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learnopengl-qt

learn opengl with Qt, and it's directory structure is mostly like the origin one.

How to use

install libraries

  • download Qt
  • install assimp and make sure that the lib path is correct in learnopengl-qt.pro bottom line LIBS += -L$$PWD/thirdparty/assimp_x64-windows/lib/ -lassimp-vc141-mt
  • this project is build in Qt 5.9.9 MSVC2017 64bit, the compiled library is in ./thirdparty/, make sure *.dll is in the same path with *.exe

run

  • open the file learnopengl-qt.pro with QtCreator

  • run it in debug/release mode

  • select a widget to show

    main window

How to add a new widget

  • create a new class like this

    class MultipleLights : public QOpenGLWidget, protected QOpenGLFunctions_3_3_Core
    {
        Q_OBJECT
    public:
        //Q_INVOKABLE is needed
        Q_INVOKABLE MultipleLights(QWidget *parent = nullptr);
        ~MultipleLights();
    
    protected:
        virtual void initializeGL() override;
        virtual void resizeGL(int w, int h) override;
        virtual void paintGL() override;
    
    private:
    };
  • inclue it in MainWindow.h

    #include "2.lighting/6.1multiple_lights/MultipleLights.h"
  • add the class name and staticMetaObject to a hashMap in MainWindow.cpp

    void MainWindow::registerMetaObject()
    {
        //add staticMetaObject of the new class you have created to a list
        m_metaObjectList << &MultipleLights::staticMetaObject;
    
        //then easily traverse the list and add QMetaObject to map and combox
        for(const QMetaObject* mo : m_metaObjectList){
            m_metaObjectMap.insert(mo->className(), mo);
            m_combox->addItem(mo->className());
        }
    }

Notes

  1. glBindFramebuffer(GL_FRAMEBUFFER, 0) may not work in QOpenGLWidget, because 0 is not QOpenGLWidget's default framebuffer, use glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebufferObject())instead. Here is my blog

  2. It seems that Qt does not have UBO(uniform buffer object), thus I made a class called OpenGLUniformbufferObject. And, you must pay attention:

    // wrong
    class OpenGLUniformbufferObject : public QOpenGLFunctions_3_3_Core
    {
        //...
        glGetActiveUniformBlockiv(m_shaderId, m_uniformBlockIndex, GL_UNIFORM_BLOCK_DATA_SIZE, &m_uboSize);
    }
    // right
    class OpenGLUniformbufferObject
    {
        //...
        // get current opengl function
        QOpenGLFunctions_3_3_Core* m_glFunc = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_3_Core>();
        m_glFunc->glGetActiveUniformBlockiv(m_shaderId, m_uniformBlockIndex, GL_UNIFORM_BLOCK_DATA_SIZE, &m_uboSize);
    }
    

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  • C++ 89.4%
  • GLSL 9.0%
  • QMake 1.6%