我使用 Visual Studio 2010 在 Windows XP (Qt 4.7.2) 中编写和测试了一些代码,然后我在另一台安装了 Windows 7 的机器上进行了尝试。
该程序打开一个 QDialog 并创建一个 QGLWidget,我在其中显示网络摄像头图像(经过一些处理)。虽然在 Windows XP 中图像显示正确,但当我在 Windows 7 机器上测试程序时,QGLWidget 变黑并且没有显示图像。但奇怪的是,当我在窗口周围移动时,它超出了屏幕的边界,当我再次停止移动时,图像会立即显示并变成黑色,这让我认为图像被正确接收/processed(有时),这可能是 QTimer 的问题。
相关代码为:
初始化:
void GLVideo::initializeGL()
{
glEnable(GL_TEXTURE_2D);
glShadeModel(GL_SMOOTH);
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClearDepth(1.0f);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
// Some OpenCV processing
// Here I declare the timer, might it be the problem?
m_timer = new QTimer(this);
connect( m_timer, SIGNAL(timeout()), this, SLOT(timeOutSlot()) );
m_timer->start( 33 );
}
每次超时调用的插槽:
void GLVideo::timeOutSlot()
{
ReceiveInfo();
LoadTextures();
}
void GLVideo::LoadTextures()
{
// Get the image from the webcam
ProcessCamera();
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D( GL_TEXTURE_2D, 0, 3, qImage->width(),
qImage->height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, qImage->bits());
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
updateGL();
}
void GLVideo::resizeGL( int width, int height )
{
height = height?height:1;
glViewport( 0, 0, (GLint)width, (GLint)height );
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
最后是 Widget 的绘制函数:
void GLVideo::paintGL()
{
glPushAttrib(GL_ALL_ATTRIB_BITS) ;
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing);
glPopAttrib() ;
glEnable(GL_TEXTURE_2D);
glShadeModel(GL_SMOOTH);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glBindTexture(GL_TEXTURE_2D, texture);
glColor4f(1.0f,1.0f,1.0f, 1.0f);
glBegin(GL_QUADS);
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.65f, 1.24f, -3.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.65f, 1.24f, -3.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.65f,-1.24f, -3.0f);
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.65f,-1.24f, -3.0f);
glEnd();
glDisable(GL_TEXTURE_2D);
glDisable(GL_DEPTH_TEST);
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
// Some 2D drawing:
}
知道我在做什么错吗?可能是 QTimer 没有调用 SLOT timeOutSlot?