d3d12::Buffer::UnmapImpl() was passing an empty range to
ID3D12Resource::Unmap(). This causes it to be a no-op when writing a
buffer. The fix is to store the entire mapped range in the Buffer,
and use it during Unmap().
Note: this doesn't seem to actually cause an issue on the D3D12 drivers I
have, so I have been unable to write a test for it. However, it does cause
an issue in RenderDoc: the buffer data appears unmodifed after the
Map/memcpy/Unmap calls. The hypothesis is that RenderDoc notices the empty
range at the API level, and leaves its shadow buffer contents unmodified.
Because I feel this change is correct regardless, I'm landing it without
a test.
Bug: dawn:25
Change-Id: Ie5dd5fcfedbe1d80c75a3d8094c97af27653ee00
Reviewed-on: https://dawn-review.googlesource.com/c/1920
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Stephen White <senorblanco@chromium.org>
3f06587542