Spectrum sampleRayDifferential(RayDifferential &ray, const Point2 &pixelSample,
const Point2 &otherSample, Float timeSample) const {
/* Record pixel index, added by Lifan */
ray.index.x = (int)std::floor(pixelSample.x);
ray.index.y = (int)std::floor(pixelSample.y);
Point2 tmp = warp::squareToUniformDiskConcentric(otherSample)
* m_apertureRadius;
ray.time = sampleTime(timeSample);
/* Compute the corresponding position on the
near plane (in local camera space) */
Point nearP = m_sampleToCamera(Point(
pixelSample.x * m_invResolution.x,
pixelSample.y * m_invResolution.y, 0.0f));
/* Aperture position */
Point apertureP(tmp.x, tmp.y, 0.0f);
/* Sampled position on the focal plane */
Float fDist = m_focusDistance / nearP.z;
Point focusP = nearP * fDist;
Point focusPx = (nearP+m_dx) * fDist;
Point focusPy = (nearP+m_dy) * fDist;
/* Turn that into a normalized ray direction, and
adjust the ray interval accordingly */
Vector d = normalize(focusP - apertureP);
Float invZ = 1.0f / d.z;
ray.mint = m_nearClip * invZ;
ray.maxt = m_farClip * invZ;
const Transform &trafo = m_worldTransform->eval(ray.time);
ray.setOrigin(trafo.transformAffine(apertureP));
ray.setDirection(trafo(d));
ray.rxOrigin = ray.ryOrigin = ray.o;
ray.rxDirection = trafo(normalize(Vector(focusPx - apertureP)));
ray.ryDirection = trafo(normalize(Vector(focusPy - apertureP)));
ray.hasDifferentials = true;
return Spectrum(1.0f);
}
Spectrum sampleRayDifferential(RayDifferential &ray, const Point2 &pixelSample,
const Point2 &otherSample, Float timeSample) const {
ray.time = sampleTime(timeSample);
const Transform &trafo = m_worldTransform->eval(ray.time);
/* Compute the corresponding position on the
near plane (in local camera space) */
Point nearP = m_sampleToCamera.transformAffine(Point(
pixelSample.x * m_invResolution.x,
pixelSample.y * m_invResolution.y, 0.0f));
nearP.z = 0.0f;
ray.setOrigin(trafo.transformAffine(nearP));
ray.setDirection(normalize(trafo(Vector(0, 0, 1))));
ray.mint = m_nearClip;
ray.maxt = m_farClip;
ray.rxOrigin = trafo(nearP + m_dx);
ray.ryOrigin = trafo(nearP + m_dy);
ray.rxDirection = ray.ryDirection = ray.d;
ray.hasDifferentials = true;
return Spectrum(1.0f);
}