Method Sync

Hydrogent/src/HnLight.cpp:427–635

}

void HnLight::Sync(pxr::HdSceneDelegate* SceneDelegate,
                   pxr::HdRenderParam*   RenderParam,
                   pxr::HdDirtyBits*     DirtyBits)
{
    if (*DirtyBits == pxr::HdLight::Clean)
        return;

    const pxr::SdfPath& Id = GetId();

    bool LightDirty = false;

    {
        bool IsVisible = SceneDelegate->GetVisible(Id);
        if (IsVisible != m_IsVisible)
        {
            m_IsVisible        = IsVisible;
            LightDirty         = true;
            m_IsShadowMapDirty = true;
        }
    }

    bool ShadowTransformDirty = false;
    if (*DirtyBits & DirtyTransform)
    {
        const pxr::GfMatrix4d Transform = SceneDelegate->GetTransform(Id);

        const float3 Position = ToFloat3(Transform.ExtractTranslation());
        if (Position != m_Position)
        {
            m_Position = Position;
            LightDirty = true;
        }

        // Convention is to emit light along -Z
        const pxr::GfVec4d zDir      = Transform.GetRow(2);
        const float3       Direction = -ToFloat3(pxr::GfVec3d{zDir[0], zDir[1], zDir[2]});
        if (Direction != m_Direction)
        {
            m_Direction = Direction;

            float3 LightSpaceX, LightSpaceY, LightSpaceZ;
            BasisFromDirection(m_Direction, true, LightSpaceX, LightSpaceY, LightSpaceZ);
            m_ViewMatrix = float4x4::ViewFromBasis(LightSpaceX, LightSpaceY, LightSpaceZ);

            LightDirty = true;
        }

        ShadowTransformDirty = true;

        *DirtyBits &= ~DirtyTransform;
    }

    if (*DirtyBits & DirtyParams)
    {
        auto LightType = GLTF::Light::TYPE::UNKNOWN;
        if (m_TypeId == pxr::HdPrimTypeTokens->distantLight)
        {
            LightType = GLTF::Light::TYPE::DIRECTIONAL;