Modify the code obtained in Exercise 3 to perform a simulation of daylighting. This modification is accomplished in a series of steps as follows.
(a) First, photons must be emitted from only one surface (choose a vertical surface - say the left side), a ``solar'' surface which simulates photons coming from the sun. They can be emitted in a constant direction, and should be emitted with a positive and a negative . Photons need not be emitted from any other surfaces. Also, if you implement a non-zero reflectance (see part (c), then all photons which get back to the ``solar'' surface should not be reflected (i.e. should be absorbed).
(b) Second, the photons from the ``solar'' surface must be traced and those which pass through the ``work'' surface (corresponding to a typical height of a desk) must be tallied. It is useful to capture the flux of these photons by partitioning the work surface into a grid (10 grids in the X direction is a good number). This work surface is a non-interacting surface, used only for tallying photons which pass through it. It is convenient to define this surface to be a plane at in the geometry given.
(c) Finally, you may wish to make the surfaces reflecting. Choosing a diffuse reflectance of 0.7 is typical of a surface painted flat white, yielding an absorptance of 0.3.