Main.cpp

/**
  GAME OF LIFE - SFML implementation
*/
#include <iostream>
#include <stdlib.h>
#include "SFML/Graphics.hpp"

#define WINDOW_WIDTH 1000
#define WINDOW_HEIGHT 700

struct Board
{
    int cells[WINDOW_WIDTH][WINDOW_HEIGHT] = {{0}};
    int cells_alive = 0;
};

void init_board(Board *board);
void board_tick(Board *board);
void copy_cells(int (&cells)[WINDOW_WIDTH][WINDOW_HEIGHT], int (&temp)[WINDOW_WIDTH][WINDOW_HEIGHT]);
int get_alive_neightboards(Board *board, int x, int y);
sf::VertexArray get_board_vertex(Board *board);

int main(const int argc, const char *argv[])
{
    Board board;
    sf::Clock clock;
    sf::RenderWindow window(sf::VideoMode(WINDOW_WIDTH, WINDOW_HEIGHT), "Game of life");

    init_board(&board);

    window.setFramerateLimit(60);

    while(window.isOpen())
    {
        sf::Event event;
        while(window.pollEvent(event))
        {
            if(event.type == sf::Event::Closed)
                window.close();
        }

        sf::Vector2i mouse = sf::Mouse::getPosition(window);
        board.cells[mouse.x][mouse.y] = 1;

        board_tick(&board);

        window.clear();
        window.draw(get_board_vertex(&board));
        window.display();
    }

    return 0;
}

void init_board(Board *board) {
    for (int x = 0; x < WINDOW_WIDTH; x++)
    {
        for (int y = 0; y < WINDOW_HEIGHT; y++)
        {
            board->cells[x][y] = rand() % 100;

            if (board->cells[x][y] == 1)
                board->cells_alive++;
            
            else
                board->cells[x][y] = 0;
            
        }
    }
}

void board_tick(Board *board) 
{
    Board temp_board(*board);

    board->cells_alive = 0;

    for (int x = 0; x < WINDOW_WIDTH; x++)
    {
        for (int y = 0; y < WINDOW_HEIGHT; y++)
        {
            int neightboards = get_alive_neightboards(board, x, y);

            if (board->cells[x][y] == 0 && neightboards == 3)
                temp_board.cells[x][y] = 1;

            else if (board->cells[x][y] == 1 && (neightboards < 2 || neightboards > 3))
                temp_board.cells[x][y] = 0;

            if (temp_board.cells[x][y] == 1)
                board->cells_alive++;
        }
    }

    copy_cells(board->cells, temp_board.cells);
}

void copy_cells(int (&cells)[WINDOW_WIDTH][WINDOW_HEIGHT], int (&temp)[WINDOW_WIDTH][WINDOW_HEIGHT])
{
    for (int x = 0; x < WINDOW_WIDTH; x++)
    {
        for (int y = 0; y < WINDOW_HEIGHT; y++)
        {
            cells[x][y] = temp[x][y];
        }
    }
}

int get_alive_neightboards(Board *board, int x, int y)
{
    int count = 0;

    count += board->cells[x-1][y-1] != NULL ? 1 : 0;
    count += board->cells[x][y-1] != NULL ? 1 : 0;
    count += board->cells[x+1][y-1] != NULL ? 1 : 0;
    count += board->cells[x-1][y] != NULL ? 1 : 0;
    count += board->cells[x+1][y] != NULL ? 1 : 0;
    count += board->cells[x-1][y+1] != NULL ? 1 : 0;
    count += board->cells[x][y+1] != NULL ? 1 : 0;
    count += board->cells[x+1][y+1] != NULL ? 1 : 0;

    return count;
}

sf::VertexArray get_board_vertex(Board *board)
{
    sf::VertexArray points(sf::Points, board->cells_alive);

    int k = 0;
    for (int x = 0; x < WINDOW_WIDTH; x++)
    {
        for (int y = 0; y < WINDOW_HEIGHT; y++)
        {
            if (board->cells[x][y] == 1)
                points[k++].position = sf::Vector2f(x, y);
        }
    }

    return points;
}