VTK实现三视图显示及交互STL模型

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。

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效果演示

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要点

1. 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。
2. 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。
3. 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。

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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();
}