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authorTavian Barnes <tavianator@gmail.com>2011-09-12 19:45:37 -0400
committerTavian Barnes <tavianator@gmail.com>2011-09-12 22:09:38 -0400
commiteb5c280be7850872e4f94f1b914d35967d71fbce (patch)
tree8113c8ad21d0ef0a5cdcf1ecf26429aafe51ec92 /libdimension
parent68c7874484767e02366873a32b7420c52476fdb8 (diff)
downloaddimension-eb5c280be7850872e4f94f1b914d35967d71fbce.tar.xz
Implement cone caps as separate objects.
Diffstat (limited to 'libdimension')
-rw-r--r--libdimension/cone.c113
1 files changed, 68 insertions, 45 deletions
diff --git a/libdimension/cone.c b/libdimension/cone.c
index 688b19b..2cd5c8a 100644
--- a/libdimension/cone.c
+++ b/libdimension/cone.c
@@ -29,7 +29,6 @@
/** Cone payload type. */
typedef struct dmnsn_cone_payload {
double r1, r2;
- bool open;
} dmnsn_cone_payload;
/** Intersection callback for a cone. */
@@ -66,47 +65,6 @@ dmnsn_cone_intersection_fn(const dmnsn_object *cone, dmnsn_line l,
p = dmnsn_line_point(l, t);
}
- if (!payload->open && l.n.y) {
- /* Test for cap intersections */
- double tcap1 = (-1.0 - l.x0.y)/l.n.y;
- double tcap2 = (+1.0 - l.x0.y)/l.n.y;
-
- double tcap, r;
- dmnsn_vector norm;
- if (tcap1 < tcap2) {
- tcap = tcap1;
- r = r1;
- norm = dmnsn_new_vector(0.0, -1.0, 0.0);
- } else {
- tcap = tcap2;
- r = r2;
- norm = dmnsn_new_vector(0.0, 1.0, 0.0);
- }
- dmnsn_vector pcap = dmnsn_line_point(l, tcap);
-
- if (tcap < 0.0 || pcap.x*pcap.x + pcap.z*pcap.z >= r*r) {
- if (tcap2 <= tcap1) {
- tcap = tcap1;
- r = r1;
- norm = dmnsn_new_vector(0.0, -1.0, 0.0);
- } else {
- tcap = tcap2;
- r = r2;
- norm = dmnsn_new_vector(0.0, 1.0, 0.0);
- }
- pcap = dmnsn_line_point(l, tcap);
- }
-
- if (tcap >= 0.0
- && (tcap < t || p.y <= -1.0 || p.y >= 1.0)
- && pcap.x*pcap.x + pcap.z*pcap.z < r*r)
- {
- intersection->t = tcap;
- intersection->normal = norm;
- return true;
- }
- }
-
if (t >= 0.0 && p.y > -1.0 && p.y < 1.0) {
dmnsn_vector norm = dmnsn_vector_normalized(
dmnsn_new_vector(p.x, -(r2 - r1)*sqrt(p.x*p.x + p.z*p.z)/2.0, p.z)
@@ -131,6 +89,50 @@ dmnsn_cone_inside_fn(const dmnsn_object *cone, dmnsn_vector point)
&& point.y > -1.0 && point.y < 1.0;
}
+/** Cone cap intersection function. */
+static bool
+dmnsn_cone_cap_intersection_fn(const dmnsn_object *cap, dmnsn_line l,
+ dmnsn_intersection *intersection)
+{
+ if (l.n.y != 0.0) {
+ double *rptr = cap->ptr, r = *rptr;
+ double t = -l.x0.y/l.n.y;
+ dmnsn_vector p = dmnsn_line_point(l, t);
+ if (t >= 0.0 && p.x*p.x + p.z*p.z <= r*r) {
+ intersection->t = t;
+ intersection->normal = dmnsn_new_vector(0.0, -1.0, 0.0);
+ return true;
+ }
+ }
+
+ return false;
+}
+
+/** Inside callback for a cone cap. */
+static bool
+dmnsn_cone_cap_inside_fn(const dmnsn_object *cone, dmnsn_vector point)
+{
+ return false;
+}
+
+/** Allocate a new cone cap. */
+dmnsn_object *
+dmnsn_new_cone_cap(double r)
+{
+ dmnsn_object *cap = dmnsn_new_object();
+ cap->intersection_fn = dmnsn_cone_cap_intersection_fn;
+ cap->inside_fn = dmnsn_cone_cap_inside_fn;
+ cap->bounding_box.min = dmnsn_new_vector(-r, 0.0, -r);
+ cap->bounding_box.max = dmnsn_new_vector(+r, 0.0, +r);
+
+ double *payload = dmnsn_malloc(sizeof(double));
+ *payload = r;
+ cap->ptr = payload;
+ cap->free_fn = dmnsn_free;
+
+ return cap;
+}
+
/* Allocate a new cone object */
dmnsn_object *
dmnsn_new_cone(double r1, double r2, bool open)
@@ -143,10 +145,31 @@ dmnsn_new_cone(double r1, double r2, bool open)
cone->bounding_box.max = dmnsn_new_vector(rmax, 1.0, rmax);
dmnsn_cone_payload *payload = dmnsn_malloc(sizeof(dmnsn_cone_payload));
- payload->r1 = r1;
- payload->r2 = r2;
- payload->open = open;
+ payload->r1 = r1;
+ payload->r2 = r2;
cone->ptr = payload;
cone->free_fn = dmnsn_free;
+
+ /* Implement closed cones as a union with the caps */
+ if (!open) {
+ dmnsn_object *cap1 = dmnsn_new_cone_cap(r1);
+ dmnsn_object *cap2 = dmnsn_new_cone_cap(r2);
+ cap1->intrinsic_trans = dmnsn_translation_matrix(
+ dmnsn_new_vector(0.0, -1.0, 0.0)
+ );
+ cap2->intrinsic_trans = dmnsn_translation_matrix(
+ dmnsn_new_vector(0.0, +1.0, 0.0)
+ );
+ /* Flip the normal around for the top cap */
+ cap2->intrinsic_trans.n[1][1] = -1.0;
+
+ dmnsn_array *withcaps = dmnsn_new_array(sizeof(dmnsn_object *));
+ dmnsn_array_push(withcaps, &cone);
+ dmnsn_array_push(withcaps, &cap1);
+ dmnsn_array_push(withcaps, &cap2);
+ cone = dmnsn_new_csg_union(withcaps);
+ dmnsn_delete_array(withcaps);
+ }
+
return cone;
}