Method Execute

Hydrogent/src/Tasks/HnBeginFrameTask.cpp:671–724

}

void HnBeginFrameTask::Execute(pxr::HdTaskContext* TaskCtx)
{
    if (m_RenderIndex == nullptr)
    {
        UNEXPECTED("Render index is null. This likely indicates that Prepare() has not been called.");
        return;
    }

    HnRenderDelegate* RenderDelegate = static_cast<HnRenderDelegate*>(m_RenderIndex->GetRenderDelegate());
    IDeviceContext*   pCtx           = RenderDelegate->GetDeviceContext();

    // NB: we can't move the buffer update to Prepare() because we need TAA parameters
    //     that are set by HnPostProcessTask::Prepare().
    if (IBuffer* pFrameAttribsCB = RenderDelegate->GetFrameAttribsCB())
    {
        float2 JitterOffsets{0, 0};
        bool   UseTAA = false;
        // Set by HnPostProcessTask::Prepare()
        GetTaskContextData(TaskCtx, HnRenderResourceTokens->taaJitterOffsets, JitterOffsets);
        GetTaskContextData(TaskCtx, HnRenderResourceTokens->useTaa, UseTAA);

        bool FallBackPsoInUse = false;
        if (GetTaskContextData(TaskCtx, HnRenderResourceTokens->fallBackPsoInUse, FallBackPsoInUse, /*Required = */ false))
        {
            if (FallBackPsoInUse)
            {
                if (m_FallBackPsoUseStartTime < 0)
                {
                    // Fallback PSO is in use for the first time
                    m_FallBackPsoUseStartTime = m_CurrFrameTime;
                    m_FallBackPsoUseEndTime   = -1;
                }
            }
            else if (m_FallBackPsoUseEndTime < 0)
            {
                // First frame after fallback PSO was used
                m_FallBackPsoUseEndTime = m_CurrFrameTime;
            }
        }
        // Reset the fallBackPsoInUse flag.
        // HnRenderRprimsTask::Execute sets it to true if the fallback PSO was used.
        (*TaskCtx)[HnRenderResourceTokens->fallBackPsoInUse] = pxr::VtValue{false};

        bool CameraTransformDirty = false;
        UpdateFrameConstants(pCtx, pFrameAttribsCB, UseTAA, JitterOffsets, CameraTransformDirty);
        (*TaskCtx)[HnRenderResourceTokens->frameShaderAttribs] = pxr::VtValue{reinterpret_cast<HLSL::PBRFrameAttribs*>(m_FrameAttribsData.data())};
        // Will be used by HnPostProcessTask::Execute()
        (*TaskCtx)[HnRenderResourceTokens->cameraTransformDirty] = pxr::VtValue{CameraTransformDirty};
    }
    else
    {
        UNEXPECTED("Frame attribs constant buffer is null");
    }
}

} // namespace USD