[Qt-interest] View JPEG in QGLWidget

[Brilliantov Kirill Vladimirovich]

>
> OK, I think I've found the source of the problem ? incorrect vertex coordinates.

Hello, Constantin!
Your sample correct work with static image, but with dinamic image 
(images from IP-camera) I get only black screen.

My code:
bool mode = isValid();

enum gl_mode_e {
	GL_MODE_PAINTER, ///< use QPainter
	GL_MODE_NATIVE	///< use OpenGL
};

void Image::initializeGL()
{
	if (GL_MODE_NATIVE == mode) {
		glClearColor(0.0, 0.0, 0.0, 0.0);
		glDisable(GL_DEPTH_TEST);
		glEnable(GL_TEXTURE_2D);
		glGenTextures(1, &texture);
		glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
		glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
	}
}
void Image::paintGL()
{
	switch (mode) {
		case GL_MODE_NATIVE:
			glClear(GL_COLOR_BUFFER_BIT);
			glTranslatef(-image.width()/2, -image.height()/2, 0.0);
			glBindTexture(GL_TEXTURE_2D, texture);
			image = QGLWidget::convertToGLFormat(QImage::fromData(jpg));
			if (1 == frame_number)
				glTexImage2D(GL_TEXTURE_2D, 0, 4, image.width(),
							 image.height(), 0, GL_RGBA, GL_UNSIGNED_BYTE,
							 image.bits());
			else
				glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, image.width(),
								image.height(),	GL_RGBA, GL_UNSIGNED_BYTE,
								image.bits());
			glBegin(GL_QUADS);
				//top left
				glTexCoord2f(0.0, 1.0);
				glVertex2f(-1.0, 1.0);
				//bottom left
				glTexCoord2f(0.0, 0.0);
				glVertex2f(-1.0, -1.0);
				//bottom right
				glTexCoord2f(1.0, 0.0);
				glVertex2f(1.0, -1.0);
				//top right
				glTexCoord2f(1.0, 1.0);
				glVertex2f(1.0, 1.0);
			glEnd();
			break;
		case GL_MODE_PAINTER:
			QPainter paint(this);
			paint.drawImage(0, 0, QImage::fromData(jpg));
			break;
	}
	show();
}

I see image when I use GL_MODE_PAINTER, but with GL_MODE_NATIVE I see 
only black screen;

Can your help me?
Thank you and excuse me for my bad english.