GLTFExporter
vtk-examples/Cxx/IO/GLTFExporter
Description¶
The examples uses vtkGLTFExporter to save the current scene in a .gltf file. The saved file called GLTFExporter.gltf is saved in the directory where the example is run. That file can be imported using vtkGLTFImporter.
Warning
Currently the camera is not writeen properly so the exported scene will not match the imported scene.
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
GLTFExporter.cxx
#include <vtkActor.h>
#include <vtkArrowSource.h>
#include <vtkCamera.h>
#include <vtkGLTFExporter.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkMath.h>
#include <vtkMinimalStandardRandomSequence.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSphereSource.h>
#include <vtkTransform.h>
#include <vtkTransformPolyDataFilter.h>
#include <array>
int main(int argc, char* argv[])
{
if (argc < 2)
{
std::cout << "Usage: GLTFExporter file.gltf e.g. GLTFExporter.gltf"
<< std::endl;
return EXIT_FAILURE;
}
vtkNew<vtkNamedColors> colors;
// Set the background color.
vtkColor3d backgroundColor = colors->GetColor3d("SlateGray");
// Create an arrow.
vtkNew<vtkArrowSource> arrowSource;
// Generate a random start and end point
double startPoint[3];
double endPoint[3];
vtkNew<vtkMinimalStandardRandomSequence> rng;
rng->SetSeed(8775070); // For testing.
for (auto i = 0; i < 3; ++i)
{
rng->Next();
startPoint[i] = rng->GetRangeValue(-10, 10);
rng->Next();
endPoint[i] = rng->GetRangeValue(-10, 10);
}
// Compute a basis
double normalizedX[3];
double normalizedY[3];
double normalizedZ[3];
// The X axis is a vector from start to end
vtkMath::Subtract(endPoint, startPoint, normalizedX);
double length = vtkMath::Norm(normalizedX);
vtkMath::Normalize(normalizedX);
// The Z axis is an arbitrary vector cross X
double arbitrary[3];
for (auto i = 0; i < 3; ++i)
{
rng->Next();
arbitrary[i] = rng->GetRangeValue(-10, 10);
}
vtkMath::Cross(normalizedX, arbitrary, normalizedZ);
vtkMath::Normalize(normalizedZ);
// The Y axis is Z cross X
vtkMath::Cross(normalizedZ, normalizedX, normalizedY);
vtkNew<vtkMatrix4x4> matrix;
// Create the direction cosine matrix
matrix->Identity();
for (auto i = 0; i < 3; i++)
{
matrix->SetElement(i, 0, normalizedX[i]);
matrix->SetElement(i, 1, normalizedY[i]);
matrix->SetElement(i, 2, normalizedZ[i]);
}
// Apply the transforms
vtkNew<vtkTransform> transform;
transform->Translate(startPoint);
transform->Concatenate(matrix);
transform->Scale(length, length, length);
// Transform the polydata
vtkNew<vtkTransformPolyDataFilter> transformPD;
transformPD->SetTransform(transform);
transformPD->SetInputConnection(arrowSource->GetOutputPort());
// Create a mapper and actor for the arrow
vtkNew<vtkPolyDataMapper> mapper;
vtkNew<vtkActor> actor;
#ifdef USER_MATRIX
mapper->SetInputConnection(arrowSource->GetOutputPort());
actor->SetUserMatrix(transform->GetMatrix());
#else
mapper->SetInputConnection(transformPD->GetOutputPort());
#endif
actor->SetMapper(mapper);
actor->GetProperty()->SetColor(colors->GetColor3d("Cyan").GetData());
// Create spheres for start and end point
vtkNew<vtkSphereSource> sphereStartSource;
sphereStartSource->SetCenter(startPoint);
sphereStartSource->SetRadius(0.8);
vtkNew<vtkPolyDataMapper> sphereStartMapper;
sphereStartMapper->SetInputConnection(sphereStartSource->GetOutputPort());
vtkNew<vtkActor> sphereStart;
sphereStart->SetMapper(sphereStartMapper);
sphereStart->GetProperty()->SetColor(colors->GetColor3d("Yellow").GetData());
vtkNew<vtkSphereSource> sphereEndSource;
sphereEndSource->SetCenter(endPoint);
sphereEndSource->SetRadius(0.8);
vtkNew<vtkPolyDataMapper> sphereEndMapper;
sphereEndMapper->SetInputConnection(sphereEndSource->GetOutputPort());
vtkNew<vtkActor> sphereEnd;
sphereEnd->SetMapper(sphereEndMapper);
sphereEnd->GetProperty()->SetColor(colors->GetColor3d("Magenta").GetData());
// Create a renderer, render window, and interactor
vtkNew<vtkRenderer> renderer;
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->AddRenderer(renderer);
renderWindow->SetSize(640, 480);
renderWindow->SetWindowName("GLTFExporter");
vtkNew<vtkInteractorStyleTrackballCamera> style;
vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
renderWindowInteractor->SetRenderWindow(renderWindow);
renderWindowInteractor->SetInteractorStyle(style);
// Add the actor to the scene
renderer->AddActor(actor);
renderer->AddActor(sphereStart);
renderer->AddActor(sphereEnd);
renderer->SetBackground(backgroundColor.GetData());
// Render and interact
renderWindow->Render();
renderer->GetActiveCamera()->Azimuth(30);
renderer->GetActiveCamera()->Elevation(30);
renderer->ResetCameraClippingRange();
renderWindowInteractor->Start();
vtkNew<vtkGLTFExporter> writer;
writer->SetFileName(argv[1]);
writer->InlineDataOn();
writer->SetRenderWindow(renderWindow);
writer->Write();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(GLTFExporter)
find_package(VTK COMPONENTS
vtkCommonColor
vtkCommonCore
vtkCommonDataModel
vtkCommonTransforms
vtkFiltersGeneral
vtkFiltersSources
vtkIOExport
vtkIOExportOpenGL2
vtkIOExportPDF
vtkInteractionStyle
vtkRenderingContextOpenGL2
vtkRenderingCore
vtkRenderingFreeType
vtkRenderingGL2PSOpenGL2
vtkRenderingOpenGL2
QUIET
)
if (NOT VTK_FOUND)
message("Skipping GLTFExporter: ${VTK_NOT_FOUND_MESSAGE}")
return()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
# old system
include(${VTK_USE_FILE})
add_executable(GLTFExporter MACOSX_BUNDLE GLTFExporter.cxx )
target_link_libraries(GLTFExporter PRIVATE ${VTK_LIBRARIES})
else()
# 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(GLTFExporter MACOSX_BUNDLE GLTFExporter.cxx )
target_link_libraries(GLTFExporter PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS GLTFExporter
MODULES ${VTK_LIBRARIES}
)
endif()
Download and Build GLTFExporter¶
Click here to download GLTFExporter and its CMakeLists.txt file. Once the tarball GLTFExporter.tar has been downloaded and extracted,
cd GLTFExporter/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:
./GLTFExporter
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.