Transform normals as pseudovectors, not vectors.

Also clarify the vector transformation API.  Instead of
dmnsn_transform_vector(), we have:
  - dmnsn_transform_point()
  - dmnsn_transform_direction()
  - dmnsn_transform_normal()

2 files changed, 4 insertions, 2 deletions

diff --git a/libdimension-python/dimension.pxd b/libdimension-python/dimension.pxd
index 42fda7e..1164be5 100644
--- a/libdimension-python/dimension.pxd
+++ b/libdimension-python/dimension.pxd
@@ -130,7 +130,9 @@ cdef extern from "../libdimension/dimension.h":
   dmnsn_matrix dmnsn_matrix_inverse(dmnsn_matrix m)
 
   dmnsn_matrix dmnsn_matrix_mul(dmnsn_matrix lhs, dmnsn_matrix rhs)
-  dmnsn_vector dmnsn_transform_vector(dmnsn_matrix lhs, dmnsn_vector rhs)
+  dmnsn_vector dmnsn_transform_point(dmnsn_matrix lhs, dmnsn_vector rhs)
+  dmnsn_vector dmnsn_transform_direction(dmnsn_matrix lhs, dmnsn_vector rhs)
+  dmnsn_vector dmnsn_transform_normal(dmnsn_matrix lhs, dmnsn_vector rhs)
 
   dmnsn_matrix dmnsn_scale_matrix(dmnsn_vector s)
   dmnsn_matrix dmnsn_translation_matrix(dmnsn_vector d)
diff --git a/libdimension-python/dimension.pyx b/libdimension-python/dimension.pyx
index a1c8710..48e8de1 100644
--- a/libdimension-python/dimension.pyx
+++ b/libdimension-python/dimension.pyx
@@ -263,7 +263,7 @@ cdef class Matrix:
     if isinstance(rhs, Matrix):
       return _Matrix(dmnsn_matrix_mul(lhs._m, (<Matrix>rhs)._m))
     else:
-      return _Vector(dmnsn_transform_vector(lhs._m, (<Vector>rhs)._v))
+      return _Vector(dmnsn_transform_point(lhs._m, (<Vector>rhs)._v))
 
   def __richcmp__(Matrix lhs not None, Matrix rhs not None, int op):
     cdef double sum = 0.0