From 507b9b255702d938713aaa10eb723587e7f3fe2a Mon Sep 17 00:00:00 2001
From: Edwin Jakobs <edwin@rndr.studio>
Date: Sat, 22 Aug 2020 00:20:32 +0200
Subject: [PATCH] [orx-color] Improve DemoHSLUV02

---
 orx-color/src/demo/kotlin/DemoHSLUV02.kt | 34 ++++++++++++++++++------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/orx-color/src/demo/kotlin/DemoHSLUV02.kt b/orx-color/src/demo/kotlin/DemoHSLUV02.kt
index 4337b8bb..ffbe6caa 100644
--- a/orx-color/src/demo/kotlin/DemoHSLUV02.kt
+++ b/orx-color/src/demo/kotlin/DemoHSLUV02.kt
@@ -1,4 +1,4 @@
-// Visualize HSLUV color space
+// Visualize HSLUV color space by drawing a phyllotaxis pattern
 
 import org.openrndr.application
 import org.openrndr.color.ColorRGBa
@@ -6,9 +6,22 @@ import org.openrndr.extensions.SingleScreenshot
 import org.openrndr.extras.color.spaces.toHSLUVa
 import org.openrndr.math.Polar
 import org.openrndr.math.Vector2
+import kotlin.math.sqrt
 
 fun main() {
     application {
+        configure {
+            width = 720
+            height = 720
+        }
+
+        val g = Math.PI * 2.0 * (1.0 - 1.0 / 1.61803398875)
+        fun phyllotaxis(count: Int) = sequence {
+            for (i in 0 until count) {
+                yield(Polar(Math.toDegrees(i * 1.0), g * i))
+            }
+        }
+
         program {
             // -- this block is for automation purposes only
             if (System.getProperty("takeScreenshot") == "true") {
@@ -18,17 +31,22 @@ fun main() {
             }
 
             extend {
+                drawer.clear(ColorRGBa.GRAY)
                 val color = ColorRGBa.RED
                 val hc = color.toHSLUVa()
                 drawer.stroke = null
                 drawer.strokeWeight = 0.0
-                for (h in 0 until 360 step 10) {
-                    for (s in 0 until 10) {
-                        for (l in 9 downTo 0) {
-                            val position = Polar(h.toDouble(), s * 25.0).cartesian + Vector2(width/ 2.0, height / 2.0)
-                            drawer.fill = hc.shiftHue(h.toDouble()).saturate(s/9.0).shade((9-l)/4.5).toRGBa().toSRGB()
-                            drawer.circle(position, kotlin.math.sqrt(s/10.0)*25.0 * l/9.0)
-                        }
+
+                val count = 400
+                val bobRadius = 20.0
+
+                for (i in phyllotaxis(count)) {
+                    val h = i.theta
+                    val s = i.radius / (count * g)
+                    for (l in 9 downTo 0) {
+                        val position = i.cartesian / (count * g) * (width / 2.0 - bobRadius) + Vector2(width / 2.0, height / 2.0)
+                        drawer.fill = hc.shiftHue(h).saturate(s).shade((9 - l) / 4.5).toRGBa().toSRGB()
+                        drawer.circle(position, sqrt(s) * 20.0 * l / 9.0)
                     }
                 }
             }