/****************************************************************
// Compile and run from the command line with:
// g++ prot.cpp -l SDL
// ./a.out
//
// Requires the SDL library and neutronlib.h
/****************************************************************/

#include <stdlib.h>
#include <SDL/SDL.h>
#include <stdio.h>
#include <math.h>
#include <time.h> 
#include "neutronlib.h"
struct grid
{
  int hash;        // distance between grid lines
  int titx;        // x location of the tit
  int tity;        // y location of the tit
  int wavelength;  // distance between peaks
  int xx;          // left-right grid starting point
  int yy;          // up-down grid starting point
  int colorx;
  int colory;
  int colorbk;
  int tog;
  void sweet(int x, int y, int th){
    th *= 2;
    putpixel(maxx - x + 1, y - th, colory);         // 1 = x + 1, y
    putpixel(maxx - x + 1, y + 1 - th, colory);     // 2 = x + 1, y + 1
    putpixel(maxx - x, y + 1 - th, colory);         // 3 = x, y + 1
    putpixel(maxx - x - 1, y + 1 - th, colory);     // 4 = x - 1, y + 1
    putpixel(maxx - x - 1, y - th, colory);         // 5 = x - 1, y
    putpixel(maxx - x  - 1, y - 1 - th, colory);    // 6 = x - 1, y - 1
    putpixel(maxx - x, y - 1 - th, colory);         // 7 = x, y - 1
    putpixel(maxx - x + 1, y - 1 - th, colory);     // 8 = x + 1, y - 1
    
    putpixel(maxx - x + 1, maxy - y - th, colory);
    putpixel(maxx - x + 1, maxy - y + 1 - th, colory);
    putpixel(maxx - x, maxy - y + 1 - th, colory);
    putpixel(maxx - x - 1, maxy - y + 1 - th, colory);
    putpixel(maxx - x - 1, maxy - y - th, colory);
    putpixel(maxx - x - 1, maxy - y - 1 - th, colory);
    putpixel(maxx - x, maxy - y - 1 - th, colory);
    putpixel(maxx - x + 1, maxy - y - 1 - th, colory);

    putpixel(x + 1, y - th, colory);
    putpixel(x + 1, y + 1 - th, colory);
    putpixel(x, y + 1 - th, colory);
    putpixel(x - 1, y + 1 - th, colory);
    putpixel(x - 1, y - th, colory);
    putpixel(x - 1, y - 1 - th, colory);
    putpixel(x, y - 1 - th, colory);
    putpixel(x + 1, y - 1 - th, colory);

    putpixel(x + 1, maxy - y - th, colory);
    putpixel(x + 1, maxy - y + 1 - th, colory);
    putpixel(x, maxy - y + 1 - th, colory);
    putpixel(x - 1, maxy - y + 1 - th, colory);
    putpixel(x - 1, maxy - y - th, colory);
    putpixel(x - 1, maxy - y - 1 - th, colory);
    putpixel(x, maxy - y - 1 - th, colory);
    putpixel(x + 1, maxy - y - 1 - th, colory);
  }
  void mkgrid(){
    double x, y, xxx, th = 0;
    double xxxx = xx;
    ColorFill(colorbk, maxx, maxy);
    
    for(xxx = 0; xxx < maxx; xxx ++){
      x = xxxx; y = yy;              // th is virtical offset for tit
      while(y < maxy){
        x += 1;
        if(tog == 1){ 
          y += 1; 
          tog = 0; 
        }
        else tog = 1; 
        double dx = titx - x;
        double dy = tity - y;
        double dif = sqrt(dx * dx + dy * dy);
        dif /= 40;
        if(dif < .2) dif = .2;
        th = 20 / (dif);

        putpixel(maxx - x, y - th, colory);
        putpixel(maxx - x, maxy - y - th, colory);
        putpixel(x, y - th, colory);        
        putpixel(x, maxy - y - th, colory);
        if(th > 15){                 // Enhance sweet spot   
          sweet(x, y, th);
        }
      }
      xxxx += hash;
    }
  }
  void reset(){
    hash = 15;
    titx = maxx / 2;
    tity = maxy / 2;
    xx = 0;
    yy = 0;
    tog = 0;
    colorx = 0xff0000;
    colory = 0xffffff;
    colorbk = 0x000000;
    wavelength = 500;
  }
};

int main(int argc, char **argv)
{ // Default screen size and color is in neutronlib.h
  minx = 0; maxx = 1920; miny = 0; maxy = 960; // Custom screen size redefined
  char c = 0;
  int x, y, updt = 10;
  grid grid0;
  if((SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO)==-1)) { 
    printf("Could not initialize SDL: %s.\n", SDL_GetError());
    exit(-1);
  }
  init_screen(maxx, maxy);
  grid0.reset();
  SDL_UpdateRect(screen, minx, miny, maxx, maxy);
  while(1){
    ColorFill(color, maxx, maxy);
    c = keystroke();
    grid0.mkgrid();
    SDL_UpdateRect(screen, minx, miny, maxx, maxy);
    if(c == 'q') break;
    if(c == 'd') SDL_Delay(5000);
    if(c == 'c') grid0.colorbk += 0xff;
    SDL_Delay(1);
    if(grid0.titx < maxx) grid0.titx += 1;
    else grid0.reset();
  }
  SDL_Quit();
}