【转】《基于MFC的OpenGL编程》Part 16 Reflection

Reflections

Adding reflections to a program too can improve its realism to a great extent. Here we'll look at a simple method to create reflection where we simply redraw the object with an appropriate transformation and make the surface in between translucent. This creates an effective illusion of reflection!!

1,设置光源代码修改如下：

void CCY457OpenGLView::SetupLighting ()
{
      //Material Properties
       GLfloat matSpecular[] = { 1.0f, 0.0f, 0.0f, 0.7f};
       GLfloat matShininess[] = { 50.0f};
       GLfloat matAmbient[] = { 0.25f, 0.25f, 0.25f, 0.7f};
       GLfloat matDiffuse[] = { 0.5f, 0.5f, 0.5f, 0.7f};
       glMaterialfv(GL_FRONT, GL_SPECULAR, matSpecular);
       glMaterialfv(GL_FRONT, GL_SHININESS, matShininess);
       glMaterialfv(GL_FRONT, GL_DIFFUSE, matDiffuse);
       glMaterialfv(GL_FRONT, GL_AMBIENT, matAmbient);
      //Lighting Parameters
      //Enable Lighting
       glEnable(GL_LIGHTING);
      //Specify a single directional light
       GLfloat ambient1[] = { 0.5f,0.5f,0.5f};
       GLfloat diffuse1[] = { 0.5f,0.5f,0.5f};
       GLfloat specular1[] = { 1.0f,0.0f,0.0f};
       GLfloat position1[] = { 0.0f,0.0f,5.0f,0.0};
       glLightfv(GL_LIGHT0, GL_AMBIENT, ambient1);
       glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse1);
       glLightfv(GL_LIGHT0, GL_SPECULAR, specular1);
       glLightfv(GL_LIGHT0, GL_POSITION, position1);    
       glEnable(GL_LIGHT0);
      //Specify a single positional spotlight
       GLfloat ambient2[] = { 1.0f,1.0f,0.0f};
       GLfloat diffuse2[] = { 1.0f,0.0f,0.0f};
       GLfloat position2[] = { 1.0f,0.0f,5.0f,1.0};
       GLfloat direction2[] = {0.0f,0.0f,-5.0f};
       glLightfv(GL_LIGHT1, GL_AMBIENT, ambient2);
       glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse2);
       glLightfv(GL_LIGHT1, GL_POSITION, position2);
       glLightfv(GL_LIGHT1, GL_SPOT_DIRECTION, direction2);
       glLightf(GL_LIGHT1, GL_SPOT_CUTOFF, 15.0f);
       glEnable(GL_LIGHT1);
}

2,绘制函数修改如下：

void CCY457OpenGLView::RenderScene ()
{//绘制函数
       glTranslatef(0.0f,0.0f,-8.0f);
      // Save matrix state and do the rotation
       glPushMatrix();
            glRotatef(m_xRot, 1.0f, 0.0f, 0.0f);
            DrawCube();
            glPopMatrix();
            glPushMatrix();
                  glTranslatef(0.0f, -3.0f, 0.0f);
                  glScalef(1.0f, -1.0f, 1.0f);
                  glRotatef(m_xRot, 1.0f, 0.0f, 0.0f);
                  DrawCube();
            glPopMatrix();
           // Draw bottom of floor
            glEnable(GL_BLEND);
            glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
            glPushMatrix();
            glEnable(GL_TEXTURE_2D);
            glBindTexture(GL_TEXTURE_2D, m_Texture[3]);
            glBegin(GL_POLYGON);
                  glTexCoord2f(0.0f, 0.0f);
                  glVertex3f(-5.0f, -1.5f, 5.0f );
                  glTexCoord2f(1.0f, 0.0f);
                  glVertex3f(-5.0f, -1.5f, -5.0f );
                  glTexCoord2f(1.0f, 1.0f);
                  glVertex3f(5.0f, -1.5f, -5.0f );
                  glTexCoord2f(0.0f, 1.0f);
                  glVertex3f(5.0f, -1.5f, 5.0f );
            glEnd();
       glPopMatrix();
       glDisable(GL_TEXTURE_2D);
       glDisable(GL_BLEND);
}
void CCY457OpenGLView::DrawCube ()
{
            glEnable(GL_TEXTURE_2D);
            glBindTexture(GL_TEXTURE_2D,m_Texture[0]);
           //Front Face
            glBegin(GL_POLYGON);
                  glTexCoord2f(0,0);
                  glVertex3f(-1.0f,-1.0f,0.0f);
                  glTexCoord2f(1,0);
                  glVertex3f( 1.0f,-1.0f,0.0f);
                  glTexCoord2f(1,1);
                  glVertex3f( 1.0f, 1.0f,0.0f);
                  glTexCoord2f(0,1);
                  glVertex3f(-1.0f, 1.0f,0.0f);
            glEnd();
           //Back Face
            glBegin(GL_POLYGON);
                  glTexCoord2f(1,0);
                  glVertex3f(-1.0f,-1.0f,-1.0f);
                  glTexCoord2f(1,1);
                  glVertex3f(-1.0f, 1.0f,-1.0f);
                  glTexCoord2f(0,1);
                  glVertex3f( 1.0f, 1.0f,-1.0f);
                  glTexCoord2f(0,0);
                  glVertex3f( 1.0f,-1.0f,-1.0f);
            glEnd();
            glBindTexture(GL_TEXTURE_2D,m_Texture[1]);
           //Left Face
            glBegin(GL_POLYGON);
                  glTexCoord2f(1,0);
                  glVertex3f(-1.0f,-1.0f, 0.0f);
                  glTexCoord2f(1,1);
                  glVertex3f(-1.0f, 1.0f, 0.0f);
                  glTexCoord2f(0,1);
                  glVertex3f(-1.0f, 1.0f,-1.0f);
                  glTexCoord2f(0,0);
                  glVertex3f(-1.0f,-1.0f,-1.0f);
            glEnd();
           //Right Face
            glBegin(GL_POLYGON);
                  glTexCoord2f(0,0);
                  glVertex3f(1.0f,-1.0f, 0.0f);
                  glTexCoord2f(1,0);
                  glVertex3f(1.0f,-1.0f,-1.0f);
                  glTexCoord2f(1,1);
                  glVertex3f(1.0f, 1.0f,-1.0f);
                  glTexCoord2f(0,1);
                  glVertex3f(1.0f, 1.0f, 0.0f);
            glEnd();
            glBindTexture(GL_TEXTURE_2D,m_Texture[2]);
           //Top Face
            glBegin(GL_POLYGON);
                  glTexCoord2f(0,0);
                  glVertex3f(-1.0f, 1.0f, 0.0f);
                  glTexCoord2f(0,1);
                  glVertex3f( 1.0f, 1.0f, 0.0f);
                  glTexCoord2f(1,1);
                  glVertex3f( 1.0f, 1.0f, -1.0f);
                  glTexCoord2f(1,0);
                  glVertex3f(-1.0f, 1.0f, -1.0f);
            glEnd();
           //Botton Face
            glBegin(GL_POLYGON);
                  glTexCoord2f(0,1);
                  glVertex3f(-1.0f, -1.0f, 0.0f);
                  glTexCoord2f(0,0);
                  glVertex3f(-1.0f, -1.0f, -1.0f);
                  glTexCoord2f(1,0);
                  glVertex3f( 1.0f, -1.0f, -1.0f);
                  glTexCoord2f(1,1);
                  glVertex3f( 1.0f, -1.0f, 0.0f);
            glEnd();
            glDisable(GL_TEXTURE_2D);
}