Coming back to an old project I noticed a memory leak while expanding the vertex buffer. The reason why I need to expand my vertex buffer is that some of my 3D objects grow to be more complex over time (and I can't tell beforehand which of them will grow). So, to expand the buffer I essentially create a larger buffer, copy the content from the old resource, and switch to the new one instead. See below for the sharpDX / pseudo code.
It's not the most efficient way I'm sure but it works. Notice that I do dispose my oldResource after copying. At first I just unmapped it and thought that it would be enough. It wasn't. It was leaking memory. After adding the Dispose command I got rid of the leak, although I started to experience crashes every now and then. It crashes because the device was removed (DXGI_ERROR_DEVICE_HUNG) at various locations in my code. Why?
After expanding the buffer I recreate the bundles etc, so they should all refer to the new location. Is some kind of fence needed? Then why did it work before adding the Dispose line?
Maybe I have just missed to update some part of the code about this new memory location.
If you have a proper way of expanding a vertex buffer “in flight” I'm all ears ?.
Resource newVertexBuffer = device.CreateCommittedResource(
new HeapProperties(HeapType.Default),
HeapFlags.None,
ResourceDescription.Buffer(newBufferSize),
ResourceStates.CopyDestination);
copyCommandList.CopyBufferRegion(
newVertexBuffer, 0, oldResource, 0, oldBufferSize);
copyCommandList.Close();
copyCommandQueue.ExecuteCommandList(copyCommandList);
copyCommandList.Reset(copyCommandAllocator, pipelineState);
WaitForCopy();
oldResource.Unmap(0);
oldResource.Dispose(); // <-- NOTE THIS ONE
oldResource = newVertexBuffer;
bufferView.BufferLocation = newVertexBuffer.GPUVirtualAddress;
bufferView.SizeInBytes = newBufferSize;
