c++ - qt openGL - 球体变形

Question

我正在尝试绘制一个球体和一个围绕它旋转的立方体。我能够完美地分别绘制它们。然而，一旦我将两者画在一起，我就会得到奇怪的结果。

• 我的球体变形了。

• 当我有意改变立方体的角度(通过按下按钮)时，它就从我的屏幕上消失了。当我只绘制立方体然后改变角度时一切正常。

为什么？

图片:http://imgur.com/dIngayh (立方体看起来没问题，但球体太拉伸(stretch)了)

我的代码:

void MyGLWidget::paintGL()
{
    glScalef(1,1,1);
    setLight();
    drawSun();
    drawCube();
}

void MyGLWidget::initializeGL()
{
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glShadeModel(GL_SMOOTH);
    glEnable(GL_TEXTURE_2D);
}
void MyGLWidget::drawSun()
{
   glPushMatrix();
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
   glScalef(1,1,1);
  glLoadIdentity();
    GLUquadricObj *quadric=gluNewQuadric();
    gluQuadricNormals(quadric, GLU_SMOOTH);
    glColor3f(1,1,0);
    gluSphere(quadric, 0.25, 360,360);
    gluDeleteQuadric(quadric);
    glPopMatrix();
}


void MyGLWidget::drawCube()
{

    glTranslatef(0, 0, 0);
    glRotatef(getCubeAngle(), 1.0f, 0.0f, 0.0f); 
    glRotatef(0, 0.0f, 1.0f, 0.0f); 
    glRotatef(0, 0.0f, 0.0f, 1.0f); 
    glTranslatef( 0.5, 0, 0); 

    glBegin(GL_QUADS);

 //back side of cube
       glColor3f(255,0,0);
       glVertex3f(-0.1, 0.1,-0.1 );//upper left corner
       glVertex3f(0.1, 0.1,-0.1); //uper right
       glVertex3f(0.1,-0.1,-0.1 ); // down left
       glVertex3f(-0.1,-0.1,-0.1); // down right


 /*draws other parts of the cube in the same way*/

        glEnd();
        glFlush();
}
/**/

void MyGLWidget::setLight()
{
    // Prepare light parameters.
           float SHINE_ALL_DIRECTIONS = 1;
           float lightPos[4] = {-30, 0, 0, SHINE_ALL_DIRECTIONS};
           float lightColorAmbient[4] = {50, 50, 0.1, 1};
           float lightColorSpecular[4] = {150, 150, 0.5, 1};

           // Set light parameters.
           glLightfv(GL_LIGHT1, GL_POSITION, lightPos);
           glLightfv(GL_LIGHT1, GL_AMBIENT, lightColorAmbient);
           glLightfv(GL_LIGHT1, GL_SPECULAR, lightColorSpecular);

           // Enable lighting in GL.
           glEnable(GL_LIGHT1);
           glEnable(GL_LIGHTING);

           // Set material properties.
           float rgba[3] = {0.3, 0.5, 1};
           glMaterialfv(GL_FRONT, GL_AMBIENT, rgba);
           glMaterialfv(GL_FRONT, GL_SPECULAR, rgba);
           glMaterialf(GL_FRONT, GL_SHININESS, 0.5f);

}

Answer 1

尝试添加这个:

void MyGLWidget::resizeGL(int width, int height);
{ 
  glViewport(0, 0, width, height);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glScalef(height *1./width, 1.0, 1.0);
  glMatrixMode(GL_MODELVIEW);
}

and more read here (rus)