Add brightness factor for lightbulbs with power white LEDs but low brightness RGB

code/espurna/config/general.h

@@ -725,6 +725,10 @@ PROGMEM const char* const custom_reset_string[] = {
 #define LIGHT_USE_GAMMA         0           // Use gamma correction for color channels
 #define LIGHT_USE_CSS           1           // Use CSS style to report colors (1=> "#FF0000", 0=> "255,0,0")
 #define LIGHT_USE_RGB           0           // Use RGB color selector (1=> RGB, 0=> HSV)
+#ifndef LIGHT_WHITE_FACTOR
+#define LIGHT_WHITE_FACTOR      1           // When using LIGHT_USE_WHITE with uneven brightness LEDs,
+                                            // this factor is used to scale the white channel to match brightness
+#endif
 
 #define LIGHT_USE_TRANSITIONS   1           // Transitions between colors
 #define LIGHT_TRANSITION_STEP   10          // Time in millis between each transtion step

code/espurna/config/hardware.h

@@ -636,6 +636,7 @@
     #define MY92XX_DCKI_PIN     14
     #define MY92XX_COMMAND      MY92XX_COMMAND_DEFAULT
     #define MY92XX_MAPPING      4, 3, 5, 0, 1
+    #define LIGHT_WHITE_FACTOR  (0.1)                    // White LEDs are way more bright in the B1
 
 #elif defined(ITEAD_SONOFF_LED)
 

code/espurna/light.ino

@@ -89,31 +89,28 @@ void _generateBrightness() {
     // Convert RGB to RGBW
     if (_light_has_color && _light_use_white) {
 
-        unsigned char white, max_in, max_out;
-        double factor = 0;
-
-        white = std::min(_light_channel[0].inputValue, std::min(_light_channel[1].inputValue, _light_channel[2].inputValue));
-        max_in = std::max(_light_channel[0].inputValue, std::max(_light_channel[1].inputValue, _light_channel[2].inputValue));
-
+        // Substract the common part from RGB channels and add it to white channel. So [250,150,50] -> [200,100,0,50
+        unsigned char white = std::min(_light_channel[0].inputValue, std::min(_light_channel[1].inputValue, _light_channel[2].inputValue));
         for (unsigned int i=0; i < 3; i++) {
             _light_channel[i].value = _light_channel[i].inputValue - white;
         }
         _light_channel[3].value = white;
         _light_channel[3].inputValue = 0;
 
-        max_out = std::max(std::max(_light_channel[0].value, _light_channel[1].value), std::max(_light_channel[2].value, _light_channel[3].value));
-        if (max_out > 0) {
-            factor = (double) (max_in / max_out);
-        }
-
         // Scale up to equal input values. So [250,150,50] -> [200,100,0,50] -> [250, 125, 0, 63]
+        unsigned char max_in = std::max(_light_channel[0].inputValue, std::max(_light_channel[1].inputValue, _light_channel[2].inputValue));
+        unsigned char max_out = std::max(std::max(_light_channel[0].value, _light_channel[1].value), std::max(_light_channel[2].value, _light_channel[3].value));
+        double factor = (max_out > 0) ? (double) (max_in / max_out) : 0;
         for (unsigned int i=0; i < 4; i++) {
             _light_channel[i].value = round((double) _light_channel[i].value * factor * brightness);
         }
 
-        // Don't apply brightness, it is already in the inputValue:
-        if (_light_channel.size() == 5) {
-            _light_channel[4].value = _light_channel[4].inputValue;
+        // Scale white channel to match brightness
+        _light_channel[3].value = constrain(_light_channel[3].value * LIGHT_WHITE_FACTOR, 0, 255);
+
+        // For the rest of channels, don't apply brightness, it is already in the inputValue:
+        for (unsigned char i=4; i < _light_channel.size(); i++) {
+            _light_channel[i].value = _light_channel[i].inputValue;
         }
 
     } else {