Smooth Move example

module TSBS
  #============================================================================
  # Easing movement just in case. Thanks to Galenmereth
  # ---------------------------------------------------------------------------
  # time      = Current time (frame)
  # start     = Start value
  # change    = Desired change in value
  # duration  = Duration total (frames)
  # Returns: Value modified by t
  # ---------------------------------------------------------------------------
  # * Easing movement method : Linear
  # ---------------------------------------------------------------------------
  def self.linear(time, start, change, total_time)
    return change * time / total_time + start
  end
  # ---------------------------------------------------------------------------
  # * Easing movement method : Smooth in
  # ---------------------------------------------------------------------------
  def self.smooth_in(time, start, change, total_time)
    time /= total_time.to_f
    return change*time*time*time + start
  end
  # ---------------------------------------------------------------------------
  # * Easing movement method : Smooth out
  # ---------------------------------------------------------------------------
  def self.smooth_out(time, start, change, total_time)
    time /= total_time.to_f
    time -= 1
    return change*(time*time*time + 1) + start
  end
end

class Sprite_Njajal < Sprite

  def initialize
    super()
    self.bitmap = Bitmap.new(32,32)
    bitmap.fill_rect(bitmap.rect, Color.new(255,255,255))
    self.x = 300
    self.y = 200
    @dur = 0
    @time = 0
  end

  def update
    super
    if @dur != @time
      self.x = TSBS.smooth_out(@time, @ori_x, @tx - @ori_x, @dur)
      self.y = TSBS.smooth_out(@time, @ori_y, @ty - @ori_y, @dur)
      @time += 1
    end
  end

  def smooth(tx,ty,dur)
    @ori_x = self.x
    @ori_y = self.y
    @tx = tx
    @ty = ty
    @dur = dur
    @time = 0
  end

end

$sprite = Sprite_Njajal.new

loop do
  Graphics.update
  Input.update
  $sprite.update
  if Input.trigger?(:C)
    $sprite.smooth(100,100,60)
  end
end