Debugging

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• Misc
  • Third exam
    • Next Monday (May 4)
    • Comprehensive exam re putting together ray tracing ideas
      • Mainly math, maybe a little re programming
    • Likely to pose some ray tracing scenario common to all questions, then ask 3 - 4 questions about building a ray tracer for it
    • Individual questions similar in style to other exams
    • Rules similar to other exams, e.g., open references
  • Project presentations
    • Wednesday, May 13, noon
    • Plan to talk for 10 - 15 minutes, for an audience who knows ray tracing and general math, but not your specific area
    • Describe problem/question
    • Discuss/show methods/models/research/results, including demos as appropriate
    • Discuss conclusions/further work
    • Donuts and cider (or pizza?)
  • SOFIs
    • Fill them out via http://go.geneseo.edu/sofi_survey
    • Useful to me in improving courses
• Questions?
• Testing and Debugging
  • Small test cases
  • Black box tests
  • White box tests
  • “Assume-it-works” tests
  • Regression test
  • Example: triangles in my ray tracer
    • Suspicious 0s in triangle transformation matrix
    • Turned out to be expected for this triangle
    • Debugging = form and test hypotheses
  • Other debugging tips
    • Conditional breakpoints let you state a condition that must be true in order to trigger a breakpoint
      • Useful if execution reaches the breakpoint many times, but only some are interesting re the bug
    • Ability to execute Matlab statements in command window while stopped at a breakpoint lets you examine program in great detail
• Next
  • Photon mapping
  • Recursion

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