Perspective Projection and 3D world coordinates

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0 comments, last by Bacterius 12 years ago
[color=#333333]How can I define real world coordinates when I am in perspective mode ? I do not understand how the frustum relates the the coordinates in the 3D world. Where is the camera located ? what is the maximum you can go along any axis ? How does this relate to the frustum ?
[color=#333333]I have been stuck on this problem for a good week now, any input would be greatly appreciated.
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World space coordinates are converted to camera space by multiplying them by the view matrix. This has the effect of translating and rotating the world around so that the camera is at the origin and facing along the positive Z axis (by convention). Then you multiply the camera space coordinates by the perspective (projection) matrix which produces a pyramid-shaped space (which means objects further from the camera will be closer to the screen's center when mapped to a 2D screen), and you finally clip off the near and far planes to obtain a frustum.

“If I understand the standard right it is legal and safe to do this but the resulting value could be anything.”

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