using segment buffer instead of local buffer for PS (#4776)

- using segment buffer instead of local buffer to save FX ram
- fix rendering if gamma correction is disabled
- some code cleanup
- Fix for low RAM: reduce number of particles dynamically
- updated add and scale color functions to not use references
- FPS is now more consistent and on average about 15% faster

Author: DedeHai

wled00/FX.cpp

@@ -8837,7 +8837,7 @@ uint16_t mode_particleGEQ(void) {
         //set particle properties TODO: could also use the spray...
         PartSys->particles[i].ttl = 20 + map(SEGMENT.intensity, 0,255, emitspeed>>1, emitspeed + hw_random16(emitspeed)) ; // set particle alive, particle lifespan is in number of frames
         PartSys->particles[i].x = xposition + hw_random16(binwidth) - (binwidth>>1); // position randomly, deviating half a bin width
-        PartSys->particles[i].y = PS_P_RADIUS; // start at the bottom (PS_P_RADIUS is minimum position a particle is fully in frame)
+        PartSys->particles[i].y = 0; // start at the bottom
         PartSys->particles[i].vx = hw_random16(SEGMENT.custom1>>1)-(SEGMENT.custom1>>2) ; //x-speed variation: +/- custom1/4
         PartSys->particles[i].vy = emitspeed;
         PartSys->particles[i].hue = (bin<<4) + hw_random16(17) - 8; // color from palette according to bin

wled00/FX.h

@@ -686,6 +686,7 @@ class Segment {
 
     // 1D strip
     uint16_t virtualLength() const;
+    uint16_t maxMappingLength() const;
     [[gnu::hot]] void setPixelColor(int n, uint32_t c) const; // set relative pixel within segment with color
     inline void setPixelColor(unsigned n, uint32_t c) const                    { setPixelColor(int(n), c); }
     inline void setPixelColor(int n, byte r, byte g, byte b, byte w = 0) const { setPixelColor(n, RGBW32(r,g,b,w)); }
@@ -808,6 +809,8 @@ class Segment {
     inline void wu_pixel(uint32_t x, uint32_t y, CRGB c) {}
   #endif
   friend class WS2812FX;
+  friend class ParticleSystem2D;
+  friend class ParticleSystem1D;
 };
 
 // main "strip" class (108 bytes)

wled00/FX_fcn.cpp

@@ -645,6 +645,14 @@ uint16_t Segment::virtualLength() const {
   return vLength;
 }
 
+#ifndef WLED_DISABLE_2D
+// maximum length of a mapped 1D segment, used in PS for buffer allocation
+uint16_t Segment::maxMappingLength() const {
+  uint32_t vW = virtualWidth();
+  uint32_t vH = virtualHeight();
+  return max(sqrt32_bw(vH*vH + vW*vW), (uint32_t)getPinwheelLength(vW, vH)); // use diagonal
+}
+#endif
 // pixel is clipped if it falls outside clipping range
 // if clipping start > stop the clipping range is inverted
 bool IRAM_ATTR_YN Segment::isPixelClipped(int i) const {