From 5aba53b75e9376698b1d05938f2d537d842f78d0 Mon Sep 17 00:00:00 2001
From: Brian Cully <bjc@kublai.com>
Date: Mon, 13 Aug 2018 22:10:51 -0400
Subject: [PATCH] Smooth out hue transitions.

In spite of the API taking uint16_t for the HSV parameters for hsv()
(which appears to be in order to retain compatibility with existing
plugins), the expected values are actually in the 0 ... 255 range.

Update calls to make sure values passed are within that range. This
did mean flattening out the value portion from 128 ... 255 to a flat
255, which isn't ideal, but I didn't have a better idea off the top of
my head.

The effect of this change is that there are no longer oddly flashing
colors while cycling through the ripple effect.

In addition I've added a starting_hue constant (set to a shade of
purple I like, but easily changed), and a compile time #ifdef that
controls whether or not to cycle hues, called
CONSTANT_HUE. Personally, I prefer the CONSTANT_HUE effect, which is
less blingy, but IMHO shows the ripple effect better. This should
probably be turned into a run time switch.
---
 src/Kaleidoscope/LED-Wavepool.cpp | 17 ++++++++++++-----
 src/Kaleidoscope/LED-Wavepool.h   |  3 +++
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/src/Kaleidoscope/LED-Wavepool.cpp b/src/Kaleidoscope/LED-Wavepool.cpp
index 24d90d3..73c8cc7 100644
--- a/src/Kaleidoscope/LED-Wavepool.cpp
+++ b/src/Kaleidoscope/LED-Wavepool.cpp
@@ -21,9 +21,10 @@
 
 namespace kaleidoscope {
 
-#define INTERPOLATE  // smoother, slower animation
+#define INTERPOLATE // smoother, slower animation
 #define MS_PER_FRAME 40  // 40 = 25 fps
 #define FRAMES_PER_DROP 120  // max time between raindrops during idle animation
+#undef CONSTANT_HUE
 
 int8_t WavepoolEffect::surface[2][WP_WID*WP_HGT];
 uint8_t WavepoolEffect::page = 0;
@@ -90,8 +91,10 @@ void WavepoolEffect::update(void) {
   // rotate the colors over time
   // (side note: it's weird that this is a 16-bit int instead of 8-bit,
   //  but that's what the library function wants)
-  static uint8_t current_hue = 0;
+  static uint16_t current_hue = starting_hue;
+  #ifndef CONSTANT_HUE
   current_hue ++;
+  #endif
 
   frames_since_event ++;
 
@@ -197,14 +200,18 @@ void WavepoolEffect::update(void) {
       #endif
 
       uint8_t intensity = abs(height) * 2;
+      uint8_t saturation = 0xff - intensity;
+      uint8_t value = (intensity >= 128) ? 255 : intensity << 1;
 
       // color starts white but gets dimmer and more saturated as it fades,
       // with hue wobbling according to height map
+      #ifdef CONSTANT_HUE
+      int16_t hue = current_hue;
+      #else
       int16_t hue = (current_hue + height + (height>>1)) & 0xff;
+      #endif
 
-      cRGB color = hsvToRgb(hue,
-                            0xff - intensity,
-                            ((uint16_t)intensity)*2);
+      cRGB color = hsvToRgb(hue, saturation, value);
 
       ::LEDControl.setCrgbAt(r, c, color);
     }
diff --git a/src/Kaleidoscope/LED-Wavepool.h b/src/Kaleidoscope/LED-Wavepool.h
index a803cdd..b289573 100644
--- a/src/Kaleidoscope/LED-Wavepool.h
+++ b/src/Kaleidoscope/LED-Wavepool.h
@@ -31,6 +31,9 @@ class WavepoolEffect : public LEDMode {
 
   // ms before idle animation starts after last keypress
   static uint16_t idle_timeout;
+  // initial hue at keyboard boot, or all the time if CONSTANT_HUE is
+  // defined.
+  const uint8_t starting_hue = 192;
 
  protected:
   void setup(void) final;