This is to allow StretchRect to pass the texture filter to WineD3D.
DirectDraw sets the texture filter to WINED3DTEXF_NONE, simmilar to all
other functions which do not need filtering.
Previously the surfaces stored a flag if the system memory copy was
ahead of the gl copy(SFLAG_DIRTY) or the gl copy is
ahead(SFLAG_GLDIRTY). The pbuffer copy was 'managed' differently using
SFLAG_INPBUFFER and SFLAG_INTEXTURE.
This patch replaces them with 3 flags, INSYSMEM, INPBUFFER and
INTEXTURE which specify which copy contains the most up to date
copy. It is perfectly valid to have more than one of those flags
set. One must be set at least (except at init, when no content is in
the surface yet). When one copy is modified, the flags for the others
are removed.
The method is removed because it does not really help with
anything. It should not be exported from wined3d, there is no need for
the other libs to call it. It does not help abstraction and code
simplification in any way because it is very specific and the code
calling it has to know what is happening in the surface to use this
method.
This helps performance a bit because the function does not have to
wait for the 2nd read to finish before returning. Only do that if we
have an aux buffer to mess with for free though.
Plain OpenGL does not provide any signed pixel formats, so the
unsigned GL_RGB is used for loading perturbation data into pixel
shaders that use texbem. For correct loading, the signedness has to be
considered.
The hwstretch blit code creates a new texture each time it is called
to back up the back buffer and releases it afterwards. It is more
efficient to keep the texture and release it with the surface.
OpenGL AUX buffers provide a way for offscreen rendering which is very
similar to our back buffer "offscreen" rendering emulation. Not all
card support aux buffers, but if they are available they are a nice
present which is easy to use.
Until we have proper subrectangle handling for offscreen surfaces,
surface conversion has to use the real surface sizes, and not the size
of the opengl subrectangle that it is going to upload. Due to the
power of 2 limitations the gl height may be bigger than the real
surface height. If that is not the case, the uploading function will
pick the correct parts from the converted surface data.
