#include <GL/glut.h>
#include <stdio.h>
#include <math.h>

typedef GLfloat Matrix3x3[3][3];
const GLdouble pi = 3.14158;

typedef struct wcPt2D {
    GLfloat x, y;
} wcPt2D;

void init(void) {
  /* determina cor da janela de branca*/
  glClearColor(1.0, 1.0, 1.0, 1.0);
}

void paint_circle_points(wcPt2D point, wcPt2D origin) {
    printf("%f %f\n", point.x, point.y);
    
    glBegin(GL_POINTS);
        glVertex2f(origin.x + point.x, origin.y + point.y); 
        glVertex2f(origin.x + point.x, origin.y - point.y);
        glVertex2f(origin.x - point.x, origin.y + point.y);
        glVertex2f(origin.x - point.x, origin.y - point.y);
        glVertex2f(origin.x + point.y, origin.y + point.x);
        glVertex2f(origin.x + point.y, origin.y - point.x);
        glVertex2f(origin.x - point.y, origin.y + point.x);
        glVertex2f(origin.x - point.y, origin.y - point.x);
    glEnd();
}

void draw_circle(wcPt2D origin, GLint radius) {
    GLint x, y, theta;
    GLfloat d;
    wcPt2D p;
    
    for (theta = 0; theta <= 45; theta++) {
        p.x = radius * cos(theta * pi / 180.0);
        p.y = radius * sin(theta * pi / 180.0);
        
        paint_circle_points(p, origin);
    }
}

/* Janela inicial */
GLsizei winWidth = 600, winHeight = 600;
/* limites para as coordenadas do mundo */
GLfloat xwcMin = -300.0, xwcMax = 300.0;
GLfloat ywcMin = -300.0, ywcMax = 300.0;

void winReshapeFcn(GLint newWidth, GLint newHeight) {
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluOrtho2D(xwcMin, xwcMax, ywcMin, ywcMax);
  glClear(GL_COLOR_BUFFER_BIT);
}


void displayFcn(void) {
  glColor3d(1.0, 0.0, 0.0);
  wcPt2D origin = {150.0, 150.0};
  GLfloat radius = 50.0;
  
  glColor3f(1.0, 0.0, 0.0);
  
  draw_circle(origin, radius);
  
  /*
  glBegin(GL_QUADS);
    glVertex2f(0, 0);
    glVertex2f(0, 150);
    glVertex2f(150, 150);
    glVertex2f(150, 0);
  glEnd();
  */
  glFlush();
}


int main(int argc, char ** argv) {
  glutInit( & argc, argv);
  glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
  glutInitWindowSize(winWidth, winHeight);
  glutInitWindowPosition(50, 50);
  glutCreateWindow("Draw Circle");
  init();
  glutDisplayFunc(displayFcn);
  glutReshapeFunc(winReshapeFcn);
  glutMainLoop();
}