Question

我只是喜欢这个链接： http://blog.qt.digia.com/blog/2014/11/20/qt-weekly-20-completing-the-offering-qopenglwindow-and-qrasterwindow/?utm_source=tuicool

我按链接说。但是我无法得到正确的结果。只有背景颜色。我的代码有什么不对吗？

我的代码：

class Render : public QOpenGLWindow
{
public:
    Render();
    ~Render();
protected:
    void initializeGL();
    void paintGL();
    void resizeGL(int  w ,int h);
     QOpenGLFunctions * f;
     QOpenGLBuffer * triangle;
     QOpenGLVertexArrayObject * vao;
     QOpenGLShaderProgram * program;
      QMatrix4x4 mv,p;
      QTimer * time;
      float rota;
     //QPainter * painter;

};

GLfloat tri[] =
{
    0.0f,1.0f,-1.0f,1.0f,
     1.0f,1.0f,-1.0f,1.0f,
     1.0f,0.0f,-1.0f,1.0f,

};
Render::Render()
{
    QSurfaceFormat format;
    format.setDepthBufferSize(24);
    format.setStencilBufferSize(8);
    format.setVersion(3,3);
    format.setProfile(QSurfaceFormat::CoreProfile);
    setFormat(format);
    time = new QTimer;
    connect(time,SIGNAL(timeout()),this,SLOT(update()));
    time->start(50);
    rota = 0;


}

Render::~Render()
{

}
void Render::initializeGL()
{
//    f = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_3_Core>();
//    f->initializeOpenGLFunctions();

    f = context()->functions();


    program =  new QOpenGLShaderProgram;
    program->addShaderFromSourceCode(QOpenGLShader::Vertex,
                                     "#version 330 core \n\
                                     layout(location = 0) in vec4 vertex;\
            uniform mat4 mvp;\
                                     void main() \
            {\
                gl_Position = mvp * vertex;\
             }");

    program->addShaderFromSourceCode(QOpenGLShader::Fragment,
                                     "#version 330 core \n\
                                     out vec4 fragColor;\
            void main() \
    { \
        fragColor = vec4(0.0f,1.0f,0.0f,1.0f);\
    }");
    program->link();

    vao = new QOpenGLVertexArrayObject;
    vao->create();
    vao->bind();
    triangle = new QOpenGLBuffer(QOpenGLBuffer::VertexBuffer);
    triangle->create();
    triangle->bind();

    triangle->setUsagePattern(QOpenGLBuffer::StaticDraw);
    triangle->allocate(tri,sizeof(tri));
    program->enableAttributeArray(0);
    program->setAttributeBuffer(0,GL_FLOAT,0,4,0);
    f->glEnable(GL_DEPTH_TEST);


}
void Render::resizeGL(int w ,int h)
{
    p.setToIdentity();
     p.perspective(35.0f,float(w)/float(h),1.0f,30.0f);
}
void Render::paintGL()
{
    program->bind();
    f->glClearColor(0.5,0.5f,0.5f,1.0f);
    f->glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    f->glViewport(0,0,width(),height());

    mv.setToIdentity();

    mv.lookAt(QVector3D(0.0f,0.0f,5.0f),QVector3D(0.0f,0.0f,0.0f),QVector3D(0.0f,1.0f,0.0f));
    mv.rotate(0.5+rota,0,1,0);
    program->setUniformValue("mvp",p*mv);
    vao->bind();
    f->glDrawArrays(GL_TRIANGLES,0,3);
    rota=rota+1.5;
    rota=rota>360.0?0:rota;


    QPainter pp(this);

    pp.drawText(10,20,"dsdsds");
    update();
}

Answer 1

当我需要这样做时，我覆盖了paintEvent并使用了QPainter::beginNativePainting (); / QPainter::endNativePainting ();

void Render::paintEvent(QPaintEvent *)
{

    QPainter p(this);
    p.beginNativePainting ();
    makeCurrent ();
    //restore and save state so they don't interact
    glEnable (GL_DEPTH_TEST);
    glClear (GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
    paintGL ();
    glClear (GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
    glDisable (GL_DEPTH_TEST);
    p.endNativePainting ();

    //other painting
}

Answer 2

我有同样的问题，可以通过在使用QPainter之前释放顶点缓冲区来解决它。所以你可能想尝试一下 vao-＆GT;释放（）; triangle-＆GT;释放（）; 程序 - ＆GT;释放（）; 在初始化QPainter之前。

Answer 3

这是我在＆＃34; QOpenGLWidget＆＃34;中的作用。我不需要在＆＃34; beginNativePainting（）＆＃34;之间放置OpenGL代码。和＆＃34; beginNativePainting（）＆＃34; Qpainter函数调用。我不需要覆盖paintEvent ...这与您共享的链接中的内容类似。

1）在＆＃34; QOpenGLWidget＆＃34;的构造函数中将格式设置为＆＃34; CompatibilityProfile＆＃34; 例如：

QSurfaceFormat  format;
format.setProfile(QSurfaceFormat::CompatibilityProfile);
QSurfaceFormat::setDefaultFormat(format);
this->setFormat(format);

2）在你的游戏循环功能中确保发布程序，VAO，VBO和＆amp;完成OpenGL代码之后，在调用Qpainter并在函数的最后使用它之前的EBO。例如：

VAO.release();
VBO->release();
EBO->release();
m_program->release();
QPainter painter(this);
painter.begin(this);
painter.setRenderHint(QPainter::Antialiasing);
painter.drawText(10,20,"dsdsds");
painter.end();

Answer 4

我在Qt 5.8中遇到了同样的问题。解决方案不仅仅是致电

vao->release();
triangle->release();
program->release();

丹尼尔建议，但也要打电话

program->disableAttributeArray(0);

在着色器程序发布之前

。

因此，基本上任何在GPU上绑定或启用的东西都需要被禁用或释放。

QOpenGLWindow QPainter混合渲染

4 个答案: