use video scaling instead of NPB luminance & new ABL (#4798)

* updated color scaling to preserve hue at low brightness resulting in much better colors
* replace NPBlg with NPB, moved brightness scaling to bus manager
* improved gamma table calculation: fixed mismatch in inverting gamma table calculation: inversion should now be as good as it gets
* code cleanup, fixed gamma being applied in unnecessary places

Improvements to ABL handling:
- removed strip level handling, ist now all done on bus level
- limiter now respects pixel mapping
- proper handling of white channel
- improved current estimation
- current is now always correctly reported to UI
- minimal FPS impact if the ABL is not limiting but slighly higher impact for global ABL limit due to double-scaling

- moved brightness scaling to BusDigital
- created new header file colors.h to be able to access color functions in bus-manager.
- updated colo_fade() with better video scaling to preserve hue's at low brightness
- added IRAM_ATTR to color_fade (negligible speed impact when compared to inline and benefits other functions)
- added IRAM_ATTR to color_blend as it is used a lot throughout the code, did not test speed impact but adding it to color_fade made it almost on-par with an inlined function

Additional changes:
- fixes for properly handling `scaledBri()` (by @blazoncek)
- also use bit-shift instead of division in blending for ESP8266
- improvements for faster "softlight" calculation in blending
- changed some variables to uint8_t to maybe let the compiler optimize better, uint8_t can be faster if read, store and set are all done in uint8_t, which is the case in the ones I changed
- various minor code formatting changes

Author: DedeHai

wled00/FX.cpp

@@ -7528,9 +7528,9 @@ uint16_t mode_2Ddistortionwaves() {
       byte valueG = gdistort + ((a2-( ((xoffs - cx1) * (xoffs - cx1) + (yoffs - cy1) * (yoffs - cy1))>>7 ))<<1);
       byte valueB = bdistort + ((a3-( ((xoffs - cx2) * (xoffs - cx2) + (yoffs - cy2) * (yoffs - cy2))>>7 ))<<1);
 
-      valueR = gamma8(cos8_t(valueR));
-      valueG = gamma8(cos8_t(valueG));
-      valueB = gamma8(cos8_t(valueB));
+      valueR = cos8_t(valueR);
+      valueG = cos8_t(valueG);
+      valueB = cos8_t(valueB);
 
       if(SEGMENT.palette == 0) {
         // use RGB values (original color mode)

wled00/FX_fcn.cpp

@@ -1194,8 +1194,9 @@ void WS2812FX::finalizeInit() {
     if (busEnd > _length) _length = busEnd;
     // This must be done after all buses have been created, as some kinds (parallel I2S) interact
     bus->begin();
-    bus->setBrightness(bri);
+    bus->setBrightness(scaledBri(bri));
   }
+  BusManager::initializeABL(); // init brightness limiter
   DEBUG_PRINTF_P(PSTR("Heap after buses: %d\n"), ESP.getFreeHeap());
 
   Segment::maxWidth  = _length;
@@ -1297,7 +1298,7 @@ static uint8_t _add       (uint8_t a, uint8_t b) { unsigned t = a + b; return t
 static uint8_t _subtract  (uint8_t a, uint8_t b) { return b > a ? (b - a) : 0; }
 static uint8_t _difference(uint8_t a, uint8_t b) { return b > a ? (b - a) : (a - b); }
 static uint8_t _average   (uint8_t a, uint8_t b) { return (a + b) >> 1; }
-#ifdef CONFIG_IDF_TARGET_ESP32C3
+#if defined(ESP8266) || defined(CONFIG_IDF_TARGET_ESP32C3)
 static uint8_t _multiply  (uint8_t a, uint8_t b) { return ((a * b) + 255) >> 8; } // faster than division on C3 but slightly less accurate
 #else
 static uint8_t _multiply  (uint8_t a, uint8_t b) { return (a * b) / 255; } // origianl uses a & b in range [0,1]
@@ -1308,10 +1309,10 @@ static uint8_t _darken    (uint8_t a, uint8_t b) { return a < b ? a : b; }
 static uint8_t _screen    (uint8_t a, uint8_t b) { return 255 - _multiply(~a,~b); } // 255 - (255-a)*(255-b)/255
 static uint8_t _overlay   (uint8_t a, uint8_t b) { return b < 128 ? 2 * _multiply(a,b) : (255 - 2 * _multiply(~a,~b)); }
 static uint8_t _hardlight (uint8_t a, uint8_t b) { return a < 128 ? 2 * _multiply(a,b) : (255 - 2 * _multiply(~a,~b)); }
-#ifdef CONFIG_IDF_TARGET_ESP32C3
-static uint8_t _softlight (uint8_t a, uint8_t b) { return (((b * b * (255 - 2 * a) + 255) >> 8) + 2 * a * b + 255) >> 8; } // Pegtop's formula (1 - 2a)b^2 + 2ab
+#if defined(ESP8266) || defined(CONFIG_IDF_TARGET_ESP32C3)
+static uint8_t _softlight (uint8_t a, uint8_t b) { return (((b * b * (255 - 2 * a))) + ((2 * a * b + 256) << 8)) >> 16; } // Pegtop's formula (1 - 2a)b^2
 #else
-static uint8_t _softlight (uint8_t a, uint8_t b) { return (b * b * (255 - 2 * a) / 255 + 2 * a * b) / 255; } // Pegtop's formula (1 - 2a)b^2 + 2ab
+static uint8_t _softlight (uint8_t a, uint8_t b) { return (b * b * (255 - 2 * a) + 255 * 2 * a * b) / (255 * 255); } // Pegtop's formula (1 - 2a)b^2 + 2ab
 #endif
 static uint8_t _dodge     (uint8_t a, uint8_t b) { return _divide(~a,b); }
 static uint8_t _burn      (uint8_t a, uint8_t b) { return ~_divide(a,~b); }
@@ -1550,66 +1551,6 @@ void WS2812FX::blendSegment(const Segment &topSegment) const {
   Segment::setClippingRect(0, 0);             // disable clipping for overlays
 }
 
-// To disable brightness limiter we either set output max current to 0 or single LED current to 0
-static uint8_t estimateCurrentAndLimitBri(uint8_t brightness, uint32_t *pixels) {
-  unsigned milliAmpsMax = BusManager::ablMilliampsMax();
-  if (milliAmpsMax > 0) {
-    unsigned milliAmpsTotal = 0;
-    unsigned avgMilliAmpsPerLED = 0;
-    unsigned lengthDigital = 0;
-    bool useWackyWS2815PowerModel = false;
-
-    for (size_t i = 0; i < BusManager::getNumBusses(); i++) {
-      const Bus *bus = BusManager::getBus(i);
-      if (!(bus && bus->isDigital() && bus->isOk())) continue;
-      unsigned maPL = bus->getLEDCurrent();
-      if (maPL == 0 || bus->getMaxCurrent() > 0) continue; // skip buses with 0 mA per LED or max current per bus defined (PP-ABL)
-      if (maPL == 255) {
-        useWackyWS2815PowerModel = true;
-        maPL = 12; // WS2815 uses 12mA per channel
-      }
-      avgMilliAmpsPerLED += maPL * bus->getLength();
-      lengthDigital += bus->getLength();
-      // sum up the usage of each LED on digital bus
-      uint32_t busPowerSum = 0;
-      for (unsigned j = 0; j < bus->getLength(); j++) {
-        uint32_t c = pixels[j + bus->getStart()];
-        byte r = R(c), g = G(c), b = B(c), w = W(c);
-        if (useWackyWS2815PowerModel) { //ignore white component on WS2815 power calculation
-          busPowerSum += (max(max(r,g),b)) * 3;
-        } else {
-          busPowerSum += (r + g + b + w);
-        }
-      }
-      // RGBW led total output with white LEDs enabled is still 50mA, so each channel uses less
-      if (bus->hasWhite()) {
-        busPowerSum *= 3;
-        busPowerSum >>= 2; //same as /= 4
-      }
-      // powerSum has all the values of channels summed (max would be getLength()*765 as white is excluded) so convert to milliAmps
-      milliAmpsTotal += (busPowerSum * maPL * brightness) / (765*255);
-    }
-    if (lengthDigital > 0) {
-      avgMilliAmpsPerLED /= lengthDigital;
-
-      if (milliAmpsMax > MA_FOR_ESP && avgMilliAmpsPerLED > 0) { //0 mA per LED and too low numbers turn off calculation
-        unsigned powerBudget = (milliAmpsMax - MA_FOR_ESP); //80/120mA for ESP power
-        if (powerBudget > lengthDigital) { //each LED uses about 1mA in standby, exclude that from power budget
-          powerBudget -= lengthDigital;
-        } else {
-          powerBudget = 0;
-        }
-        if (milliAmpsTotal > powerBudget) {
-          //scale brightness down to stay in current limit
-          unsigned scaleB = powerBudget * 255 / milliAmpsTotal;
-          brightness = ((brightness * scaleB) >> 8) + 1;
-        }
-      }
-    }
-  }
-  return brightness;
-}
-
 void WS2812FX::show() {
   if (!_pixels) return; // no pixels allocated, nothing to show
 
@@ -1637,10 +1578,6 @@ void WS2812FX::show() {
   show_callback callback = _callback;
   if (callback) callback(); // will call setPixelColor or setRealtimePixelColor
 
-  // determine ABL brightness
-  uint8_t newBri = estimateCurrentAndLimitBri(_brightness, _pixels);
-  if (newBri != _brightness) BusManager::setBrightness(newBri);
-
   // paint actual pixels
   int oldCCT = Bus::getCCT(); // store original CCT value (since it is global)
   // when cctFromRgb is true we implicitly calculate WW and CW from RGB values (cct==-1)
@@ -1651,7 +1588,11 @@ void WS2812FX::show() {
     if (_pixelCCT) { // cctFromRgb already exluded at allocation
       if (i == 0 || _pixelCCT[i-1] != _pixelCCT[i]) BusManager::setSegmentCCT(_pixelCCT[i], correctWB);
     }
-    BusManager::setPixelColor(getMappedPixelIndex(i), realtimeMode && arlsDisableGammaCorrection ? _pixels[i] : gamma32(_pixels[i]));
+
+    uint32_t c = _pixels[i]; // need a copy, do not modify _pixels directly (no byte access allowed on ESP32)
+    if(c > 0 && !(realtimeMode && arlsDisableGammaCorrection))
+        c = gamma32(c); // apply gamma correction if enabled note: applying gamma after brightness has too much color loss
+    BusManager::setPixelColor(getMappedPixelIndex(i), c);
   }
   Bus::setCCT(oldCCT);  // restore old CCT for ABL adjustments
 
@@ -1663,9 +1604,6 @@ void WS2812FX::show() {
   // See https://github.com/Makuna/NeoPixelBus/wiki/ESP32-NeoMethods#neoesp32rmt-methods
   BusManager::show();
 
-  // restore brightness for next frame
-  if (newBri != _brightness) BusManager::setBrightness(_brightness);
-
   if (diff > 0) { // skip calculation if no time has passed
     size_t fpsCurr = (1000 << FPS_CALC_SHIFT) / diff; // fixed point math
     _cumulativeFps = (FPS_CALC_AVG * _cumulativeFps + fpsCurr + FPS_CALC_AVG / 2) / (FPS_CALC_AVG + 1);   // "+FPS_CALC_AVG/2" for proper rounding
@@ -1730,7 +1668,7 @@ void WS2812FX::setBrightness(uint8_t b, bool direct) {
   if (_brightness == 0) { //unfreeze all segments on power off
     for (const Segment &seg : _segments) seg.freeze = false; // freeze is mutable
   }
-  BusManager::setBrightness(b);
+  BusManager::setBrightness(scaledBri(b));
   if (!direct) {
     unsigned long t = millis();
     if (_segments[0].next_time > t + 22 && t - _lastShow > MIN_SHOW_DELAY) trigger(); //apply brightness change immediately if no refresh soon