HUB75 speedups and minor improvements

* HUB75: allow to use native driver gamma correction - requires to undo WLED gamma
* added unGamma24() function
* HUB75: optimized setPixelColor()
* some experimental HUB75 stuff

wled00/bus_manager.cpp

@@ -501,6 +501,7 @@ void BusNetwork::cleanup() {
 
 BusHub75Matrix::BusHub75Matrix(BusConfig &bc) : Bus(bc.type, bc.start, bc.autoWhite) {
 
+  _valid = false;
   mxconfig.double_buff = false; // default to off, known to cause issue with some effects but needs more memory
 
 
@@ -594,6 +595,13 @@ BusHub75Matrix::BusHub75Matrix(BusConfig &bc) : Bus(bc.type, bc.start, bc.autoWh
   mxconfig.gpio.d = 21;
   mxconfig.gpio.e = 12;
 
+  // mxconfig.double_buff = true; // <------------- Turn on double buffer
+  // mxconfig.driver = HUB75_I2S_CFG::ICN2038S;  // experimental - use specific shift register driver
+  //mxconfig.latch_blanking = 3;
+  // mxconfig.i2sspeed = HUB75_I2S_CFG::HZ_10M;  // experimental - 5MHZ should be enugh, but colours looks slightly better at 10MHz
+  //mxconfig.min_refresh_rate = 90;
+  //mxconfig.min_refresh_rate = 120;
+
 #else
   USER_PRINTLN("MatrixPanel_I2S_DMA - Default pins");
   /*
@@ -691,18 +699,25 @@ BusHub75Matrix::BusHub75Matrix(BusConfig &bc) : Bus(bc.type, bc.start, bc.autoWh
 }
 
 void BusHub75Matrix::setPixelColor(uint16_t pix, uint32_t c) {
-  r = R(c);
-  g = G(c);
-  b = B(c);
+  if (!_valid || pix >= _len) return;
+#ifndef NO_CIE1931
+  c = unGamma24(c); // to use the driver linear brightness feature, we first need to undo WLED gamma correction
+#endif
+  uint8_t r = R(c);
+  uint8_t g = G(c);
+  uint8_t b = B(c);
+
   if(fourScanPanel != nullptr) {
-    x = pix % fourScanPanel->width();
-    y = floor(pix / fourScanPanel->width());
-    fourScanPanel->drawPixelRGB888(x, y, r, g, b);
+    int pxwidth = fourScanPanel->width();
+    int x = pix % pxwidth;
+    int y = pix / pxwidth;
+    fourScanPanel->drawPixelRGB888(int16_t(x), int16_t(y), r, g, b);
   }
   else {
-    x = pix % display->width();
-    y = floor(pix / display->width());
-    display->drawPixelRGB888(x, y, r, g, b);
+    int pxwidth = display->width();
+    int x = pix % pxwidth;
+    int y = pix / pxwidth;
+    display->drawPixelRGB888(int16_t(x), int16_t(y), r, g, b);
   }
 }
 

wled00/bus_manager.h

@@ -4,6 +4,7 @@
 #ifdef WLED_ENABLE_HUB75MATRIX
 #include <ESP32-HUB75-MatrixPanel-I2S-DMA.h>
 #include <ESP32-VirtualMatrixPanel-I2S-DMA.h>
+//extern volatile bool previousBufferFree; // experimental
 #endif
 /*
  * Class for addressing various light types
@@ -348,6 +349,7 @@ class BusHub75Matrix : public Bus {
     void show() {
       if(mxconfig.double_buff) {
         display->flipDMABuffer(); // Show the back buffer, set currently output buffer to the back (i.e. no longer being sent to LED panels)
+        // while(!previousBufferFree) delay(1);   // experimental - Wait before we allow any writing to the buffer. Stop flicker.
         display->clearScreen();   // Now clear the back-buffer
       }
     }
@@ -377,7 +379,6 @@ class BusHub75Matrix : public Bus {
     MatrixPanel_I2S_DMA *display = nullptr;
     VirtualMatrixPanel  *fourScanPanel = nullptr;
     HUB75_I2S_CFG mxconfig;
-    uint8_t r, g, b, x, y;
     
 };
 #endif

wled00/colors.cpp

@@ -413,6 +413,12 @@ uint8_t unGamma8(uint8_t value) {
   if (gammaTinv[255] == 0) calcInvGammaTable(gammaCorrectVal);
   return gammaTinv[value];
 }
+
+uint32_t unGamma24(uint32_t c) {
+  if ((gammaCorrectVal < 0.999f) || (gammaCorrectVal > 3.0f)) return c;
+  if (gammaTinv[255] == 0) calcInvGammaTable(gammaCorrectVal);
+  return RGBW32(gammaTinv[R(c)], gammaTinv[G(c)], gammaTinv[B(c)], W(c));
+}
 // wleDMM end
 
 uint8_t gamma8_cal(uint8_t b, float gamma)

wled00/fcn_declare.h

@@ -69,6 +69,7 @@ void calcGammaTable(float gamma);
 uint8_t __attribute__((pure)) gamma8(uint8_t b);                                              // WLEDMM: added attribute pure
 uint32_t __attribute__((pure)) gamma32(uint32_t);                                             // WLEDMM: added attribute pure
 uint8_t unGamma8(uint8_t value);                                                              // WLEDMM revert gamma correction
+uint32_t unGamma24(uint32_t c);                                                               // WLEDMM for 24bit color (white left as-is)
 
 //dmx_output.cpp
 void initDMXOutput();

wled00/wled.h

@@ -8,7 +8,7 @@
  */
 
 // version code in format yymmddb (b = daily build)
-#define VERSION 2407171
+#define VERSION 2408050
 
 // WLEDMM  - you can check for this define in usermods, to only enabled WLEDMM specific code in the "right" fork. Its not defined in AC WLED.
 #define _MoonModules_WLED_