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dvwood
01-09-2009, 09:38 AM
The rendering of shadows in OpenGL - true or false?
A is integrated in the library and can be enabled with a single command.
B requires multiple rendering passes and a shadow map.
C uses a depth map created by rendering the scene from the light source position.
D uses ray-tracing and triangle-to-viewing-ray intersection
E is most efficient for static scene parts, if shadows are part of a texture

ok, i havent gotten that far in my SuperBible, so i am not aware of shadows yet, but i would love to be pre-prepared on this one :)
Help is super appreciated!
thanks!

Zengar
01-09-2009, 12:55 PM
Basically, everything except A can be true. But I am not sure what your examiner wants to hear.

k_szczech
01-09-2009, 12:56 PM
Firsst of all do not create separate thread for each set of questions. Keep it all in one thread.

A - False
B - False, but answer True (I assume that person who wrote this test forgot about shadow volumes, which require multiple passes but do not require shadow map)
C - False, but answer true for the same reason as above.
D - False (but of course one could try doing it this way)
E - True, although putting shadows into textures is in conflict with other, even basic techniques (specular lighting for exampe).

dvwood
01-09-2009, 01:09 PM
Thank you for the answers!
As i havent gotten to the pipeline yet, and still trying to caputer every matrix, i have some more questions:

What of these is part of the geometry stage in the Rendering Pipeline ?
A multiplication of the vertex coordinates with the projection matrix
B bilinear texture filtering
C multiplication of the vertex coordinates with the modelview matrix
D cube mapping
E lighting calculation for each pixel

thank you once again for the help!

zeoverlord
01-09-2009, 07:40 PM
A - True
B - False, but could be True if you do it yourself as vertex texture lookup.
C - True
D - False, but again could be True if you do this too as vertex texture lookup, at least if you do it manually.
E - False, however if you had small enough polygons it would technically be true.

But you should answer A and C if this question is anything like the previous one.