Hello.

In D3D12HelloTriangle example there's an interesting synchronization in LoadAssets() function. They call WaitForPreviousFrame() function. I understand why we need it during a rendering. But in this particular example I can't get the purpose of a such synchronization. They are not submitting anything to the gpu (or they do???). They're using an upload heap for the single resource here - vertex buffer. As I understand the upload resource exists on the cpu side and the data is transferred every time the gpu needs it. So no need a fence here. They also create a root signature, pso, fence object itself. So maybe for this objects we need a synchronization? Is it somewhere in documentation?

Yeah, there's no need to wait for commands to finish executing because they don't actually issue any commands. If you look at some of the other samples, they all have a wait at the end of LoadAssets. They do this so that they can ensure that any GPU copies finish before they destroy upload resources. So for instance if you look at the HelloTexture sample, it goes like this:

• Create upload resource
• Map upload resource, and fill it with data
• Issue GPU copy commands on a direct command list
• Submit the direct command list
• Wait for the GPU to finish executing the command list
• ComPtr destructor calls Release on the upload resource, destroying it