《基于MFC的OpenGL编程》Part 14 Quadrics

本文在第11篇文章的基础上，为其加入显示各种二次曲面的代码；

Quadrics

Every quadric has a few settings associated with it. We have to create a quadric first and then customize its settings to render the shape we want. The gluNewQuadric function creates a state variable that describes the current drawing style, orientation, lighting mode, texturing mode and the callback functions. Once we use this function to create a new quadric, we can customize the drawing of shapes by changing its state using functions such as

gluQuadricDrawStyle - which selects the type of OpenGL drawing primitives that are used to drw the shape.

gluQuadricOrientation - which controls the direction of the lighting normals.

gluQuadricNormals - which controls the generation of lighting normals.

gluQuadricTexture - which generates texture coordinates automatically for the quadric.

1,在CCY457OpenGLView类中加入下列变量，用来表示二次曲面类型：

    //Quadric
     GLuint m_Quadric;

2，加入五个控制二次曲面类型的菜单项及其事件处理函数

void CCY457OpenGLView::OnQuadricSphere()
{//球体
     m_Quadric = 0 ;
     InvalidateRect(NULL,FALSE);
}
void CCY457OpenGLView::OnUpdateQuadricSphere(CCmdUI* pCmdUI)
{
    if(m_Quadric == 0 )
         pCmdUI-> SetRadio(TRUE);
    else
         pCmdUI -> SetRadio(FALSE);    
}
void CCY457OpenGLView::OnQuadricCone()
{//圆锥
     m_Quadric = 2 ;    
     InvalidateRect(NULL,FALSE);
}
void CCY457OpenGLView::OnUpdateQuadricCone(CCmdUI* pCmdUI)
{
    if(m_Quadric == 2 )
         pCmdUI-> SetRadio(TRUE);
    else
         pCmdUI -> SetRadio(FALSE);    
}
void CCY457OpenGLView::OnQuadricCylinder()
{//柱体
     m_Quadric = 1 ;
     InvalidateRect(NULL,FALSE);
}
void CCY457OpenGLView::OnUpdateQuadricCylinder(CCmdUI* pCmdUI)
{
    if(m_Quadric == 1 )
         pCmdUI-> SetRadio(TRUE);
    else
         pCmdUI -> SetRadio(FALSE);    
}
void CCY457OpenGLView::OnQuadricDisk()
{//圆盘
     m_Quadric = 3 ;
     InvalidateRect(NULL,FALSE);
}
void CCY457OpenGLView::OnUpdateQuadricDisk(CCmdUI* pCmdUI)
{
    if(m_Quadric == 3 )
         pCmdUI-> SetRadio(TRUE);
    else
         pCmdUI -> SetRadio(FALSE);
}
void CCY457OpenGLView::OnQuadricPartialdisk()
{////半圆盘
     m_Quadric = 4 ;
     InvalidateRect(NULL,FALSE);
    
}
void CCY457OpenGLView::OnUpdateQuadricPartialdisk(CCmdUI* pCmdUI)
{
    if(m_Quadric == 4 )
         pCmdUI-> SetRadio(TRUE);
    else
         pCmdUI -> SetRadio(FALSE);    
}

3,绘制函数修改如下：

void CCY457OpenGLView::RenderScene ()
{//绘制函数
         glTranslatef(0.0f,0.0f,-5.0f );
         glRotatef(m_xRot,1.0f,0.0f,0.0f );
         glRotatef(m_yRot,0.0f,1.0f,0.0f );
         glEnable(GL_TEXTURE_2D);
         glBindTexture(GL_TEXTURE_2D,m_Texture[0 ]);
         GLUquadricObj* obj;
         obj = gluNewQuadric();
         gluQuadricNormals(obj, GLU_SMOOTH);
         gluQuadricTexture(obj, GL_TRUE);
        switch (m_Quadric)
         {
            case 0:     gluSphere(obj, 1, 20, 20 );
                    break ;
            case 1:     gluCylinder(obj, 1, 1, 3, 20, 20 );
                    break ;
            case 2: gluCylinder(obj, 0.1, 1, 3, 20, 20 );
                    break ;
            case 3: gluDisk(obj, 0.5, 1, 20, 20 );
                    break ;
            case 4: gluPartialDisk(obj, 0.5, 1, 20, 20, 10, 180 );
                    break ;
         }
         glDisable(GL_TEXTURE_2D);
}