#include <iostream>
#include <vector>
#include <cmath>

#include "Angel.h"
#include <GL/glew.h>
#include "keys.h"

using namespace std;

// globals
vector<vec2> data;
GLenum DRAWING_MODE;

// Constants
const int POINTS = 20;

void Init(void) {
    vec2 tmp;
    float theta;
   
    srand(time(NULL));

    // background clear color
    glClearColor(1.0,1.0,1.0,1.0);

    // start off with a random color
    glColor3f(1.0,0,0);

    // I want to be able to see what is happening with polygons
    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

    // generate the data on a circle
    for( theta=0;theta<2*M_PI;theta+= 2*M_PI/POINTS) {
       tmp.x = .5*cos(theta);
       tmp.y = .5*sin(theta);
       data.push_back(tmp);
    }

    // a default mode for drawing things
    DRAWING_MODE = GL_POINTS;

    return;
}

void display(void) {
    int i;

    // erase the board
    glClear( GL_COLOR_BUFFER_BIT );

    // draw the shape
    glBegin(DRAWING_MODE);
    for(i=0;i<data.size();i++) {
       glVertex2f(data[i].x,data[i].y);
    }
    glEnd();

    // swap buffers
    glutSwapBuffers();

    return;
}

int main( int argc, char **argv ) {
    glutInit( &argc, argv );
    glutInitDisplayMode( GLUT_RGBA | GLUT_DOUBLE );
    glutInitWindowSize( 512, 512 );

    glutCreateWindow( "Graphics Primitives, Old Way" );

    GLenum err = glewInit();
    if (GLEW_OK != err) {
        /* Problem: glewInit failed, something is seriously wrong. */
        cout << "glewInit failed, aborting." << endl;
        exit (1);
    }

    // calculate all of the data up front.
    Init();

    glutDisplayFunc(display);
    glutKeyboardFunc(keyboard);

    glutMainLoop();
    return 0;
}