Add brightness setting to gamma calculation

Author: penfold42

ESPixelStick.h

@@ -145,6 +145,7 @@ typedef struct {
     PixelColor  pixel_color;    /* Pixel color order */
     bool        gamma;          /* Use gamma map? */
     float       gammaVal;       /* gamma value to use */
+    float       briteVal;       /* brightness lto use */
 #elif defined(ESPS_MODE_SERIAL)
     /* Serial */
     SerialType  serial_type;    /* Serial type */

ESPixelStick.ino

@@ -587,6 +587,10 @@ void validateConfig() {
     if (config.gammaVal <= 0) {
         config.gammaVal = 2.2;
     }
+    // default gamma value
+    if (config.briteVal <= 0) {
+        config.briteVal = 1.0;
+    }
 #elif defined(ESPS_MODE_SERIAL)
     // Set Mode
 //    config.devmode = DevMode::MSERIAL;
@@ -639,7 +643,7 @@ void updateConfig() {
 #if defined(ESPS_MODE_PIXEL)
     pixels.begin(config.pixel_type, config.pixel_color, config.channel_count / 3);
     pixels.setGamma(config.gamma);
-    updateGammaTable(config.gammaVal);
+    updateGammaTable(config.gammaVal, config.briteVal);
 
 #elif defined(ESPS_MODE_SERIAL)
     serial.begin(&SEROUT_PORT, config.serial_type, config.channel_count, config.baudrate);
@@ -711,6 +715,7 @@ void dsDeviceConfig(JsonObject &json) {
     config.pixel_color = PixelColor(static_cast<uint8_t>(json["pixel"]["color"]));
     config.gamma = json["pixel"]["gamma"];
     config.gammaVal = json["pixel"]["gammaVal"];
+    config.briteVal = json["pixel"]["briteVal"];
 
 #elif defined(ESPS_MODE_SERIAL)
     /* Serial */
@@ -831,6 +836,7 @@ void serializeConfig(String &jsonString, bool pretty, bool creds) {
     pixel["color"] = static_cast<uint8_t>(config.pixel_color);
     pixel["gamma"] = config.gamma;
     pixel["gammaVal"] = config.gammaVal;
+    pixel["briteVal"] = config.briteVal;
 
 #elif defined(ESPS_MODE_SERIAL)
     // Serial

gamma.cpp

@@ -20,9 +20,9 @@ uint8_t GAMMA_TABLE[] = {
     222,224,227,229,231,233,235,237,239,241,244,246,248,250,252,255
 };
 
-void updateGammaTable(float gammaVal) {
+void updateGammaTable(float gammaVal, float briteVal) {
   for (int i=0; i<256; i++) {
-    GAMMA_TABLE[i] = (uint8_t) 255.0 * pow(i/255.0, gammaVal) + 0.5;
+    GAMMA_TABLE[i] = min( (uint8_t) 255.0 * pow(i*briteVal/255.0, gammaVal) + 0.5, 255);
   }
 }
 

gamma.h

@@ -4,6 +4,6 @@
 /* Gamma correction table */
 extern uint8_t GAMMA_TABLE[];
 
-void updateGammaTable(float gammaVal);
+void updateGammaTable(float gammaVal, float briteVal);
 
 #endif /* GAMMA_H_ */

html/index.html

@@ -170,8 +170,10 @@
             </div>          
             <div class="form-group">
               <label class="control-label col-sm-2" for="p_gammaVal">Gamma Value</label>
-              <div class="col-sm-5"><input type="text" class="form-control" id="p_gammaVal" name="p_gammaVal" placeholder="Gamma Value" onchange="refreshPixel()"></div>
-	      <div class="col-sm-5"><a target="_gamma" href="/gamma.html">View Graph</a></div>
+              <div class="col-sm-3"><input type="text" class="form-control" id="p_gammaVal" name="p_gammaVal" placeholder="Gamma Value" onchange="refreshPixel()"></div>
+              <label class="control-label col-sm-2" for="p_briteVal">Brightness</label>
+              <div class="col-sm-3"><input type="text" class="form-control" id="p_briteVal" name="p_briteVal" placeholder="Brightness" onchange="refreshPixel()"></div>
+	      <div class="col-sm-2"><a target="_gamma" href="/gamma.html">View Graph</a></div>
             </div>
           </div>
 

html/script.js

@@ -489,6 +489,7 @@ function getConfig(data) {
         $('#p_color').val(config.pixel.color);
         $('#p_gamma').prop('checked', config.pixel.gamma);
         $('#p_gammaVal').val(config.pixel.gammaVal);
+        $('#p_briteVal').val(config.pixel.briteVal);
 
         if(config.e131.channel_count / 3 <8 ) {
             $('#v_columns').val(config.e131.channel_count / 3);
@@ -674,7 +675,8 @@ function submitConfig() {
                 'type': parseInt($('#p_type').val()),
                 'color': parseInt($('#p_color').val()),
                 'gamma': $('#p_gamma').prop('checked'),
-                'gammaVal': parseFloat($('#p_gammaVal').val())
+                'gammaVal': parseFloat($('#p_gammaVal').val()),
+                'briteVal': parseFloat($('#p_briteVal').val())
             },
             'serial': {
                 'type': parseInt($('#s_proto').val()),