OffScreenRendering
vtk-examples/Cxx/Utilities/OffScreenRendering
Description¶
This example renders a scene directly to a file without displaying a window. You must turn on VTK_OPENGL_HAS_OSMESA in the VTK advanced build configuration.
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
OffScreenRendering.cxx
#include <vtkVersion.h>
#if VTK_MAJOR_VERSION >= 6
int main(int, char* argv[])
{
std::cout << argv[0] << " requires VTK 5.10 or earlier. This VTK version is "
<< vtkVersion::GetVTKVersion() << std::endl;
return EXIT_SUCCESS;
}
#else
#include <vtkActor.h>
#include <vtkGraphicsFactory.h>
#include <vtkImagingFactory.h>
#include <vtkPNGWriter.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>
#include <vtkWindowToImageFilter.h>
int main(int, char*[])
{
// Setup offscreen rendering
vtkSmartPointer<vtkGraphicsFactory> graphics_factory =
vtkSmartPointer<vtkGraphicsFactory>::New();
graphics_factory->SetOffScreenOnlyMode(1);
graphics_factory->SetUseMesaClasses(1);
vtkSmartPointer<vtkImagingFactory> imaging_factory =
vtkSmartPointer<vtkImagingFactory>::New();
imaging_factory->SetUseMesaClasses(1);
// Create a sphere
vtkSmartPointer<vtkSphereSource> sphereSource =
vtkSmartPointer<vtkSphereSource>::New();
// Create a mapper and actor
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("screenshot.png");
writer->SetInputConnection(windowToImageFilter->GetOutputPort());
writer->Write();
return EXIT_SUCCESS;
}
#endif
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(OffScreenRendering)
find_package(VTK COMPONENTS
CommonCore
CommonDataModel
FiltersSources
IOImage
InteractionStyle
RenderingContextOpenGL2
RenderingCore
RenderingFreeType
RenderingGL2PSOpenGL2
RenderingOpenGL2
)
if (NOT VTK_FOUND)
message(FATAL_ERROR "OffScreenRendering: Unable to find the VTK build folder.")
endif()
# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(OffScreenRendering MACOSX_BUNDLE OffScreenRendering.cxx )
target_link_libraries(OffScreenRendering PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS OffScreenRendering
MODULES ${VTK_LIBRARIES}
)
Download and Build OffScreenRendering¶
Click here to download OffScreenRendering and its CMakeLists.txt file. Once the tarball OffScreenRendering.tar has been downloaded and extracted,
cd OffScreenRendering/build
If VTK is installed:
cmake ..
If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:
cmake -DVTK_DIR:PATH=/home/me/vtk_build ..
Build the project:
make
and run it:
./OffScreenRendering
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.