Merge pull request Aircoookie#4250 from DedeHai/FPS_calc_averaging

Fixed & improved FPS calculation

wled00/FX.h

@@ -47,6 +47,15 @@
 #define FRAMETIME_FIXED  (1000/WLED_FPS)
 #define FRAMETIME        strip.getFrameTime()
 
+// FPS calculation (can be defined as compile flag for debugging)
+#ifndef FPS_CALC_AVG
+#define FPS_CALC_AVG 7 // average FPS calculation over this many frames (moving average)
+#endif
+#ifndef FPS_MULTIPLIER
+#define FPS_MULTIPLIER 1 // dev option: multiplier to get sub-frame FPS without floats
+#endif
+#define FPS_CALC_SHIFT 7 // bit shift for fixed point math
+
 /* each segment uses 82 bytes of SRAM memory, so if you're application fails because of
   insufficient memory, decreasing MAX_NUM_SEGMENTS may help */
 #ifdef ESP8266
@@ -729,7 +738,7 @@ class WS2812FX {  // 96 bytes
       _transitionDur(750),
       _targetFps(WLED_FPS),
       _frametime(FRAMETIME_FIXED),
-      _cumulativeFps(2),
+      _cumulativeFps(50 << FPS_CALC_SHIFT),
       _isServicing(false),
       _isOffRefreshRequired(false),
       _hasWhiteChannel(false),

wled00/FX_fcn.cpp

@@ -1412,10 +1412,12 @@ void WS2812FX::show() {
 
   unsigned long showNow = millis();
   size_t diff = showNow - _lastShow;
-  size_t fpsCurr = 200;
-  if (diff > 0) fpsCurr = 1000 / diff;
-  _cumulativeFps = (3 * _cumulativeFps + fpsCurr +2) >> 2;   // "+2" for proper rounding (2/4 = 0.5)
-  _lastShow = showNow;
+
+  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
+    _lastShow = showNow;
+  }
 }
 
 /**
@@ -1432,7 +1434,7 @@ bool WS2812FX::isUpdating() const {
  */
 uint16_t WS2812FX::getFps() const {
   if (millis() - _lastShow > 2000) return 0;
-  return _cumulativeFps +1;
+  return (FPS_MULTIPLIER * _cumulativeFps) >> FPS_CALC_SHIFT; // _cumulativeFps is stored in fixed point
 }
 
 void WS2812FX::setTargetFps(uint8_t fps) {