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visit-dav / visit

VisIt - Visualization and Data Analysis for Mesh-based Scientific Data
https://visit.llnl.gov
BSD 3-Clause "New" or "Revised" License
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OSPRay shadows accumulate #4355

Open aowen87 opened 4 years ago

aowen87 commented 4 years ago

Describe the bug

This is related to #3480 When rendering with OSPRay, shadows have some odd behaviors. When shadows are first enabled, the rendered shadows are fairly faint. If you click on the render screen once, the shadows get slightly darker. If you continue clicking, the shadows continue to get darker until they are fully black. The same behavior occurs when disabling shadows; they slowly reduce in intensity with each mouse click.

If you click and drag the render screen, this process seems to accelerate, and the result is that the shadows appear to suddenly get dark or suddenly vanish.

Helpful additional information (Please click check boxes AFTER submitting ticket)

Impact

Likelihood

Expected behavior

Shadows should not darken/lighten depending on independent mouse clicks; there should be some consistency, and they should really only change as the lighting changes.

aowen87 commented 4 years ago

clicking "Draw" seems to bypass this problem completely; the shadows will vanish/appear immediately.

aowen87 commented 4 years ago

This issue is not just with shadows. It also exists with the ambient occlusion samples, annotation objects, and probably others.

ARSanderson commented 3 years ago

I am able to duplicate this issue on VTK master / OSPRay 2.5 by turning shadows on and changing the AO samples.

If I increase the AO sampling and repeatedly press "apply" the shadow is lighter. But if I rotate it immediately gets lighter. The opposite happens if I reduce the AO sampling.

I have been able to duplicate this issue in the VTK TestRendererType test. As such, it is not VisIt. but further down the pipeline. I have submitted an issue with VTK:

https://gitlab.kitware.com/vtk/vtk/-/issues/18217