How to make a 2d grid with c#

Question

I want to start making 2d simulations like conway's game of life, pathfinding and sand simulations and so.. I understand the concept and that I have to make a grid... The thing is that i can't find how to make a grid.. I have tried searching and I don't seem to find a proper tutorial or something helpful... I am using monogame framework and have some knowledge with c#. I just want to understand how to make one so i can use it to make simulations if someone can break it down for me or give me an existing tutorial I'll be thankful.

Answer 1

A grid is implemented in an array of simple values(byte, uint, float...) or objects depending on complexity.

For pathfinding, it is not uncommon to use a parallel grid for indication of visited or changed nodes.

Game of life example:

// class level variables 
const int WIDTH = 32;
const int HEIGHT = 32;
byte[,] Grid = new byte[WIDTH,HEIGHT]; // byte is 1/4 smaller than bool
byte[,] NextGrid = new byte[WIDTH,HEIGHT];
// 1 is alive 0 is dead

//in Initialize()

// build a period 2 Blinker
Grid[5,4] = 1;
Grid[5,5] = 1;
Grid[5,6] = 1;


//in Update()
// follow row major form and  count the 8 possible live neighbors
for (int y=0;y<HEIGHT;y++)
   for (int x=0;x<WIDTH;x++)
   {
      byte nLiveCount = 0;
      if(x > 0) // left 3
      {
         nLiveCount += Grid[x-1,y];
         if(y > 0)
            nLiveCount += Grid[x-1,y-1];
         if(y < HEIGHT - 1)
            nLiveCount += Grid[x-1,y+1];
      }
      if(x < WiDTH - 1) // right 3
      {
         nLiveCount += Grid[x+1,y];
         if(y > 0)
            nLiveCount += Grid[x+1,y-1];
         if(y < HEIGHT - 1)
            nLiveCount += Grid[x+1,y+1];
      }
      if(y < HEIGHT - 1) // above
         nLiveCount += Grid[x,y+1];
      if(y > 0) // below
         nLiveCount += Grid[x,y-1];

      if(Grid[x,y]== 1) // test live
      {
         if((nLiveCount == 2 || nLiveCount ==3))
            NextGrid[x,y] = 1;
      }   
      else
         if(nLiveCount == 3) // birth
            NextGrid[x,y] = 1;
   }
Grid = NextGrid;
NextGrid = new byte[WIDTH,HEIGHT]; // Ready nextGrid for next step

// in Draw()

// this assumes 2 loaded 8x8 textures called black and white
for (int y=0;y<HEIGHT;y++)
   for (int x=0;x<WIDTH;x++)
      spriteBatch.Draw((Grid[x,y]==1)?black:white, new Vector2(8 * x, 8 * y), Color.White);

// could be simplified to a single white texture 8x8 with:
//spriteBatch.Draw(white, new Vector2(8 * x, 8 * y), (Grid[x,y]==1) ? Color.Black : Color.White);