Exercises

  1. ① How many photons would a 50-W lightbulb that emits light at the single wavelength lamda equals 600 normal n normal m emit in 1 second?
  2. ② Implement a new representation for spectral basis functions in pbrt. Compare both image quality and rendering time to the RGBSpectrum and SampledSpectrum representations implemented in this chapter. Be sure to include tricky situations like fluorescent lighting.
  3. ① Compute the irradiance at a point due to a unit-radius disk h units directly above its normal with constant outgoing radiance of 10 W/ normal m squared normal s normal r . Do the computation twice, once as an integral over solid angle and once as an integral over area. (Hint: If the results don’t match at first, see Section 13.6.2.)
  4. ① Similarly, compute the irradiance at a point due to a square quadrilateral with outgoing radiance of 10 W/ normal m squared normal s normal r that has sides of length 1 and is 1 unit directly above the point in the direction of its surface normal.