#include<windows.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
#include<GL/gl.h>
#include<GL/glu.h>
#include<GL/glut.h>
const int screenWidth = 640*2;
const int screenHeight = 480*2;
GLdouble A,B,C,D; // values for scaling and shifting
void myInit(void)
{
glClearColor(1.0, 1.0, 1.0, 0.0); //background color is white
glColor3f(0.0f, 0.0f, 0.0f); //drawing color is black
glPointSize(4.0); //a dot is 2 by 2 pixels
//glLineWidth(4.0); //a line is 4 times thicker
//initialize view (simple orthographic projection)
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-1.0,1.0,-1.0, 1.0, -1.0, 1.0);
A = screenWidth/4.0; //Set values for scaling and shifting
B= 0.0;
C=D=screenHeight/2.0;
//set the viewing coordinates
gluOrtho2D(0.0, 640.0, 0.0, 480.0);
}
void myDisplay(void)
{
glClear(GL_COLOR_BUFFER_BIT); //clear the screen
// glRecti(10,10,150,60); //draw a rectangle with background color
glPointSize(2.0);
GLint h = 300, k = 300, x, x2, y, a = 150, b = 25;
x = 0,y=b;
int aa=a*a,bb=b*b,aa2=aa*2,bb2=bb*2;
int fx=0, fy=aa2*b;
int p= bb-aa*b+0.25*aa;
while(fx<fy)
{
glBegin(GL_POINTS);
{
glVertex2i(x+h,y+k);
glVertex2i(-x+h,-y+k);
glVertex2i(-x+h,y+k);
glVertex2i(x+h,-y+k);
}
glEnd();
x++;
fx=fx+bb2;
if(p<0)
p=p+fx+bb;
else{
y–;
fy=fy-aa2;
p=p+fx+bb-fy;
}
}
glBegin(GL_POINTS);
{
glVertex2i(x+h,y+k);
glVertex2i(-x+h,-y+k);
glVertex2i(-x+h,y+k);
glVertex2i(x+h,-y+k);
}
glEnd();
p=bb*(x+0.5)*(x+0.5)+aa*(y-1)*(y-1)-aa*bb;
while(y>0){
y–;
fy=fy-aa2;
if(p>=0)
p=p-fy+aa;
else{
x++;
fx=fx+bb2;
p=p+fx-fy+aa;
}
glBegin(GL_POINTS);
{
glVertex2i(x+h,y+k);
glVertex2i(-x+h,-y+k);
glVertex2i(-x+h,y+k);
glVertex2i(x+h,-y+k);
}
glEnd();
glFlush(); //send all output to display
}
int main(int argc, char** argv)
{
glutInit(&argc, argv); //initialize the toolkit
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); //set the display mode
glutInitWindowSize(640,480); //set window size
//set window position on screen
glutInitWindowPosition(100,150);
//open the screen window and set the name
glutCreateWindow(“My First Window”);
//register the callback functions
glutDisplayFunc(myDisplay);
myInit();
glutMainLoop(); //go into a perpetual loop
return 1;
}
