一、先记录一下下载过程中踩过的坑
问题1：QVTKOpenGLNativeWidget和QVTKWidget
之前从来没有接触过QT中显示3D点云方面的知识，了解到可以用pcl，然后在网上各种找pcl下载的相关内容，想要在QT中显示出来，需要用到VTK，又开始找VTK的下载的相关内容。
网上大多数推荐的pcl1.9+vtk7.1，用QVTKWidget这个控件来显示，然后找了篇文章跟着流程进行下载。
但是！！！后来知道，不只要显示点云，还要显示模型。查找资料之后发现QVTKWidget这个控件不能显示模型，需要用QVTKOpenGLNativeWidget，刺激的来了，vtk8.2版本之后才有这个控件。(之后会介绍QVTKOpenGLNativeWidget和QVTKWidget的区别)
所以我现在要卸载vtk7.1，下载vtk8.2或以上版本。
问题2：关于sudo apt-get install libvtk7.1-qt libvtk7.1 libvtk7-qt-dev
之前找的下载pcl1.9+vtk7.1的帖子中，安装依赖都会安装sudo apt-get install libvtk7.1-qt libvtk7.1 libvtk7-qt-dev，我以为这个依赖是必不可少的，但是卸载之后，尝试将7.1改成8.2，结果是找不到的。
我以为这个是必不可少的，然后又下回来了，用这个依赖，然后下载的8.2版本，但是用之前的例子直接崩溃了，然后把这个依赖卸载之后就跑起来了。
所以是8.2版本不需要这个依赖了吗？？？？
问题3：报错 error: qvtkopenglnativewidget.h: 没有那个文件或目录
将vtk8.2版本中的控件还是为QVTKWidget，需要手动提升为QVTKOpenGLNativeWidget控件。（如何提升也会在后面介绍）
提升为QVTKOpenGLNativeWidget控件之后，编辑是会报错的，找不到qvtkopenglnativewidget.h文件。
这是因为这个文件的名称是大写的QVTKOpenGLNativeWidget.h。
问题4：报错opengl版本太低
最一开始运行是会报一下错误
ERROR: In /home/li/VTK-8.2.0/Rendering/OpenGL2/vtkOpenGLRenderWindow.cxx, line 754
vtkGenericOpenGLRenderWindow (0x558f595d1520): Unable to find a valid OpenGL 3.2 or later implementation. Please update your video card driver to the latest version. If you are using Mesa please make sure you have version 11.2 or later and make sure your driver in Mesa supports OpenGL 3.2 such as llvmpipe or openswr. If you are on windows and using Microsoft remote desktop note that it only supports OpenGL 3.2 with nvidia quadro cards. You can use other remoting software such as nomachine to avoid this issue.
ERROR: In /home/li/VTK-8.2.0/Rendering/OpenGL2/vtkShaderProgram.cxx, line 446
vtkShaderProgram (0x558f595b6740): 1: #version 150
2: #ifndef GL_ES
3: #define highp
4: #define mediump
5: #define lowp
6: #endif // GL_ES
7: #define attribute in
8: #define varying out
9:
10:
11: /*=========================================================================
12:
13: Program: Visualization Toolkit
14: Module: vtkPolyDataVS.glsl
15:
16: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
17: All rights reserved.
18: See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
19:
20: This software is distributed WITHOUT ANY WARRANTY; without even
21: the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
22: PURPOSE. See the above copyright notice for more information.
23:
24: =========================================================================*/
25:
26: in vec4 vertexMC;
27:
28: // frag position in VC
29: out vec4 vertexVCVSOutput;
30:
31: // optional normal declaration
32: //VTK::Normal::Dec
33:
34: // extra lighting parameters
35: //VTK::Light::Dec
36:
37: // Texture coordinates
38: //VTK::TCoord::Dec
39:
40: // material property values
41: //VTK::Color::Dec
42:
43: // clipping plane vars
44: //VTK::Clip::Dec
45:
46: // camera and actor matrix values
47: uniform mat4 MCDCMatrix;
48: uniform mat4 MCVCMatrix;
49:
50: // Apple Bug
51: //VTK::PrimID::Dec
52:
53: // Value raster
54: //VTK::ValuePass::Dec
55:
56: // picking support
57: //VTK::Picking::Dec
58:
59: void main()
60: {
61: //VTK::Color::Impl
62:
63: //VTK::Normal::Impl
64:
65: //VTK::TCoord::Impl
66:
67: //VTK::Clip::Impl
68:
69: //VTK::PrimID::Impl
70:
71: vertexVCVSOutput = MCVCMatrix * vertexMC;
72: gl_Position = MCDCMatrix * vertexMC;
73:
74:
75: //VTK::ValuePass::Impl
76:
77: //VTK::Light::Impl
78:
79: //VTK::Picking::Impl
80: }
ERROR: In /home/li/VTK-8.2.0/Rendering/OpenGL2/vtkShaderProgram.cxx, line 447
vtkShaderProgram (0x558f595b6740): 0:1(10): error: GLSL 1.50 is not supported. Supported versions are: 1.10, 1.20, 1.30, 1.00 ES, 3.00 ES, 3.10 ES, and 3.20 ES
QOpenGLWidget允许在平台支持时使用不同的OpenGL版本和配置文件。
需要在main.cpp中的QApplication之前调用QSurfaceFormat::setDefaultFormat(QVTKOpenGLNativeWidget::defaultFormat());