VRMLImporterDemo
vtk-examples/Cxx/IO/VRMLImporterDemo
Description¶
vtkVRMLImporter imports multiple vtkActor models. Sometimes the vtkPolyData require modifications. For example the data in this example does not have normals. The example uses [vtkActor](https://www.vtk.org/doc/nightly/html/classvtkActor.html#details)Collection to walk each model's vtkPolyData and inserts a vtkPolyDataNormals if the normals do not exist.
Bug
vtkVRMLImporter files use a shininess between 0 and 1, while vtk's vtkProperty has a specular power between 0 and 128. The example corrects this if the specular power is <= 1.0.
Bug
vtkVRMLImporter incorrectly creates a vtkLookupTable for colorPerVertex. This example converts the vtkLookupTable to vtkPointData.
Tip
The Virtual Insect website has lots of cool wrl models of insects.
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
VRMLImporterDemo.cxx
#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkLookupTable.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPointData.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkPolyDataNormals.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkUnsignedCharArray.h>
#include <vtkVRMLImporter.h>
int main(int argc, char* argv[])
{
if (argc < 2)
{
std::cout << "Required arguments: Filename e.g. grasshop.wrl" << std::endl;
return EXIT_FAILURE;
}
std::string filename = argv[1];
std::cout << "Reading " << filename << std::endl;
vtkNew<vtkNamedColors> colors;
vtkNew<vtkRenderer> renderer;
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->AddRenderer(renderer);
renderWindow->SetWindowName("VRMLImporterDemo");
vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
renderWindowInteractor->SetRenderWindow(renderWindow);
// VRML Import
vtkNew<vtkVRMLImporter> importer;
importer->SetFileName(filename.c_str());
importer->SetRenderWindow(renderWindow);
importer->Update();
auto actors = renderer->GetActors();
std::cout << "There are " << actors->GetNumberOfItems() << " actors"
<< std::endl;
actors->InitTraversal();
for (vtkIdType a = 0; a < actors->GetNumberOfItems(); ++a)
{
vtkActor* actor = actors->GetNextActor();
// The importer shininess parameter is between 0 and 1. VTK specular power
// is usually 10-100. Also, the default for the specular factor for VRML is
// 1, while VTK's is 0
double specularPower = actor->GetProperty()->GetSpecularPower();
if (specularPower <= 1.0)
{
actor->GetProperty()->SetSpecularPower(specularPower * 128.0);
}
double specular = actor->GetProperty()->GetSpecular();
if (specular == 0.0)
{
actor->GetProperty()->SetSpecular(1.0);
}
#if 0
// The VRML default ambient intensity is .2
double ambientIntensity = actor->GetProperty()->GetAmbient();
if (ambientIntensity == 0.0)
{
actor->GetProperty()->SetAmbient(.2);
}
#endif
vtkPolyDataMapper* mapper =
dynamic_cast<vtkPolyDataMapper*>(actor->GetMapper());
if (mapper)
{
vtkPolyData* dataSet = dynamic_cast<vtkPolyData*>(mapper->GetInput());
if (!dataSet->GetPointData()->GetNormals())
{
vtkNew<vtkPolyDataNormals> normals;
normals->SetInputData(dataSet);
normals->SplittingOff();
normals->Update();
mapper->SetInputData(normals->GetOutput());
}
// If there is a lookup table, convert it to point data
vtkLookupTable* lut =
dynamic_cast<vtkLookupTable*>(mapper->GetLookupTable());
if (lut && mapper->GetScalarVisibility())
{
vtkNew<vtkUnsignedCharArray> pc;
pc->SetNumberOfComponents(4);
pc->SetNumberOfTuples(lut->GetNumberOfColors());
for (int t = 0; t < lut->GetNumberOfColors(); ++t)
{
double* lutc = lut->GetTableValue(t);
unsigned char lutuc[4];
lut->GetColorAsUnsignedChars(lutc, lutuc);
pc->SetTypedTuple(t, lutuc);
}
mapper->SetLookupTable(NULL);
mapper->GetInput()->GetPointData()->SetScalars(pc);
}
}
}
renderer->ResetCamera();
renderer->GetActiveCamera()->Azimuth(30);
renderer->GetActiveCamera()->Elevation(30);
renderer->GetActiveCamera()->Dolly(1.4);
renderer->ResetCameraClippingRange();
renderer->SetBackground(colors->GetColor3d("SpringGreen").GetData());
renderWindow->SetSize(640, 480);
renderWindow->Render();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(VRMLImporterDemo)
find_package(VTK COMPONENTS
CommonColor
CommonCore
CommonDataModel
FiltersCore
IOImport
InteractionStyle
RenderingContextOpenGL2
RenderingCore
RenderingFreeType
RenderingGL2PSOpenGL2
RenderingOpenGL2
)
if (NOT VTK_FOUND)
message(FATAL_ERROR "VRMLImporterDemo: 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(VRMLImporterDemo MACOSX_BUNDLE VRMLImporterDemo.cxx )
target_link_libraries(VRMLImporterDemo PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS VRMLImporterDemo
MODULES ${VTK_LIBRARIES}
)
Download and Build VRMLImporterDemo¶
Click here to download VRMLImporterDemo and its CMakeLists.txt file. Once the tarball VRMLImporterDemo.tar has been downloaded and extracted,
cd VRMLImporterDemo/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:
./VRMLImporterDemo
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.