Class IntegerSampleStatistics

openpgl/data/SampleStatistics.h:248–433

#define INTEGER_SAMPLE_STATS_BOUND_SCALE (1.0f + 2.f / INTEGER_BINS)

struct IntegerSampleStatistics
{
    Point3i mean{0};
    Vector3i variance{0};
    uint32_t numSamples{0};
    // measured sample bound in the discretized integer domain
    BBoxi intSampleBounds{openpgl::Vector3i(std::numeric_limits<int>::max()), openpgl::Vector3i(-std::numeric_limits<int>::max())};
    // actual measured sample bound (float)
    BBox sampleBounds{openpgl::Vector3(std::numeric_limits<float>::max()), openpgl::Vector3(-std::numeric_limits<float>::max())};
    Vector3 sampleBoundsMin{0};
    Vector3 sampleBoundsMax{0};

    // sample bound stats to center the collected samples before discretization
    Vector3 sampleBoundsCenter{0};
    Vector3 sampleBoundsHalfExtend{0};
    Vector3 invSampleBoundsHalfExtend{0};

    IntegerSampleStatistics()
    {
        mean = Point3i(0);
        variance = Vector3i(0);
        numSamples = 0;
        intSampleBounds = BBoxi(openpgl::Vector3i(std::numeric_limits<int>::max()), openpgl::Vector3i(-std::numeric_limits<int>::max()));
        sampleBounds = BBox(openpgl::Vector3(std::numeric_limits<float>::max()), openpgl::Vector3(-std::numeric_limits<float>::max()));
        sampleBoundsMin = Vector3(0);
        sampleBoundsMax = Vector3(0);
        sampleBoundsCenter = Vector3(0);
        sampleBoundsHalfExtend = Vector3(0);
        invSampleBoundsHalfExtend = Vector3(0);
    }

    IntegerSampleStatistics(const BBox &bounds)
    {
        mean = Point3i(0);
        variance = Vector3i(0);
        numSamples = 0;
        intSampleBounds = BBoxi(openpgl::Vector3i(std::numeric_limits<int>::max()), openpgl::Vector3i(-std::numeric_limits<int>::max()));
        sampleBounds = BBox(openpgl::Vector3(std::numeric_limits<float>::max()), openpgl::Vector3(-std::numeric_limits<float>::max()));

        // scaling the boundary of the samples to avoid discretization problems at the boundaries
        BBox scaledBounds = bounds;
        Vector3 center = scaledBounds.center();
        scaledBounds.lower = center + INTEGER_SAMPLE_STATS_BOUND_SCALE * (scaledBounds.lower - center);
        scaledBounds.upper = center + INTEGER_SAMPLE_STATS_BOUND_SCALE * (scaledBounds.upper - center);

        sampleBoundsMin = scaledBounds.lower;
        sampleBoundsMax = scaledBounds.upper;
        sampleBoundsHalfExtend = (scaledBounds.upper - scaledBounds.lower) * 0.5f;

        // Checking and compenstaing for sampled bounds with dimensions of zero extend (e.g. plane)
        invSampleBoundsHalfExtend.x = sampleBoundsHalfExtend.x > 0.f ? 1.0f / sampleBoundsHalfExtend.x : 0.f;
        invSampleBoundsHalfExtend.y = sampleBoundsHalfExtend.y > 0.f ? 1.0f / sampleBoundsHalfExtend.y : 0.f;
        invSampleBoundsHalfExtend.z = sampleBoundsHalfExtend.z > 0.f ? 1.0f / sampleBoundsHalfExtend.z : 0.f;
        sampleBoundsCenter = sampleBoundsMin + sampleBoundsHalfExtend;

        OPENPGL_ASSERT(embree::isvalid(invSampleBoundsHalfExtend.x));
        OPENPGL_ASSERT(embree::isvalid(invSampleBoundsHalfExtend.y));
        OPENPGL_ASSERT(embree::isvalid(invSampleBoundsHalfExtend.z));