[PATCH] wined3d: Use query buffer objects for occlusion queries.

[Henri Verbeet]

On 3 September 2018 at 04:40, Andrew Wesie <awesie at gmail.com> wrote:
> +#define INVALID_QUERY_RESULT ((UINT64)-1)

While at least for occlusion queries this would be a very unlikely
result, it's not in general an invalid query result. I think ideally
we'd write QUERY_RESULT_AVAILABLE to the buffer object as well, but
based on the language in the extension spec, I don't see the
requirement that that should flush lifted. On the other hand, based on
a quick look at the Mesa source, it's not obvious to me that it
actually does flush. Perhaps this is ok in practice, and just an
oversight in the spec language.

Something else that's not entirely clear from the extension spec is
when glGetQueryObjectui64v(..., QUERY_RESULT,...) should return. I
think in practice it will return immediately, but based on the spec
language, perhaps an argument could be made that it should wait until
the data is in the buffer object, especially when that has been mapped
with MAP_COHERENT_BIT.