Chapter 0 Exercise 10

Ramblurr · Ramblurr · commit b70a08e17db2 · 2024-06-03T18:13:47.000+02:00
diff --git a/notebooks/chapter_0.md b/notebooks/chapter_0.md
@@ -252,3 +252,17 @@ Well this one is pretty cool. The sliders control (in order from left to right):
 * Amount `yoff` is incremented by
 
 Finally there is a checkbox to enable animation using the 3rd dimension of the perlin noise.
+
+
+## [Exercise 0.9: Perlin Noise Landscape](https://natureofcode.com/random/#exercise-09)
+
+```clojure
+^{::clerk/no-cache true ::clerk/viewer clerk/code}
+(slurp "src/noc/chapter_0_10e.cljs")
+(show-sketch :c0.10e)
+```
+
+The performance for this one is pretty bad here in the notebook. I'm not 100%
+sure why. I switched from a naive nested 2-d vector to using transients, but
+that didn't have much of an effect. Some day I'll come back and investigate
+more.
diff --git a/src/noc/chapter_0_10e.cljs b/src/noc/chapter_0_10e.cljs
@@ -0,0 +1,84 @@
+(ns noc.chapter-0-10e
+  (:require
+   [quil.sketch :as ap :include-macros true]
+   [quil.core :as q]))
+
+(def size [640 240])
+
+(defn init-terrain [cell-size width height]
+  (let [cols (quot width cell-size)
+        rows (quot height cell-size)]
+    {:cell-size cell-size
+     :w width
+     :h height
+     :cols  cols
+     :rows  rows
+     :zoff 0.0
+     :cells []}))
+
+;; My initial naive impl
+#_(defn tick-terrain [{:keys [cols rows zoff] :as terrain}]
+    (let [updated-cells (vec (map-indexed
+                              (fn [i _]
+                                (vec (map-indexed
+                                      (fn [j _]
+                                        (q/map-range (q/noise (+ (* i 0.1) zoff) (+ (* j 0.1) zoff) zoff) 0 1 -120 120))
+                                      (range rows))))
+                              (range cols)))
+          new-zoff (+ zoff 0.01)]
+      (assoc terrain :cells updated-cells :zoff new-zoff)))
+
+;; Using transients to try and speed it up
+(defn tick-terrain [{:keys [cols rows zoff] :as terrain}]
+  (let [updated-cells (persistent!
+                       (reduce
+                        (fn [acc i]
+                          (assoc! acc i
+                                  (persistent!
+                                   (reduce
+                                    (fn [inner-acc j]
+                                      (assoc! inner-acc j
+                                              (q/map-range (q/noise (+ (* i 0.1) zoff) (+ (* j 0.1) zoff) zoff) 0 1 -120 120)))
+                                    (transient []) (range rows)))))
+                        (transient []) (range cols)))
+        new-zoff (+ zoff 0.01)]
+    (assoc terrain :cells updated-cells :zoff new-zoff)))
+
+(defn init-state [{:keys [width height]}]
+  {:terrain
+   (tick-terrain (init-terrain 20 800 400))
+   :theta 0.0})
+
+(defn setup! [{:keys [width height terrain]}]
+  (q/background 255))
+
+(defn tick [state]
+  (-> state
+      (update :terrain tick-terrain)
+      (update :theta #(+ % 0.0025))))
+
+(defn draw-terrain! [{:keys [cells cell-size cols rows w h]}]
+  (doseq [x (range (dec cols))]
+    ;;  Quil bug https://github.com/quil/quil/issues/415
+    (.beginShape (ap/current-applet) (aget js/p5.prototype "QUAD_STRIP"))
+    (doseq [y (range rows)]
+      (q/stroke 0)
+      (let [current-elevation (get-in cells [x y])
+            current-shade (q/map-range current-elevation -120 120 0 255)
+            x-coordinate (- (* x cell-size) (/ w 2))
+            y-coordinate (- (* y cell-size) (/ h 2))]
+        (q/fill current-shade 255)
+        (q/vertex x-coordinate y-coordinate current-elevation)
+        (q/vertex (+ x-coordinate cell-size) y-coordinate (get-in cells [(inc x) y]))))
+    (q/end-shape)))
+
+(defn draw! [{:keys [terrain theta] :as state}]
+  (q/background 255)
+  (q/push-style)
+  (q/push-matrix)
+  (q/translate 0 20 -200)
+  (q/rotate-x (/ q/PI 3))
+  (q/rotate-z theta)
+  (draw-terrain! terrain)
+  (q/pop-matrix)
+  (q/pop-style))
diff --git a/src/noc/sketch.clj b/src/noc/sketch.clj
@@ -6,3 +6,11 @@
     :tick ~(symbol (str chapter "/tick"))
     :draw ~(symbol (str chapter "/draw!"))
     :size ~(symbol (str chapter "/size"))})
+
+(defmacro sketch-3d-> [chapter]
+  `{:init ~(symbol (str chapter "/init-state"))
+    :setup ~(symbol (str chapter "/setup!"))
+    :tick ~(symbol (str chapter "/tick"))
+    :draw ~(symbol (str chapter "/draw!"))
+    :size ~(symbol (str chapter "/size"))
+    :renderer :p3d})
diff --git a/src/noc/sketch.cljs b/src/noc/sketch.cljs
@@ -1,5 +1,5 @@
 (ns noc.sketch
-  (:require-macros [noc.sketch :refer [sketch->]])
+  (:require-macros [noc.sketch :refer [sketch-> sketch-3d->]])
   (:require [quil.core :as q]
             [quil.middleware :as m]
             [quil.sketch :as ap :include-macros true]
@@ -17,22 +17,25 @@
             [noc.chapter-0-7e :as c0.7e]
             [noc.chapter-0-7 :as c0.7]
             [noc.chapter-0-8e :as c0.8e]
-            [noc.chapter-0-9e :as c0.9e]))
+            [noc.chapter-0-9e :as c0.9e]
+            [noc.chapter-0-10e :as c0.10e]))
 
-(def sketches {:walker (sketch-> c0.1)
-               :rand-dist (sketch-> c0.2)
-               :walker-right (sketch-> c0.3)
-               :walker-dynamic (sketch-> c0.3e)
-               :random-gaussian (sketch-> c0.4)
-               :c0.4e (sketch-> c0.4e)
-               :c0.5e (sketch-> c0.5e)
-               :c0.5 (sketch-> c0.5)
-               :c0.6e (sketch-> c0.6e)
-               :c0.6 (sketch-> c0.6)
-               :c0.7e (sketch-> c0.7e)
-               :c0.7 (sketch-> c0.7)
-               :c0.8e (sketch-> c0.8e)
-               :c0.9e (sketch-> c0.9e)})
+(def sketches
+  {:walker (sketch-> c0.1)
+   :rand-dist (sketch-> c0.2)
+   :walker-right (sketch-> c0.3)
+   :walker-dynamic (sketch-> c0.3e)
+   :random-gaussian (sketch-> c0.4)
+   :c0.4e (sketch-> c0.4e)
+   :c0.5e (sketch-> c0.5e)
+   :c0.5 (sketch-> c0.5)
+   :c0.6e (sketch-> c0.6e)
+   :c0.6 (sketch-> c0.6)
+   :c0.7e (sketch-> c0.7e)
+   :c0.7 (sketch-> c0.7)
+   :c0.8e (sketch-> c0.8e)
+   :c0.9e (sketch-> c0.9e)
+   :c0.10e (sketch-3d-> c0.10e)})
 
 (defn load-sketch [s]
   (when-let [sk (get sketches s)]
@@ -141,12 +144,14 @@
 
 (defn show-sketch [adjust-frame {:keys [init setup tick draw size] :as opts} el]
   {:applet (apply q/sketch (apply concat
-                                  (-> opts
-                                      (assoc :middleware [m/fun-mode])
-                                      (assoc :host el)
-                                      (assoc :update (partial tick-wrapper tick))
-                                      (assoc :setup (partial setup-wrapper (partial adjust-frame el) init setup))
-                                      (assoc :draw (partial draw-wrapper draw)))))
+                                  (doto
+                                   (-> opts
+                                       (assoc :middleware [m/fun-mode])
+                                       (assoc :host el)
+                                       (assoc :update (partial tick-wrapper tick))
+                                       (assoc :setup (partial setup-wrapper (partial adjust-frame el) init setup))
+                                       (assoc :draw (partial draw-wrapper draw)))
+                                    prn)))
    :sketch-name (:sketch-name opts)
    :opts opts
    :el el})
