Optimize texture MIPmap level switching for TIFF textures -- when merely switching MIP levels, almost no metadata is changing, so there's no need to clear m_spec and rediscover all the metadata from scratch.
Optimize texture MIPmap level switching for TIFF textures -- when merely
switching MIP levels, almost no metadata is changing, so there's no need
to clear m_spec and rediscover all the metadata from scratch.

mcanthony/oiio,cwilling/oiio,OpenImageIO/oiio,lgritz/oiio,mcanthony/oiio,bdeluca/oiio,YangYangTL/oiio,micler/oiio,scott-wilson/oiio,lgritz/oiio,jeremyselan/oiio,sambler/oiio,bdeluca/oiio,scott-wilson/oiio,cwilling/oiio,micler/oiio,OpenImageIO/oiio,cwilling/oiio,mcanthony/oiio,sambler/oiio,OpenImageIO/oiio,YangYangTL/oiio,scott-wilson/oiio,sambler/oiio,bdeluca/oiio,cwilling/oiio,jeremyselan/oiio,micler/oiio,YangYangTL/oiio,sambler/oiio,lgritz/oiio,OpenImageIO/oiio,mcanthony/oiio,lgritz/oiio,YangYangTL/oiio,bdeluca/oiio,scott-wilson/oiio,micler/oiio,jeremyselan/oiio