Can i draw QRect with QPainter and draw something with OpenGL together? - c++

Question

Qt 5.8.0. MinGW 32 bit.
I need to draw objects of different shapes on the screen. I use OpenGL to speed up and draw different shapes, but I also need to draw in QPaint.
I try to draw Rect with Qpainter (drawText function). Text show on screen, but rect not show on screen.
Example
How do I draw a rectangle with QPainter, not with OpenGL? I want to draw 3 shapes: a triangle and a rectangle using OpenGL, a rectangle using QPainter. My app should to draw any shapes (using QPainter) and sometimes draw particles with OpenGL acceleration. How can I combine this in one widget?
part of DrawingWidget.cpp:
void DrawingWidget::paintGL()
{
m_painter = new QPainter(this);
m_painter->beginNativePainting();
m_program->bind();
m_modelView.setToIdentity();
m_modelView.translate(-1.5f, 0.0f, -6.0f);
m_program->setUniformValue("mvpMatrix", m_projection * m_modelView);
glBindBuffer(GL_ARRAY_BUFFER, m_vboIds[0]);
m_program->enableAttributeArray(m_posAttr);
m_program->setAttributeBuffer(m_posAttr, GL_FLOAT, 0, 3);
glBindBuffer(GL_ARRAY_BUFFER, m_vboIds[1]);
m_program->enableAttributeArray(m_colAttr);
m_program->setAttributeBuffer(m_colAttr, GL_FLOAT, 0, 3);
glDrawArrays(GL_TRIANGLES, 0, 3);
m_modelView.translate(3.0f, 0.0f, 0.0f);
m_program->setUniformValue("mvpMatrix", m_projection * m_modelView);
glBindBuffer(GL_ARRAY_BUFFER, m_vboIds[2]);
m_program->enableAttributeArray(m_posAttr);
m_program->setAttributeBuffer(m_posAttr, GL_FLOAT, 0, 3);
glBindBuffer(GL_ARRAY_BUFFER, m_vboIds[3]);
m_program->enableAttributeArray(m_colAttr);
m_program->setAttributeBuffer(m_colAttr, GL_FLOAT, 0, 3);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
m_program->release();
m_painter->endNativePainting();
drawText();
m_painter->end();
}
void DrawingWidget::drawText()
{
m_painter->setPen(QColor(Qt::green));
m_painter->setBrush(QBrush(QColor(Qt::red)));
m_painter->drawRect(QRect(QPoint(10, 10), QPoint(50, 44)));
m_painter->drawText(0, 40, QString("TEST"));
}
main:
int main(int argc, char **argv)
{
QApplication app(argc, argv);
QSurfaceFormat format;
format.setProfile(QSurfaceFormat::OpenGLContextProfile::CompatibilityProfile);
DrawingWidget GLWidget;
GLWidget.setFormat(format);
GLWidget.resize(800, 600);
GLWidget.show();
return app.exec();
}
18.04.17
ahaha, so, when i will draw to rect after draw text app is working, but not working if i try draw text after rect or try draw rect without text
m_painter->setPen(QColor(Qt::green));
m_painter->setBrush(QBrush(QColor(Qt::red)));
m_painter->drawText(0, 40, QString("TEST"));
for (int i = 0; i < 6; i++) {
int x = rand() % this->width();
int y = rand() % this->height();
m_painter->drawRect(QRect(QPoint(x, y), QPoint(x + 15, y + 15)));
}