stoplight.rb

SMC takes a state machine stored in a .sm file and generates a State pattern in twelve programming l

				@_canvas.itemconfigure(@_south_light['GREEN'], 'fill' => 'green')
			elsif color == 'yellow' then
				@_canvas.itemconfigure(@_north_light['GREEN'], 'fill' => 'white')
				@_canvas.itemconfigure(@_south_light['GREEN'], 'fill' => 'white')
				@_canvas.itemconfigure(@_north_light['YELLOW'], 'fill' => 'yellow')
				@_canvas.itemconfigure(@_south_light['YELLOW'], 'fill' => 'yellow')
			end
		end
	end

	def SetTimer(timer)
		@_timerID = TkAfter.new(@_timeouts[timer], 1, proc { timeout } )
		@_timerID.start
	end

	def StopTimer()
		unless @_timerID.nil? then
			@_timerID.cancel
			@_timerID = nil
		end
	end

	def timeout()
		@_timerID = nil
		@_fsm.Timeout
	end

	def ResetLights()
		@_canvas.itemconfigure(@_east_light['YELLOW'], 'fill' => 'white')
		@_canvas.itemconfigure(@_west_light['YELLOW'], 'fill' => 'white')
		@_canvas.itemconfigure(@_east_light['RED'], 'fill' => 'white')
		@_canvas.itemconfigure(@_west_light['RED'], 'fill' => 'white')
		@_canvas.itemconfigure(@_east_light['GREEN'], 'fill' => 'white')
		@_canvas.itemconfigure(@_west_light['GREEN'], 'fill' => 'white')

		@_canvas.itemconfigure(@_north_light['YELLOW'], 'fill' => 'white')
		@_canvas.itemconfigure(@_south_light['YELLOW'], 'fill' => 'white')
		@_canvas.itemconfigure(@_north_light['RED'], 'fill' => 'white')
		@_canvas.itemconfigure(@_south_light['RED'], 'fill' => 'white')
		@_canvas.itemconfigure(@_north_light['GREEN'], 'fill' => 'white')
		@_canvas.itemconfigure(@_south_light['GREEN'], 'fill' => 'white')
	end

	# InformVehicles --
	#
	#   Tell the vehicles that were waiting on the green light
	#   that they can go now.
	#
	# Arguments:
	#   direction   Which light turned green.

	def InformVehicles(direction)
		if      direction == 'north' then
			for vehicle in @_northVehicleList do
				vehicle.lightGreen
			end
			@_northVehicleList = []
		elsif direction == 'south' then
			for vehicle in @_southVehicleList do
				vehicle.lightGreen
			end
			@_southVehicleList = []
		elsif direction == 'east' then
			for vehicle in @_eastVehicleList do
				vehicle.lightGreen
			end
			@_eastVehicleList = []
		elsif direction == 'west' then
			for vehicle in @_westVehicleList do
				vehicle.lightGreen
			end
			@_westVehicleList = []
		end
	end

	def drawRoads()
		# The roads are drawn as follows:
		#
		#        (x2,y1)   (x4,y1)
		#             |  |  |
		#             |     |
		#             |  |  |
		# (x1,y2)     |     |       (x5,y2)
		# ------------+  |  +------------
		#         (x2,y2) (x4,y2)
		# - - - - - -        - - - - - -
		#         (x2,y4) (x4,y4)   (x5,y4)
		# ------------+     +------------
		# (x1,y4)     |  |  |
		#             |     |
		#             |  |  |
		#             |     |
		#        (x2,y5) |(x4,y5)

		# Calculate the line segment's length.
		xLength = getRoadLengthX / 2 - @_roadWidth / 2
		yLength = getRoadLengthY / 2 - @_roadWidth / 2

		# Calculate the major coordinates.
		x1 = 0
		y1 = 0
		x2 = xLength
		y2 = yLength
		x3 = @_canvas.cget('width').to_i / 2
		y3 = @_canvas.cget('height').to_i / 2
		x4 = @_canvas.cget('width').to_i - xLength
		y4 = @_canvas.cget('height').to_i - yLength
		x5 = @_canvas.cget('width').to_i
		y5 = @_canvas.cget('height').to_i

		# Put green lawns around the road.
		TkcRectangle.new(@_canvas, x1, y1, x2, y2,
			'outline' => "",
			'fill' => 'green'
		)
		TkcRectangle.new(@_canvas, x1, y4, x2, y5,
			'outline' => "",
			'fill' => 'green'
		)
		TkcRectangle.new(@_canvas, x4, y4, x5, y5,
			'outline' => "",
			'fill' => 'green'
		)
		TkcRectangle.new(@_canvas, x4, y1, x5, y2,
			'outline' => "",
			'fill' => 'green'
		)

		# Draw four connected lines where each drawing uses three
		# coordinates.
		TkcLine.new(@_canvas, x1, y2, x2, y2, x2, y1)
		TkcLine.new(@_canvas, x4, y1, x4, y2, x5, y2)
		TkcLine.new(@_canvas, x1, y4, x2, y4, x2, y5)
		TkcLine.new(@_canvas, x4, y5, x4, y4, x5, y4)

		# Now draw the lane markings.
		TkcLine.new(@_canvas, x1, y3, x2, y3)
		TkcLine.new(@_canvas, x3, y1, x3, y2)
		TkcLine.new(@_canvas, x4, y3, x5, y3)
		TkcLine.new(@_canvas, x3, y4, x3, y5)
	end

	def drawLights()
		# The lights are drawns as follows:
		#
		#  y1          +---+
		#              | o |green
		#              | o |yellow
		#              | o |red
		#  y2  +-------+---+-------+
		#      | o o o |   | o o o |
		#  y3  +-------+---+-------+
		#              | o |red
		#              | o |yellow
		#              | o |green
		#  y4          +---+
		#
		#    x1       x2   x3     x4
		# Store each light as a separate element in a table.

		# Figure out the coordinates for the stoplights.
		x1 = @_canvas.cget('width').to_i / 2 - @_lightWidth / 2 - @_lightHeight
		y1 = @_canvas.cget('height').to_i / 2 - @_lightWidth / 2 - @_lightHeight
		x2 = x1 + @_lightHeight
		y2 = y1 + @_lightHeight
		x3 = x2 + @_lightWidth
		y3 = y2 + @_lightWidth
		x4 = x3 + @_lightHeight
		y4 = y3 + @_lightHeight

		# Draw the four stop lights boxes.
		TkcRectangle.new(@_canvas, x2, y1, x3, y2,
				'outline' => 'black',
				'fill' => 'black',
				'width' => 1
		)
		TkcRectangle.new(@_canvas, x1, y2, x2, y3,
				'outline' => 'black',
				'fill' => 'black',
				'width' => 1
		)
		TkcRectangle.new(@_canvas, x2, y3, x3, y4,
				'outline' => 'black',
				'fill' => 'black',
				'width' => 1
		)
		TkcRectangle.new(@_canvas, x3, y2, x4, y3,
				'outline' => 'black',
				'fill' => 'black',
				'width' => 1
		)

		# Draw the lights within the stoplights. Save the
		# canvas items into an array because they will be
		# referenced later. Because there are two lights
		@_north_light['RED'] = TkcOval.new(@_canvas,
				x2 + @_lightSpace,
				y1 + @_lightSpace,
				x3 - @_lightSpace,
				y1 + @_lightSpace + @_lightDiameter,
				'outline' => 'black',
				'fill' => 'white'
		)
		@_north_light['YELLOW'] = TkcOval.new(@_canvas,
				x2 + @_lightSpace,
				y1 + @_lightSpace * 2 + @_lightDiameter,
				x3 - @_lightSpace,
				y1 + @_lightSpace * 2 + @_lightDiameter * 2,
				'outline' => 'black',
				'fill' => 'white'
		)
		@_north_light['GREEN'] = TkcOval.new(@_canvas,
				x2 + @_lightSpace,
				y1 + @_lightSpace * 3 + @_lightDiameter * 2,
				x3 - @_lightSpace,
				y1 + @_lightSpace * 3 + @_lightDiameter * 3,
				'outline' => 'black',
				'fill' => 'white'
		)

		@_west_light['RED'] = TkcOval.new(@_canvas,
				x1 + @_lightSpace,
				y2 + @_lightSpace,
				x1 + @_lightSpace + @_lightDiameter,
				y3 - @_lightSpace,
				'outline' => 'black',
				'fill' => 'white'
		)
		@_west_light['YELLOW'] = TkcOval.new(@_canvas,
				x1 + @_lightSpace * 2 + @_lightDiameter,
				y2 + @_lightSpace,
				x1 + @_lightSpace * 2 + @_lightDiameter * 2,
				y3 - @_lightSpace,
				'outline' => 'black',
				'fill' => 'white'
		)
		@_west_light['GREEN'] = TkcOval.new(@_canvas,
				x1 + @_lightSpace * 3 + @_lightDiameter * 2,
				y2 + @_lightSpace,
				x1 + @_lightSpace * 3 + @_lightDiameter * 3,
				y3 - @_lightSpace,
				'outline' => 'black',
				'fill' => 'white'
		)

		@_south_light['GREEN'] = TkcOval.new(@_canvas,
				x2 + @_lightSpace,
				y3 + @_lightSpace,
				x3 - @_lightSpace,
				y3 + @_lightSpace + @_lightDiameter,
				'outline' => 'black',
				'fill' => 'white'
		)
		@_south_light['YELLOW'] = TkcOval.new(@_canvas,
				x2 + @_lightSpace,
				y3 + @_lightSpace * 2 + @_lightDiameter,
				x3 - @_lightSpace,
				y3 + @_lightSpace * 2 + @_lightDiameter * 2,
				'outline' => 'black',
				'fill' => 'white'
		)
		@_south_light['RED'] = TkcOval.new(@_canvas,
				x2 + @_lightSpace,
				y3 + @_lightSpace * 3 + @_lightDiameter * 2,
				x3 - @_lightSpace,
				y3 + @_lightSpace * 3 + @_lightDiameter * 3,
				'outline' => 'black',
				'fill' => 'white'
		)

		@_east_light['GREEN'] = TkcOval.new(@_canvas,
				x3 + @_lightSpace,
				y2 + @_lightSpace,
				x3 + @_lightSpace + @_lightDiameter,
				y3 - @_lightSpace,
				'outline' => 'black',
				'fill' => 'white'
		)
		@_east_light['YELLOW'] = TkcOval.new(@_canvas,
				x3 + @_lightSpace * 2 + @_lightDiameter,
				y2 + @_lightSpace,
				x3 + @_lightSpace * 2 + @_lightDiameter * 2,
				y3 - @_lightSpace,
				'outline' => 'black',
				'fill' => 'white'
		)
		@_east_light['RED'] = TkcOval.new(@_canvas,
				x3 + @_lightSpace * 3 + @_lightDiameter * 2,
				y2 + @_lightSpace,
				x3 + @_lightSpace * 3 + @_lightDiameter * 3,
				y3 - @_lightSpace,
				'outline' => 'black',
				'fill' => 'white'
		)
	end

end