Vec3f TraceBase::attenuatedEmission(PathSampleGenerator &sampler,
const Primitive &light,
const Medium *medium,
float expectedDist,
IntersectionTemporary &data,
IntersectionInfo &info,
int bounce,
bool startsOnSurface,
Ray &ray,
Vec3f *transmittance)
{
CONSTEXPR float fudgeFactor = 1.0f + 1e-3f;
if (light.isDirac()) {
ray.setFarT(expectedDist);
} else {
if (!light.intersect(ray, data) || ray.farT()*fudgeFactor < expectedDist)
return Vec3f(0.0f);
}
info.p = ray.pos() + ray.dir()*ray.farT();
info.w = ray.dir();
light.intersectionInfo(data, info);
Vec3f shadow = generalizedShadowRay(sampler, ray, medium, &light, startsOnSurface, true, bounce);
if (transmittance)
*transmittance = shadow;
if (shadow == 0.0f)
return Vec3f(0.0f);
return shadow*light.evalDirect(data, info);
}
SurfaceScatterEvent TraceBase::makeLocalScatterEvent(IntersectionTemporary &data, IntersectionInfo &info,
Ray &ray, PathSampleGenerator *sampler) const
{
TangentFrame frame;
info.primitive->setupTangentFrame(data, info, frame);
bool hitBackside = frame.normal.dot(ray.dir()) > 0.0f;
bool isTransmissive = info.bsdf->lobes().isTransmissive();
bool flipFrame = _settings.enableTwoSidedShading && hitBackside && !isTransmissive;
if (flipFrame) {
// TODO: Should we flip info.Ns here too? It doesn't seem to be used at the moment,
// but it may be in the future. Modifying the intersection info itself could be a bad
// idea though
frame.normal = -frame.normal;
frame.tangent = -frame.tangent;
}
return SurfaceScatterEvent(
&info,
sampler,
frame,
frame.toLocal(-ray.dir()),
BsdfLobes::AllLobes,
flipFrame
);
}
bool Quad::intersect(Ray &ray, IntersectionTemporary &data) const
{
float nDotW = ray.dir().dot(_frame.normal);
if (std::abs(nDotW) < 1e-6f)
return false;
float t = _frame.normal.dot(_base - ray.pos())/nDotW;
if (t < ray.nearT() || t > ray.farT())
return false;
Vec3f q = ray.pos() + t*ray.dir();
Vec3f v = q - _base;
float l0 = v.dot(_edge0)*_invUvSq.x();
float l1 = v.dot(_edge1)*_invUvSq.y();
if (l0 < 0.0f || l0 > 1.0f || l1 < 0.0f || l1 > 1.0f)
return false;
ray.setFarT(t);
QuadIntersection *isect = data.as<QuadIntersection>();
isect->p = q;
isect->u = l0;
isect->v = 1.0f - l1;
isect->backSide = nDotW >= 0.0f;
data.primitive = this;
return true;
}
Vec3f AtmosphericMedium::transmittance(PathSampleGenerator &/*sampler*/, const Ray &ray) const
{
Vec3f p = (ray.pos() - _center);
float t0 = p.dot(ray.dir());
float t1 = ray.farT() + t0;
float h = (p - t0*ray.dir()).length();
return std::exp(-_sigmaT*densityIntegral(h, t0, t1));
}
bool Cylinder::intersect_unit_circle( const Ray& inc, Ray& hit )
{
double Z = inc.from().z();
double z = -inc.dir().z();
Vec3 v = inc.from() + inc.dir() * Z / z;
v.z() = 0;
if( v.l2() > 1 ) return false;
hit.from() = v;
return true;
}
bool Triangle::hit ( const Ray& original_ray, interval_t& tmin ) const
{
Ray ray = original_ray.transform(inv_trans_);
float A = a_[0] - b_[0];
float B = a_[1] - b_[1];
float C = a_[2] - b_[2];
float D = a_[0] - c_[0];
float E = a_[1] - c_[1];
float F = a_[2] - c_[2];
float G = ray.dir()[0];
float H = ray.dir()[1];
float I = ray.dir()[2];
float J = a_[0] - ray.origin()[0];
float K = a_[1] - ray.origin()[1];
float L = a_[2] - ray.origin()[2];
float EIHF = E*I - H*F;
float GFDI = G*F - D*I;
float DHEG = D*H - E*G;
float denom = A*EIHF + B*GFDI + C*DHEG;
float beta = ( J*EIHF + K*GFDI + L*DHEG ) / denom;
if ( beta <= 0.0 or beta >= 1.0 )
return false;
float AKJB = A*K - J*B;
float JCAL = J*C - A*L;
float BLKC = B*L - K*C;
float gamma = ( I*AKJB + H*JCAL + G*BLKC ) / denom;
if ( gamma <= 0.0 or beta + gamma >= 1.0 )
return false;
float t = -( F*AKJB + E*JCAL + D*BLKC ) / denom;
if ( t > epsilon )
{
tmin = t;
return true;
}
return false;
}
inline RTCRay convert(const Ray &r)
{
RTCRay ray;
ray.org[0] = r.pos().x();
ray.org[1] = r.pos().y();
ray.org[2] = r.pos().z();
ray.dir[0] = r.dir().x();
ray.dir[1] = r.dir().y();
ray.dir[2] = r.dir().z();
ray.tnear = r.nearT();
ray.tfar = r.farT();
ray.geomID = RTC_INVALID_GEOMETRY_ID;
ray.primID = RTC_INVALID_GEOMETRY_ID;
return ray;
}
Vec3f TraceBase::volumePhaseSample(const Primitive &light,
PathSampleGenerator &sampler,
MediumSample &mediumSample,
const Medium *medium,
int bounce,
const Ray &parentRay)
{
PhaseSample phaseSample;
if (!mediumSample.phase->sample(sampler, parentRay.dir(), phaseSample))
return Vec3f(0.0f);
Ray ray = parentRay.scatter(mediumSample.p, phaseSample.w, 0.0f);
ray.setPrimaryRay(false);
IntersectionTemporary data;
IntersectionInfo info;
Vec3f e = attenuatedEmission(sampler, light, medium, -1.0f, data, info, bounce, false, ray, nullptr);
if (e == Vec3f(0.0f))
return Vec3f(0.0f);
Vec3f phaseF = e*phaseSample.weight;
phaseF *= SampleWarp::powerHeuristic(phaseSample.pdf, light.directPdf(_threadId, data, info, mediumSample.p));
return phaseF;
}
Vec3f TraceBase::volumeLightSample(PathSampleGenerator &sampler,
MediumSample &mediumSample,
const Primitive &light,
const Medium *medium,
int bounce,
const Ray &parentRay)
{
LightSample lightSample;
if (!light.sampleDirect(_threadId, mediumSample.p, sampler, lightSample))
return Vec3f(0.0f);
Vec3f f = mediumSample.phase->eval(parentRay.dir(), lightSample.d);
if (f == 0.0f)
return Vec3f(0.0f);
Ray ray = parentRay.scatter(mediumSample.p, lightSample.d, 0.0f);
ray.setPrimaryRay(false);
IntersectionTemporary data;
IntersectionInfo info;
Vec3f e = attenuatedEmission(sampler, light, medium, lightSample.dist, data, info, bounce, false, ray, nullptr);
if (e == 0.0f)
return Vec3f(0.0f);
Vec3f lightF = f*e/lightSample.pdf;
if (!light.isDirac())
lightF *= SampleWarp::powerHeuristic(lightSample.pdf, mediumSample.phase->pdf(parentRay.dir(), lightSample.d));
return lightF;
}
bool TraceBase::volumeLensSample(const Camera &camera,
PathSampleGenerator &sampler,
MediumSample &mediumSample,
const Medium *medium,
int bounce,
const Ray &parentRay,
Vec3f &weight,
Vec2f &pixel)
{
LensSample lensSample;
if (!camera.sampleDirect(mediumSample.p, sampler, lensSample))
return false;
Vec3f f = mediumSample.phase->eval(parentRay.dir(), lensSample.d);
if (f == 0.0f)
return false;
Ray ray = parentRay.scatter(mediumSample.p, lensSample.d, 0.0f);
ray.setPrimaryRay(false);
ray.setFarT(lensSample.dist);
Vec3f transmittance = generalizedShadowRay(sampler, ray, medium, nullptr, false, true, bounce);
if (transmittance == 0.0f)
return false;
weight = f*transmittance*lensSample.weight;
pixel = lensSample.pixel;
return true;
}
bool intersectAabb(const Aabb& box, const Ray& ray, floating& a, floating& b) {
const Point origin = ray.origin();
const Vector dir = ray.dir();
a = std::numeric_limits<floating>::min();
b = std::numeric_limits<floating>::max();
for (uint8_t i = 0; i < 3; ++i) {
if (almost_zero(dir[i])) {
if (origin[i] < box.m_p1[i] || origin[i] > box.m_p2[i]) {
return false;
}
continue;
}
floating idir = 1.0 / dir[i];
floating at = (box.m_p1[i] - origin[i]) * idir;
floating bt = (box.m_p2[i] - origin[i]) * idir;
if (at > bt)
idir = at, at = bt, bt = idir;
if (at > a)
a = at;
if (bt < b)
b = bt;
if (b < 0 || a > b)
return false;
}
return true;
}
bool Cube::intersect(Ray &ray, IntersectionTemporary &data) const
{
Vec3f p = _invRot*(ray.pos() - _pos);
Vec3f d = _invRot*ray.dir();
Vec3f invD = 1.0f/d;
Vec3f relMin((-_scale - p));
Vec3f relMax(( _scale - p));
float ttMin = ray.nearT(), ttMax = ray.farT();
for (int i = 0; i < 3; ++i) {
if (invD[i] >= 0.0f) {
ttMin = max(ttMin, relMin[i]*invD[i]);
ttMax = min(ttMax, relMax[i]*invD[i]);
} else {
ttMax = min(ttMax, relMin[i]*invD[i]);
ttMin = max(ttMin, relMax[i]*invD[i]);
}
}
if (ttMin <= ttMax) {
if (ttMin > ray.nearT() && ttMin < ray.farT()) {
data.primitive = this;
ray.setFarT(ttMin);
data.as<CubeIntersection>()->backSide = false;
} else if (ttMax > ray.nearT() && ttMax < ray.farT()) {
data.primitive = this;
ray.setFarT(ttMax);
data.as<CubeIntersection>()->backSide = true;
}
return true;
}
return false;
}
bool Sphere::intersectP(Ray &ray){
float a, b, c,t1, t2, discriminant;
Vector3f dir = ray.dir();
Vector3f e_minus_c = ray.pos().sub(center);
a = dir.dot(dir);
b= (2*dir).dot((e_minus_c));
c = (e_minus_c).dot(e_minus_c)-pow(radius,2.0);
discriminant = pow(b,2.0)-(4*a*c);
if(discriminant < 0){
return false;
}
else{
float sqrtdisc = sqrt(discriminant);
t1 = (-b + sqrtdisc) / (2 * a);
t2 = (-b - sqrtdisc) / (2 * a);
if((t1 > ray.t_min() && t1 < ray.t_max()) ||
(t2 > ray.t_min() && t2 < ray.t_max())){
return true;
}
else{
return false;
}
}
}
/**
* Performs ray/box intersection. Returns true if the ray
* intersects the box, and the hit time for the entry/exit
* in tmin/tmax respectively.
*/
bool AABB::intersect(const Ray& ray, float& tmin, float& tmax) const
{
float t0 = ray.minT;
float t1 = ray.maxT;
// Loop over the three axes and compute the hit time for the
// two axis-aligned bounding box planes in each, decreasing the
// parametric range of the ray until start>end time, which means
// the ray missed the box, or until we finish which means there
// is an intersection.
for (int i = 0; i < 3; i++) {
float invDir = 1.0f / ray.dir(i);
float tNear = (mMin(i) - ray.orig(i)) * invDir;
float tFar = (mMax(i) - ray.orig(i)) * invDir;
if (tNear > tFar) swap(tNear,tFar);
if (tNear > t0) t0 = tNear;
if (tFar < t1) t1 = tFar;
if (t0 > t1) return false;
}
tmin = t0;
tmax = t1;
return true;
}
bool Sphere::intersect(Ray &ray, IntersectionTemporary &data) const
{
Vec3f p = ray.pos() - _pos;
float B = p.dot(ray.dir());
float C = p.lengthSq() - _radius*_radius;
float detSq = B*B - C;
if (detSq >= 0.0f) {
float det = std::sqrt(detSq);
float t = -B - det;
if (t < ray.farT() && t > ray.nearT()) {
ray.setFarT(t);
data.primitive = this;
data.as<SphereIntersection>()->backSide = false;
return true;
}
t = -B + det;
if (t < ray.farT() && t > ray.nearT()) {
ray.setFarT(t);
data.primitive = this;
data.as<SphereIntersection>()->backSide = true;
return true;
}
}
return false;
}
bool Quad::occluded(const Ray &ray) const
{
float nDotW = ray.dir().dot(_frame.normal);
float t = _frame.normal.dot(_base - ray.pos())/nDotW;
if (t < ray.nearT() || t > ray.farT())
return false;
Vec3f q = ray.pos() + t*ray.dir();
Vec3f v = q - _base;
float l0 = v.dot(_edge0)*_invUvSq.x();
float l1 = v.dot(_edge1)*_invUvSq.y();
if (l0 < 0.0f || l0 > 1.0f || l1 < 0.0f || l1 > 1.0f)
return false;
return true;
}
float AtmosphericMedium::pdf(PathSampleGenerator &/*sampler*/, const Ray &ray, bool onSurface) const
{
if (_absorptionOnly) {
return 1.0f;
} else {
Vec3f p = (ray.pos() - _center);
float t0 = p.dot(ray.dir());
float t1 = ray.farT() + t0;
float h = (p - t0*ray.dir()).length();
Vec3f transmittance = std::exp(-_sigmaT*densityIntegral(h, t0, t1));
if (onSurface) {
return transmittance.avg();
} else {
return (density(h, t0)*_sigmaT*transmittance).avg();
}
}
}
Vec3f AtmosphericMedium::transmittanceAndPdfs(PathSampleGenerator &/*sampler*/, const Ray &ray, bool startOnSurface,
bool endOnSurface, float &pdfForward, float &pdfBackward) const
{
Vec3f p = (ray.pos() - _center);
float t0 = p.dot(ray.dir());
float t1 = ray.farT() + t0;
float h = (p - t0*ray.dir()).length();
Vec3f transmittance = std::exp(-_sigmaT*densityIntegral(h, t0, t1));
if (_absorptionOnly) {
pdfForward = pdfBackward = 1.0f;
} else {
pdfForward = endOnSurface ? transmittance.avg() : (density(h, t1)*_sigmaT*transmittance).avg();
pdfBackward = startOnSurface ? transmittance.avg() : (density(h, t0)*_sigmaT*transmittance).avg();
}
return transmittance;
}
Vec3f ExponentialMedium::transmittance(PathSampleGenerator &/*sampler*/, const Ray &ray) const
{
float x = _falloffScale*(ray.pos() - _unitPoint).dot(_unitFalloffDirection);
float dx = _falloffScale*ray.dir().dot(_unitFalloffDirection);
if (ray.farT() == Ray::infinity() && dx <= 0.0f)
return Vec3f(0.0f);
else
return std::exp(-_sigmaT*densityIntegral(x, dx, ray.farT()));
}
bool ExponentialMedium::sampleDistance(PathSampleGenerator &sampler, const Ray &ray,
MediumState &state, MediumSample &sample) const
{
if (state.bounce > _maxBounce)
return false;
float x = _falloffScale*(ray.pos() - _unitPoint).dot(_unitFalloffDirection);
float dx = _falloffScale*ray.dir().dot(_unitFalloffDirection);
float maxT = ray.farT();
if (_absorptionOnly) {
if (maxT == Ray::infinity() && dx <= 0.0f)
return false;
sample.t = maxT;
sample.weight = std::exp(-_sigmaT*densityIntegral(x, dx, ray.farT()));
sample.pdf = 1.0f;
sample.exited = true;
} else {
int component = sampler.nextDiscrete(3);
float sigmaTc = _sigmaT[component];
float xi = 1.0f - sampler.next1D();
float logXi = std::log(xi);
float t = inverseOpticalDepth(x, dx, sigmaTc, logXi);
sample.t = min(t, maxT);
sample.weight = std::exp(-_sigmaT*densityIntegral(x, dx, sample.t));
sample.exited = (t >= maxT);
if (sample.exited) {
sample.pdf = sample.weight.avg();
} else {
float rho = density(x, dx, sample.t);
sample.pdf = (rho*_sigmaT*sample.weight).avg();
sample.weight *= rho*_sigmaS;
}
sample.weight /= sample.pdf;
state.advance();
}
sample.p = ray.pos() + sample.t*ray.dir();
sample.phase = _phaseFunction.get();
return true;
}
bool AtmosphericMedium::sampleDistance(PathSampleGenerator &sampler, const Ray &ray,
MediumState &state, MediumSample &sample) const
{
if (state.bounce > _maxBounce)
return false;
Vec3f p = (ray.pos() - _center);
float t0 = p.dot(ray.dir());
float h = (p - t0*ray.dir()).length();
float maxT = ray.farT() + t0;
if (_absorptionOnly) {
sample.t = ray.farT();
sample.weight = std::exp(-_sigmaT*densityIntegral(h, t0, maxT));
sample.pdf = 1.0f;
sample.exited = true;
} else {
int component = sampler.nextDiscrete(3);
float sigmaTc = _sigmaT[component];
float xi = 1.0f - sampler.next1D();
float t = inverseOpticalDepth(h, t0, sigmaTc, xi);
sample.t = min(t, maxT);
sample.weight = std::exp(-_sigmaT*densityIntegral(h, t0, sample.t));
sample.exited = (t >= maxT);
if (sample.exited) {
sample.pdf = sample.weight.avg();
} else {
float rho = density(h, sample.t);
sample.pdf = (rho*_sigmaT*sample.weight).avg();
sample.weight *= rho*_sigmaS;
}
sample.weight /= sample.pdf;
sample.t -= t0;
state.advance();
}
sample.p = ray.pos() + sample.t*ray.dir();
sample.phase = _phaseFunction.get();
return true;
}
bool TraceBase::handleSurface(SurfaceScatterEvent &event, IntersectionTemporary &data,
IntersectionInfo &info, const Medium *&medium,
int bounce, bool adjoint, bool enableLightSampling, Ray &ray,
Vec3f &throughput, Vec3f &emission, bool &wasSpecular,
Medium::MediumState &state, Vec3f *transmittance)
{
const Bsdf &bsdf = *info.bsdf;
// For forward events, the transport direction does not matter (since wi = -wo)
Vec3f transparency = bsdf.eval(event.makeForwardEvent(), false);
float transparencyScalar = transparency.avg();
Vec3f wo;
if (event.sampler->nextBoolean(transparencyScalar) ){
wo = ray.dir();
event.pdf = transparencyScalar;
event.weight = transparency/transparencyScalar;
event.sampledLobe = BsdfLobes::ForwardLobe;
throughput *= event.weight;
} else {
if (!adjoint) {
if (enableLightSampling && bounce < _settings.maxBounces - 1)
emission += estimateDirect(event, medium, bounce + 1, ray, transmittance)*throughput;
if (info.primitive->isEmissive() && bounce >= _settings.minBounces) {
if (!enableLightSampling || wasSpecular || !info.primitive->isSamplable())
emission += info.primitive->evalDirect(data, info)*throughput;
}
}
event.requestedLobe = BsdfLobes::AllLobes;
if (!bsdf.sample(event, adjoint))
return false;
wo = event.frame.toGlobal(event.wo);
if (!isConsistent(event, wo))
return false;
throughput *= event.weight;
wasSpecular = event.sampledLobe.hasSpecular();
if (!wasSpecular)
ray.setPrimaryRay(false);
}
bool geometricBackside = (wo.dot(info.Ng) < 0.0f);
medium = info.primitive->selectMedium(medium, geometricBackside);
state.reset();
ray = ray.scatter(ray.hitpoint(), wo, info.epsilon);
return true;
}
inline bool YZRect::hit(const Ray& r, float t_min, float t_max, hit_record& rec) const
{
auto t = (_k-r.origin().x)/r.dir().x;
if(t < t_min || t > t_max) return false;
auto interesction = r.pointAtParam(t);
if(interesction.y < _y_dim.x || interesction.y > _y_dim.y || interesction.z < _z_dim.x || interesction.z > _z_dim.y) return false;
rec.uv = glm::vec2((interesction.y - _y_dim.x)/(_y_dim.y - _y_dim.x), (interesction.z - _z_dim.x)/(_z_dim.y - _z_dim.x));
rec.t = t;
rec.mat = _mat;
rec.p = interesction;
rec.n = glm::vec3(1,0,0);
return true;
}
bool Sphere::intersect(Ray& ray, float *thit, LocalGeo *local){
/*If the discriminant is positive, there are two solutions: one solution where
the ray enters the sphere and one where it leaves. If the discriminant is zero, the
ray grazes the sphere touching it at exactly one point.*/
float a, b, c, discriminant;
Vector3f dir = ray.dir();
Vector3f e_minus_c = ray.pos().sub(center);
a = dir.dot(dir);
b= (2*dir).dot((e_minus_c));
c = (e_minus_c).dot(e_minus_c)-pow(radius,2.0);
discriminant = pow(b,2.0)-(4*a*c);
if(discriminant < 0){
return false;
}
else {
float discr = pow( dir.dot(e_minus_c) ,2.0) - a*c;
float t1 = (-dir.dot(e_minus_c) - sqrt( discr ))/a;
float t2= (-dir.dot(e_minus_c) + sqrt( discr ))/a;
float t = fmin(t1,t2);
if (t<ray.t_min() || t>ray.t_max()){
return false;
}
else {
*thit=t;
ray.pos().add(t*ray.dir());
local->setPos(ray.pos());
local->setNormal((ray.pos().sub(center))/radius); //normal will be vector3f
}
return true;
}
}
float Triangle::crossing(const Ray & r)
{
//_mm_prefetch(&v0, _MM_HINT_T0);
vec4 pos = r.pos();
vec4 dir = r.dir();
vec4 t = v0 - pos;
vec4 q = cross(dir, t);
vec4 tmp (dot(t, normal), dot(e2, q), dot(e1, q), 0.0f);
vec4 tuv = tmp * 1.0f / dot (dir, normal);
int b = (tuv[1]>=0.0f && tuv[2]>=0.0f && tuv[0]>=0.0f && (tuv[1] + tuv[2] <= 1.0f));
return b*tuv[0] + (b - 1);
}
float ExponentialMedium::pdf(PathSampleGenerator &/*sampler*/, const Ray &ray, bool onSurface) const
{
if (_absorptionOnly) {
return 1.0f;
} else {
float x = _falloffScale*(ray.pos() - _unitPoint).dot(_unitFalloffDirection);
float dx = _falloffScale*ray.dir().dot(_unitFalloffDirection);
Vec3f transmittance = std::exp(-_sigmaT*densityIntegral(x, dx, ray.farT()));
if (onSurface) {
return transmittance.avg();
} else {
return (density(x, dx, ray.farT())*_sigmaT*transmittance).avg();
}
}
}
bool Sphere::occluded(const Ray &ray) const
{
Vec3f p = ray.pos() - _pos;
float B = p.dot(ray.dir());
float C = p.lengthSq() - _radius*_radius;
float detSq = B*B - C;
if (detSq >= 0.0f) {
float det = std::sqrt(detSq);
float t = -B - det;
if (t < ray.farT() && t > ray.nearT())
return true;
t = -B + det;
if (t < ray.farT() && t > ray.nearT())
return true;
}
return false;
}
bool TraceBase::handleVolume(PathSampleGenerator &sampler, MediumSample &mediumSample,
const Medium *&medium, int bounce, bool adjoint, bool enableLightSampling,
Ray &ray, Vec3f &throughput, Vec3f &emission, bool &wasSpecular)
{
wasSpecular = !enableLightSampling;
if (!adjoint && enableLightSampling && bounce < _settings.maxBounces - 1)
emission += throughput*volumeEstimateDirect(sampler, mediumSample, medium, bounce + 1, ray);
PhaseSample phaseSample;
if (!mediumSample.phase->sample(sampler, ray.dir(), phaseSample))
return false;
ray = ray.scatter(mediumSample.p, phaseSample.w, 0.0f);
ray.setPrimaryRay(false);
throughput *= phaseSample.weight;
return true;
}
Vec3f ExponentialMedium::transmittanceAndPdfs(PathSampleGenerator &/*sampler*/, const Ray &ray, bool startOnSurface,
bool endOnSurface, float &pdfForward, float &pdfBackward) const
{
float x = _falloffScale*(ray.pos() - _unitPoint).dot(_unitFalloffDirection);
float dx = _falloffScale*ray.dir().dot(_unitFalloffDirection);
if (ray.farT() == Ray::infinity() && dx <= 0.0f) {
pdfForward = pdfBackward = 0.0f;
return Vec3f(0.0f);
}
Vec3f transmittance = std::exp(-_sigmaT*densityIntegral(x, dx, ray.farT()));
if (_absorptionOnly) {
pdfForward = pdfBackward = 1.0f;
} else {
pdfForward = endOnSurface ? transmittance.avg() : (density(x, dx, ray.farT())*_sigmaT*transmittance).avg();
pdfBackward = startOnSurface ? transmittance.avg() : (density(x, dx, 0.0f)*_sigmaT*transmittance).avg();
}
return transmittance;
}
bool Cube::occluded(const Ray &ray) const
{
Vec3f p = _invRot*(ray.pos() - _pos);
Vec3f d = _invRot*ray.dir();
Vec3f invD = 1.0f/d;
Vec3f relMin((-_scale - p));
Vec3f relMax(( _scale - p));
float ttMin = ray.nearT(), ttMax = ray.farT();
for (int i = 0; i < 3; ++i) {
if (invD[i] >= 0.0f) {
ttMin = max(ttMin, relMin[i]*invD[i]);
ttMax = min(ttMax, relMax[i]*invD[i]);
} else {
ttMax = min(ttMax, relMin[i]*invD[i]);
ttMin = max(ttMin, relMax[i]*invD[i]);
}
}
return ttMin <= ttMax;
}
