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-rw-r--r--dimension/realize.c5
-rw-r--r--libdimension/cylinder.c58
-rw-r--r--libdimension/dimension/objects.h4
-rw-r--r--tests/libdimension/render.c17
4 files changed, 63 insertions, 21 deletions
diff --git a/dimension/realize.c b/dimension/realize.c
index 15eb334..dc315d8 100644
--- a/dimension/realize.c
+++ b/dimension/realize.c
@@ -863,12 +863,13 @@ dmnsn_realize_cylinder(dmnsn_astnode astnode)
double theta1 = dmnsn_vector_axis_angle(dmnsn_y, dir, dmnsn_x);
double theta2 = dmnsn_vector_axis_angle(dmnsn_y, dir, dmnsn_z);
- dmnsn_object *cylinder = dmnsn_new_cylinder(dmnsn_realize_integer(open));
+ dmnsn_object *cylinder
+ = dmnsn_new_cylinder(r, r, dmnsn_realize_integer(open));
/* Transformations: lift the cylinder to start at the origin, scale, rotate,
and translate properly */
cylinder->trans = dmnsn_translation_matrix(dmnsn_new_vector(0.0, 1.0, 0.0));
cylinder->trans = dmnsn_matrix_mul(
- dmnsn_scale_matrix(dmnsn_new_vector(r, l/2.0, r)),
+ dmnsn_scale_matrix(dmnsn_new_vector(1.0, l/2.0, 1.0)),
cylinder->trans
);
cylinder->trans = dmnsn_matrix_mul(
diff --git a/libdimension/cylinder.c b/libdimension/cylinder.c
index 159d520..62c1476 100644
--- a/libdimension/cylinder.c
+++ b/libdimension/cylinder.c
@@ -32,17 +32,29 @@ static bool dmnsn_cylinder_intersection_fn(const dmnsn_object *cylinder,
static bool dmnsn_cylinder_inside_fn(const dmnsn_object *cylinder,
dmnsn_vector point);
+/* Payload type */
+typedef struct dmnsn_cylinder_payload {
+ double r1, r2;
+ bool open;
+} dmnsn_cylinder_payload;
+
/* Allocate a new cylinder object */
dmnsn_object *
-dmnsn_new_cylinder(bool open)
+dmnsn_new_cylinder(double r1, double r2, bool open)
{
dmnsn_object *cylinder = dmnsn_new_object();
cylinder->intersection_fn = &dmnsn_cylinder_intersection_fn;
cylinder->inside_fn = &dmnsn_cylinder_inside_fn;
cylinder->bounding_box.min = dmnsn_new_vector(-1.0, -1.0, -1.0);
cylinder->bounding_box.max = dmnsn_new_vector(1.0, 1.0, 1.0);
- /* (bool)cyliner->ptr == open */
- cylinder->ptr = open ? cylinder : NULL;
+
+ dmnsn_cylinder_payload *payload
+ = dmnsn_malloc(sizeof(dmnsn_cylinder_payload));
+ payload->r1 = r1;
+ payload->r2 = r2;
+ payload->open = open;
+ cylinder->ptr = payload;
+ cylinder->free_fn = &dmnsn_free;
return cylinder;
}
@@ -52,12 +64,17 @@ dmnsn_cylinder_intersection_fn(const dmnsn_object *cylinder, dmnsn_line line,
dmnsn_intersection *intersection)
{
dmnsn_line l = dmnsn_transform_line(cylinder->trans_inv, line);
+ dmnsn_cylinder_payload *payload = cylinder->ptr;
+ double r1 = payload->r1, r2 = payload->r2;
- /* Solve (x0 + nx*t)^2 + (z0 + nz*t)^2 == 1 */
+ /* Solve (x0 + nx*t)^2 + (z0 + nz*t)^2
+ == (((r2 - r1)*(y0 + ny*t) + r1 + r2)/2)^2 */
double a, b, c, t;
- a = l.n.x*l.n.x + l.n.z*l.n.z;
- b = 2.0*(l.n.x*l.x0.x + l.n.z*l.x0.z);
- c = l.x0.x*l.x0.x + l.x0.z*l.x0.z - 1.0;
+ a = l.n.x*l.n.x + l.n.z*l.n.z - l.n.y*l.n.y*(r2 - r1)*(r2 - r1)/4.0;
+ b = 2.0*(l.n.x*l.x0.x + l.n.z*l.x0.z)
+ - l.n.y*(r2 - r1)*(l.x0.y*(r2 - r1) + r2 + r1)/2.0;
+ c = l.x0.x*l.x0.x + l.x0.z*l.x0.z
+ - (l.x0.y*(r2 - r1) + r2 + r1)*(l.x0.y*(r2 - r1) + r2 + r1)/4;
if (b*b - 4.0*a*c >= 0.0) {
t = (-b - sqrt(b*b - 4.0*a*c))/(2.0*a);
@@ -68,31 +85,40 @@ dmnsn_cylinder_intersection_fn(const dmnsn_object *cylinder, dmnsn_line line,
p = dmnsn_line_point(l, t);
}
- if (!cylinder->ptr && l.n.y) {
+ 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;
+ 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 >= 1.0) {
- tcap = dmnsn_max(tcap1, tcap2);
+ 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);
- norm = dmnsn_vector_negate(norm);
}
if (tcap >= 0.0
&& (tcap < t || p.y <= -1.0 || p.y >= 1.0)
- && pcap.x*pcap.x + pcap.z*pcap.z < 1.0)
+ && pcap.x*pcap.x + pcap.z*pcap.z < r*r)
{
intersection->ray = line;
intersection->t = tcap;
@@ -104,10 +130,12 @@ dmnsn_cylinder_intersection_fn(const dmnsn_object *cylinder, dmnsn_line line,
}
if (t >= 0.0 && p.y > -1.0 && p.y < 1.0) {
- p.y = 0;
+ dmnsn_vector norm = dmnsn_vector_normalize(
+ dmnsn_new_vector(p.x, -(r2 - r1)*sqrt(p.x*p.x + p.z*p.z)/2.0, p.z)
+ );
intersection->ray = line;
intersection->t = t;
- intersection->normal = dmnsn_transform_normal(cylinder->trans, p);
+ intersection->normal = dmnsn_transform_normal(cylinder->trans, norm);
intersection->texture = cylinder->texture;
intersection->interior = cylinder->interior;
return true;
diff --git a/libdimension/dimension/objects.h b/libdimension/dimension/objects.h
index 8f30eae..91c9127 100644
--- a/libdimension/dimension/objects.h
+++ b/libdimension/dimension/objects.h
@@ -36,7 +36,7 @@ dmnsn_object *dmnsn_new_sphere(void);
/* A cube, axis-aligned, from (-1, -1, -1) to (1, 1, 1) */
dmnsn_object *dmnsn_new_cube(void);
-/* A cylinder, of radius 1, from y = -1 to y = 1 */
-dmnsn_object *dmnsn_new_cylinder(bool open);
+/* A cylinder/cone, from r = r1 at y = -1, to r = r2 at y = 1 */
+dmnsn_object *dmnsn_new_cylinder(double r1, double r2, bool open);
#endif /* DIMENSION_OBJECTS_H */
diff --git a/tests/libdimension/render.c b/tests/libdimension/render.c
index 3f4525d..0a50ed1 100644
--- a/tests/libdimension/render.c
+++ b/tests/libdimension/render.c
@@ -106,16 +106,29 @@ dmnsn_new_test_scene(void)
plane->texture->pigment = dmnsn_new_solid_pigment(dmnsn_white);
dmnsn_array_push(scene->objects, &plane);
- dmnsn_object *cylinder = dmnsn_new_cylinder(false);
+ dmnsn_object *cylinder = dmnsn_new_cylinder(0.1, 0.1, false);
cylinder->trans =
dmnsn_matrix_mul(
dmnsn_rotation_matrix(dmnsn_new_vector(dmnsn_radians(-45.0), 0.0, 0.0)),
- dmnsn_scale_matrix(dmnsn_new_vector(0.1, 1.25, 0.1))
+ dmnsn_scale_matrix(dmnsn_new_vector(1.0, 1.25, 1.0))
);
cylinder->texture = dmnsn_new_texture();
cylinder->texture->pigment = dmnsn_new_solid_pigment(dmnsn_red);
dmnsn_array_push(scene->objects, &cylinder);
+ dmnsn_object *cone = dmnsn_new_cylinder(0.1, 0.0, true);
+ cone->trans =
+ dmnsn_matrix_mul(
+ dmnsn_rotation_matrix(dmnsn_new_vector(dmnsn_radians(-45.0), 0.0, 0.0)),
+ dmnsn_matrix_mul(
+ dmnsn_translation_matrix(dmnsn_new_vector(0.0, 1.375, 0.0)),
+ dmnsn_scale_matrix(dmnsn_new_vector(1.0, 0.125, 1.0))
+ )
+ );
+ cone->texture = dmnsn_new_texture();
+ cone->texture->pigment = dmnsn_new_solid_pigment(dmnsn_red);
+ dmnsn_array_push(scene->objects, &cone);
+
return scene;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 01:08:08 +0000