Mip filter is causing image to shift

This topic contains 1 reply, has 2 voices, and was last updated by  Tobias Hector 4 years, 4 months ago.

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  • #31303

    BrianL76
    Member

    I’ve recently updated to the latest release. I hadn’t looked at this issue before, so I can’t say if it has always been there. However, it currently appears as though the filter for the mips is being applied in such a way that it’s causing the image to shift up and to the right. I assume it has to do with not centering the filter around the texel that’s being sampled.

    Anyway, here’s a comparison between an older version of the NVidia Texture Tools compressor (left) and the latest PVR compressor (right). With the images laid out in this manner, it’s a bit tough to see the shift, but it’s definitely present. If you flip through them rapidly, it’s easier to see.

    Also, for some reason compressing to DXT1 results in a black image. DXT5 seems to work fine.

    #37435

    Hi Brian,

    This is actually a known issue which has been fixed in the latest PVRTexTool which should be released by the end of the week. There are also other known issues with the way PVRTexTool resizes images which should be addressed in the 3.2 release at the end of August.

    As for the DXTC issue, I believe this is probably tied to one of two other recent fixes I made – is the image a power of two image, or does it have alpha values? There are possibilities that either of these things could cause the problem. Again, this should be fixed in the update at the end of the week.

    Regards,
    Tobias

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