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authorTavian Barnes <tavianator@gmail.com>2011-09-14 18:56:08 -0400
committerTavian Barnes <tavianator@gmail.com>2011-09-14 19:03:07 -0400
commit1374b946398544a28ac989c75570d4b7c6937873 (patch)
treed3f05e23b5c39201292bfaddaca23220de6652f7 /libdimension
parent4bfa19e5a0b426ea6ec99dfebaeb35e507136b74 (diff)
downloaddimension-1374b946398544a28ac989c75570d4b7c6937873.tar.xz
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()
Diffstat (limited to 'libdimension')
-rw-r--r--libdimension/bench/geometry.c20
-rw-r--r--libdimension/dimension/geometry.h41
-rw-r--r--libdimension/dimension/object.h27
-rw-r--r--libdimension/geometry.c20
-rw-r--r--libdimension/pigment.c2
-rw-r--r--libdimension/raytrace.c2
6 files changed, 67 insertions, 45 deletions
diff --git a/libdimension/bench/geometry.c b/libdimension/bench/geometry.c
index a952631..4b8c12a 100644
--- a/libdimension/bench/geometry.c
+++ b/libdimension/bench/geometry.c
@@ -1,5 +1,5 @@
/*************************************************************************
- * Copyright (C) 2009-2010 Tavian Barnes <tavianator@tavianator.com> *
+ * Copyright (C) 2009-2011 Tavian Barnes <tavianator@tavianator.com> *
* *
* This file is part of The Dimension Benchmark Suite. *
* *
@@ -149,11 +149,23 @@ main(void)
});
printf("dmnsn_matrix_mul(): %ld\n", sandglass.grains);
- /* dmnsn_transform_vector() */
+ /* dmnsn_transform_point() */
sandglass_bench_fine(&sandglass, {
- vector = dmnsn_transform_vector(matrix, vector);
+ vector = dmnsn_transform_point(matrix, vector);
});
- printf("dmnsn_transform_vector(): %ld\n", sandglass.grains);
+ printf("dmnsn_transform_point(): %ld\n", sandglass.grains);
+
+ /* dmnsn_transform_direction() */
+ sandglass_bench_fine(&sandglass, {
+ vector = dmnsn_transform_direction(matrix, vector);
+ });
+ printf("dmnsn_transform_direction(): %ld\n", sandglass.grains);
+
+ /* dmnsn_transform_normal() */
+ sandglass_bench_fine(&sandglass, {
+ vector = dmnsn_transform_normal(matrix, vector);
+ });
+ printf("dmnsn_transform_normal(): %ld\n", sandglass.grains);
/* dmnsn_transform_line() */
sandglass_bench_fine(&sandglass, {
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);
}
diff --git a/libdimension/geometry.c b/libdimension/geometry.c
index 83be0f9..c6a4da2 100644
--- a/libdimension/geometry.c
+++ b/libdimension/geometry.c
@@ -113,8 +113,8 @@ dmnsn_alignment_matrix(dmnsn_vector from, dmnsn_vector to,
{
double theta1 = dmnsn_axis_angle(from, to, axis1);
dmnsn_matrix align1 = dmnsn_rotation_matrix(dmnsn_vector_mul(theta1, axis1));
- from = dmnsn_transform_vector(align1, from);
- axis2 = dmnsn_transform_vector(align1, axis2);
+ from = dmnsn_transform_direction(align1, from);
+ axis2 = dmnsn_transform_direction(align1, axis2);
double theta2 = dmnsn_axis_angle(from, to, axis2);
dmnsn_matrix align2 = dmnsn_rotation_matrix(dmnsn_vector_mul(theta2, axis2));
@@ -381,41 +381,41 @@ dmnsn_transform_bounding_box(dmnsn_matrix trans, dmnsn_bounding_box box)
dmnsn_vector corner;
dmnsn_bounding_box ret;
- ret.min = dmnsn_transform_vector(trans, box.min);
+ ret.min = dmnsn_transform_point(trans, box.min);
ret.max = ret.min;
corner = dmnsn_new_vector(box.min.x, box.min.y, box.max.z);
- corner = dmnsn_transform_vector(trans, corner);
+ corner = dmnsn_transform_point(trans, corner);
ret.min = dmnsn_vector_min(ret.min, corner);
ret.max = dmnsn_vector_max(ret.max, corner);
corner = dmnsn_new_vector(box.min.x, box.max.y, box.min.z);
- corner = dmnsn_transform_vector(trans, corner);
+ corner = dmnsn_transform_point(trans, corner);
ret.min = dmnsn_vector_min(ret.min, corner);
ret.max = dmnsn_vector_max(ret.max, corner);
corner = dmnsn_new_vector(box.min.x, box.max.y, box.max.z);
- corner = dmnsn_transform_vector(trans, corner);
+ corner = dmnsn_transform_point(trans, corner);
ret.min = dmnsn_vector_min(ret.min, corner);
ret.max = dmnsn_vector_max(ret.max, corner);
corner = dmnsn_new_vector(box.max.x, box.min.y, box.min.z);
- corner = dmnsn_transform_vector(trans, corner);
+ corner = dmnsn_transform_point(trans, corner);
ret.min = dmnsn_vector_min(ret.min, corner);
ret.max = dmnsn_vector_max(ret.max, corner);
corner = dmnsn_new_vector(box.max.x, box.min.y, box.max.z);
- corner = dmnsn_transform_vector(trans, corner);
+ corner = dmnsn_transform_point(trans, corner);
ret.min = dmnsn_vector_min(ret.min, corner);
ret.max = dmnsn_vector_max(ret.max, corner);
corner = dmnsn_new_vector(box.max.x, box.max.y, box.min.z);
- corner = dmnsn_transform_vector(trans, corner);
+ corner = dmnsn_transform_point(trans, corner);
ret.min = dmnsn_vector_min(ret.min, corner);
ret.max = dmnsn_vector_max(ret.max, corner);
corner = dmnsn_new_vector(box.max.x, box.max.y, box.max.z);
- corner = dmnsn_transform_vector(trans, corner);
+ corner = dmnsn_transform_point(trans, corner);
ret.min = dmnsn_vector_min(ret.min, corner);
ret.max = dmnsn_vector_max(ret.max, corner);
diff --git a/libdimension/pigment.c b/libdimension/pigment.c
index 8c1cc9a..3650ba3 100644
--- a/libdimension/pigment.c
+++ b/libdimension/pigment.c
@@ -71,7 +71,7 @@ dmnsn_color
dmnsn_evaluate_pigment(const dmnsn_pigment *pigment, dmnsn_vector v)
{
if (pigment->pigment_fn) {
- dmnsn_vector v_trans = dmnsn_transform_vector(pigment->trans_inv, v);
+ dmnsn_vector v_trans = dmnsn_transform_point(pigment->trans_inv, v);
return pigment->pigment_fn(pigment, v_trans);
} else {
return pigment->quick_color;
diff --git a/libdimension/raytrace.c b/libdimension/raytrace.c
index fdfa3cb..4ee451a 100644
--- a/libdimension/raytrace.c
+++ b/libdimension/raytrace.c
@@ -139,7 +139,7 @@ dmnsn_initialize_raytrace_state(dmnsn_raytrace_state *state,
state->interior = intersection->object->interior;
state->r = dmnsn_line_point(intersection->ray, intersection->t);
- state->pigment_r = dmnsn_transform_vector(
+ state->pigment_r = dmnsn_transform_point(
intersection->object->pigment_trans,
state->r
);