public void update(float startX, float fromY, float toY, float size) {
		this.fromY = fromY;
		this.size = size;
		this.startX = startX;
		this.centerY = -1;
		float coef = 0.4f + random.nextFloat() * 0.8f; // randomize speed of movement
		this.speed = (toY - fromY) / BUBBLE_ANIMATION_DURATION * coef;
		this.virtualSpeed = 2f / BUBBLE_ANIMATION_DURATION * coef;
		getColor()[3] = 1f;
	}
Update bubble's area of movement.
@param startX start X position
@param fromY start Y position
@param toY end Y position
@param size size of bubble
library/src/main/java/com/cleveroad/audiovisualization/GLBubble.java