]]
+    (q/line a b))
+  (doseq [cell grid
+          [a b] (g/edges cell)]
+    (q/line a b))
+  (q/no-stroke)
+  (q/fill 320 100 70)
+  (doseq [cell grid
+          line (:lines state)
+          isecs (->>
+                 (map #(g/intersect-line line %) (g/edges cell))
+                 (keep #(when (= (:type %) :intersect) (:p %))))
+          :let [[i1 i2] isecs]]
+    (q/ellipse i1 i2 5 5)))
+
+#_:clj-kondo/ignore
+(q/defsketch fourty-one
+  :title "Fourty One"
+  :size [width height]
+  :settings (fn []
+              (q/smooth 2)
+              (q/pixel-density (q/display-density)))
+  :setup setup
+  :update #'update-state
+  :mouse-pressed #'mouse-pressed
+  :draw #'draw-state
+  :features [:keep-on-top :no-bind-output]
+  :middleware [qm/pause-on-error qm/fun-mode (screenshottable)])