Game of Life Clone

[2NywAqkS]

Just for practice, I'm making a colone of Conway's Game of Life.
At the start of the program I fill the window with 1024 cells like this:

for (int i = 0; i < 32; i++)
{
	for (int j = 0; j < 32; j++)
	{
		cellVector.push_back(Cell(j, i));
	}
}

Then every step each cell is calcualted like this

void Cell::Calculate()
{
	if (cellVector[(y-1)*32+x-1].alive) nbrs ++;
	if (cellVector[(y-1)*32+x].alive) nbrs ++;
	if (cellVector[(y-1)*32+x+1].alive) nbrs ++;
	if (cellVector[y*32+x-1].alive) nbrs ++;
	if (cellVector[y*32+x+1].alive) nbrs ++;
	if (cellVector[(y+1)*32+x-1].alive) nbrs ++;
	if (cellVector[(y+1)*32+x].alive) nbrs ++;
	if (cellVector[(y+1)*32+x+1].alive) nbrs ++;
	if (nbrs < 2) alive = false;
	if (nbrs > 3) alive = false;
	if (nbrs == 3) alive = true;
	nbrs = 0;
	gen = prevGen;
}

This works but not quite like how I expected. You do get weird patterns and movements but it doesn't seem to follow the traditional rules. What's more I occasionally get and unhandled exception error. I think this is because sometimes it has to calculate place that don't exist in the vector array. Can someone please help me with this.

If I haven't made myself very clear or haven't provided enough code, I've uploaded the sorce here: http://www.wizardchip.com/main.cpp

Thanks,
Rowan.

[Lowest0ne]

I just made a little GLUT program, GLUT windows/callback is much easier than windows.h. Here's a site I found: http://www.lighthouse3d.com/tutorials/glut-tutorial/

Not sure about your drawing pattern.

x and y are somewhere between 0 and 32, right? Why the 32 in your operations? You must go beyond 1024 at some point.

Maybe try checking values via a MessageBox for each operation:

if ((y-1)*32+x-1 >= 1024) MessageBox(NULL, L"(y-1)*32+x-1", NULL, NULL);
else if (cellVector[(y-1)*32+x].alive) nbrs ++;

Just to figure out which one is going over 1023

[2NywAqkS]

ok, thanks LowestOne. That seemed to clear up the edge problems but the rules are still not right. Any ideas?

[SexyBachelor]

Could you please explain what the pattern is supposed to do? (in Calculate())

Also, in Cell, what are the variables nbrs and prevGen for?

I'm getting that x and y are the position and alive dictates which color to color the cell

And one more thing... I'm surprised you're not getting any segmentation faults.

if (cellVector[(y-1)*32+x-1].alive) nbrs ++;

Just this first line, if y was 0 and x was less than 32 you'd have yourself an index access using a negative index.

Since this:

for (int i = 0; i < 32; i++)
	{
		for (int j = 0; j < 32; j++)
		{
			cellVector.push_back(Cell(j, i));
		}
	}

is how you initialize the cells, I don't see how you don't end up getting this segmentation fault.

[2NywAqkS]

I'm making a clone of Conway's Game of Life
http://en.wikipedia.org/wiki/Conway's_Game_of_Life

And The problem you described was fixed thanks to LowestOne.

[SexyBachelor]

LowestOne showed you that your indicies may be going over 1023, I was suggesting that they may be negative (less than 0).

Cool program, never heard about it until now.

[2NywAqkS]

I found the problem. Without going into to much detail, I found you have to separate the getting neighbours function and deciding on whether something is alive or not.