我要评论vtk实现stl模型的三视图显示及交互
最近收到需求，要实现多视图显示同一个stl模型，并且控制主窗口要其他试图窗口也跟着交互，花了点时间去尝试一下，把这个效果给实现出来了，而且实现也挺简单。
效果演示
要点
- 用同一个vtkrenderer传三次给vtkrenderwindow是不行的，要创建三个vtkrenderer来显示用一个vtkactor，分别传给vtkrenderwindow才行。
- 用同一个vtkcamera同时控制三个vtkrenderer是不行的，因为vtkcamera的参数发生改变，会同步影响，要实现不同的视角，还是需要准备三个vtkcamera分别传给三个vtkrenderer。
- 既然要实现控制一个主vtkcamera，影响另外两个辅vtkcamera也要同步更新，那最直接的方法就是用回调函数。
代码实现
#include <iostream>
#include <vtkautoinit.h>
#include <vtkstlreader.h>
#include <vtkplyreader.h>
#include <vtkpolydatamapper.h>
#include <vtksmartpointer.h>
#include <vtkactor.h>
#include <vtkcamera.h>
#include <vtkrenderer.h>
#include <vtkrenderwindow.h>
#include <vtktransform.h>
#include <vtkgenericopenglrenderwindow.h>
#include <vtkrenderwindowinteractor.h>
#include <vtkinteractorstyletrackballcamera.h>
#include <vtkcommand.h>
vtk_module_init(vtkrenderingopengl2)
vtk_module_init(vtkinteractionstyle);
vtk_module_init(vtkrenderingfreetype);
class vtkupdatecamera : public vtkcommand
{
public:
static vtkupdatecamera* new()
{
return new vtkupdatecamera;
}
void execute(vtkobject* caller, unsigned long vtknotused(event), void* calldata)
{
//获取主camera
vtkrenderer* renderer = dynamic_cast<vtkrenderer*>(caller);
auto camera = renderer->getactivecamera();
//更新两个辅助camera的参数
camera1->setposition(camera->getposition());
camera1->setfocalpoint(camera->getfocalpoint());
camera1->setviewup(camera->getviewup());
camera1->azimuth(90);
camera1->modified();
//通过调整摄像头的viewup的旋转角度，为辅助摄像头实现上试图，左视图的朝向
camera2->setposition(camera->getposition());
camera2->setfocalpoint(camera->getfocalpoint());
double* viewup = camera->getviewup();
double* direction = camera->getdirectionofprojection();
double view[3];
vtkmath::cross(direction, viewup, view);
camera2->setviewup(view);
camera2->azimuth(-90);
camera2->modified();
}
void setcamera1(vtkcamera* c)
{
camera1 = c;
}
void setcamera2(vtkcamera* c)
{
camera2 = c;
}
private:
vtkcamera* camera1;
vtkcamera* camera2;
};
int main()
{
vtksmartpointer<vtkstlreader> reader = vtksmartpointer<vtkstlreader>::new();
reader->setfilename("d://bunny.stl");
reader->update();
vtksmartpointer<vtkpolydatamapper> mapper = vtksmartpointer<vtkpolydatamapper>::new();
mapper->setinputdata(reader->getoutput());
vtksmartpointer<vtkactor> actor = vtksmartpointer<vtkactor>::new();
actor->setmapper(mapper);
double* bounds = reader->getoutput()->getbounds();
vtksmartpointer<vtkcamera> camera = vtksmartpointer<vtkcamera>::new();
camera->setposition(0, bounds[2]- 200, 0);
camera->setfocalpoint(reader->getoutput()->getcenter());
camera->setviewup(0, 0, 1);
vtksmartpointer<vtkcamera> camera1 = vtksmartpointer<vtkcamera>::new();
vtksmartpointer<vtkcamera> camera2 = vtksmartpointer<vtkcamera>::new();
//为主渲染器准备更新摄像头的回调函数
vtksmartpointer<vtkupdatecamera> callback = vtksmartpointer<vtkupdatecamera>::new();
callback->setcamera1(camera1);
callback->setcamera2(camera2);
//---------设置主渲染器----------
vtksmartpointer<vtkrenderer> renderer = vtksmartpointer<vtkrenderer>::new();
renderer->addactor(actor);
renderer->setactivecamera(camera);
renderer->setbackground(1, 1, 1);
renderer->setviewport(0, 0, 0.33, 1);
//为主渲染器绑定回调函数，使用anyevent为了使任何交互都影响两个辅助摄像头
renderer->addobserver(vtkcommand::anyevent, callback);
//---------设置第一个辅助渲染器----------
vtksmartpointer<vtkrenderer> renderer1 = vtksmartpointer<vtkrenderer>::new();
auto actors = renderer->getactors();
actors->inittraversal();
for (int i = 0; i < actors->getnumberofitems(); i++)
{
renderer1->addactor(actors->getnextactor());
}
renderer1->setactivecamera(camera1);
renderer1->setviewport(0.33, 0, 0.66, 1);
renderer1->setbackground(1, 1, 1);
//---------设置第二个辅助渲染器----------
vtksmartpointer<vtkrenderer> renderer2 = vtksmartpointer<vtkrenderer>::new();
renderer2->setactivecamera(camera2);
renderer2->setviewport(0.66, 0, 1, 1);
renderer2->setbackground(1, 1, 1);
actors->inittraversal();
for (int i = 0; i < actors->getnumberofitems(); i++)
{
renderer2->addactor(actors->getnextactor());
}
vtksmartpointer<vtkrenderwindow> renderwindow = vtksmartpointer<vtkrenderwindow>::new();
renderwindow->addrenderer(renderer);
renderwindow->addrenderer(renderer1);
renderwindow->addrenderer(renderer2);
renderwindow->setsize(1200, 400);
vtksmartpointer<vtkinteractorstyletrackballcamera> style = vtksmartpointer<vtkinteractorstyletrackballcamera>::new();
vtksmartpointer<vtkrenderwindowinteractor> rwi = vtksmartpointer<vtkrenderwindowinteractor>::new();
rwi->setrenderwindow(renderwindow);
rwi->setinteractorstyle(style);
rwi->start();
}
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