direct3d11: don't allocate texture sizes with half pixels
direct3d11: don't allocate texture sizes with half pixels

also only display pixels for that visible area

Signed-off-by: Hugo Beauzée-Luyssen <3faf7ed52fa83d583fc670a96bcf92da270d0767@beauzee.fr>

xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc