replaced repeated progress() calculation calls with a variable (#4256)

progress() is called in setPixelColor(), calculating the transition progress for each pixel. Replaced that call with an inline function to get the new segment variable.
The progress is updated in service() when handleTransition() is called.
The new variable is in a spot where padding is added, so this should not use more RAM.
Result: over 10% increase in FPS on 16x16 matrix

* removed IRAM_ATTR: `updateTransitionProgress()` is called only once per frame, no need to put it in RAM.
* changed transitionprogress to static, private variable, this is now more aligned with other variables using the same logic
* added inline: the function is only used in one place

wled00/FX.h

@@ -369,6 +369,7 @@ typedef struct Segment {
     };
     uint8_t startY;  // start Y coodrinate 2D (top); there should be no more than 255 rows
     uint8_t stopY;   // stop Y coordinate 2D (bottom); there should be no more than 255 rows
+    // note: two bytes of padding are added here
     char    *name;
 
     // runtime data
@@ -424,6 +425,7 @@ typedef struct Segment {
     static CRGBPalette16 _newRandomPalette;   // target random palette
     static uint16_t _lastPaletteChange;       // last random palette change time in millis()/1000
     static uint16_t _lastPaletteBlend;        // blend palette according to set Transition Delay in millis()%0xFFFF
+    static uint16_t _transitionprogress;      // current transition progress 0 - 0xFFFF
     #ifndef WLED_DISABLE_MODE_BLEND
     static bool          _modeBlend;          // mode/effect blending semaphore
     #endif
@@ -565,12 +567,13 @@ typedef struct Segment {
     // transition functions
     void     startTransition(uint16_t dur);     // transition has to start before actual segment values change
     void     stopTransition();                  // ends transition mode by destroying transition structure (does nothing if not in transition)
-    inline void handleTransition() { if (progress() == 0xFFFFU) stopTransition(); }
+    inline void handleTransition() { updateTransitionProgress(); if (progress() == 0xFFFFU) stopTransition(); }
     #ifndef WLED_DISABLE_MODE_BLEND
     void     swapSegenv(tmpsegd_t &tmpSegD);    // copies segment data into specifed buffer, if buffer is not a transition buffer, segment data is overwritten from transition buffer
     void     restoreSegenv(tmpsegd_t &tmpSegD); // restores segment data from buffer, if buffer is not transition buffer, changed values are copied to transition buffer
     #endif
-    [[gnu::hot]] uint16_t progress() const;                  // transition progression between 0-65535
+    [[gnu::hot]] void updateTransitionProgress();            // set current progression of transition
+    inline uint16_t progress() const { return _transitionprogress; };  // transition progression between 0-65535
     [[gnu::hot]] uint8_t  currentBri(bool useCct = false) const; // current segment brightness/CCT (blended while in transition)
     uint8_t  currentMode() const;                            // currently active effect/mode (while in transition)
     [[gnu::hot]] uint32_t currentColor(uint8_t slot) const;  // currently active segment color (blended while in transition)

wled00/FX_fcn.cpp

@@ -75,6 +75,7 @@ CRGBPalette16 Segment::_randomPalette     = generateRandomPalette();  // was CRG
 CRGBPalette16 Segment::_newRandomPalette  = generateRandomPalette();  // was CRGBPalette16(DEFAULT_COLOR);
 uint16_t      Segment::_lastPaletteChange = 0; // perhaps it should be per segment
 uint16_t      Segment::_lastPaletteBlend  = 0; //in millis (lowest 16 bits only)
+uint16_t      Segment::_transitionprogress  = 0xFFFF;
 
 #ifndef WLED_DISABLE_MODE_BLEND
 bool Segment::_modeBlend = false;
@@ -305,12 +306,12 @@ void Segment::stopTransition() {
 }
 
 // transition progression between 0-65535
-uint16_t IRAM_ATTR Segment::progress() const {
+inline void Segment::updateTransitionProgress() {
+  _transitionprogress = 0xFFFFU;
   if (isInTransition()) {
     unsigned diff = millis() - _t->_start;
-    if (_t->_dur > 0 && diff < _t->_dur) return diff * 0xFFFFU / _t->_dur;
+    if (_t->_dur > 0 && diff < _t->_dur) _transitionprogress = diff * 0xFFFFU / _t->_dur;
   }
-  return 0xFFFFU;
 }
 
 #ifndef WLED_DISABLE_MODE_BLEND