[vtk-developers] Software vs hardware interpolation

[Kilgus, Thomas]

Hi,

as mentioned in my previous post (http://vtk.1045678.n5.nabble.com/software-rendering-td5557078.html ), I observed different interpolation behaviors in software and hardware rendering of images in VTK.

Here you can see an example: http://cdash.mitk.org/testDetails.php?test=2749290&build=107877

The test shows the result of an image rendered with software rendering. The input 5x5 pixel image is scaled (interpolated) to 8x8. If you render the same image with hardware support, a nearest neighbor interpolation will be applied and the result will look like the ValidImage on the bottom of the page. I don't think that any interpolation can be considered wrong or right, but I think both, software and hardware rendering, should have a common default behavior.

Please can anyone comment on this? Is there any possibility to enforce the same interpolation in software rendering? For reliable testing in different environments it is necessary both rendering methods act with the same default behavior, since it is not deterministic whether your machine is able to render with hardware support or with software rendering. (For instance a VPN connection established to a windows machine blocks the GPU for some reason, Virtual Machines show different behavior etc.)

Regards
Thomas

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