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TomM
11-27-2004, 02:25 PM
I've been playing with sample code and don't quite understand what unit of measure is used for vertices. If I plot a line with the the vertices (0,0) and (5,0), will that line be 5 pixels long?

dorbie
11-27-2004, 11:43 PM
This is determined by transformation through the model and viewing matrix and the viewport size.

OpenGL transforms all rendering to normalized device coordinates and then to the viewport. Device coords -1 to +1 map to the viewport after projection matrix transformation.

For most stuff you don't need to think in these terms. Just understand how glViewport and glFrustum calls work and you'll be fine.