Make rainbow effects more colorful (wled#3681)

* Make color_wheel rotate in HSV sapce instead of linearly interpolating R->G->B
* Remove the rainbow wheel option, as that is the same as the rainbow palette
* Use hsv2rgb for color_wheel

This is the current result of the discussion in wled#3681

Author: TripleWhy

wled00/FX_fcn.cpp

@@ -1085,27 +1085,14 @@ void Segment::blur(uint8_t blur_amount, bool smear) const {
 /*
  * Put a value 0 to 255 in to get a color value.
  * The colours are a transition r -> g -> b -> back to r
- * Inspired by the Adafruit examples.
+ * Rotates the color in HSV space, where pos is H. (0=0deg, 256=360deg)
  */
 uint32_t Segment::color_wheel(uint8_t pos) const {
-  if (palette) return color_from_palette(pos, false, false, 0); // never wrap palette
+  if (palette) return color_from_palette(pos, false, false, 0); // only wrap if "always wrap" is set
   uint8_t w = W(getCurrentColor(0));
-  pos = 255 - pos;
-  if (useRainbowWheel) {
-    CRGB rgb;
-    hsv2rgb_rainbow(CHSV(pos, 255, 255), rgb);
-    return RGBW32(rgb.r, rgb.g, rgb.b, w);
-  } else {
-    if (pos < 85) {
-      return RGBW32((255 - pos * 3), 0, (pos * 3), w);
-    } else if (pos < 170) {
-      pos -= 85;
-      return RGBW32(0, (pos * 3), (255 - pos * 3), w);
-    } else {
-      pos -= 170;
-      return RGBW32((pos * 3), (255 - pos * 3), 0, w);
-    }
-  }
+  uint32_t rgb;
+  hsv2rgb(CHSV32(static_cast<uint16_t>(pos << 8), 255, 255), rgb);
+  return rgb | (w << 24); // add white channel
 }
 
 /*

wled00/cfg.cpp

@@ -519,7 +519,6 @@ bool deserializeConfig(JsonObject doc, bool fromFS) {
   CJSON(briMultiplier, light[F("scale-bri")]);
   CJSON(paletteBlend, light[F("pal-mode")]);
   CJSON(strip.autoSegments, light[F("aseg")]);
-  CJSON(useRainbowWheel, light[F("rw")]);
 
   CJSON(gammaCorrectVal, light["gc"]["val"]); // default 2.2
   float light_gc_bri = light["gc"]["bri"];
@@ -1042,7 +1041,6 @@ void serializeConfig(JsonObject root) {
   light[F("scale-bri")] = briMultiplier;
   light[F("pal-mode")] = paletteBlend;
   light[F("aseg")] = strip.autoSegments;
-  light[F("rw")] = useRainbowWheel;
 
   JsonObject light_gc = light.createNestedObject("gc");
   light_gc["bri"] = (gammaCorrectBri) ? gammaCorrectVal : 1.0f;  // keep compatibility

wled00/data/settings_leds.htm

@@ -908,7 +908,6 @@ <h3>Advanced</h3>
 			<option value="3">None (not recommended)</option>
 		</select><br>
 		Use harmonic <i>Random Cycle</i> palette: <input type="checkbox" name="TH"><br>
-		Use &quot;rainbow&quot; color wheel: <input type="checkbox" name="RW"><br>
 		Target refresh rate: <input type="number" class="s" min="0" max="250" name="FR" oninput="UI()" required> FPS
 		<div id="fpsNone" class="warn" style="display: none;">&#9888; Unlimited FPS Mode is experimental &#9888;<br></div>
 		<div id="fpsHigh" class="warn" style="display: none;">&#9888; High FPS Mode is experimental.<br></div>

wled00/set.cpp

@@ -351,7 +351,6 @@ void handleSettingsSet(AsyncWebServerRequest *request, byte subPage)
     t = request->arg(F("TP")).toInt();
     randomPaletteChangeTime = MIN(255,MAX(1,t));
     useHarmonicRandomPalette = request->hasArg(F("TH"));
-    useRainbowWheel = request->hasArg(F("RW"));
 
     nightlightTargetBri = request->arg(F("TB")).toInt();
     t = request->arg(F("TL")).toInt();

wled00/wled.h

@@ -625,7 +625,6 @@ WLED_GLOBAL unsigned long transitionStartTime;
 WLED_GLOBAL bool          jsonTransitionOnce       _INIT(false);  // flag to override transitionDelay (playlist, JSON API: "live" & "seg":{"i"} & "tt")
 WLED_GLOBAL uint8_t       randomPaletteChangeTime  _INIT(5);      // amount of time [s] between random palette changes (min: 1s, max: 255s)
 WLED_GLOBAL bool          useHarmonicRandomPalette _INIT(true);   // use *harmonic* random palette generation (nicer looking) or truly random
-WLED_GLOBAL bool          useRainbowWheel          _INIT(false);  // use "rainbow" color wheel instead of "spectrum" color wheel
 
 // nightlight
 WLED_GLOBAL bool nightlightActive _INIT(false);

wled00/xml.cpp

@@ -382,7 +382,6 @@ void getSettingsJS(byte subPage, Print& settingsScript)
     printSetFormValue(settingsScript,PSTR("TL"),nightlightDelayMinsDefault);
     printSetFormValue(settingsScript,PSTR("TW"),nightlightMode);
     printSetFormIndex(settingsScript,PSTR("PB"),paletteBlend);
-    printSetFormCheckbox(settingsScript,PSTR("RW"),useRainbowWheel);
     printSetFormValue(settingsScript,PSTR("RL"),rlyPin);
     printSetFormCheckbox(settingsScript,PSTR("RM"),rlyMde);
     printSetFormCheckbox(settingsScript,PSTR("RO"),rlyOpenDrain);