《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);

}