DragonRuby - Fiber Animation

main.rb

class MoveOrchestration
  attr :camera_center, :camera_scale

  def initialize(probe:, celestial_body:)
    @probe = probe
    @celestial_body = celestial_body
    @fiber = build_fiber
    @camera_center = { x: @probe.x, y: @probe.y }
    @camera_scale = 1.5
  end

  def build_fiber
    Fiber.new do
      @probe.action! :moving
      source = { x: @probe.x, y: @probe.y }
      at = Kernel.tick_count
      orbiting_id = @probe.orbiting_id
      destination_id = @celestial_body.id

      # move to center
      loop do
        target = @probe.celestial_bodies[orbiting_id]
        distance = Geometry.distance(source, target)
        duration = 60
        perc = Easing.smooth_stop(start_at: at,
                                  duration: duration,
                                  tick_count: Kernel.tick_count, power: 2)

        @probe.x = source.x + (target.x - source.x) * perc
        @probe.y = source.y + (target.y - source.y) * perc

        if at.elapsed_time >= duration
          break
        end
        @camera_center = { x: @probe.x, y: @probe.y }
        @camera_scale = 1.5
        Fiber.yield
      end

      at = Kernel.tick_count

      # move to target
      loop do
        target = @probe.celestial_bodies[destination_id]
        source = @probe.celestial_bodies[orbiting_id]
        distance = Geometry.distance(source, target)
        duration = (distance.fdiv(2150) * 60).clamp(60, 300)
        perc = Easing.smooth_stop(start_at: at,
                                  duration: duration,
                                  tick_count: Kernel.tick_count, power: 2)

        @probe.x = source.x + (target.x - source.x) * perc
        @probe.y = source.y + (target.y - source.y) * perc
        @camera_center = { x: @probe.x, y: @probe.y }
        @camera_scale = 0.5

        if at.elapsed_time >= duration
          @probe.orbiting_id = destination_id
          @probe.orbit_at = Kernel.tick_count
          @probe.destination_id = nil
          @probe.destination_at = Kernel.tick_count
          @probe.orbit_at = Kernel.tick_count
          @probe.action! :main_menu
          break
        end
        Fiber.yield
      end
    end
  end

  def alive?
    @fiber.alive?
  end

  def resume
    @fiber.resume
  end
end