player.rb

class Player
  ROTATION_SPEED = 3
  ACCELERATION = 2
  FRICTION = 0.9
  attr_reader :x, :y, :angle, :radius     # shortcut for GETters

  def initialize(window)
    @x = 750
    @y = 750
    @angle = 0
    @image = Gosu::Image.new('images/witch.png')
    @velocity_x = 0
    @velocity_y = 0
    @radius = 20
    @window = window
  end

  def draw
    @image.draw_rot(@x, @y, 0, @angle)
  end

  def turn_right
    #@angle += ROTATION_SPEED       # if left not move but change angle
    @velocity_x += Gosu.offset_x(@angle+90, ACCELERATION)
  end

  def turn_left
    #@angle -= ROTATION_SPEED       # if right not move but change angle
    @velocity_x -= Gosu.offset_x(@angle+90, ACCELERATION)
  end

  def accelerate
    #@velocity_x += Gosu.offset_x(@angle, ACCELERATION)     # if left & right not move but change angle
    @velocity_y += Gosu.offset_y(@angle, ACCELERATION)
  end

  def goback
    #@velocity_x -= Gosu.offset_x(@angle, ACCELERATION)     # if left & right not move but change angle
    @velocity_y -= Gosu.offset_y(@angle, ACCELERATION)
  end

  def move
    @x += @velocity_x
    @y += @velocity_y
    @velocity_x *= FRICTION
    @velocity_y *= FRICTION
    if @x > @window.width - @radius then
      @velocity_x = 0
      @x = @window.width - @radius
    end
    if @x < @radius then
      @velocity_x = 0
      @x = @radius
    end
    if @y > @window.height - @radius then
      @velocity_y = 0
      @y = @window.height - @radius
    end
    if @y < @radius then
      @velocity_y = 0
      @y = @radius
    end
  end
end