Question

我使用QOpenGLWidget派生自己的小部件渲染OpenGL。我想稍后设置顶点数据或尽可能改变它们而不是initializeGL()。尝试通过在initializedGL()中给出顶点来绘制三角形是可以的。但是我希望随时在外部调用updateModel()函数来改变模型。在initializeGL()中，注释行是QOpenGLWidget的标准用法。它运作良好。当我调用updateModel()更改顶点时，它无法绘制任何内容。怎么了？感谢。

#include "openglwindow.h"
#include <QDebug>
#include <QOpenGLShader>
#include <QOpenGLShaderProgram>
#include <QDebug>
#include <QMouseEvent>
#include <QWheelEvent>
#include <QVector3D>
#include <QTimer>

OpenGLWidget::OpenGLWidget(QWidget *parent):
    QOpenGLWidget(parent),
    m_vshader(0),
    m_fshader(0),
    m_program(0),
    m_mousePressed(false),
    m_eye(QVector3D(0,0,10)),
    m_center(QVector3D(0,0,0)),
    m_up(QVector3D(0,1,0)),
    m_verticalAngle(45.f){


    m_modelUpdated = false;
    setMinimumSize(300,300);
    //matrix initialization
    m_model.setToIdentity();
    m_view.lookAt(m_eye,m_center,m_up),
    m_projection.perspective(m_verticalAngle,aspectRatio(),0.01f,100.0f);

    m_timer = new QTimer(this);
    m_timer->setInterval(10);
    connect(m_timer,&QTimer::timeout,this,QOverload<>::of(&QWidget::update));


}
OpenGLWidget::~OpenGLWidget()
{
//    makeCurrent();
//    delete m_program;
//    delete m_vshader;
//    delete m_fshader;
//    m_vbo.destroy();
//    m_vao.destroy();
//    doneCurrent();
}

void OpenGLWidget::initializeGL()
{

   qDebug()<<"initializeGL()";
   initializeOpenGLFunctions();
   glEnable(GL_DEPTH_TEST);

   glClearColor(.2f,.3f,.3f,1.0f);

    //Initialized program shader
   m_vshader = new QOpenGLShader(QOpenGLShader::Vertex);
   const char * vcode =
          "#version 330 core \
           layout (location = 0) in vec3 aPos;\
           layout (location = 1) in vec3 aNor; \
           uniform mat4 model; \
           uniform mat4 view; \
           uniform mat4 projection;\
           out vec3 Normal;\
           out vec3 FragPos;\
           void main() \
           {            \
               gl_Position = projection*view*model*vec4(aPos,1.0);\
               Normal = aNor;\
               FragPos = vec3(model*vec4(aPos,1.0));\
           }";
   m_vshader->compileSourceCode(vcode);

   m_fshader = new QOpenGLShader(QOpenGLShader::Fragment);
   const char * fcode =
          "#version 330 core \
           out vec4 FragColor;  \
           in vec3 Normal;\
           in vec3 FragPos;\
           void main()\
           { \
               FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\
           } ";

   m_fshader->compileSourceCode(fcode);
   m_program = new QOpenGLShaderProgram();
   m_program->addShader(m_vshader);
   m_program->addShader(m_fshader);
   m_program->link();
   m_program->bind();

   m_attriPos = m_program->attributeLocation("aPos");
//   m_modelAttriLocation = m_program->attributeLocation("model");
//   m_viewAttriLocation = m_program->attributeLocation("view");
//   m_projectAttriLocation = m_program->attributeLocation("projection");

//    m_vertices<<QVector3D(-0.5f,-0.5f,0.0f)
//           <<QVector3D(0.5f,-0.5f,0.0f)
//          <<QVector3D(0.0f,0.5f,0.0f)
//         <<QVector3D(-0.5f,0.5f,0.0f)
//        <<QVector3D(0.5f,0.5f,0.0f)
//       <<QVector3D(0.0f,-0.5f,0.0f);



     //create VAO
    m_vao.create();
    m_vao.bind();


     //create VBO
    m_vbo.create();
    qDebug()<<m_vbo.bind();
    m_vbo.setUsagePattern(QOpenGLBuffer::StaticDraw);
    m_vbo.allocate(m_vertices.constData(),m_vertices.count()*3*sizeof(float));

    m_program->enableAttributeArray(0);
    m_program->setAttributeBuffer(0,GL_FLOAT,0,3);

    //m_vbo.release();
    //m_vao.release();
    m_program->release();

}
void OpenGLWidget::resizeGL(int w, int h){

    //Updating m_projection matrix here
    m_projection.setToIdentity();
    m_projection.perspective(45.0f,w/float(h),0.01f,100.0f);

}
void OpenGLWidget::paintGL(){
    //glClearColor(.2f,.3f,.3f,1.0f);
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
//    m_program->bind();
//    {
//        m_program->setUniformValue("projection",m_projection);
//        m_program->setUniformValue("view",m_view);
//        m_program->setUniformValue("model",m_model);
//        m_vao.bind();
//        glDrawArrays(GL_TRIANGLES,0,3);
//        m_vao.release();
//    }
//    m_program->release();
    paintModel();
}

void OpenGLWidget::mousePressEvent(QMouseEvent *event)
{
    m_mousePressed = true;
    m_prevXPos = event->x();
    m_prevYPos = event->y();
}

void OpenGLWidget::mouseMoveEvent(QMouseEvent *event)
{
    if(m_mousePressed == true){
        //update matrix here
        int deltaX = event->x()-m_prevXPos;
        int deltaY = event->y()-m_prevXPos;
        updateCameraVectors(deltaX,deltaY);
    }
}

void OpenGLWidget::mouseReleaseEvent(QMouseEvent *event)
{
   m_mousePressed = false;
}

void OpenGLWidget::wheelEvent(QWheelEvent *event)
{
   updateCameraVectors(0,0,event->angleDelta().y());
}



float OpenGLWidget::aspectRatio()
{
    return width()/static_cast<float>(height());
}

void OpenGLWidget::paintModel()
{
       m_program->bind();
       {
           m_vao.bind();
           m_program->setUniformValue("projection",m_projection);
           m_program->setUniformValue("view",m_view);
           m_program->setUniformValue("model",m_model);
           glDrawArrays(GL_TRIANGLES,0,m_vertices.count());
           m_vao.release();
       }
       m_program->release();
}    
void OpenGLWidget::updateModel(const QVector<QVector3D> &model)
{
   m_vertices = model;
   if(isValid() == false)
       return;


   makeCurrent();


   m_vbo.destroy();
   m_vao.destroy();
   if(m_vbo.isCreated() == false){
       m_vao.create();
       m_vao.bind();

       m_vbo.create();
       m_vbo.bind();
       m_vbo.setUsagePattern(QOpenGLBuffer::StaticDraw);
       m_vbo.allocate(m_vertices.constData(),m_vertices.count()*3*sizeof(float));

       for(GLenum err;(err = glGetError())!=GL_NO_ERROR;){
           qDebug()<<"error:"<<err;
       }
       m_vbo.release();
       m_vao.release();
   }

   doneCurrent();

}

Answer 1

当删除并重新创建VBO / VAO时，您还必须重做VAO设置，即

m_program->enableAttributeArray(0);
m_program->setAttributeBuffer(0,GL_FLOAT,0,3);

您可能会感到困惑，因为这些函数是在着色器程序对象上调用的，但它们实际上是VAO状态的一部分。

注意，在updateModel中再次删除和生成VAO / VBO并不是必需的。如果要更改顶点，只需使用新数据调用m_vbo.allocate即可。

如何动态更改QOpenGLWidget中的顶点？

1 个答案: