Warp schrieb:

>   I don't remember now how the trick was applied, exactly. The idea was,
> I think, to transform the scene so that the view frustum (which in the
> original untransformed scene is a truncated square pyramid) becomes a
> unit cube. Then all the polygons are clipped against this unit cube (which,
> as you can guess, is a lot simpler than doing it against a free truncated
> pyramid). Then a simple orthogonal projection onto the near-plane (basically
> dropping the z coordinate) is enough to get the final perspective projection.
> Hence the near and far clipping planes could indeed be "encoded" into the
> transformation matrix by specifying the depth scaling (which, I suppose,
> would prove my original assertion in this thread wrong).

Isn't such a transformation non-affine? So it wouldn't be possible to do 
it with a simple 4x4 matrix multiplication.

=> more data than just the 4x4 matrix would be needed.

(Though of course part of the 4x4 matrix might be misused to store that 
data, as the 4th row of an affine transformation matrix is 0;0;0;1 
anyway, so that data can easily be reconstructed.)

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