Method PickSegments

GTE/Graphics/Picker.cpp:376–443

}

void Picker::PickSegments(std::shared_ptr<Visual> const& visual, char const* positions,
    uint32_t vstride, IndexBuffer* ibuffer, Line3<float> const& line)
{
    // Compute distances from the model-space segments to the line.
    uint32_t const firstSegment = ibuffer->GetFirstPrimitive();
    uint32_t const numSegments = ibuffer->GetNumActivePrimitives();
    bool isIndexed = ibuffer->IsIndexed();
    IPType primitiveType = ibuffer->GetPrimitiveType();
    for (uint32_t i = firstSegment; i < firstSegment + numSegments; ++i)
    {
        // Get the vertex indices for the segment.
        uint32_t v0, v1;
        if (isIndexed)
        {
            ibuffer->GetSegment(i, v0, v1);
        }
        else if (primitiveType == IP_POLYSEGMENT_DISJOINT)
        {
            v0 = 2 * i;
            v1 = v0 + 1;
        }
        else  // primitiveType == IP_POLYSEGMENT_CONTIGUOUS
        {
            v0 = i;
            v1 = v0 + 1;
        }

        // Get the vertex positions.
        auto p0 = *reinterpret_cast<Vector3<float> const*>(positions + static_cast<size_t>(v0) * vstride);
        auto p1 = *reinterpret_cast<Vector3<float> const*>(positions + static_cast<size_t>(v1) * vstride);

        // Create the query segment in model space.
        Segment3<float> segment(p0, p1);

        // Compute segment-line distance.
        DCPQuery<float, Line3<float>, Segment3<float>> query;
        auto result = query(line, segment);
        if (result.distance <= mMaxDistance && mTMin <= result.parameter[0] && result.parameter[0] <= mTMax)
        {
            PickRecord record;
            record.visual = visual;
            record.primitiveType = primitiveType;
            record.primitiveIndex = i;
            record.vertexIndex[0] = static_cast<int32_t>(v0);
            record.vertexIndex[1] = static_cast<int32_t>(v1);
            record.vertexIndex[2] = -1;
            record.t = result.parameter[0];
            record.bary[0] = 1.0f - result.parameter[1];
            record.bary[1] = result.parameter[1];
            record.bary[2] = 0.0f;
            record.linePoint = HLift(result.closest[0], 1.0f);
            record.primitivePoint = HLift(result.closest[1], 1.0f);

#if defined (GTE_USE_VEC_MAT)
            record.linePoint = record.linePoint * visual->worldTransform;
            record.primitivePoint = record.primitivePoint * visual->worldTransform;
#else
            record.linePoint = visual->worldTransform * record.linePoint;