Transforming between
World coordinates
and Pixels
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gglMatrix

gglMatrix provides translation from Pixels to OpenGL world coordinates. It links the ModelView and Projection matrices and the ViewPort so you don't have to.

This is a replacement for gluProject and gluUnProject if you don't want to have to distribute glu.

Once you've set the ViewPort,Projection and ModelView, you can do things like this:

  GLdouble x,y,z;
  gglMatrix Tx;
  CPoint Pixel(2,3);
  Tx.Pixel2World(Pixel, x,y,z);
  ...
  Tx.World2Pixel(x,y,z, Pixel);

It should be fairly quick to do many translations because the time-consuming bit is in the constructor which calls SetFromGL(). Optimising compilers can potentially run this sort of matrix code in parallel.


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