19、osg中控制帧速实例
// Example1.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#include <osgLib.h>
#include <osgDB/ReadFile>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
#include <osgGA/GUIEventAdapter>
#include <osgGA/TrackballManipulator>
#include <iostream>
using namespace std;
class TestHandler:public osgGA::GUIEventHandler
{
public:
bool handle(const osgGA::GUIEventHandler &ea,osgGA::GUIActionAdapter &aa)
{
return true;
}
virtual void getUsage(osg::ApplicationUsage &usage) const
{
usage.addKeyboardMouseBinding("sxj","sxjlinux");
}
};
int _tmain(int argc, _TCHAR* argv[])
{
osg::ref_ptr<osgViewer::Viewer> viewer=new osgViewer::Viewer;
//申请一个定时器类
osg::Timer *timer=new osg::Timer;
osg::Timer_t start_timer=0,end_timer=0;
osg::Timer_t start_frame_timer=0,end_frame_timer=0;
double start_timer1=0.0,end_timer1=0.0;
//控制帧速使用睡眠时间
double sleep_time=0.0;
double last_sleep=0.0001;
//每帧的实际使用时间
double current_time=0.0;
//每帧控制法
double per_str_time=0.0;
double per_end_time=0.0;
//得到一个tick值为多少Seconds
cout<<timer->getSecondsPerTick()<<endl;
start_timer=timer->tick();
start_timer1=viewer->elapsedTime();
timer->setStartTick();
osg::ref_ptr<osg::Node> node=osgDB::readNodeFile("glider.osg");
cout<<"方法一、读取模型的时间为："<<timer->time_s()<<endl;
end_timer=timer->tick();
end_timer1=viewer->elapsedTime();
cout<<"方法二、读取模型的时间为："<<timer->delta_s(start_timer,end_timer)<<endl;
cout<<"方法三、读取模型的时间为："<<end_timer1-start_timer1<<endl;
viewer->addEventHandler(new osgViewer::HelpHandler); //帮助事件
viewer->addEventHandler(new TestHandler);
viewer->addEventHandler(new osgViewer::StatsHandler);//显示帧事件
viewer->addEventHandler(new osgViewer::WindowSizeHandler);//是否全屏事件
viewer->addEventHandler(new osgViewer::ScreenCaptureHandler);//截图事件
viewer->addEventHandler(new osgViewer::RecordCameraPathHandler);//记录当前的路径事件
viewer->setSceneData(node.get());
viewer->realize();
viewer->setCameraManipulator(new osgGA::TrackballManipulator);//加入操作器
//vewer->run();
int counts=0;//计算帧速
while(!viewer->done())//此循环默认情况下一般每秒钟执行60次
{
per_str_time=timer->tick();
if (counts==0)
{
start_frame_timer=timer->tick();
}
counts++;
viewer->frame();
//方法二
per_end_time=timer->tick();
//0.1表示10帧每秒钟
//sleep_time=0.1-timer->delta_s(per_str_time,per_end_time);
/*控制帧速的公式为：每帧睡眠的时间=期望每帧绘制的时间-实际绘制的时间
假如：帧速为x,那么每帧绘制的时间为：1.0/x(秒)，实际绘制的的时间为：t
那么需要睡眠的时间=1.0/x-t
*/
//delta_s是计算per_str_time，per_end_time之间的差值，就是per_end_time-per_str_time
sleep_time=1.0/35.0-timer->delta_s(per_str_time,per_end_time);
//sleep_time是得到每帧
//如果sleep_time的值小于0，则说明实际绘制的时间大于期望的时间
//因此此时就不需要再睡眠了，如果在继续睡眠，则效率会更差
if (sleep_time<0)
{
sleep_time=0.0;
}
OpenThreads::Thread::microSleep(sleep_time*1000000);
if (counts==3)
{
//限制帧速为10，每帧为0.1秒，那么10帧就为1秒
end_frame_timer=timer->tick();
cout<<"当前帧速为："<<counts/timer->delta_s(start_frame_timer,end_frame_timer)<<endl;
counts=0;
//得到当前每帧绘制所用时间
//sleep_time=0.1-(timer->delta_s(start_frame_timer,end_frame_timer))/3;//方法一
//if (sleep_time<0)//如果小于0，则表示实际绘制的时间，比期望的时间要大
//{
// //比如期望的帧数为10，但实际绘制的为8帧，因此8-10会小于0
// sleep_time=last_sleep*0.8;
// last_sleep=sleep_time;
//}
}
}
return 0;
}
其中osgLib.h的内容为：
#ifdef _DEBUG #pragma comment(lib,"osgAnimationd.lib") #pragma comment(lib,"osgTerraind.lib") #pragma comment(lib,"osgQtd.lib") #pragma comment(lib,"osgParticled.lib") #pragma comment(lib,"osgPresentationd.lib") #pragma comment(lib,"osgShadowd.lib") #pragma comment(lib,"osgSimd.lib") #pragma comment(lib,"osgVolumed.lib") #pragma comment(lib,"osgManipulatord.lib") #pragma comment(lib,"osgFXd.lib") #pragma comment(lib,"osgWidgetd.lib") #pragma comment(lib,"osgViewerd.lib") #pragma comment(lib,"osgTextd.lib") #pragma comment(lib,"osgGAd.lib") #pragma comment(lib,"osgDBd.lib") #pragma comment(lib,"osgUtild.lib") #pragma comment(lib,"osgd.lib") #pragma comment(lib,"OpenThreadsd.lib") #else #pragma comment(lib,"osgAnimation.lib") #pragma comment(lib,"osgTerrain.lib") #pragma comment(lib,"osgQt.lib") #pragma comment(lib,"osgParticle.lib") #pragma comment(lib,"osgPresentation.lib") #pragma comment(lib,"osgShadow.lib") #pragma comment(lib,"osgSim.lib") #pragma comment(lib,"osgVolume.lib") #pragma comment(lib,"osgManipulator.lib") #pragma comment(lib,"osgFX.lib") #pragma comment(lib,"osgWidget.lib") #pragma comment(lib,"osgViewer.lib") #pragma comment(lib,"osgText.lib") #pragma comment(lib,"osgGA.lib") #pragma comment(lib,"osgDB.lib") #pragma comment(lib,"osgUtil.lib") #pragma comment(lib,"osg.lib") #pragma comment(lib,"OpenThreads.lib") #endif
运行效果为：
