/*  draw_ngons.cpp
 *  This program demonstrates the drawing of a set of regular polygons
 *  Click the right button to exit.
 */
#include << X11/Xlib.h>
#include << fstream.h>
#include << math.h>
#include << GL/glut.h>
#include << GL/gl.h>
#include << stdlib.h>
#include << stdio.h>
#include "Canvas.h"

const int numVerts = 6;
const double radius = 2.0;
const double worldWidth = 4.0;
const double worldHeight = 3.0;        
const int screenWidth = 640;
const int screenHeight = 480;
Canvas cvs(screenWidth, screenHeight, "Try out Canvas");

void myInit(void) 
{
    cvs.setBackgroundColor (1.0, 1.0, 1.0);   // set black background color
    cvs.setColor (0.0, 0.0, 0.0);       // set the drawing color
    glPointSize (4.0);                  // set dot size 2 x 2
}

void ngon(int n, float cx, float cy, float radius, float rotAngle)
{      // assumes global Canvas object, cvs
    if(n < 3) return;     // bad number of sides
    double angle = rotAngle * 3.14159265 / 180;  // initial angle
    double angleInc = 2 * 3.14159265 /n;         //angle increment
    cvs.moveTo(radius * cos(angle) + cx, radius * sin(angle) + cy);
    for(int k = 0; k < n; k++)  // repeat n times
    {
        angle += angleInc; 
        cvs.lineTo(radius * cos(angle) + cx, radius * sin(angle) + cy);
    }
}

void myDisplay(void)
{
double i = 0.0;

    cvs.clearScreen();     // clear the screen
    cvs.setWindow(-worldWidth, worldWidth, -worldHeight, worldHeight);
    cvs.setViewport(0, screenWidth, 0, screenHeight);
    while (i < 360) {
        ngon(numVerts, 0.0, 0.0, radius, i);
        i += 17.0;
    }
}

void myMouse(int button, int state, int x, int y)
{
  switch (button) {
     case GLUT_RIGHT_BUTTON:
        if (state == GLUT_DOWN)
           exit (-1);
        break;
     default:
        break;
  }
}

int main(int argc, char** argv)
{

   myInit ();
   glutDisplayFunc(myDisplay);              // register redraw function
   glutMouseFunc(myMouse);                  // register myMouse function
   glutMainLoop();                          // go into a perpetual loop
   return 0;
}