- Third exam
- Monday (May 4)
- Comprehensive exam re putting together ray tracing ideas
- Scenario: 4-dimensional (length, width, depth, time) ray tracing
- Mainly math, maybe a little re programming
- Be ready for open-ended but not terribly advanced math
- 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, including questions
- Pizza and soda
- SOFIs
- Fill them out via http://go.geneseo.edu/sofi_survey
- Useful to me in improving courses
- Found and fixed triangle bug
- Finding it was combination of clues from debugger and reasoning about where bug must be
- Testing the fix
- Run test script we made for this bug
- Run reflected-ball script (“assume-it-works” and regression test)
- Ray tracing involves lots of computations based on lighting information
- Photon mapping caches information about light intensity, direction, etc. to avoid computing it over and over again
- To do this, you need some way to store information associated with points in space
- “kd-tree” is one popular way to do this
- “kd-tree” is one popular way to do this
- Recursive definitions are common
- F0 = 0; F1 = 1; Fn = Fn-1 + Fn-2
- kd-Tree = struct if # points = 1 or 0
- = x,y,z boundary with 2 other kd-Trees if # points > 1
- These definitions define an idea in terms of itself, but are sound because the self-reference is always to smaller instances
- Such definitions translate naturallly into algorithms that call themselves
- The algorithms work for the same reason the definitions do: recursive calls always solve smaller problems
fib( n ) if n == 0 return 0 else if n == 1 return 1 else return fib(n-1) + fib(n-2)search( T, (x,y,z) ) if T has 0 points return “failure” else if T has 1 point equal to (x,y,z) return info about point else if T has 1 point not equal to (x,y,z) return “failure” else if x <= boundary search( left, (x,y,z) ) else search( right, (x,y,z) ) ... similar code for searching based on y and z, depending on how tree is split ...
- Test Monday
- Presentations at noon, May 13
- Project paper due then