《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);
}