public void update(long time){
		walk.update(time);
		level.getBackground().setX(x);
		if(time - previousTime >= timeFrame) {
			// movement over y and x
			upY();
			upX();
			// Calculation Stubi position :
			int i = y/Obstacle.getHeight(); // Stubi's head position in grid
			int j = x/Obstacle.getWidth(); // Stubi's left side position in the grid
			int k = x%Obstacle.getWidth(); // Stubi's x coord in the (i,j) block in the grid
			int l  = y%Obstacle.getHeight(); // Stubi's y coord in the (i,j) block in the grid
			// collision :
			collisionUpdate(i,j,k,l);
			// dmg
			dmgUpdate(i,j,k,l);
		}
	}