These functions calculate
projective_coordinates
. proj indicates which projection is to be performed. If it isProjections::PERSP
, then f indicates whichFocus
is to be used (in the first version), or the global variabledefault_focus
is used (in the second). IfProjections::PARALLEL_X_Y
,Projections::PARALLEL_X_Z
, orProjections::PARALLEL_Z_Y
is used, f is ignored, since these projections don't use aFocus
. Currently, no other projections are defined. The x and y coordinates inprojective_coordinates
are multiplied by factor with the default being 1.