Method GetModelSpacePlanes

GTE/Graphics/PlanarReflectionEffect.cpp:259–310

}

void PlanarReflectionEffect::GetModelSpacePlanes()
{
    for (size_t i = 0; i < mPlaneVisuals.size(); ++i)
    {
        auto const& visual = mPlaneVisuals[i];
        auto const& vbuffer = visual->GetVertexBuffer();
        auto const& vformat = vbuffer->GetFormat();

        // Verify the vertex format satisfies the constraints.
        int32_t index = vformat.GetIndex(VASemantic::POSITION, 0);
        LogAssert(
            index >= 0,
            "The POSITION semantic must occur with unit 0.");

        DFType posType = vformat.GetType(index);
        LogAssert(
            posType == DF_R32G32B32_FLOAT || posType == DF_R32G32B32A32_FLOAT,
            "The POSITION must be 3-tuple or 4-tuple float-valued.");

        uint32_t offset = vformat.GetOffset(index);
        LogAssert(
            offset == 0,
            "The POSITION must occur first in the vertex format.");

        // Get the first triangle's vertex indices.
        auto const& ibuffer = visual->GetIndexBuffer();
        IPType primitiveType = ibuffer->GetPrimitiveType();
        LogAssert(
            primitiveType == IPType::IP_TRIMESH,
            "The visual must have TRIMESH topology (for now).");

        // Get the first triangle's vertex indices. Get the model-space
        // vertices from the vertex buffer.
        std::array<uint32_t, 3> v{};
        ibuffer->GetTriangle(0, v[0], v[1], v[2]);
        char const* rawData = vbuffer->GetData();
        size_t const stride = static_cast<size_t>(vformat.GetVertexSize());
        std::array<Vector4<float>, 3> p{};
        for (size_t j = 0; j < 3; ++j)
        {
            auto vertices = reinterpret_cast<Vector3<float> const*>(
                rawData + v[j] * stride);
            p[j] = HLift(*vertices, 1.0f);
        }

        mPlaneOrigins[i] = p[0];
        mPlaneNormals[i] = UnitCross(p[2] - p[0], p[1] - p[0]);

        // The planar reflection effect is responsible for drawing the planes.
        visual->culling = CullingMode::ALWAYS;
    }
}