Test offscreen rendering with VTK 6

compile_run.sh

#! /bin/bash

set -e

g++ -o test_offscreen.o -c test_offscreen.cpp -I$PYTHONHPC/include/vtk-6.0
g++ -o test_offscreen test_offscreen.o $PYTHONHPC/lib/libvtk*.so
LD_LIBRARY_PATH=$PYTHONHPC/lib/ ./test_offscreen

sphere.png

test_offscreen.cpp

// These 2 lines are needed due to:
// http://www.vtk.org/Wiki/VTK/VTK_6_Migration/Factories_now_require_defines
#define vtkRenderingCore_AUTOINIT 4(vtkInteractionStyle,vtkRenderingFreeType,vtkRenderingFreeTypeOpenGL,vtkRenderingOpenGL)
#define vtkRenderingVolume_AUTOINIT 1(vtkRenderingVolumeOpenGL)

#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkPolyData.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>
#include <vtkWindowToImageFilter.h>
#include <vtkPNGWriter.h>
#include <vtkGraphicsFactory.h>

int main ()
{
    //sphere 1
    vtkSmartPointer<vtkSphereSource> sphereSource = vtkSmartPointer<vtkSphereSource>::New();

    vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
    mapper->SetInputConnection(sphereSource->GetOutputPort());


    vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
    actor->SetMapper(mapper);

    // a renderer and render window
    vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
    vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
    renderWindow->SetOffScreenRendering(1);
    renderWindow->AddRenderer(renderer);

    // add the actors to the scene
    renderer->AddActor(actor);
    renderer->SetBackground(1, 1, 1); // Background color white

    renderWindow->Render();

    vtkSmartPointer<vtkWindowToImageFilter> windowToImageFilter =
        vtkSmartPointer<vtkWindowToImageFilter>::New();
    windowToImageFilter->SetInput(renderWindow);
    windowToImageFilter->Update();

    vtkSmartPointer<vtkPNGWriter> writer = vtkSmartPointer<vtkPNGWriter>::New();
    writer->SetFileName("sphere.png");
    writer->SetInputConnection(windowToImageFilter->GetOutputPort());
    writer->Write();

    return 0;
}

test_offscreen.py

#! ./local/bin/python

from vtk import (vtkSphereSource, vtkPolyDataMapper, vtkActor, vtkRenderer,
        vtkRenderWindow, vtkWindowToImageFilter, vtkPNGWriter)

sphereSource = vtkSphereSource()
mapper = vtkPolyDataMapper()
mapper.SetInputConnection(sphereSource.GetOutputPort())

actor = vtkActor()
actor.SetMapper(mapper)

renderer = vtkRenderer()
renderWindow = vtkRenderWindow()
renderWindow.SetOffScreenRendering(1)
renderWindow.AddRenderer(renderer)

renderer.AddActor(actor)
renderer.SetBackground(1, 1, 1)

renderWindow.Render()

windowToImageFilter = vtkWindowToImageFilter()
windowToImageFilter.SetInput(renderWindow)
windowToImageFilter.Update()

writer = vtkPNGWriter()
writer.SetFileName("sphere.png")
writer.SetInputConnection(windowToImageFilter.GetOutputPort())
writer.Write()

A small tip in case anyone is wondering: If you want a transparent (alpha 0) background: renderWindow.SetAlphaBitPlanes(1) and windowToImageFilter.SetInputBufferTypeToRGBA().

Does this support running on a headerless remote server?

@Guptajakala I think it did, but this is a very old set of scripts, over 6 years old at this point, so it might not compile properly anymore.

@Guptajakala I think it did, but this is a very old set of scripts, over 6 years old at this point, so it might not compile properly anymore.

I just compiled VTK-9.0.1 with OSMESA enabled.

Following the guide and replace the OffScreenRendering.cxx file content with your test_offscreen.cpp, it works.

@Guptajakala I think it did, but this is a very old set of scripts, over 6 years old at this point, so it might not compile properly anymore.

I just compiled VTK-9.0.1 with OSMESA enabled.

Following the guide and replace the OffScreenRendering.cxx file content with your test_offscreen.cpp, it works.

thank you!

Perfect, I am glad it is still useful!

…

On Wed, Jul 1, 2020, at 5:52 AM, Bingliang wrote: ***@***.**** commented on this gist. > @Guptajakala <https://github.com/Guptajakala> I think it did, but this is a very old set of scripts, over 6 years old at this point, so it might not compile properly anymore. I just compiled VTK-9.0.1 with OSMESA enabled. Following the guide <https://lorensen.github.io/VTKExamples/site/Cxx/Utilities/OffScreenRendering/> and replace the `OffScreenRendering.cxx` file content with your `test_offscreen.cpp`, it works. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <https://gist.github.com/5687727#gistcomment-3360632>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAFAWAXCBPQJON6UM4PSWDRZMPPLANCNFSM4J2YBOVQ>.