LED-Wavepool: Add a way to use an explicit hue for the animation

While the rainbow colors are great, some may want to restrict the colors to a
single hue. For this purpose, the `ripple_hue` property was introduced. It
defaults to `Wavepool.rainbow_hue` (a special value that tells the plugin to use
multiple hues).

Inspired by @bjc's ToyKeeper/Kaleidoscope-LED-Wavepool#8.

Signed-off-by: Gergely Nagy <algernon@keyboard.io>

doc/plugin/LED-Wavepool.md

@@ -25,7 +25,7 @@ void setup (){
 It is recommended to place the activation of the plugin as early as possible, so
 the plugin can catch all relevant key presses.
 
-## Plugin methods
+## Plugin properties
 
 The plugin provides the `WavepoolEffect` object, which has the following
 properties:
@@ -39,6 +39,16 @@ properties:
 >
 > Default is 5000 (5 seconds).
 
+### `.ripple_hue`
+
+> The Hue of the ripple animation. If set, the light splashing across the
+> keyboard will use this value instead of all colors of the rainbow.
+>
+> Setting it to the special value of `Wavepool.rainbow_hue` will cause the
+> plugin to use all colors again.
+>
+> Defaults to `Wavepool.rainbow_hue`.
+
 ## Dependencies
 
 * [Kaleidoscope-LEDControl](LEDControl.md)

examples/LEDs/LED-Wavepool/LED-Wavepool.ino

@@ -50,6 +50,7 @@ void setup() {
   Kaleidoscope.setup();
 
   WavepoolEffect.idle_timeout = 5000;  // 5 seconds
+  WavepoolEffect.ripple_hue = WavepoolEffect.rainbow_hue;
   WavepoolEffect.activate();
 }
 

src/kaleidoscope/plugin/LED-Wavepool.cpp

@@ -29,6 +29,7 @@ int8_t WavepoolEffect::surface[2][WP_WID * WP_HGT];
 uint8_t WavepoolEffect::page = 0;
 uint8_t WavepoolEffect::frames_since_event = 0;
 uint16_t WavepoolEffect::idle_timeout = 5000;  // 5 seconds
+int16_t WavepoolEffect::ripple_hue = WavepoolEffect::rainbow_hue; // automatic hue
 
 // map native keyboard coordinates (16x4) into geometric space (14x5)
 PROGMEM const uint8_t WavepoolEffect::rc2pos[ROWS * COLS] = {
@@ -189,10 +190,14 @@ void WavepoolEffect::update(void) {
 
       uint8_t intensity = abs(height) * 2;
       uint8_t saturation = 0xff - intensity;
+      uint8_t value = (intensity >= 128) ? 255 : intensity << 1;
+      int16_t hue = ripple_hue;
+
+      if (ripple_hue == rainbow_hue) {
         // color starts white but gets dimmer and more saturated as it fades,
         // with hue wobbling according to height map
-      int16_t hue = (current_hue + height + (height >> 1)) & 0xff;
+        hue = (current_hue + height + (height >> 1)) & 0xff;
-      uint8_t value = (intensity >= 128) ? 255 : intensity << 1;
+      }
 
       cRGB color = hsvToRgb(hue, saturation, value);
 

src/kaleidoscope/plugin/LED-Wavepool.h

@@ -34,7 +34,9 @@ class WavepoolEffect : public LEDMode {
 
   // ms before idle animation starts after last keypress
   static uint16_t idle_timeout;
+  static int16_t ripple_hue;
 
+  static constexpr int16_t rainbow_hue = INT16_MAX;
  protected:
   void update(void) final;