VTK8.2: Color buffer depth

Development
1

I’m currently running VTK8.2 and python3.7 on the new Mac Mini 2018. However, the vtkPropPicker throw the following error:

ERROR: In /VTK 8.2.0/Rendering/Core/vtkHardwareSelector.cxx, line 288
vtkOpenGLHardwareSelector (0x7fa1d4a9aa80): Color buffer depth must be at least 8 bit. Currently: 0, 8, 8

The vtkPropPicker was working with VTK8.1 but not sure why it does not work with VTK8.2

2

I believe this is fixed in VTK master.

3

Yes. This problem is resolved in VTK-master.

4

Hi,

I’m still experiencing issues with the colorbuffer in my picker. Is this problem resolved in the final 8.2.0 release (current release branch 3bea923b3c)?

If not, could you point me to the commit that fixed the issue in the master branch?

Thanks,
Christophe

5

Fixed in https://gitlab.kitware.com/vtk/vtk/merge_requests/4940 which is 7 months old but too new for 8.2

6

Hi Ken,

Thanks for the info. I fixed my issues by turning off FXAA anti-aliassing, don’t really know why that influenced the color buffer.

7

I can answer that :slight_smile: The color buffer code checks for error conditions and if it finds an error it returns 0 for that color. Unfortunately the old code did not clear any prior errors before checking. So any prior OpenGL error would cause the red channel to report 0 depth. In this case it seems FXAA is causing an OpenGL error on your system which then causes the issue in reporting the color depth. The fixed code should be immune to prior opengl errors.

8

Hello,
I’m running into the same problem here on tag v8.2.0, running under iOS simulator.
I tried turning the FXAA off with no success. I also applied the error cleaning part of the patch mentioned above (couldn’t apply the patch directly - too far from v8.2.0):

// make sure we clear any errors before we start
// otherwise we may get incorrect results
while (glGetError() != GL_NO_ERROR)
{
}

Error persists!
Would the iOS simulator and OpenGL2 combination be the problem?
Thanks a lot in advance