{
	Calculate coordinates for a 180 degree fisheye lens onto local geom.
	Assume view direction is (0,1,0), view up (0,0,1), (1,0,0) right.
	View origin is (0,0,0).

	11/21/2006	G. Ward
}

Fnorm = 1/sqrt(Px*Px + Py*Py + Pz*Pz);
FDx = Px*Fnorm;
FDy = Py*Fnorm;
FDz = Pz*Fnorm;

fish_Rxz = sqrt(FDx*FDx + FDz*FDz);
fish_Ry = acos(FDy) / PI;

fish_u = .5 + FDx/fish_Rxz * fish_Ry;
fish_v = .5 + FDz/fish_Rxz * fish_Ry;
