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Jasonb
04-07-2000, 09:20 PM
How exactly does hardware tranformation and lighting work. (im mainly interested in the transformation)

I try using this

1) Set the translation
2) Rotate the object
3) use glGetFloatV(GL_MODELVIEW_MATRIX,mat) to get the transformed matrix.

is this method classed as using hardware transformation? or is it some other way?

Humus
04-08-2000, 04:58 AM
All OpenGL programs that doesn't try to calculate everything on it's own will use the any T&L capabilities of the graphic adapter. However, i'm am not sure if the actual calculation of the matrixes are done in hardware of these accelerators.

MikeC
04-09-2000, 03:57 AM
Whether or not a given OpenGL transform call uses hardware T&L is up to the driver and the hardware. It's transparent to the programmer.

AFAIK hardware T&L isn't so much about calculating the transforms (e.g. glRotate, glMultMatrix) as about transforming the vertices you issue by the current modelview matrix. Which isn't something you do explicitly anyway - it happens whenever you call glVertex etc.