等值面体绘制：
#include <vtkSmartPointer.h>
#include <vtkImageData.h>
#include <vtkStructuredPoints.h>
#include <vtkStructuredPointsReader.h>
#include <vtkVolumeRayCastIsosurfaceFunction.h>
#include <vtkVolumeRayCastMapper.h>
#include <vtkColorTransferFunction.h>
#include <vtkPiecewiseFunction.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkVolumeProperty.h>
#include <vtkAxesActor.h>
#include <vtkImageShiftScale.h>
#include <vtkImageCast.h>
//等值面体绘制效果
int main(int argc, char *argv[])
{
vtkSmartPointer<vtkStructuredPointsReader> reader =
vtkSmartPointer<vtkStructuredPointsReader>::New();
reader->SetFileName("../mummy.128.vtk");
reader->Update();
//等值面绘制函数用来渲染体数据中的特定等值面
vtkSmartPointer<vtkVolumeRayCastIsosurfaceFunction> rayCastFun =
vtkSmartPointer<vtkVolumeRayCastIsosurfaceFunction>::New();
rayCastFun->SetIsoValue(100);//用于设置等值面的值 小于该值的小于该像素的不透明度都设置为0
//定义一个光线投影体绘制
vtkSmartPointer<vtkVolumeRayCastMapper> volumeMapper =
vtkSmartPointer<vtkVolumeRayCastMapper>::New();
volumeMapper->SetInputData(reader->GetOutput());//接受输入数据
volumeMapper->SetVolumeRayCastFunction(rayCastFun);//必须设置，否则出错 设置光线投影函数类型
vtkSmartPointer<vtkVolumeProperty> volumeProperty =
vtkSmartPointer<vtkVolumeProperty>::New();
volumeProperty->SetInterpolationTypeToLinear();//设置线性插值类型
volumeProperty->ShadeOn();
volumeProperty->SetAmbient(0.2);//阴影色
volumeProperty->SetDiffuse(0.6);//弥漫性
volumeProperty->SetSpecular(0.4);//高光 这个属性到0.8有一种“铜”制的效果~~
////透明度映射函数定义
//给数据点赋不透明值。体绘制中，需要显示三维数据场的内部结构，因而需要生成具有透明度的图像。
vtkSmartPointer<vtkPiecewiseFunction> compositeOpacity =
vtkSmartPointer<vtkPiecewiseFunction>::New();
compositeOpacity->AddPoint(70, 0.00);
compositeOpacity->AddPoint(90, 0.40);
compositeOpacity->AddPoint(180, 0.60);
volumeProperty->SetScalarOpacity(compositeOpacity);
////颜色映射函数定义
//给数据点赋颜色值，将分类后的组织信息分别予以不同的颜色，便于图像分析。
vtkSmartPointer<vtkColorTransferFunction> color =
vtkSmartPointer<vtkColorTransferFunction>::New();
color->AddRGBPoint(0.000, 0.00, 0.00, 0.00);
color->AddRGBPoint(64.00, 1.00, 0.52, 0.30);
color->AddRGBPoint(190.0, 1.00, 1.00, 1.00);
color->AddRGBPoint(220.0, 0.20, 0.20, 0.20);
volumeProperty->SetColor(color);
// vtkVolume掌管映射器和属性对象，可控制体数据的位置和朝向
vtkSmartPointer<vtkVolume> volume =
vtkSmartPointer<vtkVolume>::New();
volume->SetMapper(volumeMapper);//生成体对象
volume->SetProperty(volumeProperty);//设置体对象属型
vtkSmartPointer<vtkRenderer> ren = vtkSmartPointer<vtkRenderer>::New();
ren->SetBackground(1.0, 1.0, 1.0);
ren->AddVolume(volume);
vtkSmartPointer<vtkRenderWindow> renWin = vtkSmartPointer<vtkRenderWindow>::New();
renWin->AddRenderer(ren);
renWin->SetSize(640, 480);
renWin->Render();
renWin->SetWindowName("IsoSurfaceVolRenderingApp");
vtkSmartPointer<vtkRenderWindowInteractor> iren =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
iren->SetRenderWindow(renWin);
ren->ResetCamera();
renWin->Render();
iren->Start();
return EXIT_SUCCESS;
}
忽略掉上面的红字，本来是想做表情包的==
二维纹理映射：
渲染速度快于光线投影体绘制，但是只支持alpha合成技术，而且切片上使用双线性插值实现纹理映射，切片之间不存在插值，渲染质量有所下降；且需要在三个方向上保存相应的纹理图像堆栈，占用内存大
#include <vtkSmartPointer.h>
#include <vtkImageData.h>
#include <vtkStructuredPoints.h>
#include <vtkStructuredPointsReader.h>
#include <vtkVolumeTextureMapper2D.h>
#include <vtkColorTransferFunction.h>
#include <vtkPiecewiseFunction.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkVolumeProperty.h>
#include <vtkAxesActor.h>
#include <vtkImageShiftScale.h>
#include <vtkImageCast.h>
int main(int argc, char *argv[])
{
vtkSmartPointer<vtkStructuredPointsReader> reader =
vtkSmartPointer<vtkStructuredPointsReader>::New();
reader->SetFileName("../mummy.128.vtk");
reader->Update();
//上一份代码的mapper(现查了一下是制图的意思==)叫做vtkVolumeRayCastMapper
vtkSmartPointer<vtkVolumeTextureMapper2D> volumeMapper =
vtkSmartPointer<vtkVolumeTextureMapper2D>::New();
volumeMapper->SetInputData(reader->GetOutput());
//这部分设置体绘制属性的写法和上一份一样==
vtkSmartPointer<vtkVolumeProperty> volumeProperty =
vtkSmartPointer<vtkVolumeProperty>::New();
volumeProperty->SetInterpolationTypeToLinear();
volumeProperty->ShadeOn();
volumeProperty->SetAmbient(0.4);
volumeProperty->SetDiffuse(0.6);
volumeProperty->SetSpecular(0.2);
//透明度设置，老生常谈了==
vtkSmartPointer<vtkPiecewiseFunction> compositeOpacity =
vtkSmartPointer<vtkPiecewiseFunction>::New();
compositeOpacity->AddPoint(70, 0.00);
compositeOpacity->AddPoint(90, 0.40);
compositeOpacity->AddPoint(180, 0.60);
volumeProperty->SetScalarOpacity(compositeOpacity);
//颜色映射函数定义，依旧是一样的 下面的函数也都一样的==怪不得书上不再写了
vtkSmartPointer<vtkColorTransferFunction> color =
vtkSmartPointer<vtkColorTransferFunction>::New();
color->AddRGBPoint(0.000, 0.00, 0.00, 0.00);
color->AddRGBPoint(64.00, 1.00, 0.52, 0.30);
color->AddRGBPoint(190.0, 1.00, 1.00, 1.00);
color->AddRGBPoint(220.0, 0.20, 0.20, 0.20);
volumeProperty->SetColor(color);
vtkSmartPointer<vtkVolume> volume =
vtkSmartPointer<vtkVolume>::New();
volume->SetMapper(volumeMapper);
volume->SetProperty(volumeProperty);
vtkSmartPointer<vtkRenderer> ren = vtkSmartPointer<vtkRenderer>::New();
ren->SetBackground(1.0, 1.0, 1.0);
ren->AddVolume(volume);
vtkSmartPointer<vtkRenderWindow> renWin = vtkSmartPointer<vtkRenderWindow>::New();
renWin->AddRenderer(ren);
renWin->SetSize(640, 480);
renWin->Render();
renWin->SetWindowName("Texture2DVolRenderingApp");
vtkSmartPointer<vtkRenderWindowInteractor> iren =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
iren->SetRenderWindow(renWin);
ren->ResetCamera();
renWin->Render();
iren->Start();
return EXIT_SUCCESS;
}
（配字怎么样
三维纹理映射：
三维映射是将体数据映射到一组与视图平面平行的四边形，避免二维纹理映射方法中因为纹理图像切换产生的瑕疵现象。除了类变成了~3D，其他都一样，注释省略==
vtkSmartPointer<vtkStructuredPointsReader> reader =
vtkSmartPointer<vtkStructuredPointsReader>::New();
reader->SetFileName("../mummy.128.vtk");
reader->Update();
vtkSmartPointer<vtkVolumeTextureMapper3D> volumeMapper =
vtkSmartPointer<vtkVolumeTextureMapper3D>::New();
volumeMapper->SetInputData(reader->GetOutput());
vtkSmartPointer<vtkVolumeProperty> volumeProperty =
vtkSmartPointer<vtkVolumeProperty>::New();
volumeProperty->SetInterpolationTypeToLinear();
volumeProperty->ShadeOn();
volumeProperty->SetAmbient(0.4);
volumeProperty->SetDiffuse(0.6);
volumeProperty->SetSpecular(0.2);
vtkSmartPointer<vtkPiecewiseFunction> compositeOpacity =
vtkSmartPointer<vtkPiecewiseFunction>::New();
compositeOpacity->AddPoint(70, 0.00);
compositeOpacity->AddPoint(90, 0.40);
compositeOpacity->AddPoint(180, 0.60);
volumeProperty->SetScalarOpacity(compositeOpacity);
vtkSmartPointer<vtkColorTransferFunction> color =
vtkSmartPointer<vtkColorTransferFunction>::New();
color->AddRGBPoint(0.000, 0.00, 0.00, 0.00);
color->AddRGBPoint(64.00, 1.00, 0.52, 0.30);
color->AddRGBPoint(190.0, 1.00, 1.00, 1.00);
color->AddRGBPoint(220.0, 0.20, 0.20, 0.20);
volumeProperty->SetColor(color);
vtkSmartPointer<vtkVolume> volume =
vtkSmartPointer<vtkVolume>::New();
volume->SetMapper(volumeMapper);
volume->SetProperty(volumeProperty);
vtkSmartPointer<vtkRenderer> ren = vtkSmartPointer<vtkRenderer>::New();
ren->SetBackground(1.0, 1.0, 1.0);
ren->AddVolume(volume);
vtkSmartPointer<vtkRenderWindow> renWin = vtkSmartPointer<vtkRenderWindow>::New();
renWin->AddRenderer(ren);
renWin->SetSize(640, 480);
renWin->Render();
renWin->SetWindowName("Texture3DVolRenderingApp");
int valid = volumeMapper->IsRenderSupported(volumeProperty, ren);
if (!valid) return EXIT_SUCCESS;//判断是否支持当前渲染
vtkSmartPointer<vtkRenderWindowInteractor> iren =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
iren->SetRenderWindow(renWin);
ren->ResetCamera();
renWin->Render();
iren->Start();
return EXIT_SUCCESS;
下面好好说说不透明度传输函数，颜色传输函数、光照与阴影
不透明度传输函数
就是这段文字
vtkSmartPointer<vtkPiecewiseFunction> compositeOpacity = vtkSmartPointer<vtkPiecewiseFunction>::New(); compositeOpacity->AddPoint(70, 0.00); compositeOpacity->AddPoint(90, 0.40); compositeOpacity->AddPoint(180, 0.60); volumeProperty->SetScalarOpacity(compositeOpacity);
AddPoint只是其中一种定义标量线性分段函数的方法。第一个参数x是自变量，这里指灰度值；y是映射值，这里指不透明度
addsegment是另一种，直接添加一条线段，即添加两个断点x1,y1,x2,y2
梯度不透明函数添加方法是 SetGradientOpacity()
颜色传输函数
将一个标量映射成一个颜色值，可以是rgb也可以是hsv rgb换成HSV就可以啦
vtkSmartPointer<vtkColorTransferFunction> color = vtkSmartPointer<vtkColorTransferFunction>::New(); color->AddRGBPoint(0.000, 0.00, 0.00, 0.00); color->AddRGBPoint(64.00, 1.00, 0.52, 0.30); color->AddRGBPoint(190.0, 1.00, 1.00, 1.00); color->AddRGBPoint(220.0, 0.20, 0.20, 0.20); volumeProperty->SetColor(color);
光线与阴影
之前的注释这里有点不准确QAQ
volumeProperty->ShadeOn();//开启阴影效果 volumeProperty->SetAmbient(0.4);//设置环境光系数 volumeProperty->SetDiffuse(0.6);//设置散射光系数 volumeProperty->SetSpecular(0.2);//设置反射光系数
一般情况下，三个系数和=1，为提高亮度，之和可能大于1
在这三个系数中，当环境光占主导时，阴影效果不明显；散射光系数占主导时，显示效果比较粗糙；反射光占主导时，显示效果比较光滑。阴影效果关闭时，等同于环境光系数=1.0，其他两个系数=0
时间： 2024-10-11 06:20:27