int intersect_shadow(float t, t_scene *scene, t_ray *ray)
{
t_vec3 intersect_pt;
t_ray shadow;
float t_tmp;
intersect_pt.x = ray->o.x + t * ray->d.x;
intersect_pt.y = ray->o.y + t * ray->d.y;
intersect_pt.z = ray->o.z + t * ray->d.z;
init_coord(&shadow.o, 0, 0, -30);
init_vec3(&(shadow.d), shadow.o.x - intersect_pt.x, shadow.o.y - intersect_pt.y, shadow.o.z - intersect_pt.z);
t_tmp = -1;
while (scene != NULL)
{
if (scene->type == CIRCLE)
t_tmp = intersect_circle(&shadow, scene->object);
else if (scene->type == PLANE)
t_tmp = intersect_plane(&shadow, scene->object);
else if (scene->type == CYLINDER)
t_tmp = intersect_cylinder(&shadow, scene->object);
if (t_tmp > 0)
{
return (1);
}
scene = scene->next;
}
return (0);
}
static gboolean
intersect_cylinder (GimpVector3 vp,
GimpVector3 dir,
FaceIntersectInfo *face_intersect)
{
gdouble a, b, c, d, e, f, tmp, l;
gboolean result = FALSE;
gint i;
#define sqr(a) (a*a)
a = sqr (dir.x) + sqr (dir.z);
b = 2.0 * (vp.x * dir.x + vp.z * dir.z);
c = sqr (vp.x) + sqr (vp.z) - sqr (mapvals.cylinder_radius);
d = sqr (b) - 4.0 * a * c;
if (d >= 0.0)
{
e = sqrt (d);
f = 2.0 * a;
if (f != 0.0)
{
result = TRUE;
face_intersect[0].t = (-b+e)/f;
face_intersect[1].t = (-b-e)/f;
if (face_intersect[0].t>face_intersect[1].t)
{
tmp = face_intersect[0].t;
face_intersect[0].t = face_intersect[1].t;
face_intersect[1].t = tmp;
}
for (i = 0; i < 2; i++)
{
face_intersect[i].s.x = vp.x + face_intersect[i].t * dir.x;
face_intersect[i].s.y = vp.y + face_intersect[i].t * dir.y;
face_intersect[i].s.z = vp.z + face_intersect[i].t * dir.z;
face_intersect[i].n = face_intersect[i].s;
face_intersect[i].n.y = 0.0;
gimp_vector3_normalize(&face_intersect[i].n);
l = mapvals.cylinder_length/2.0;
face_intersect[i].u = (atan2(face_intersect[i].s.x,face_intersect[i].s.z)+G_PI)/(2.0*G_PI);
face_intersect[i].v = (face_intersect[i].s.y+l)/mapvals.cylinder_length;
/* Mark hitpoint as on the cylinder hull */
/* ===================================== */
face_intersect[i].face = 0;
/* Check if we're completely off the cylinder axis */
/* =============================================== */
if (face_intersect[i].s.y>l || face_intersect[i].s.y<-l)
{
/* Check if we've hit a cap */
/* ======================== */
if (face_intersect[i].s.y>l)
{
if (intersect_circle(vp,dir,l,&face_intersect[i])==FALSE)
result = FALSE;
else
{
face_intersect[i].face = 2;
face_intersect[i].v = 1 - face_intersect[i].v;
gimp_vector3_set(&face_intersect[i].n, 0.0, 1.0, 0.0);
}
}
else
{
if (intersect_circle(vp,dir,-l,&face_intersect[i])==FALSE)
result = FALSE;
else
{
face_intersect[i].face = 1;
gimp_vector3_set(&face_intersect[i].n, 0.0, -1.0, 0.0);
}
}
}
}
}
}
#undef sqr
return result;
}