bugfix #2 for switched-off segments

segments that are "off" were still rendered during transitions.

Author: softhack007

wled00/FX.h

@@ -380,6 +380,7 @@ typedef struct Segment {
     };
     uint8_t  grouping, spacing;
     uint8_t  opacity;
+    uint8_t  lastBri;             // WLEDMM optimization for black-to-black "transitions"
     bool needsBlank;              // WLEDMM indicates that Segment needs to be blanked (due to change of mirror / reverse / transpose / spacing)
     uint32_t colors[NUM_COLORS];
     uint8_t  cct;                 //0==1900K, 255==10091K
@@ -490,6 +491,7 @@ typedef struct Segment {
       grouping(1),
       spacing(0),
       opacity(255),
+      lastBri(255),
       needsBlank(false),
       colors{DEFAULT_COLOR,BLACK,BLACK},
       cct(127),

wled00/FX_fcn.cpp

@@ -1935,6 +1935,7 @@ void WS2812FX::service() {
         now = millis() + timebase;
 #endif
         seg.startFrame();   // WLEDMM
+        if (!_triggered && (seg.currentBri(seg.opacity) == 0) && (seg.lastBri == 0)) continue; // WLEDMM skip totally black segments
         // effect blending (execute previous effect)
         // actual code may be a bit more involved as effects have runtime data including allocated memory
         //if (seg.transitional && seg._modeP) (*_mode[seg._modeP])(progress());
@@ -1944,6 +1945,7 @@ void WS2812FX::service() {
         if (seg.mode != FX_MODE_HALLOWEEN_EYES) seg.call++;
         if (seg.transitional && frameDelay > FRAMETIME) frameDelay = FRAMETIME; // force faster updates during transition
 
+        seg.lastBri = seg.currentBri(seg.on ? seg.opacity:0);                   // WLEDMM remember for next time
         seg.handleTransition();
       }