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#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; }
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; }
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
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);
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()
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);
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
vtk等值面体绘制|纹理映射体绘制 附:不透明传输函数,颜色传输函数、光照与阴影
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原文地址:http://blog.csdn.net/zhou_yujia/article/details/51334503