#include <iostream>
#include <stdlib.h>
#include "Angel.h"

typedef vec2 point2;
const int numPoints = 5000;

void init(void) {

    //Initialize random number generator
    std::srand((uint)std::time(0));
    
    point2 points[numPoints];
    
    //The vertices of a triangle in a plane
    point2 vertices[3] ={point2(-1.0,-1.0),
        point2(0.0,1.0),
        point2(1.0, -1.0)};
    
    //An arbitrary point inside the triangle
    points[0] = point2(0.25, 0.25);
    
    for(int k = 1; k < numPoints; ++k) {
        
        //Picks a random vertex
        int j = rand()%3;
        
        //Computes the point halfway between the
        //selected vertex and the previous point
        points[k] = (points[k-1]+vertices[j])/2.0;
    }
    // Load shaders and use the resulting shader program
    GLuint program = InitShader( "vshader.glsl", "fshader.glsl" );
    glUseProgram( program );
    // Create a vertex array object
    GLuint vao;
    glGenVertexArraysAPPLE( 1, &vao );
    glBindVertexArrayAPPLE( vao );
    // Create and initialize a buffer object
    GLuint buffer;
    glGenBuffers( 1, &buffer );
    glBindBuffer( GL_ARRAY_BUFFER, buffer );
    glBufferData( GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW );
    // Initialize the vertex position attribute from the vertex shader
    GLuint loc = glGetAttribLocation( program, "vPosition" );
    glEnableVertexAttribArray( loc );
    glVertexAttribPointer( loc, 2, GL_FLOAT, GL_FALSE, 0,
                          BUFFER_OFFSET(0) );
    glClearColor( 1.0, 1.0, 1.0, 1.0 ); // white background
}
//----------------------------------------------------------------------
void display( void ) {
    glClear( GL_COLOR_BUFFER_BIT );     // clear the window
    glDrawArrays( GL_POINTS, 0, numPoints );    // draw the points
    glFlush();
}
//----------------------------------------------------------------------
int main( int argc, char **argv ) {
    glutInit( &argc, argv );
    glutInitDisplayMode( GLUT_RGBA | GLUT_3_2_CORE_PROFILE);
    glutInitWindowSize( 512, 512 );
    // If you are using freeglut, the next two lines will check if
    // the code is truly 3.2. Otherwise, comment them out
    glutCreateWindow( "Sierpinski Gasket" );
    init();
    glutDisplayFunc( display );
    glutMainLoop();
    return 0; }