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-rw-r--r--libdimension/dimension/geometry.h41
-rw-r--r--libdimension/dimension/object.h27
2 files changed, 39 insertions, 29 deletions
diff --git a/libdimension/dimension/geometry.h b/libdimension/dimension/geometry.h
index 45aa6c6..d2ad362 100644
--- a/libdimension/dimension/geometry.h
+++ b/libdimension/dimension/geometry.h
@@ -375,9 +375,9 @@ dmnsn_matrix dmnsn_matrix_inverse(dmnsn_matrix A);
/** Multiply two matricies. */
dmnsn_matrix dmnsn_matrix_mul(dmnsn_matrix lhs, dmnsn_matrix rhs);
-/** Transform a vector by a matrix. */
+/** Transform a point by a matrix. */
DMNSN_INLINE dmnsn_vector
-dmnsn_transform_vector(dmnsn_matrix T, dmnsn_vector v)
+dmnsn_transform_point(dmnsn_matrix T, dmnsn_vector v)
{
/* 9 multiplications, 9 additions */
dmnsn_vector r;
@@ -387,6 +387,36 @@ dmnsn_transform_vector(dmnsn_matrix T, dmnsn_vector v)
return r;
}
+/** Transform a direction by a matrix. */
+DMNSN_INLINE dmnsn_vector
+dmnsn_transform_direction(dmnsn_matrix T, dmnsn_vector v)
+{
+ /* 9 multiplications, 9 additions */
+ dmnsn_vector r;
+ r.x = T.n[0][0]*v.x + T.n[0][1]*v.y + T.n[0][2]*v.z;
+ r.y = T.n[1][0]*v.x + T.n[1][1]*v.y + T.n[1][2]*v.z;
+ r.z = T.n[2][0]*v.x + T.n[2][1]*v.y + T.n[2][2]*v.z;
+ return r;
+}
+
+/**
+ * Transform a pseudovector by a matrix.
+ * @param[in] Tinv The inverse of the transformation matrix.
+ * @param[in] v The pseudovector to transform
+ * @return The transformed pseudovector.
+ */
+DMNSN_INLINE dmnsn_vector
+dmnsn_transform_normal(dmnsn_matrix Tinv, dmnsn_vector v)
+{
+ /* Multiply by the transpose of the inverse
+ (9 multiplications, 6 additions) */
+ dmnsn_vector r;
+ r.x = Tinv.n[0][0]*v.x + Tinv.n[1][0]*v.y + Tinv.n[2][0]*v.z;
+ r.y = Tinv.n[0][1]*v.x + Tinv.n[1][1]*v.y + Tinv.n[2][1]*v.z;
+ r.z = Tinv.n[0][2]*v.x + Tinv.n[1][2]*v.y + Tinv.n[2][2]*v.z;
+ return r;
+}
+
/** Transform a bounding box by a matrix. */
dmnsn_bounding_box dmnsn_transform_bounding_box(dmnsn_matrix T,
dmnsn_bounding_box box);
@@ -401,11 +431,8 @@ dmnsn_transform_line(dmnsn_matrix T, dmnsn_line l)
{
/* 18 multiplications, 24 additions */
dmnsn_line ret;
- ret.x0 = dmnsn_transform_vector(T, l.x0);
- ret.n = dmnsn_vector_sub(
- dmnsn_transform_vector(T, dmnsn_vector_add(l.x0, l.n)),
- ret.x0
- );
+ ret.x0 = dmnsn_transform_point(T, l.x0);
+ ret.n = dmnsn_transform_direction(T, l.n);
return ret;
}
diff --git a/libdimension/dimension/object.h b/libdimension/dimension/object.h
index 8254782..8b497ce 100644
--- a/libdimension/dimension/object.h
+++ b/libdimension/dimension/object.h
@@ -112,24 +112,6 @@ void dmnsn_delete_object(dmnsn_object *object);
void dmnsn_initialize_object(dmnsn_object *object);
/**
- * Transform a surface normal vector.
- * @param[in] trans The transformation matrix.
- * @param[in] normal The normal vector to transform
- * @return The transformed normal vector.
- */
-DMNSN_INLINE dmnsn_vector
-dmnsn_transform_normal(dmnsn_matrix trans, dmnsn_vector normal)
-{
- return dmnsn_vector_normalized(
- dmnsn_vector_sub(
- dmnsn_transform_vector(trans, normal),
- /* Optimized form of dmnsn_transform_vector(trans, dmnsn_zero) */
- dmnsn_new_vector(trans.n[0][3], trans.n[1][3], trans.n[2][3])
- )
- );
-}
-
-/**
* Appropriately transform a ray, then test for an intersection.
* @param[in] object The object to test.
* @param[in] line The ray to test.
@@ -144,9 +126,10 @@ dmnsn_object_intersection(const dmnsn_object *object, dmnsn_line line,
intersection->object = NULL;
if (object->intersection_fn(object, line_trans, intersection)) {
/* Get us back into world coordinates */
- intersection->ray = line;
- intersection->normal = dmnsn_transform_normal(object->trans,
- intersection->normal);
+ intersection->ray = line;
+ intersection->normal = dmnsn_vector_normalized(
+ dmnsn_transform_normal(object->trans_inv, intersection->normal)
+ );
if (!intersection->object) {
intersection->object = object;
}
@@ -166,6 +149,6 @@ dmnsn_object_intersection(const dmnsn_object *object, dmnsn_line line,
DMNSN_INLINE bool
dmnsn_object_inside(const dmnsn_object *object, dmnsn_vector point)
{
- point = dmnsn_transform_vector(object->trans_inv, point);
+ point = dmnsn_transform_point(object->trans_inv, point);
return object->inside_fn(object, point);
}