[2/5] WineD3D: Add an internal event query finish function

[Henri Verbeet]

On 16 February 2010 14:59, Stefan Dösinger <stefandoesinger at gmx.at> wrote:
>

Patch 1:
>      if (!pData || !dwSize) return S_OK;
...
> +    if (data)
This should be unnecessary, since you already checked "pData" above.
Otherwise the patch looks reasonable.

Patch 4:
> +        GLenum gl_ret = GL_EXTCALL(glClientWaitSync(query->object.sync, GL_SYNC_FLUSH_COMMANDS_BIT, ~0U));
...
> +            /* We don't expect a timeout for a ~584 year wait */
Actually, ~0U would be slightly more than 4 seconds.

Patch 7:
> +    for(i = 0; i < This->num_buffer_queries; i++)
> +    {
> +        wined3d_event_query_issue(This->buffer_queries[i], This);
> +    }
You should do this before the flush, otherwise the query might never
finish if it's in a different context.

> Concerning GL_SYNC_FLUSH_COMMANDS:
>> You certainly need to flush, but that's not the point. Using
>> GL_SYNC_FLUSH_COMMANDS is either unnecessary if you already flush
>> after glFenceSync(), or doesn't solve the problem for fences in
>> different contexts if you don't. Note that the existing code doesn't
>> have to flush after glFenceSync() because we use a 0 timeout in
>> GetData().
> The existing code has to honor D3DGETDATA_FLUSH if the app passes it. The 0 timeout doesn't help us if the app does something like this
>
> BOOL data;
> do
> {
>    IWineD3DQuery_GetData(event_query, D3DGETDATA_FLUSH, &data);
> } while(!data);
>
> in a single threaded environment.
>
Sure, but if you want queries to work reliably across contexts you
need to flush after issuing them.