PoC Rotate Segment

wled00/FX.cpp

@@ -188,6 +188,108 @@ uint16_t mode_copy_segment(void) {
 }
 static const char _data_FX_MODE_COPY[] PROGMEM = "Copy Segment@,Color shift,Lighten,Brighten,ID,Axis(2D),FullStack(last frame);;;12;ix=0,c1=0,c2=0,c3=0";
 
+uint16_t mode_rotate_segment(void) {
+
+  uint32_t sourceid = SEGMENT.custom3;
+  Segment& sourcesegment = strip.getSegment(sourceid);
+
+  if (!sourcesegment.isActive() || 
+      !sourcesegment.is2D() ||
+       sourceid >= strip.getSegmentsNum() ||
+       sourceid == strip.getCurrSegmentId()) {
+         SEGMENT.fadeToBlackBy(5); // fade out
+         return FRAMETIME;
+        }
+
+  const int cols = SEG_W, rows = SEG_H;
+  const int midX = cols / 2;
+  const int midY = rows / 2;
+  int angleInc = map(SEGMENT.speed, 0, 255, 1, 16);
+  SEGENV.aux0 = (SEGENV.aux0 + angleInc) % 360;
+
+  int16_t shearX;
+  int16_t shearY;
+  const uint8_t Scale_Shift = 10;
+  const int Fixed_Scale = (1 << Scale_Shift);
+  const int RoundVal = (1 << (Scale_Shift - 1));
+
+  int zoomOffset = SEGMENT.intensity - 128; // -128 - 127
+  const int zoomRange = (Fixed_Scale * 3) / 4;  // 768
+  int zoomScale = Fixed_Scale + (zoomOffset * zoomRange) / 128;
+  if (zoomScale <= 0) zoomScale = 1; // avoid divide-by-zero and negative zoom
+
+  int shearAngle = SEGENV.aux0;
+
+  bool flip = (shearAngle > 90 && shearAngle < 270); // Flip to avoid instability near 180°
+  shearAngle = flip ? (shearAngle + 180) % 360 : shearAngle;
+
+  // Calculate shearX and shearY
+  float angleRadians = radians(shearAngle);
+  shearX = -tanf(angleRadians / 2) * Fixed_Scale;
+  shearY =  sinf(angleRadians)     * Fixed_Scale;
+
+  SEGMENT.fill(0); // clear segment before drawing rotated copy
+
+  const int srcWidth  = sourcesegment.width();
+  const int srcHeight = sourcesegment.height();
+  const int WRAP_PAD_X = srcWidth  << 5; // ×32
+  const int WRAP_PAD_Y = srcHeight << 5; // Ensures wrap works with large negative coordinates when zoomed out
+
+  // Use inverse mapping: iterate destination pixels, find source coordinates
+  for (int destY = 0; destY < rows; destY++) {
+    for (int destX = 0; destX < cols; destX++) {
+      // Translate destination to origin
+      int dx = destX - midX;
+      int dy = destY - midY;
+
+      // Inverse shear transformations (reverse order)
+      int x1 = dx - ((shearX * dy + RoundVal) >> Scale_Shift);
+      int y0 = dy - ((shearY * x1 + RoundVal) >> Scale_Shift);
+      int x0 = x1 - ((shearX * y0 + RoundVal) >> Scale_Shift);
+
+      // Apply zoom to source coordinates
+      x0 = (x0 * Fixed_Scale) / zoomScale;
+      y0 = (y0 * Fixed_Scale) / zoomScale;
+
+      // Handle flip
+      int srcX = flip ? (midX - x0) : (midX + x0);
+      int srcY = flip ? (midY - y0) : (midY + y0);
+
+      // Bounds check or wrap
+      if (SEGMENT.check1) { // Wrap around
+        srcX = (srcX + WRAP_PAD_X) % srcWidth;
+        srcY = (srcY + WRAP_PAD_Y) % srcHeight;
+      }
+      else if (SEGMENT.check2) { // Wrap plus mirror
+        int tileX = (srcX + WRAP_PAD_X) / srcWidth;
+        int tileY = (srcY + WRAP_PAD_Y) / srcHeight;
+
+        // Wrap src
+        srcX = (srcX + WRAP_PAD_X) % srcWidth;
+        srcY = (srcY + WRAP_PAD_Y) % srcHeight;
+
+        // Flip on odd tiles
+        if (tileX & 1) srcX = srcWidth - 1 - srcX;
+        if (tileY & 1) srcY = srcHeight - 1 - srcY;
+      }
+      else if (srcX < 0 || srcX >= srcWidth || srcY < 0 || srcY >= srcHeight) continue;
+
+      // Sample from source
+      sourcesegment.setDrawDimensions();
+      uint32_t sourcecolor = sourcesegment.getPixelColorXY(srcX, srcY);
+
+      if (sourcecolor == 0) continue; // skip black pixels already filled to black
+
+      // Write to destination
+      SEGMENT.setDrawDimensions();
+      SEGMENT.setPixelColorXY(destX, destY, sourcecolor);
+    }
+  }
+
+  return FRAMETIME;
+}
+static const char _data_FX_MODE_ROTATE[] PROGMEM = "Rotate Segment@!,Zoom,,,ID,Wrap,Mirror Wrap;;;2;sx=0,ix=128,c1=0,c2=0,c3=0";
+
 
 /*
  * Blink/strobe function
@@ -11201,6 +11303,7 @@ void WS2812FX::setupEffectData() {
   addEffect(FX_MODE_2DOCTOPUS, &mode_2Doctopus, _data_FX_MODE_2DOCTOPUS);
   addEffect(FX_MODE_2DWAVINGCELL, &mode_2Dwavingcell, _data_FX_MODE_2DWAVINGCELL);
   addEffect(FX_MODE_2DAKEMI, &mode_2DAkemi, _data_FX_MODE_2DAKEMI); // audio
+  addEffect(FX_MODE_ROTATE, &mode_rotate_segment, _data_FX_MODE_ROTATE);
 
 #ifndef WLED_DISABLE_PARTICLESYSTEM2D
   addEffect(FX_MODE_PARTICLEVOLCANO, &mode_particlevolcano, _data_FX_MODE_PARTICLEVOLCANO);

wled00/FX.h

@@ -379,7 +379,10 @@ extern byte realtimeMode;           // used in getMappedPixelIndex()
 #define FX_MODE_PS1DSONICBOOM          215
 #define FX_MODE_PS1DSPRINGY            216
 #define FX_MODE_PARTICLEGALAXY         217
-#define MODE_COUNT                     218
+
+#define FX_MODE_ROTATE                 218
+
+#define MODE_COUNT                     219
 
 
 #define BLEND_STYLE_FADE            0x00  // universal