apply method

@override void apply(Buffer source, Buffer target, double dt)

Implementation

@override
void apply(Buffer source, Buffer target, double dt) {
  final width = source.width();
  final height = source.height();
  if (width <= 0 || height <= 0) return;
  _ensure(width, height);

  final timeStep = dt <= 0 ? 1 / 60 : dt;
  _time += timeStep;

  for (var y = 0; y < height; y++) {
    for (var x = 0; x < width; x++) {
      final i = y * width + x;
      final nx = math.sin(x * 0.15 + y * 0.07 + _time * 1.3);
      final ny = math.cos(y * 0.17 + x * 0.05 + _time * 1.1);
      final jitterX = (_rng.nextDouble() * 2 - 1) * noise;
      final jitterY = (_rng.nextDouble() * 2 - 1) * noise;
      _vx[i] = (_vx[i] * damping) + (nx * flow + jitterX) * timeStep;
      _vy[i] = (_vy[i] * damping) + (ny * flow + jitterY) * timeStep;
    }
  }

  for (var y = 0; y < height; y++) {
    for (var x = 0; x < width; x++) {
      final i = y * width + x;
      final dx = _vx[i] * strength;
      final dy = _vy[i] * strength;
      final sx = (x + dx).round().clamp(0, width - 1);
      final sy = (y + dy).round().clamp(0, height - 1);
      final cell = source.cellAt(sx, sy);
      if (cell == null || cell.width == 0) {
        target.setCell(x, y, Cell.emptyCell());
      } else {
        target.setCell(x, y, cell);
      }
    }
  }
}