Add rainbow picker

README.md

@@ -16,6 +16,19 @@ This program is used to pick colors that look good on the LED kit.
 
 This program shows a color on initial button press, and will turn off on the 2nd press.
 
+## `src/rainbow_picker.cpp`
+
+<a title="Gringer, Public domain, via Wikimedia Commons" href="https://commons.wikimedia.org/wiki/File:Blended_colour_wheel.svg">
+    <img width="128" alt="Blended colour wheel" src="https://upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Blended_colour_wheel.svg/128px-Blended_colour_wheel.svg.png">
+</a>
+
+This program cycles through colors of the color wheel. Usage:
+
+1. Press to begin color cycling.
+2. Press to stop at a color.
+3. Press again to resume color cycling.
+4. Long press to turn off.
+
 ## `src/performance.cpp`
 
 This program defines a performance consisting of scenes which are defined by colors and transitions between colors. Contains generic structs which I hope to pull out into a separate file eventually.

src/rainbow-picker.cpp

@@ -0,0 +1,47 @@
+// Inspired by ChaosNuggets's Diabolo-Lights-Rainbow:
+// <https://github.com/ChaosNuggets/Diabolo-Lights-Rainbow/blob/3b8d74af665ea307387e30cf8260938542734877/src/main.cpp>
+
+#include <Arduino.h>
+#include <Diabolo_Light.h>
+#include <Adafruit_NeoPixel.h>
+
+Adafruit_NeoPixel pixels(
+    Diabolo_Light::NUM_LEDS,
+    Diabolo_Light::LED_PIN,
+    Diabolo_Light::LED_TYPE
+);
+uint16_t hue;
+
+void set_all_pixels(uint32_t color) {
+    for (unsigned int i = 0; i < Diabolo_Light::NUM_LEDS; i++) {
+        pixels.setPixelColor(i, color);
+    }
+    pixels.show();
+}
+
+void setup() {
+    pixels.begin();
+    Diabolo_Light::begin(
+        // num_modes. set to maximum possible value
+        255,
+
+        // time_to_turn_on
+        0,
+
+        // on_wake_up
+        [](){ hue = -1000; },
+
+        // time_to_turn_off
+        1000
+    );
+}
+
+void loop() {
+    Diabolo_Light::handle_button();
+    int mode = Diabolo_Light::get_current_mode();
+
+    if (mode %  2 == 1) {
+        set_all_pixels(pixels.ColorHSV(hue, 255, 255));
+        hue += 3;
+    }
+}