c – 光线跟踪不正确的软阴影采样

这是前后输出图像.

当我向下移动蓝色球体时,问题仍在继续(注意当球体沿着白色虚线时,人工制品会继续).
注意这个球体和arealight是相同的z偏移量.当我把蓝色球体带到屏幕前面时,神器就消失了.我认为问题是由均匀采样锥或采样球功能引起的,但不确定.

这是功能：

template <typename T>
CVector3<T> UConeSample(T u1,T u2,T costhetamax,const CVector3<T>& x,const CVector3<T>& y,const CVector3<T>& z) {
   T costheta = Math::Lerp(u1,costhetamax,T(1));
   T sintheta = sqrtf(T(1) - costheta*costheta);
   T phi = u2 * T(2) * T(M_PI);

   return cosf(phi) * sintheta * x +
          sinf(phi) * sintheta * y +
          costheta * z;
}

我正在从van Der Corput序列生成随机浮点u1,u2值.
这是球形采样方法

CPoint3<float> CSphere::Sample(const CLightSample& ls,const CPoint3<float>& p,CVector3<float> *n) const {
   // translate object to world space
   CPoint3<float> pCentre = o2w(CPoint3<float>(0.0f));
   CVector3<float> wc = Vector::Normalize(pCentre - p);
   CVector3<float> wcx,wcy;
   //create local coordinate system from wc for uniform sample cone
   Vector::CoordinateSystem(wc,&wcx,&wcy);

   //check if inside,epsilon val. this is true?
   if (Point::DistSquare(p,pCentre) - radius*radius < 1e-4f)
      return Sample(ls,n);

   // Else outside evaluate cosinus theta value
   float sinthetamax2 = radius * radius / Point::DistSquare(p,pCentre);
   float costhetamax = sqrtf(Math::Max(0.0f,1.0f - sinthetamax2));

   // Surface properties
   CSurfaceProps dg_sphere;
   float thit,ray_epsilon;
   CPoint3<float> ps;

   //create ray direction from sampled point then send ray to sphere
   CRay ray(p,Vector::UConeSample(ls.u1,ls.u2,wcx,wcy,wc),1e-3f);
   // Check intersection against sphere,fill surface properties and calculate hit point
   if (!Intersect(ray,&thit,&ray_epsilon,&dg_sphere))
      thit = Vector::Dot(pCentre - p,Vector::Normalize(ray.d));

   // Evaluate surface normal
   ps = ray(thit);
   *n = CVector3<float>(Vector::Normalize(ps - pCentre));

   //return sample point
   return ps;
}

有没有人有什么建议？谢谢.