# 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