fixed-spiral.cpp

#include <GLUT/GLUT.h>
#include<OpenGL/OpenGL.h>

#include<iostream>
//#include<time>
#include<cstdlib>

#include <cmath>
#include <cstdio>


#define PI 3.1415926535898

#define SPIRAL

void init()
{
    glClearColor(0, 0, 0, 0);
    glShadeModel(GL_FLAT);
}

void display()
{
    glClear(GL_COLOR_BUFFER_BIT);
    glColor3f(0, 1, 1);
    glLoadIdentity();
#ifdef SPIRAL
    GLfloat x, y, angle, ratio;
    
    GLint circle_points = 1000;
    GLint i;
    glBegin(GL_LINE_STRIP);
    for (i = 0; i < circle_points-1; i++)
    {
        angle = 4*2*PI*i/circle_points;
        ratio = (GLfloat)circle_points/(circle_points-i);
        x = cos(angle);
        y = sin(angle);
        glVertex2f(x/ratio, y/ratio);
    }
    glEnd();
#else
    int count;
    glBegin(GL_LINE_STRIP);
    for(count = 0; count < 10; count ++)
    {
        glVertex2f((GLfloat)-1/(count + 1), (GLfloat)1/(count + 1));
        glVertex2f((GLfloat)0/(count + 1), (GLfloat)-1/(count + 1));
        glVertex2f((GLfloat)1/(count + 2), (GLfloat)1/(count + 2));
    }
    glEnd();
#endif
    glutSwapBuffers();
    glFlush();
}

int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(500, 500);
    glutInitWindowPosition(100, 100);
    glutCreateWindow("Spiral");
    init();
    glutDisplayFunc(display);
    glutMainLoop();
    return 0;
}