[cairo] 4x4 matrices in Cairo
spitzak at gmail.com
Thu Nov 14 13:16:02 PST 2013
I did not respond to the mailing list before, but some information got lost.
> Hey guys,
> Is there a way to use 4x4 matrices in cairo?
You only need to support 3x3 matricies (because there is no Z for the
source object, and the output Z is ignored). Cairo currently supports a
2x3 matrix (affine transforms). Adding another column of (0,0,1)
transforms this into the equivalent 3x3 matrix.
> Or alternatively a may to decompose a 4x4 matrix into several 3x3 matrices?
Some early 3D hardware could only do affine transforms. To texture-map a
3D plane the rendering software had to cut it up into many thin
triangles and apply the approximate affine transform to each of them.
This is I guess possible in Cairo now, too.
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