你的代码看起来很像sample in the Invertor Mentor书。我认为你应该用glPushMatrix和glPopMatrix存储当前状态。否则转换可能会不正确。

def drawOpenGl(arg1,arg2):
    glPushMatrix()
    glTranslatef(-2.5, 0.5, -6.0)
    glColor3f( 1.0, 1.5, 0.0 )
    glPolygonMode(GL_FRONT, GL_FILL)
    glBegin(GL_TRIANGLES)
    glVertex3f(2.0,-1.2,0.0)
    glVertex3f(2.6,0.0,0.0)
    glVertex3f(2.9,-1.2,0.0)
    glEnd()
    glPopMatrix()

不确定这是否对您有用，但有一个C++示例混合了纯OpenGL几何体（矩形）和Coin3D几何体（圆锥体），并使用Quarter：

#include <QApplication>
#include <Inventor/nodes/SoBaseColor.h>
#include <Inventor/nodes/SoCone.h>
#include <Inventor/nodes/SoSeparator.h>
#include <Inventor/nodes/SoCallback.h>
#include <Quarter/Quarter.h>
#include <Quarter/QuarterWidget.h>
#include <GL/gl.h>

using namespace SIM::Coin3D::Quarter;

// Callback routine to render using OpenGL
void
myCallbackRoutine(void *, SoAction *)
{
   glPushMatrix();
   glTranslatef(0.0, -3.0, 0.0);
   glColor3f(1.0, 0.0, 0.0);
   glDisable(GL_LIGHTING);  // so we don't have to set normals
    glBegin(GL_POLYGON);
        glVertex3f(0.0, 0.0, 0.0);
        glVertex3f(0.5, 0.0, 0.0);
        glVertex3f(0.5, 0.5, 0.0);
        glVertex3f(0.0, 0.5, 0.0);
    glEnd();
    glEnable(GL_LIGHTING);
   glPopMatrix();
}

int
main(int argc, char ** argv)
{
    QApplication app(argc, argv);
    // Initializes Quarter library (and implicitly also the Coin and Qt
    // libraries).
    Quarter::init();
    // Make a dead simple scene graph by using the Coin library, only
    // containing a single yellow cone under the scenegraph root.
    SoSeparator * root = new SoSeparator;
    root->ref();
    SoBaseColor * col = new SoBaseColor;
    col->rgb = SbColor(1, 1, 0);
    root->addChild(col);
    root->addChild(new SoCone);
    
    SoCallback *myCallback = new SoCallback;
    myCallback->setCallback(myCallbackRoutine);
    root->addChild(myCallback);
    
    // Create a QuarterWidget for displaying a Coin scene graph
    QuarterWidget * viewer = new QuarterWidget;
    viewer->setSceneGraph(root);
    // make the viewer react to input events similar to the good old
    // ExaminerViewer
     viewer->setNavigationModeFile(QUrl("coin:///scxml/navigation/examiner.xml"));
    // Pop up the QuarterWidget
    viewer->show();
    // Loop until exit.
    app.exec();
    // Clean up resources.
    root->unref();
    delete viewer;
    Quarter::clean();
    return 0;
}