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Hi. I have been programming dx12 for nearly 6 months now and I think I still have a misuderstanding on swapchain flags and how they affect presentation. please correct me if I am wrong. My understanding is the following:

- DX12 only supports two swap effect flags with the flip model. ie DXGI_SWAP_EFFECT_FLIP_DISCARD and DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL . My understanding is that both these flags don't need a redirection surface hence the contents of backbuffers are displayed to the screen directly from app. The DXGI_SWAP_EFFECT_FLIP_DISCARD flag allows for an option were if the presentation queue is full and the call to IDXGISwapChain::Present() is made, whatever is at the end of this queue is discarded without ever making it to the screen, is this correct? The DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL inserts the frame to be presented at the end of the queue. does this mean that the queue can only contain one buffer at a time?

- Both DXGI_SWAP_EFFECT_FLIP_DISCARD and DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL dont support multisampling. So i have had to set my sample count to 1 and sample quality to 0 for my swapchain desc structure. My question is how would we add support for multisampling like 4xMSAA if these are the only flags supported in dx12. I have seen some usages were these were set to sample count > 1 and quality level queried which leaves me confused. I still have'nt tested multisampling as I don't use them in my experimental engine.

- The waitable Swapchain options blocks present thread from the calling application until the specified time to wait on elapses. But why would we explicilly specify wait time on swapchain?

- tearing support is included by the GPU vendor. So this allows for options like freesync and gsync to be utilized. I am using an intel gpu and I don't really know how to test this.

- It isn't a requirement for apps to toggle vsync-on on a windowed app. This is also confusing. Won't screen tearing happen anyway if my app is not synchronized with my next screen vertical blank?

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Thank you so much for taking the time to respond . This has cleared things up for me . I read carefully and will consider these options when I refactor my code. 

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