《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，加入四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);
}