+ return true;
+}
+
+bool calc_bounding_aabox(AABox *box, const GeomObject **objv, int num)
+{
+ if(num <= 0) return false;
+
+ if(!calc_bounding_aabox(box, objv[0])) {
+ return false;
+ }
+
+ for(int i=1; i<num; i++) {
+ if(!calc_bounding_aabox(box, box, objv[i])) {
+ return false;
+ }
+ }
+ return true;
+}
+
+bool calc_bounding_aabox(AABox *box, const Vec3 *v, int num, const Mat4 &xform)
+{
+ if(num <= 0) return false;
+
+ box->min = box->max = xform * v[0];
+ for(int i=1; i<num; i++) {
+ Vec3 p = xform * v[i];
+
+ for(int j=0; j<3; j++) {
+ box->min[j] = std::min(box->min[j], p[j]);
+ box->max[j] = std::max(box->max[j], p[j]);
+ }
+ }
+ return true;
+}
+
+bool calc_bounding_box(Box *box, const GeomObject *obj)
+{
+ if(!obj->valid()) {
+ box->invalidate();
+ return true;
+ }
+
+ switch(obj->type) {
+ case GOBJ_BOX:
+ *box = *(Box*)obj;
+ break;
+
+ case GOBJ_AABOX:
+ box->min = BOX(obj)->min;
+ box->max = BOX(obj)->max;
+ box->xform = Mat4::identity;
+ break;
+
+ case GOBJ_SPHERE:
+ {
+ float r = SPHERE(obj)->radius;
+ box->min = SPHERE(obj)->center - Vec3(r, r, r);
+ box->max = SPHERE(obj)->center + Vec3(r, r, r);
+ box->xform = Mat4::identity;
+ }
+ break;
+
+ case GOBJ_PLANE:
+ default:
+ return false;
+ }
+ return true;
+}
+
+bool intersect_sphere_sphere(Disc *result, const Sphere &a, const Sphere &b)
+{
+ Vec3 dir = b.center - a.center;
+
+ float dist_sq = length_sq(dir);
+ if(dist_sq <= 1e-8) return false;
+
+ float rsum = a.radius + b.radius;
+ float rdif = fabs(a.radius - b.radius);
+ if(dist_sq > rsum * rsum || dist_sq < rdif * rdif) {
+ return false;
+ }
+
+ float dist = sqrt(dist_sq);
+ float t = (dist_sq + a.radius * a.radius - b.radius * b.radius) / (2.0 * sqrt(dist_sq));
+
+ result->pt = a.center + dir * t;
+ result->normal = dir / dist;
+ result->radius = sin(acos(t)) * a.radius;
+ return true;
+}
+
+bool intersect_plane_plane(Ray *result, const Plane &a, const Plane &b)
+{
+ return false; // TODO
+}
+
+bool intersect_sphere_plane(Sphere *result, const Sphere &s, const Plane &p)
+{
+ return false; // TODO
+}
+
+bool intersect_plane_sphere(Sphere *result, const Plane &p, const Sphere &s)
+{
+ return false; // TODO
+}
+
+bool intersect_aabox_aabox(AABox *res, const AABox &a, const AABox &b)
+{
+ for(int i=0; i<3; i++) {
+ res->min[i] = std::max(a.min[i], b.min[i]);
+ res->max[i] = std::min(a.max[i], b.max[i]);
+
+ if(res->max[i] < res->min[i]) {
+ res->max[i] = res->min[i];
+ }
+ }
+ return res->min.x != res->max.x && res->min.y != res->max.y && res->min.z != res->max.z;
+}
+
+bool collision_sphere_aabox(const Sphere &s, const AABox &b)
+{
+ return b.distance_sq(s.center) <= s.radius * s.radius;