# geometry primitives
load-matrix
# 3x3 exact rotation matrices, 90 degrees around axis
# IMPORTANT NOTE: the convention in pf is to represent a linear
# transform by RIGHT multiplication:
# V M *
# where V is a matrix containing rows as vectors to be transformed
# and M is the transformation matrix. the biggest reason for this
# is of course that PF is postfix. but it also interfaces better
# with opengl and gsl
# the result of this is that M will be transposed wrt. the normal
# representation..
# NOTE: pf uses:
# vector matrix *
# so vectors are post-multiplied,
(( 1 0 0 )
( 0 0 1 )
( 0 -1 0 )) >matrix constant Rx
(( 0 0 -1 )
( 0 1 0 )
( 1 0 0 )) >matrix constant Ry
(( 0 1 0 )
(-1 0 0 )
( 0 0 1 )) >matrix constant Rz