learnopengl-qt

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

How to use

install libraries

install Qt
install vcpkg
- set VCPKG_ROOT environment variable to the vcpkg root dir
- install assimp vcpkg install assimp

run

open the file CMakeLists.txt with VS/VSCode/QtCreator or other IDEs,

if you want to build in command line:
```
mkdir build
cd build
cmake ..
cmake --build . --config Release
```
then all the things will be builded to build/bin
run it in debug/release mode
select a widget to show
for camera control, default key map is as follows, if you select a widget and find no cursor, just press Q to disable camera control

dir key

forward w

backward s

left a

right d

disable q

enable e

dir	key
forward	w
backward	s
left	a
right	d
disable	q
enable	e

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

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

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);
}

learnopengl Model-Loading does not support 3D formats with embedded textures, so don't use .glb .gltf or other formats.