how to adjust gl_pointSize when zoom in/out

Support
,
1

Hi everyone,

I have a problem need the support. I’m using vtk with python using vtkInteractorStyleTrackballCamera with the setting

``
self.interactor_style = vtk.vtkInteractorStyleTrackballCamera()
self.interactor.SetInteractorStyle(self.interactor_style)
self.interactor_style.AutoAdjustCameraClippingRangeOff()
camera = self.renderer.GetActiveCamera()
camera.ParallelProjectionOn()
```

and display a pointcloud using vtkOpenGLPolyDataMapper with input from vtkVertexGlyphFilter.
Now I want to adjust the gl_pointSize using glsl vertextShader, like when zoom in the point becomes bigger. I set SetUseProgramPointSize(True) and tried with many MC..Matrix but didn’t work.
any help would be appreciated