[vtkusers] Artifacts along bounding box edges in volume rendering
Elvis Stansvik
elvis.stansvik at orexplore.com
Mon Mar 13 03:32:58 EDT 2017
Den 13 mars 2017 8:10 fm skrev "Róbert Špir" <spir.robert at gmail.com>:
>
> Hi Elvis,
> this is caused by multisampling, if you set window->SetMultiSamples(0);
the
> artifact will disappear. I can reproduce it in your example on windows
with
> nvidia card.
>
> If you need antialiasing, you can try using FXAA which doesn't produce
these
> artifacts
Aha, thanks for having a look and clarifying. That makes perfect sense.
I'll give FXAA a go in a little while, when I'm back at work.
Elvis
> #include <vtkFXAAOptions.h>
>
> vtkSmartPointer<vtkFXAAOptions> FXAAOptions =
> vtkSmartPointer<vtkFXAAOptions>::New();
> FXAAOptions->SetRelativeContrastThreshold(0.125);
> FXAAOptions->SetHardContrastThreshold(0.045);
> FXAAOptions->SetSubpixelBlendLimit(0.75);
> FXAAOptions->SetSubpixelContrastThreshold(0.25);
> FXAAOptions->SetUseHighQualityEndpoints(true);
> FXAAOptions->SetEndpointSearchIterations(12);
>
> renderer->SetFXAAOptions(FXAAOptions);
> renderer->SetUseFXAA(true);
>
> Robert
>
> -----Original Message-----
> From: vtkusers [mailto:vtkusers-bounces at vtk.org] On Behalf Of Elvis
Stansvik
> Sent: Monday, March 13, 2017 7:53 AM
> To: VTK Users <vtkusers at vtk.org>
> Subject: Re: [vtkusers] Artifacts along bounding box edges in volume
> rendering
>
> 2017-03-10 10:11 GMT+01:00 Elvis Stansvik <elvis.stansvik at orexplore.com>:
> > 2017-03-10 10:07 GMT+01:00 Elvis Stansvik <elvis.stansvik at orexplore.com
>:
> >> Hi all,
> >>
> >> I'm trying to debug a problem with artifacts appearing around the
> >> bounding box edges in my volume rendering (at certain camera angles).
> >> I can reproduce the problem with the minimal test case below. In the
> >> attached screen shot, notice the faint white artifacts along the
> >> bounding box edges.
> >>
> >> Anyone know where these come from and how I can fix it?
> >
> > I forgot to say, this is with VTK 7.1.0.
>
> Noone who knows where this comes from? Would be great if someone could
> confirm that they can reproduce it with my test case, as I'm beginning to
> suspect it might be graphics card specific (I'm on Linux, Intel graphics).
>
> Should I post to vtk-dev perhaps?
>
> Elvis
>
> >
> > Elvis
> >
> >>
> >> Thanks in advance,
> >> Elvis
> >>
> >>
> >> main.cpp:
> >>
> >> #include <algorithm>
> >>
> >> #include <vtkCamera.h>
> >> #include <vtkColorTransferFunction.h> #include
> >> <vtkGPUVolumeRayCastMapper.h> #include <vtkImageData.h> #include
> >> <vtkNew.h> #include <vtkPiecewiseFunction.h> #include <vtkRenderer.h>
> >> #include <vtkRenderWindow.h> #include <vtkRenderWindowInteractor.h>
> >> #include <vtkVolume.h> #include <vtkVolumeProperty.h>
> >>
> >> int main(int argc, char *argv[])
> >> {
> >> vtkNew<vtkColorTransferFunction> colorFunction;
> >> colorFunction->AddRGBPoint(0.0, 0.0, 0.0, 0.0);
> >> colorFunction->AddRGBPoint(1.0, 0.0, 0.0, 0.0);
> >>
> >> vtkNew<vtkPiecewiseFunction> opacityFunction;
> >> opacityFunction->AddPoint(0.0, 0.0);
> >> opacityFunction->AddPoint(1.0, 1.0);
> >>
> >> vtkNew<vtkImageData> data;
> >> data->SetExtent(0, 200, 0, 200, 0, 200);
> >> data->AllocateScalars(VTK_FLOAT, 1);
> >> std::fill_n(static_cast<float *>(data->GetScalarPointer()),
> >> 8000000, 0.1);
> >>
> >> vtkNew<vtkGPUVolumeRayCastMapper> mapper;
> >> mapper->SetInputData(data.Get());
> >>
> >> vtkNew<vtkVolumeProperty> property;
> >> property->SetScalarOpacity(opacityFunction.Get());
> >> property->SetColor(colorFunction.Get());
> >>
> >> vtkNew<vtkVolume> volume;
> >> volume->SetMapper(mapper.Get());
> >> volume->SetProperty(property.Get());
> >>
> >> vtkNew<vtkRenderer> renderer;
> >> renderer->AddVolume(volume.Get());
> >> renderer->SetBackground(1.0, 1.0, 1.0);
> >>
> >> vtkNew<vtkRenderWindow> window;
> >> window->AddRenderer(renderer.Get());
> >>
> >> // Position camera such that artifacts appear
> >> auto camera = renderer->GetActiveCamera();
> >> camera->SetPosition(500.0, 220.0, 500.0);
> >> camera->SetFocalPoint(0.0, 80.0, 0.0);
> >> renderer->ResetCameraClippingRange();
> >>
> >> vtkNew<vtkRenderWindowInteractor> interactor;
> >> interactor->SetRenderWindow(window.Get());
> >> interactor->Start();
> >>
> >> return 0;
> >> }
> >>
> >>
> >> CMakeLists.txt:
> >>
> >> cmake_minimum_required(VERSION 3.1)
> >>
> >> project(TestCase)
> >>
> >> set(CMAKE_PREFIX_PATH ${CMAKE_PREFIX_PATH} /opt/VTK7)
> >>
> >> find_package(VTK 7.1 COMPONENTS
> >> vtkCommonCore
> >> vtkCommonDataModel
> >> vtkCommonExecutionModel
> >> vtkCommonMath
> >> vtkInteractionStyle
> >> vtkRenderingCore
> >> vtkRenderingOpenGL2
> >> vtkRenderingVolume
> >> vtkRenderingVolumeOpenGL2
> >> REQUIRED
> >> )
> >>
> >> add_executable(TestCase WIN32 main.cpp)
> >>
> >> target_link_libraries(TestCase PUBLIC
> >> vtkCommonCore
> >> vtkCommonDataModel
> >> vtkCommonExecutionModel
> >> vtkCommonMath
> >> vtkInteractionStyle
> >> vtkRenderingCore
> >> vtkRenderingOpenGL2
> >> vtkRenderingVolume
> >> vtkRenderingVolumeOpenGL2
> >> )
> >>
> >> target_include_directories(TestCase PUBLIC
> >> ${VTK_INCLUDE_DIRS}
> >> )
> >>
> >> target_compile_definitions(TestCase PUBLIC
> >> ${VTK_DEFINITIONS}
> >> )
> >>
> >> set_target_properties(TestCase PROPERTIES
> >> CXX_STANDARD 14
> >> CXX_STANDARD_REQUIRED ON
> >> )
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