C++ 用glRenderMode拾取

我试着做OpenGL挑选，所以我遵循了这篇文章（），它似乎有一个可行的解决方案，但我不能让我的工作。我有一个三维纹理多边形在我的场景，我想知道当我点击它

这是我的密码：

右键单击时启动拾取的鼠标方法：

void mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    if(event->button()==Qt::RightButton){
        pickObjects(event->pos().x(),event->pos().y());
    }
}

pickObjects方法：

#define BUFSIZE 512
void pickObjects(int x, int y)
{
    GLint viewport[4];
    GLint hits;

    GLuint selectBuf[BUFSIZE];
    glSelectBuffer (BUFSIZE, selectBuf);

    glRenderMode (GL_SELECT);

    glMatrixMode (GL_PROJECTION);
    glPushMatrix ();
    glLoadIdentity ();

    glGetIntegerv (GL_VIEWPORT, viewport);

    gluPickMatrix ((GLdouble) x, (GLdouble) (viewport[3] - y), 5.0, 5.0, viewport);
    gluPerspective(fov, this->width() / this->height(), 0.1, 1000);

    glMatrixMode(GL_MODELVIEW);

    glInitNames();

    makeCustomAnnot(GL_SELECT);

    int hits=0;

    glMatrixMode (GL_PROJECTION);
    glPopMatrix ();

    glMatrixMode(GL_MODELVIEW);

    hits = glRenderMode (GL_RENDER);
    if (hits != 0)
    {
        cout<<"FOUND " << hits << " hit(s)"<<endl; //ALWAYS GIVES 0 HITS
        processHits(hits,selectBuf);
    }

}

渲染方法：

void render()
{
    glEnable(GL_DEPTH_TEST);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    glViewport(0,0,this->width() , this->height());

    gluPerspective(fov, this->width() / this->height(), 0.1, 1000);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    glRotatef(xRot / 5.0f, 1.0f, 0.0f, 0.0f);
    glRotatef(yRot / 5.0f, 0.0f, 1.0f, 0.0f);
    glRotatef(zRot / 5.0f, 0.0f, 0.0f, 1.0f);

    glPushMatrix();
        makeCustomAnnot(GL_RENDER);
    glPopMatrix();

    glDisable(GL_DEPTH_TEST);
}

void render()
{
    glEnable(GL_DEPTH_TEST);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    glViewport(0,0,this->width() , this->height());

    gluPerspective(fov, this->width() / this->height(), 0.1, 1000);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    glRotatef(xRot / 5.0f, 1.0f, 0.0f, 0.0f);
    glRotatef(yRot / 5.0f, 0.0f, 1.0f, 0.0f);
    glRotatef(zRot / 5.0f, 0.0f, 0.0f, 1.0f);

    glRenderMode (GL_RENDER);

    glPushMatrix();
        makeCustomAnnot(GL_RENDER);
    glPopMatrix();

    glDisable(GL_DEPTH_TEST);
}

---

So hits=glRenderMode（GL_RENDER）；总是返回0个点击。我做错了什么？

所以这里是我做的，让它完美工作

processHits方法：

void processHits(GLint inHits, GLuint buffer[])
{
    unsigned int i, j;
    GLuint names, *ptr, minZ,*ptrNames, numberOfNames;

    ptr = (GLuint *) buffer;
    minZ = 0xffffffff;
    for (i = 0; i < inHits; i++) {
        names = *ptr;
        ptr++;
        if (*ptr < minZ) {
            numberOfNames = names;
            minZ = *ptr;
            ptrNames = ptr+2;
        }
        ptr += names+2;
    }

    cout << "Nearest: ";
    ptr = ptrNames;
    for (j = 0; j < numberOfNames; j++,ptr++) {
        cout<< *ptr ;
    }
}

void processHits(GLint inHits, GLuint buffer[])
{
    unsigned int i, j;
    GLuint names, *ptr, minZ,*ptrNames, numberOfNames;

    ptr = (GLuint *) buffer;
    minZ = 0xffffffff;
    for (i = 0; i < inHits; i++) {
        names = *ptr;
        ptr++;
        if (*ptr < minZ) {
            numberOfNames = names;
            minZ = *ptr;
            ptrNames = ptr+2;
        }
        ptr += names+2;
    }

    cout << "Nearest: ";
    ptr = ptrNames;
    for (j = 0; j < numberOfNames; j++,ptr++) {
        cout<< *ptr ;
    }
}

pickObjects方法，与渲染功能相同，但包含拾取说明：

#define BUFSIZE 512
unsigned int selectBuf[BUFSIZE];

void pickObjects(int x, int y)
{
    GLint viewport[4];
    GLint hits;

    glSelectBuffer (BUFSIZE, selectBuf);
    glRenderMode (GL_SELECT);

    glMatrixMode (GL_PROJECTION);
    glPushMatrix ();
    glLoadIdentity ();

    glGetIntegerv (GL_VIEWPORT, viewport);

    gluPickMatrix ((GLdouble) x, (GLdouble) (viewport[3] - y), 5.0, 5.0, viewport);
    gluPerspective(fov, this->width() / this->height(), 0.1, 1000);

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    glRotatef(xRot / 5.0f, 1.0f, 0.0f, 0.0f);
    glRotatef(yRot / 5.0f, 0.0f, 1.0f, 0.0f);
    glRotatef(zRot / 5.0f, 0.0f, 0.0f, 1.0f);

    glRotatef((float)angleV, 1.0f, 0.0f, 0.0f);

    glInitNames();
    glPushName( 10000 );

    glPushMatrix();
        makeCustomAnnot(GL_SELECT);//draw scene in GL_SELECT mode to create the names
    glPopMatrix();

    hits = glRenderMode (GL_RENDER);//get the hits in GL_RENDER mode
    if (hits != 0)
    {
        processHits(hits,selectBuf);
    }

    glPopMatrix();
    glDisable(GL_DEPTH_TEST);
}

渲染方法：

void render()
{
    glEnable(GL_DEPTH_TEST);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    glViewport(0,0,this->width() , this->height());

    gluPerspective(fov, this->width() / this->height(), 0.1, 1000);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    glRotatef(xRot / 5.0f, 1.0f, 0.0f, 0.0f);
    glRotatef(yRot / 5.0f, 0.0f, 1.0f, 0.0f);
    glRotatef(zRot / 5.0f, 0.0f, 0.0f, 1.0f);

    glPushMatrix();
        makeCustomAnnot(GL_RENDER);
    glPopMatrix();

    glDisable(GL_DEPTH_TEST);
}

void render()
{
    glEnable(GL_DEPTH_TEST);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    glViewport(0,0,this->width() , this->height());

    gluPerspective(fov, this->width() / this->height(), 0.1, 1000);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    glRotatef(xRot / 5.0f, 1.0f, 0.0f, 0.0f);
    glRotatef(yRot / 5.0f, 0.0f, 1.0f, 0.0f);
    glRotatef(zRot / 5.0f, 0.0f, 0.0f, 1.0f);

    glRenderMode (GL_RENDER);

    glPushMatrix();
        makeCustomAnnot(GL_RENDER);
    glPopMatrix();

    glDisable(GL_DEPTH_TEST);
}

---

最后点击=glRenderMode（GL_RENDER）；在pickObjects方法中，然后processHits方法精确返回拾取的对象。

hits=glRenderMode（GL\U选择）；相反，没有？@j-p我试过了，但仍然不起作用，我认为hits=glRenderMode（GL_RENDER）；是个好主意，尽管很容易把GL_选出来。没有主意？我看了其他几篇关于同一主题的文章，但我不知道我做错了什么。@j-p也许，但既然答案有效，为什么要投反对票呢。经过一些研究，我找到了所有关于使用glRenderMode进行拾取的教程，dohits=glRenderMode（GL_RENDER）；而非点击=glRenderMode（GL_选择）；示例：所以，这不是很傻，因为这显然是它的工作方式！我希望“精神病学家分析其背后的智力过程应该是有趣的”这句话不适合我，因为我不是创建OpenGL并决定其工作方式的人。对不起，你完全正确。（如果你对你的帖子做一个小的编辑（q/a）），我将能够重置否决票。