//-------------------------------------------------------------------------eiBool eiSphere::intersect(eiRay *ray, eiObject *po, eiFloat & oldt, eiPrimitive* & ret_pri, eiFloat *cust_data, HitParam *hparam)
{
if( oldt == 0.0f || ray_box( ray->src, hparam->hitPoint )
{
//compute intersecting point
eiVector oc = add( ray->src, - center ); eiFloat oc_len = dist( oc ); if( oc_len > radius || po->material->doubleSide ) { eiFloat a = dot( ray->dir, ray->dir ); eiFloat b = 2.0f * dot( oc, ray->dir); eiFloat c = dot( oc, oc ) - RR; eiFloat dt = b * b - 4.0f * a * c; eiFloat t; if(a == 0.0f || dt < 0.0f) return false; else if(dt == 0.0f) { t = - b / a * 0.5f; if(t < 0.0f) return false;
} else { a = 0.5f / a; eiFloat t1 = (- b + sqrtf( dt )) * a; eiFloat t2 = (- b - sqrtf( dt )) * a; if(t1 > 0.0f && t2 < 0.0f) t = t1; else if(t1 < 0.0f && t2 > 0.0f) t = t2; else if(t1 > 0.0f && t2 > 0.0f) t = (t1 < t2) ? t1 : t2; else return false; } eiVector tmpIntersection = add(ray->src, mulvf(ray->dir,t)); //affect shadow factor if(ray->type == RAY_SHADOW) hparam->shadow_factor *= 1.0f - po->material->opacity; //find nearest hit point if(oldt == 0.0f || t < oldt) { hparam->hitPoint = tmpIntersection; hparam->hitObj = po; ret_pri = this; oldt = t; //fill custom data return true; } } } return false;
}