It might seem like a good idea to try to use glMapBufferRange() in
buffer_direct_upload(), but it really isn't. The interesting cases for
glMapBufferRange() are GL_MAP_INVALIDATE_BUFFER_BIT or
GL_MAP_UNSYNCHRONIZED_BIT, but the only way for those to be set here
would be for the buffer to be mapped with WINED3D_MAP_DISCARD or
WINED3D_MAP_NOOVERWRITE before the buffer object was created. In that
case the GPU is obviously not using the buffer object, so
glMapBufferRange() doesn't help. On the other hand, if the buffer is
currently in use by the application and neither WINED3D_MAP_DISCARD nor
WINED3D_MAP_NOOVERWRITE is set, glMapBufferRange() would need to wait
for the GPU to finish using the buffer object, while glBufferSubData()
may decide not to.
Signed-off-by: Henri Verbeet <hverbeet@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>