// Initialization
void Init(void)? ?
{
?glClearColor(1.0,1.0,1.0,0.0); // Set white background color
?glColor3f(0.0f,0.0f,0.0f);? ? // Set the drawing color
?glMatrixMode(GL_PROJECTION);
?glLoadIdentity();
?gluOrtho2D(0.0,640.0,0.0,480.0);
}

void myDisplay()
{
?glClear(GL_COLOR_BUFFER_BIT);? ? ? //clear the screen
?GLintPoint Mypoint = {200,100};
?parameterizedHouse(Mypoint,100,100);
?drawFlurry(4,100,100);
?glFlush();
}

void main(int argc,char *argv[])
{
?glutInit(&argc, argv);? // Initialize the toolkit
?glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);? // Set display mode
?glutInitWindowPosition(100, 150);? // Set window pozition on screen
?glutInitWindowSize(640, 480);? ? ? // Set window size
?glutCreateWindow("parameterizedHouse, Flurry and drawSierpinski"); // Open the screen window
?glutDisplayFunc(myDisplay); // Register redraw function
?glutMouseFunc(myMouse);
?glutKeyboardFunc(onKeyBoard);
?Init();
?glutMainLoop();? // Go into a perpetual loop
}

效果图：

第二个例子绘制了这样一系列图形：

在其中有空间投影变换，主要应用了三个函数：

投影变换函数glViewport(), 矩阵平移函数glTranslated() 和正射投影函数 glOrtho()

上图实现代码参考《计算机图形学-用OpenGL实现第2版》：

#include ? //suitable when using Windows 95/98/NT
#include
#include
#include
//<<<<<<<<<<<<<<<<<<< axis >>>>>>>>>>>>>>
void axis(double length)
{ // draw a z-axis, with cone at end
?glPushMatrix();
?glBegin(GL_LINES);
?glVertex3d(0, 0, 0); glVertex3d(0,0,length); // along the z-axis
?glEnd();
?glTranslated(0, 0,length -0.2);
?glutWireCone(0.04, 0.2, 12, 9);
?glPopMatrix();
}?
//<<<<<<<<<<<<<<<<<<<<<<<<<<<<< displayWire >>>>>>>>>>>>>>>>>>>>>>
void displayWire(void)
{
?glMatrixMode(GL_PROJECTION); // set the view volume shape
?glLoadIdentity();
?glOrtho(-2.0*64/48.0, 2.0*64/48.0, -2.0, 2.0, 0.1, 100);//正射投影函数
?glMatrixMode(GL_MODELVIEW); // position and aim the camera
?glLoadIdentity();
?gluLookAt(2.0, 2.0, 2.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);//define viewpoint transformation

?//Draw axis
?glClear(GL_COLOR_BUFFER_BIT); // clear the screen
?glColor3d(0,0,0); // draw black lines
?axis(0.5);? ? ? // z-axis
?glPushMatrix();
?glRotated(90, 0,1.0, 0);
?axis(0.5);? ? ?// y-axis
?glRotated(-90.0, 1, 0, 0);
?axis(0.5);? ? ?// z-axis
?glPopMatrix();?

?//Draw Cube
?glPushMatrix();
?glTranslated(0.5, 0.5, 0.5); // multiply by a translation matrix, define center (0.5, 0.5, 0.5)
?glutWireCube(1.0);
?glPopMatrix();

?//Draw Sphere
?glPushMatrix();?
?glTranslated(1.0,1.0,0);?// sphere at (1,1,0)
?glutWireSphere(0.25, 10, 8);
?glPopMatrix();?

?//Draw Cone
?glPushMatrix();?
?glTranslated(1.0,0,1.0);?// cone at (1,0,1)
?glutWireCone(0.2, 0.5, 10, 8);
?glPopMatrix();

?//Draw Teapot
?glPushMatrix();
?glTranslated(1,1,1);
?glutWireTeapot(0.2); // teapot at (1,1,1)
?glPopMatrix();

?//Draw Torus
?glPushMatrix();
?glTranslated(0, 1.0 ,0); // torus at (0,1,0)
?glRotated(90.0, 1,0,0);
?glutWireTorus(0.1, 0.3, 10,10);
?glPopMatrix();

?//十二面体
?glPushMatrix();
?glTranslated(1.0, 0 ,0); // dodecahedron at (1,0,0)
?glScaled(0.15, 0.15, 0.15);
?glutWireDodecahedron();
?glPopMatrix();

?glPushMatrix();
?glTranslated(0, 1.0 ,1.0); // small cube at (0,1,1)
?glutWireCube(0.25);
?glPopMatrix();