Function update_position

src/animation.cpp:260–301

void update_position(animation_position &p_animation_position, animation const &p_animation, unsigned int const p_increase)
{
	p_animation_position.m_frame_nr_in_part += p_increase;
	if (p_animation_position.m_part_nr >= p_animation.get_num_parts())
		p_animation_position.m_part_nr = p_animation.get_num_parts() - 1;

	// After m_frame_nr_in_part was incremented by p_increase, its value
	// may lie outside of the bounds of the part. This means the new position
	// is actually beyond the current part, so try moving to the next part,
	// and see if the m_frame_nr_in_part value there is inside the bounds. If
	// not, move to the next part again etc. until m_frame_nr_in_part fits in
	// the part's bounds, or until the last part is reached.
	while (true)
	{
		animation::part const &part = *(p_animation.get_part(p_animation_position.m_part_nr));

		// If m_frame_nr_in_part lies within the bounds of the current part,
		// exit, since we are done.
		if (p_animation_position.m_frame_nr_in_part < part.m_frames.size())
			break;

		// If the current part is the last one, simply do a modulo on
		// m_frame_nr_in_part, thereby looping inside the last part.
		if (p_animation_position.m_part_nr == (p_animation.get_num_parts() - 1))
		{
			p_animation_position.m_frame_nr_in_part = p_animation_position.m_frame_nr_in_part % part.m_frames.size();
			break;
		}

		// If this point is reached, it means that (1) the current part is not
		// the last part in the animation and (2) m_frame_nr_in_part still lies
		// outside of the part's bounds. Increase the part's loop count, and
		// if the maximum number of loops is reached, advance to the next part.
		p_animation_position.m_part_loop_nr++;
		p_animation_position.m_frame_nr_in_part -= part.m_frames.size();
		if (p_animation_position.m_part_loop_nr >= part.m_num_times_to_play)
		{
			p_animation_position.m_part_loop_nr = 0;
			p_animation_position.m_part_nr++;
		}
	}
}


} // namespace easysplash end