# SimeonReilly

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1. ## Calculating vertex normals

Thanks for your help, gentlemen. It really makes a difference. Unfortunately I am not done yet! Me and my fellow students seek your patience for one more question. (Hope it doesn't look like I am pushing my luck here - just some of this stuff really wasn't explained very well at all to us, our notes are rubbish) http://www.gamedev.net/topic/602133-ray-tracing-construction-and-finding-a-pixel/
2. ## OpenGL Ray-tracing construction, and finding a pixel

So I have an exam question I'm having trouble with. As far as I can tell we're meant to set this up with OpenGL (in C/C++) (with GLUT) When it comes to answers - The more verbose and from the ground up the better. Any help is greatly appreciated.
3. ## Calculating vertex normals

okay so the equation I have for finding the triangle normals is (we have three vertices v1, v2, v3) u1 = (v2 - v1) / || (v2 -v1) || - where || A || is the magnitude of A u2 = (v3 - v1) / || (v3 - v1) || normal = u2 x u1 / || u2 x u1|| - where x denotes cross product so we get 4 triangle normals n1, n2, n3, n4 Our vertex normal vn is: vn = ( 1/4 * (n1 + n2 + n3 + n4) ) / || ( 1/4 * (n1 + n2 + n3 + n4) ) || Is this correct? Seems like something of a pain in the ass. [/quote] Can anyone verify the correctness of this?
4. ## Calculating vertex normals

okay so the equation I have for finding the triangle normals is (we have three vertices v1, v2, v3) u1 = (v2 - v1) / || (v2 -v1) || - where || A || is the magnitude of A u2 = (v3 - v1) / || (v3 - v1) || normal = u2 x u1 / || u2 x u1|| - where x denotes cross product so we get 4 triangle normals n1, n2, n3, n4 Our vertex normal vn is: vn = ( 1/4 * (n1 + n2 + n3 + n4) ) / || ( 1/4 * (n1 + n2 + n3 + n4) ) || Is this correct? Seems like something of a pain in the ass.
5. ## Calculating vertex normals

Hiyas, slightly off-center question here, no code involved! I have an exam coming up for which I am woefully unprepared. And I just can't figure out how to get this done. Could anyone fill me in? As concisely as possible? Many thanks for any help