[英]VTK Volume Visualization Issue
I am using vtk library with C++ to generate and visualize some synthetic voxel data with given color and transparency mapping. 我正在使用带有C ++的vtk库来生成和可视化具有给定颜色和透明度映射的一些合成体素数据。 An example is shown below:
一个例子如下所示:
As shown in the figure, the data is 3D in general, and it works great. 如图所示,数据一般是3D,效果很好。 However, in specific cases when the data becomes 2D, the visualization windows shows nothing .
但是,在数据变为2D的特定情况下,可视化窗口不显示任何内容 。
I am posting few lines of my code which may be helpful. 我发布了几行代码,可能会有所帮助。
imageData = vtkSmartPointer<vtkImageData>::New();
imageData->SetDimensions(X1, X2, X3); //For 2D, one of X1,X2 & X3=1
imageData->AllocateScalars(VTK_INT, 1);
int* I = new int[X1X2X3](); //int X1X2X3 = X1*X2*X3
I = static_cast<int*>(imageData->GetScalarPointer());
Please note that for 2D, either X1=1 or X2=1 or X3=1. 请注意,对于2D,X1 = 1或X2 = 1或X3 = 1。 Any suggestions?
有什么建议?
EDIT: I am adding an equivalent code, which will demonstrate the exact problem I am facing: 编辑:我正在添加一个等效的代码,它将演示我面临的确切问题:
main.cpp main.cpp中
//#include <vtkAutoInit.h> // if not using CMake to compile, necessary to use this macro
//#define vtkRenderingCore_AUTOINIT 3(vtkInteractionStyle, vtkRenderingFreeType, vtkRenderingOpenGL2)
//#define vtkRenderingVolume_AUTOINIT 1(vtkRenderingVolumeOpenGL2)
//#define vtkRenderingContext2D_AUTOINIT 1(vtkRenderingContextOpenGL2)
#include <vtkSmartPointer.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkSmartVolumeMapper.h>
#include <vtkColorTransferFunction.h>
#include <vtkVolumeProperty.h>
#include <vtkSampleFunction.h>
#include <vtkPiecewiseFunction.h>
#include <vtkImageData.h>
#include <stdlib.h>
using namespace std;
int main()
{
//Declaring Variables
vtkSmartPointer<vtkImageData> imageData;
vtkSmartPointer<vtkVolumeProperty> volumeProperty;
vtkSmartPointer<vtkPiecewiseFunction> compositeOpacity;
vtkSmartPointer<vtkColorTransferFunction> color;
vtkSmartPointer<vtkVolume> volume;
vtkSmartPointer<vtkSmartVolumeMapper> mapper;
vtkSmartPointer<vtkActor> actor;
vtkSmartPointer<vtkRenderer> renderer;
vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor;
vtkSmartPointer<vtkRenderWindow> renderWindow;
int* I;
int X1, X2, X3, X1X2X3;
//Assigning Values , Allocating Memory
X1 = 10;
X2 = 10;
X3 = 10;
X1X2X3 = X1*X2*X3;
I = new int[X1X2X3]();
imageData = vtkSmartPointer<vtkImageData>::New();
volumeProperty = vtkSmartPointer<vtkVolumeProperty>::New();
compositeOpacity = vtkSmartPointer<vtkPiecewiseFunction>::New();
color = vtkSmartPointer<vtkColorTransferFunction>::New();
volume = vtkSmartPointer<vtkVolume>::New();
mapper = vtkSmartPointer<vtkSmartVolumeMapper>::New();
actor = vtkSmartPointer<vtkActor>::New();
renderer = vtkSmartPointer<vtkRenderer>::New();
renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
volumeProperty->ShadeOff();
volumeProperty->SetInterpolationType(0);
volumeProperty->SetColor(color);
volumeProperty->SetScalarOpacity(compositeOpacity);
imageData->SetDimensions(X1, X2, X3);
imageData->AllocateScalars(VTK_INT, 1);
I = static_cast<int*>(imageData->GetScalarPointer());
renderWindow->AddRenderer(renderer);
renderWindowInteractor->SetRenderWindow(renderWindow);
renderer->SetBackground(0.5, 0.5, 0.5);
renderWindow->SetSize(800, 800);
mapper->SetBlendModeToComposite();
imageData->UpdateCellGhostArrayCache();
mapper->SetRequestedRenderModeToRayCast();
mapper->SetInputData(imageData);
volume->SetMapper(mapper);
volume->SetProperty(volumeProperty);
renderer->AddViewProp(volume);
volumeProperty->ShadeOff();
//Setting Voxel Data and Its Properties
for (int i = 0; i < X1X2X3; i++)
{
I[i] = i;
compositeOpacity->AddPoint(i, 1);
color->AddRGBPoint(i, double( rand()) / RAND_MAX, double(rand()) / RAND_MAX, double(rand()) / RAND_MAX);
}
renderer->ResetCamera();
renderWindow->Render();
renderWindowInteractor->Start();
getchar();
return 0;
}
CMakeLists.txt 的CMakeLists.txt
cmake_minimum_required(VERSION 3.0)
project(EvoSim)
set(CMAKE_CXX_STANDARD 14)
set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
set(CMAKE_USE_RELATIVE_PATHS ON)
#GRABBING VTK
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(MAIN main.cpp)
target_link_libraries(MAIN ${VTK_LIBRARIES})
This leads to an output like below (for, X1=X2=X3=10) 这导致如下输出(对于,X1 = X2 = X3 = 10)
However if I make X1=1, the output window is empty. 但是,如果我使X1 = 1,则输出窗口为空。
EDIT: 编辑:
I just observed that the number of voxels along a certain dimension, displayed on the screen are always one less than the maximum number of voxels in that dimensions. 我刚刚观察到,屏幕上显示的沿某个维度的体素数总是比该维度中的最大体素数少一个。 For example, if X1=X2=X3=10, the number of voxels in each dimensions which are displayed on vtkwindow is 9. This is not what I would expect.
例如,如果X1 = X2 = X3 = 10,则在vtkwindow上显示的每个维度中的体素数为9.这不是我所期望的。 I think this is the problem with X1=1, which makes 1-1=0 voxel display.
我认为这是X1 = 1的问题,这使得1-1 = 0体素显示。 Any suggestions??
有什么建议么??
This remained unanswered for long. 这仍然没有得到答复。 So I am adding my solution/workaround.
所以我正在添加我的解决方案/解决方法。 I had to add an extra dummy layer in each dimension of imagedata.
我必须在imagedata的每个维度中添加一个额外的虚拟层。 [See this line in the code imageData->SetDimensions(X1 +1 , X2 + 1, X3 + 1);
[在代码imageData-> SetDimensions(X1 + 1,X2 + 1,X3 + 1)中查看此行; ].
]。 Rest is self explanatory.
休息是自我解释的。
#pragma once
//#include <vtkAutoInit.h> // if not using CMake to compile, necessary to use this macro
//#define vtkRenderingCore_AUTOINIT 3(vtkInteractionStyle, vtkRenderingFreeType, vtkRenderingOpenGL2)
//#define vtkRenderingVolume_AUTOINIT 1(vtkRenderingVolumeOpenGL2)
//#define vtkRenderingContext2D_AUTOINIT 1(vtkRenderingContextOpenGL2)
#include <vtkSmartPointer.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkSmartVolumeMapper.h>
#include <vtkColorTransferFunction.h>
#include <vtkVolumeProperty.h>
#include <vtkSampleFunction.h>
#include <vtkPiecewiseFunction.h>
#include <vtkImageData.h>
#include <stdlib.h>
#include <numeric> // std::iota
using namespace std;
int main()
{
//Declaring Variables
vtkSmartPointer<vtkImageData> imageData;
vtkSmartPointer<vtkVolumeProperty> volumeProperty;
vtkSmartPointer<vtkPiecewiseFunction> compositeOpacity;
vtkSmartPointer<vtkColorTransferFunction> color;
vtkSmartPointer<vtkVolume> volume;
vtkSmartPointer<vtkSmartVolumeMapper> mapper;
vtkSmartPointer<vtkActor> actor;
vtkSmartPointer<vtkRenderer> renderer;
vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor;
vtkSmartPointer<vtkRenderWindow> renderWindow;
int X1, X2, X3, X1X2X3;
//Assigning Values , Allocating Memory
X1 = 10;
X2 = 10;
X3 = 10;
X1X2X3 = X1*X2*X3;
imageData = vtkSmartPointer<vtkImageData>::New();
imageData->SetDimensions(X1 + 1, X2 + 1, X3 + 1);
imageData->AllocateScalars(VTK_INT, 1);
volumeProperty = vtkSmartPointer<vtkVolumeProperty>::New();
compositeOpacity = vtkSmartPointer<vtkPiecewiseFunction>::New();
color = vtkSmartPointer<vtkColorTransferFunction>::New();
volume = vtkSmartPointer<vtkVolume>::New();
mapper = vtkSmartPointer<vtkSmartVolumeMapper>::New();
actor = vtkSmartPointer<vtkActor>::New();
renderer = vtkSmartPointer<vtkRenderer>::New();
renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
volumeProperty->ShadeOff();
volumeProperty->SetInterpolationType(0);
volumeProperty->SetColor(color);
volumeProperty->SetScalarOpacity(compositeOpacity);
imageData->AllocateScalars(VTK_INT, 1);
renderWindow->AddRenderer(renderer);
renderWindowInteractor->SetRenderWindow(renderWindow);
renderer->SetBackground(0.5, 0.5, 0.5);
renderWindow->SetSize(800, 800);
mapper->SetBlendModeToComposite();
imageData->UpdateCellGhostArrayCache();
mapper->SetRequestedRenderModeToRayCast();
mapper->SetInputData(imageData);
volume->SetMapper(mapper);
volume->SetProperty(volumeProperty);
renderer->AddViewProp(volume);
volumeProperty->ShadeOff();
//I is supposed to store the 3D data which has to be shown as volume visualization. This 3D data is stored
//as a 1D array in which the order of iteration over 3 dimensions is x->y->z, this leads to the following
//3D to 1D index conversion farmula index1D = i + X1*j + X1*X2*k
vector<int> I(X1X2X3,0); // No need to use int* I = new int[X1X2X3] //Vectors are good
std::iota(&I[0], &I[0] + X1X2X3, 1); //Creating dummy data as 1,2,3...X1X2X3
//Setting Voxel Data and Its Properties
for (int k = 0; k < X3 + 1 ; k++)
{
for (int j = 0; j < X2 + 1 ; j++)
{
for (int i = 0; i < X1 + 1 ; i++)
{
int* voxel = static_cast<int*>(imageData->GetScalarPointer(i, j, k));
if (i==X1 || j== X2 || k==X3)
{
//Assigning zeros to dummy voxels, these will not be displayed anyways
voxel[0] = 0;
}
else
{
//copying data from I to imagedata voxel
voxel[0] = I[i + X1*j + X1*X2*k];
}
}
}
}
//Setting Up Display Properties
for (int i = 1; i < X1X2X3; i++)
{
compositeOpacity->AddPoint(i, 1);
color->AddRGBPoint(i, double(rand()) / RAND_MAX, double(rand()) / RAND_MAX, double(rand()) / RAND_MAX);
}
renderer->ResetCamera();
renderWindow->Render();
renderWindowInteractor->Start();
getchar();
return 0;
}
Now the expected number of voxels in each dimensions (10 as per the code above), are correctly seen 现在可以正确地看到每个维度中的预期体素数(根据上面的代码为10)
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