QML and QOpengGL for printing images

[Quentin91]

Hi ! I'm not very experienced with Qt and completely new to OpenGL so I'm confused.
I need to show images in an OpenGL texture using a FBO, which works when I get the picture from my files with stbi.

But the image has to come from the sharedMemory. So my code is splitted in two different clusters :
One for getting the data from the sharedMemory using a thread that refresh the data periodically and has a structure containing a QOpenGLBuffer and a QOpenGLTexture

struct ImageSinkOpenglTextureData
{
	QOpenGLTexture* m_glTexture;
	int m_iWidth;
	int m_iHeight;
	QOpenGLBuffer* m_pboIds[2];
	int m_currentPboId;
};

Another that creates the geometry of the texture, that implements a QQuickFamebufferObject and a Renderer.

But both of these class clusters are instanciated by the QML thanks to

qmlRegisterType<imageSourceObject>("Pegase", 1, 0, "ImageSource");
qmlRegisterType<TextureViewObject>("Pegase", 1, 0, "TextureViewObject");

And I have no clue on how to give the image from the classs that manage the QSharedMemory to the class that can print the data.
Do I have to use a FBO ? I've seen that we can access to a FBO thanks to an id. But how ? Or maybe I can send a signal containing the pointer to the data to the printer ? i tried but it didn't work I could try again ?

This is where I print the data. i'm not sure about what code to show. The first method is the initialisation of the shader, vao...

void TextureViewRenderer::initialize(void)
{		
	QOpenGLShader m_shader(QOpenGLShader::Vertex);

	 mp_shaderProgram= new QOpenGLShaderProgram(QOpenGLContext::currentContext());
	
	 mp_shaderProgram->addShaderFromSourceFile(QOpenGLShader::Vertex, ConstantView::VS_FILE_PATH);//test, mais faudra mettre la valeur constant
	mp_shaderProgram->addShaderFromSourceFile(QOpenGLShader::Fragment, ConstantView::FS_FILE_PATH);

	 mp_shaderProgram->link();
	mp_vao->create();
	mp_vao->bind();

			 //init of the vertices table
	float w_vertices[VERTICES_SIZE];
			 //parcours les deux tableaux selon la longueur du plus petit au cas ou il y ait un écart (ce que serait anormal)
	for (size_t i = 0; i < (std::min(sizeof(ConstantView::DEFAULT_VERTICES), sizeof(w_vertices)) / sizeof(float)); ++i)
		 w_vertices[i] = ConstantView::DEFAULT_VERTICES[i];
			
	float w_texc[12] = { get_uMin(), get_vMax(), get_uMax(), get_vMax(), get_uMin(), get_vMin(), get_uMax(), get_vMin() };
	QString w_tmpStr("texCoord");
			
	mp_vao->release();//donc on bien set le vertex data state là

	QMatrix4x4 w_pmvMatrix;
	w_pmvMatrix.ortho(0,1,0,1,0,1);//ça change rien quand on change la valeur
			
	mp_shaderProgram->bind();
	mp_shaderProgram->release();
	cout << "TextureViewRenderer textureId " << m_textureId << endl;
}

And this one prints the images I want

void TextureViewRenderer::textureRendering(void)
			
{
	if (m_uvDirty)
	{
		TRACE_DEBUG("TextureViewRenderer::textureRendering m_ubDirty TRUE")
		m_uvDirty = false;				
	}
	//nettoie les couleurs de la frame précédente pour préparer la prochaine
	if (m_textureId == 0) 
		//glClearColor(float(++r%10)/10, float(++g % 10) / 10, float(++b % 10) / 10, float(++a % 10) / 10);
		glClearColor(0, 0, 0, 1);//PANO
	else if(m_textureId==1)
		glClearColor(1, 1, 0, 1);//petit ROI du milieu
	else if(m_textureId==2)
		glClearColor(0, 0, 1, 1);
	else 
		glClearColor(1, 0, 0, 1);
/************************************************************************************************
récupération de l'image test avec stb_image */
	int w = 12, h = 12, channels = 3;
	unsigned char* data;
	if (m_textureId == 1)
		data = stbi_load("testPicture2.jpg", &w, &h, &channels,0);
	else if(m_textureId == 3)
		data = stbi_load("testPicturePano.jpg", &w, &h, &channels, 0);
	else 
		data = stbi_load("testPicture3.jpg", &w, &h, &channels, 0);

	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	mp_shaderProgram->bind();
	glBindTexture(GL_TEXTURE_2D, m_textureId);//la doc est moyenne mais de très bonnes explications par ici https://learnopengl.com/Getting-started/Textures
	/***************************************************************************************************/
	if (mp_data)
	{
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_RGB, GL_UNSIGNED_BYTE, mp_data);
	}
	else
	{
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
        }
	/****************************************************************************************************/
			
	mp_shaderProgram->release();
	/********************/
	stbi_image_free(data);
}