I'm trying to make Conway's Game of Life in C++, and am using OpenGL (However I'm pretty new to OpenGL) because it supports negative coordinates and therefore an infinite world.  

I have a class called GameOfLife`` which handles the entire world, and has the alive cells as [x, y] coordinates in an vector. Therefore I'm going to use a for loop throughout the alive cells coordinate and render a single pixel for each coordinate.  

However whatever I have tried nothing appears on the screen no matter what I do. Below is the code with an empty `glBegin` and `glEnd` function. What should I put between these in order for it to render.

I have tried :  

dividing each coordinate by 400 to get `float` for 1 pixel .  

adding 1/400 to both x and y for the third and fourth side.

```cpp
#include "gol.h"
#include <GL/glew.h>
#include <GLFW/glfw3.h>
int main()
{
  std::vector<std::vector<int>> dupl;
  std::ifstream infile { "test.rle" };
  std::string file_contents { std::istreambuf_iterator<char>(infile), std::istreambuf_iterator<char>() };
  parse_rle(file_contents, 0, dupl);
  GameOfLife gol;
  gol.place_cells(dupl);
  //gol.update();
  GLFWwindow* window;
  if (!glfwInit())
    return 1;
  int width  = 400;
  window = glfwCreateWindow(width, width, "Window", NULL, NULL);
  if (!window) {
    glfwTerminate();
    return 1;
  }
  glfwMakeContextCurrent(window);
  if(glewInit()!=GLEW_OK)
    std::cout<<"Error"<<std::endl;
  glEnable(GL_DEPTH_TEST);
  while(!glfwWindowShouldClose(window)) {
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    for(std::vector<int> i : gol.alive)
    {
        glBegin(GL_QUADS);

        glEnd();
    }
    glfwSwapBuffers(window);
    glfwPollEvents();
  }
  glfwTerminate();
}

```