Exemple #1
0
bool Cube::samplePosition(PathSampleGenerator &sampler, PositionSample &sample) const
{
    float u = sampler.next1D();
    int dim = sampleFace(u);
    float s = (dim + 1) % 3;
    float t = (dim + 2) % 3;

    Vec2f xi = sampler.next2D();

    Vec3f n(0.0f);
    n[dim] = u < 0.5f ? -1.0f : 1.0f;

    Vec3f p(0.0f);
    p[dim] = n[dim]*_scale[dim];
    p[s] = (xi.x()*2.0f - 1.0f)*_scale[s];
    p[t] = (xi.y()*2.0f - 1.0f)*_scale[t];

    sample.p = _rot*p + _pos;
    sample.pdf = _invArea;
    sample.uv = xi;
    sample.weight = PI*_area*(*_emission)[sample.uv];
    sample.Ng = _rot*n;

    return true;
}
bool MultiQuadLight::sampleDirect(uint32 threadIndex, const Vec3f &p, PathSampleGenerator &pathSampler, LightSample &sample) const
{
    float xi = pathSampler.next1D(EmitterSample);

    ThreadlocalSampleInfo &sampler = *_samplers[threadIndex];

    std::pair<int, float> result = _sampleBvh->sampleLight(p, &sampler.sampleWeights[0],
            &sampler.insideIds[0], xi, [&](uint32 id) {
        return approximateQuadContribution(p, id);
    });
    if (result.first == -1)
        return false;

    int idx = pathSampler.next1D(EmitterSample) < 0.5f ? result.first*2 : result.first*2 + 1;

    const QuadGeometry::TriangleInfo &t = _geometry.triangle(idx);

    Vec3f q = SampleWarp::uniformTriangle(pathSampler.next2D(EmitterSample), t.p0, t.p1, t.p2);
    Vec3f L = q - p;

    float rSq = L.lengthSq();
    sample.dist = std::sqrt(rSq);
    sample.d = L/sample.dist;
    float cosTheta = -(t.Ng.dot(sample.d));
    if (cosTheta <= 0.0f)
        return false;
    sample.pdf = result.second*0.5f*rSq/(cosTheta*_triangleAreas[idx]);

    return true;
}
bool IsotropicPhaseFunction::sample(PathSampleGenerator &sampler, const Vec3f &/*wi*/, PhaseSample &sample) const
{
    sample.w = SampleWarp::uniformSphere(sampler.next2D());
    sample.weight = Vec3f(1.0f);
    sample.pdf = SampleWarp::uniformSpherePdf();
    return true;
}
Exemple #4
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bool Quad::sampleDirection(PathSampleGenerator &sampler, const PositionSample &/*point*/, DirectionSample &sample) const
{
    Vec3f d = SampleWarp::cosineHemisphere(sampler.next2D(EmitterSample));
    sample.d = _frame.toGlobal(d);
    sample.weight = Vec3f(1.0f);
    sample.pdf = SampleWarp::cosineHemispherePdf(d);

    return true;
}
Exemple #5
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bool Cube::sampleDirection(PathSampleGenerator &sampler, const PositionSample &point, DirectionSample &sample) const
{
    Vec3f d = SampleWarp::cosineHemisphere(sampler.next2D());
    sample.d = TangentFrame(point.Ng).toGlobal(d);
    sample.weight = Vec3f(1.0f);
    sample.pdf = SampleWarp::cosineHemispherePdf(d);

    return true;
}
Exemple #6
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bool Quad::samplePosition(PathSampleGenerator &sampler, PositionSample &sample) const
{
    Vec2f xi = sampler.next2D(EmitterSample);
    sample.p = _base + xi.x()*_edge0 + xi.y()*_edge1;
    sample.pdf = _invArea;
    sample.uv = xi;
    sample.weight = PI*_area*(*_emission)[sample.uv];
    sample.Ng = _frame.normal;

    return true;
}
bool EquirectangularCamera::sampleDirection(PathSampleGenerator &sampler, const PositionSample &/*point*/, Vec2u pixel,
        DirectionSample &sample) const
{
    float pdf;
    Vec2f uv = (Vec2f(pixel) + 0.5f + _filter.sample(sampler.next2D(), pdf))*_pixelSize;

    float sinTheta;
    sample.d = uvToDirection(uv, sinTheta);
    sample.weight = Vec3f(1.0f);
    sample.pdf = INV_PI*INV_TWO_PI/sinTheta;

    return true;
}
Exemple #8
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bool Quad::sampleDirect(uint32 /*threadIndex*/, const Vec3f &p, PathSampleGenerator &sampler, LightSample &sample) const
{
    if (_frame.normal.dot(p - _base) <= 0.0f)
        return false;

    Vec2f xi = sampler.next2D(EmitterSample);
    Vec3f q = _base + xi.x()*_edge0 + xi.y()*_edge1;
    sample.d = q - p;
    float rSq = sample.d.lengthSq();
    sample.dist = std::sqrt(rSq);
    sample.d /= sample.dist;
    float cosTheta = -_frame.normal.dot(sample.d);
    sample.pdf = rSq/(cosTheta*_area);

    return true;
}
Exemple #9
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bool PinholeCamera::sampleDirection(PathSampleGenerator &sampler, const PositionSample &/*point*/, Vec2u pixel,
        DirectionSample &sample) const
{
    float pdf;
    Vec2f uv = _filter.sample(sampler.next2D(CameraSample), pdf);
    Vec3f localD = Vec3f(
        -1.0f  + (float(pixel.x()) + 0.5f + uv.x())*2.0f*_pixelSize.x(),
        _ratio - (float(pixel.y()) + 0.5f + uv.y())*2.0f*_pixelSize.x(),
        _planeDist
    ).normalized();

    sample.d =  _transform.transformVector(localD);
    sample.weight = Vec3f(1.0f);
    sample.pdf = _invPlaneArea/cube(localD.z());

    return true;
}
Exemple #10
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bool CubemapCamera::sampleDirection(PathSampleGenerator &sampler, const PositionSample &/*point*/, Vec2u pixel,
        DirectionSample &sample) const
{
    Vec2f uv = (Vec2f(pixel) + 0.5f)*_pixelSize;

    int face;
    if (!uvToFace(uv, face))
        return false;

    float filterPdf;
    uv += _filter.sample(sampler.next2D(CameraSample), filterPdf)*_pixelSize;

    sample.d = uvToDirection(face, uv, sample.pdf);
    sample.weight = Vec3f(1.0f);

    return true;
}
bool HenyeyGreensteinPhaseFunction::sample(PathSampleGenerator &sampler, const Vec3f &wi, PhaseSample &sample) const
{
    Vec2f xi = sampler.next2D(MediumPhaseSample);
    if (_g == 0.0f) {
        sample.w = SampleWarp::uniformSphere(xi);
        sample.weight = Vec3f(1.0f);
        sample.pdf = SampleWarp::uniformSpherePdf();
    } else {
        float phi = xi.x()*TWO_PI;
        float cosTheta = (1.0f + _g*_g - sqr((1.0f - _g*_g)/(1.0f + _g*(xi.y()*2.0f - 1.0f))))/(2.0f*_g);
        float sinTheta = std::sqrt(max(1.0f - cosTheta*cosTheta, 0.0f));
        sample.w = TangentFrame(wi).toGlobal(Vec3f(
            std::cos(phi)*sinTheta,
            std::sin(phi)*sinTheta,
            cosTheta
        ));
        sample.weight = Vec3f(1.0f);
        sample.pdf = henyeyGreenstein(cosTheta);
    }
    return true;
}
Exemple #12
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bool PinholeCamera::sampleDirection(PathSampleGenerator &sampler, const PositionSample &point,
        DirectionSample &sample) const
{
    Vec2u pixel(sampler.next2D(CameraSample)*Vec2f(_res));
    return sampleDirection(sampler, point, pixel, sample);
}