[3/5] WineD3D: Set WINED3D_BUFFER_CREATEBO in buffer_init

[Roderick Colenbrander]

On Tue, Dec 22, 2009 at 6:44 PM, Henri Verbeet <hverbeet at gmail.com> wrote:
> 2009/12/22 Stefan Dösinger <stefan at codeweavers.com>:
>> +    conv = ((FVF & WINED3DFVF_POSITION_MASK) == WINED3DFVF_XYZRHW ) || (FVF & (WINED3DFVF_DIFFUSE | WINED3DFVF_SPECULAR));
>>      hr = buffer_init(object, This, Size, Usage, WINED3DFMT_VERTEXDATA,
>> -            Pool, GL_ARRAY_BUFFER_ARB, NULL, parent, parent_ops);
>> +            Pool, GL_ARRAY_BUFFER_ARB, NULL, parent, parent_ops, conv);
> This looks questionable, we use the FVF to determine that the buffer
> is going to need conversion, but don't pass that FVF to the buffer
> itself? Shouldn't this just use the existing code in buffer.c to
> determine when we need conversion in the first place, and just drop
> the VBO when the overhead becomes too large? Note that if we have
> EXT_vertex_array_bgra we don't need conversion for the color data in
> the first place.
>

The code mentions that when conversion is needed no VBO is created
because conversion on the VBO memory in combination with uploading and
drawStridedFast is slower than drawStridedSlow. The buffer object
extensions discourage to perform much operations on buffer memory
because typically it is uncached. Have you tried to perform conversion
on a normal memory buffer and compared performance to doing the same
on VBO memory? It might make sense to do the conversion on a normal
memory buffer and memcpy that contents to a VBO? That way you still
profit from the async uploads to the GPU and the conversion itself.

Roderick