reset method
void
reset()
Implementation
void reset() {
final random = Random();
x = random.nextDouble() * screenSize.width;
y = random.nextDouble() * screenSize.height;
speedX = random.nextDouble() * (isStrongWind ? 4 : 2) + 1;
speedY = random.nextDouble() - 0.5;
size = random.nextDouble() * 4 + 2;
opacity = random.nextDouble() * 0.5 + 0.2;
}