我想渲染一个三角形,其坐标由单独的线程不断更新(使用 m_offset)。该线程在整个运行时并行运行。
我的应用程序使用 GL 小部件初始化 QT 窗口。
#include "mainwindow.h"
#include <QApplication>
#include <iostream>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
GL 小部件 (glwidget.cpp) 定义如下:
#include "glwidget.h"
#include <iostream>
#include <thread>
GLWidget::GLWidget(QWidget *parent) : QGLWidget(parent)
{
m_offset = 0.0
// HERE, I want to start a thread on updateCoordinates().
// Something like this: (this doesn't work)
//std::thread mythread (updateCoordinates);
// or this (getting segfault)
//std::thread mythread (&GLWidget::updateCoordinates, this);
}
void GLWidget::initializeGL()
{
glClearColor(0.2, 0.2, 0.2, 1);
}
void GLWidget::paintGL()
{
glClear(GL_COLOR_BUFFER_BIT);
glBegin(GL_TRIANGLES);
glColor3f(1,0,0);
glVertex3f(-0.5+m_offset, -0.5+m_offset, 0);
glColor3f(0,1,0);
glVertex3f(0.5+m_offset, -0.5+m_offset, 0);
glColor3f(0,0,1);
glVertex3f(0.0+m_offset, 0.5+m_offset, 0);
glEnd();
}
void GLWidget::resizeGL(int w, int h)
{}
void GLWidget::updateCoordinates()
{
while(true)
{
m_offset += 0.0001;
}
}
这是相应的标题:
#ifndef GLWIDGET_H
#define GLWIDGET_H
#include <QGLWidget>
class GLWidget : public QGLWidget
{
Q_OBJECT
public:
explicit GLWidget(QWidget *parent = 0);
void initializeGL();
void paintGL();
void resizeGL(int w, int h);
void startSimulation();
void stopSimulation();
void updateCoordinates();
private:
double m_offset;
signals:
public slots:
};
#endif // GLWIDGET_H
如何在此类中创建一个连续运行 updateCooperatives()
的新线程,同时通过 paingGL()
更新图形?
谢谢!
最佳答案
您可以使用QThread 。
虽然存在其他选项,例如 QConcurrent,但有些选项question its implementation 。
创建一个从 QObject 派生的对象,该对象将负责更新坐标。每次更新后,对象可以发出带有坐标的信号,然后在主线程上接收回该信号。
class Worker : public QObject
{
Q_OBJECT
public:
Worker();
~Worker();
public slots:
void process();
signals:
typedef QVector<QPoint> PointList;
void NewCoordinates(PointList points);
private:
PointList m_pointList;
private:
};
Worker::Worker() {
// you could copy data from constructor arguments to internal variables here.
}
// --- DESTRUCTOR ---
Worker::~Worker() {
// free resources
}
// --- PROCESS ---
// Start processing data.
void Worker::process() {
// calculate new coordinates...
emit NewCoordinates(m_pointList);
}
从主线程设置并启动线程和工作实例..
QThread* thread = new QThread;
Worker* worker = new Worker();
worker->moveToThread(thread);
connect(worker, SIGNAL(error(QString)), this, SLOT(errorString(QString)));
connect(thread, SIGNAL(started()), worker, SLOT(process()));
// tidy up
connect(worker, SIGNAL(finished()), thread, SLOT(quit()));
connect(worker, SIGNAL(finished()), worker, SLOT(deleteLater()));
connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
// assuming we're in the MainWindow class, with a NewCoordinates slot function
// collect points - C++ 5 connect syntax
connect(worker, &Worker::NewCoordinates(Worker::PointList), this, &MainWindow::NewCoordinates(Worker::PointList);
// let's go
thread->start();
void MainWindow::NewCoordinates(Worker::PointList pointList)
{
// handle updated coordinates
}
要了解如何真正、真正地使用 QThread,有一篇很棒的文章 here .
关于multithreading - C++11 线程在构造函数中初始化以执行方法,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26478753/