qml porting changes the opengl scene placement

[sajis997]

I am not doing much of different that what is described in http://doc.qt.io/qt-5/qtquick-sceneg...l-example.html . Lets compare the sync() there and mine:

void Squircle::sync()
{
    if (!m_renderer) {
        m_renderer = new SquircleRenderer();
        connect(window(), SIGNAL(beforeRendering()), m_renderer, SLOT(paint()), Qt::DirectConnection);
    }
    m_renderer->setViewportSize(window()->size() * window()->devicePixelRatio());
    m_renderer->setT(m_t);
}

void Squircle::sync()
{
    if (!m_renderer) {
        m_renderer = new SquircleRenderer();
        connect(window(), SIGNAL(beforeRendering()), m_renderer, SLOT(paint()), Qt::DirectConnection);
    }
    m_renderer->setViewportSize(window()->size() * window()->devicePixelRatio());
    m_renderer->setT(m_t);
}

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Whereas I am doing the following:

void TriangleSceneItem::sync()
{
    if(mScene)
    {
        connect(mTimer,SIGNAL(timeout()),this,SLOT(updateTime()),Qt::DirectConnection);
 
        mScene->setViewportSize(window()->width() * window()->devicePixelRatio(),
                                window()->height() * window()->devicePixelRatio());
    }
}

void TriangleSceneItem::sync()
{
    if(mScene)
    {
        connect(mTimer,SIGNAL(timeout()),this,SLOT(updateTime()),Qt::DirectConnection);

        mScene->setViewportSize(window()->width() * window()->devicePixelRatio(),
                                window()->height() * window()->devicePixelRatio());
    }
}

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I am creating the timer for the animation and then setting the viewport size that is lated used during rendering. The renderer intialization is done inside the constructor.

[wysota]

As I said, look at the code of resize, not sync. By the way, what does initialize() do?

[sajis997]

This what TriangleScene::initialize() do :

void TriangleScene::initialise()
{
    //return if already initialized
    if(mInitialized)
        return;
 
    if(!initializeOpenGLFunctions())
    {
        std::cerr << "Modern OpenGL Functions could not be initialized." << std::endl;
        std::exit(EXIT_FAILURE);
    }
 
    GL_CHECK_ERRORS;
 
    //make the projection and model-view matrix
    //identity matrices
    mProjectionMatrix = glm::mat4(1.0f);
    mModelViewMatrix = glm::mat4(1.0f);
 
    loadShaders();
 
    //setup the triangle geometry
    mVertices[0].color = glm::vec3(1.0,0.0,0.0);
    mVertices[1].color = glm::vec3(0.0,1.0,0.0);
    mVertices[2].color = glm::vec3(0.0,0.0,1.0);
 
    mVertices[0].position = glm::vec3(-1,-1,0);
    mVertices[1].position = glm::vec3(0,1,0);
    mVertices[2].position = glm::vec3(1,-1,0);
 
    //setup the triangle indices
    mIndices[0] = 0;
    mIndices[1] = 1;
    mIndices[2] = 2;
 
    //check for opengl errors
    GL_CHECK_ERRORS;
 
    //setup the triangle vao and vbo stuff
    glGenVertexArrays(1,&mVaoID);
 
    glGenBuffers(1,&mVerticesID);
    glGenBuffers(1,&mIndicesID);
 
    //get the size of the Vertex struct
    GLsizei stride = sizeof(Vertex);
 
    glBindVertexArray(mVaoID);
 
    glBindBuffer(GL_ARRAY_BUFFER,mVerticesID);
    //pass triangle vertices to the buffer object
    glBufferData(GL_ARRAY_BUFFER,  //specifies the target buffer object
                 sizeof(mVertices),//specifies the size in bytes
                 &mVertices[0], // pointer to the data
                 GL_STATIC_DRAW); //usage pattern of the data
 
    GL_CHECK_ERRORS;
 
    glEnableVertexAttribArray(mTriangleShader->getAttribute("vVertex"));
    glVertexAttribPointer(mTriangleShader->getAttribute("vVertex"),3,GL_FLOAT,GL_FALSE,stride,0);
 
    GL_CHECK_ERRORS;
 
    //enable vertex attribute array for the color
    glEnableVertexAttribArray(mTriangleShader->getAttribute("vColor"));
    glVertexAttribPointer(mTriangleShader->getAttribute("vColor"),3,GL_FLOAT,GL_FALSE,stride,(const GLvoid*)offsetof(Vertex,color));
 
    GL_CHECK_ERRORS;
 
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,mIndicesID);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(mIndices),&mIndices[0],GL_STATIC_DRAW);
 
    glDisableVertexAttribArray(mTriangleShader->getAttribute("vVertex"));
    glDisableVertexAttribArray(mTriangleShader->getAttribute("vColor"));
    glBindVertexArray(0);
 
    GL_CHECK_ERRORS;
 
    mInitialized = true;
 
}
 
I think the issue lies here and I am examining it right now. Any hint from your end within the function will accelerate the process.
 
 
Thanks

void TriangleScene::initialise()
{
    //return if already initialized
    if(mInitialized)
        return;

    if(!initializeOpenGLFunctions())
    {
        std::cerr << "Modern OpenGL Functions could not be initialized." << std::endl;
        std::exit(EXIT_FAILURE);
    }

    GL_CHECK_ERRORS;

    //make the projection and model-view matrix
    //identity matrices
    mProjectionMatrix = glm::mat4(1.0f);
    mModelViewMatrix = glm::mat4(1.0f);

    loadShaders();

    //setup the triangle geometry
    mVertices[0].color = glm::vec3(1.0,0.0,0.0);
    mVertices[1].color = glm::vec3(0.0,1.0,0.0);
    mVertices[2].color = glm::vec3(0.0,0.0,1.0);

    mVertices[0].position = glm::vec3(-1,-1,0);
    mVertices[1].position = glm::vec3(0,1,0);
    mVertices[2].position = glm::vec3(1,-1,0);

    //setup the triangle indices
    mIndices[0] = 0;
    mIndices[1] = 1;
    mIndices[2] = 2;

    //check for opengl errors
    GL_CHECK_ERRORS;

    //setup the triangle vao and vbo stuff
    glGenVertexArrays(1,&mVaoID);

    glGenBuffers(1,&mVerticesID);
    glGenBuffers(1,&mIndicesID);

    //get the size of the Vertex struct
    GLsizei stride = sizeof(Vertex);

    glBindVertexArray(mVaoID);

    glBindBuffer(GL_ARRAY_BUFFER,mVerticesID);
    //pass triangle vertices to the buffer object
    glBufferData(GL_ARRAY_BUFFER,  //specifies the target buffer object
                 sizeof(mVertices),//specifies the size in bytes
                 &mVertices[0], // pointer to the data
                 GL_STATIC_DRAW); //usage pattern of the data

    GL_CHECK_ERRORS;

    glEnableVertexAttribArray(mTriangleShader->getAttribute("vVertex"));
    glVertexAttribPointer(mTriangleShader->getAttribute("vVertex"),3,GL_FLOAT,GL_FALSE,stride,0);

    GL_CHECK_ERRORS;

    //enable vertex attribute array for the color
    glEnableVertexAttribArray(mTriangleShader->getAttribute("vColor"));
    glVertexAttribPointer(mTriangleShader->getAttribute("vColor"),3,GL_FLOAT,GL_FALSE,stride,(const GLvoid*)offsetof(Vertex,color));

    GL_CHECK_ERRORS;

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,mIndicesID);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(mIndices),&mIndices[0],GL_STATIC_DRAW);

    glDisableVertexAttribArray(mTriangleShader->getAttribute("vVertex"));
    glDisableVertexAttribArray(mTriangleShader->getAttribute("vColor"));
    glBindVertexArray(0);

    GL_CHECK_ERRORS;

    mInitialized = true;

}

I think the issue lies here and I am examining it right now. Any hint from your end within the function will accelerate the process.


Thanks

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