July 9, 2013

Surely you remember that old cell phone game, "Snake"? The one where you had to eat the apples but not run into yourself? Gah, that game was a blast, and I spent a ton of time playing it in my younger years. It'd been a while since I had played, so I thought I would remake it in Excel. You know... for fun.

History

I used to work at an accounting firm, so I spent a lot of time in Excel. I picked up a book about programming VBA for Excel, because it really helped me do my job much better. (As a sidenote: learn to code not to know how to code, but so you can use it to accomplish some other thing. I love coding, but I love doing things with code more.)

I was at a training event for the firm once, and on the flight home rather than watching TV or playing a game, I thought I'd try to make Snake in Excel.

It's Alive!

It seemed like a good idea, just because the old cell phone screens were so grid based, and Excel is the same way. Why not just use cells as giant "pixels" and use them draw the game? So that's what I did. The first thing the game does is resize the columns and rows to make cells squares. Then it draws up the borders, drops in a snake and an apple, and you're off to the races. I had to import a few libraries to get it working, the main one is the timer library that allows the program to "run". Each time the timer ticks, it moves the snake in whichever direction it's going and see if it has collided with anything.

The snake, the apple, and the walls are simply cells that are formatted in different, defined ways. Every time the snake moves, it checks to see if it hit an apple, if so, it shows the apple moving through the snake's body and then extends the snake by one cell. If it's a wall, the borders all turn red, and you're dead.

Levels

After a while, the main level gets pretty boh-ring. It is just a box after all. So why don't we mix it up?

Like the snake and the apple, the walls are just another cell that has been formatted in a certain way. The "apple" algorithm will place the apple randomly in the cage, but never on the walls. That would be frustrating, huh? But how do you make levels? Easy, I made a way for you.

With the level editor, all you really have to know how to do is use the "Format Painter." You can add rows and columns to make the level wider or taller and then use the format painter to add walls. To place the snake, you just put an "X" in the cell you want the head to be in and choose the starting direction. (Make sure you leave enough room for the snake's body!)

You can share and import levels too, right from the front-end, no coding required.

If you want to get really funky, you can look at the "Levels" sheet to see how all that data is stored.

Scores

The scoring is weighted based on your chosen speed, and the "softness" of the walls you choose. I used a formula to determine the points-per-apple:

Score = ApplesEaten * (1 + (Speed-3)*.3 + (3-Forgiveness)*.2)

If you set the speed and forgiveness factors to 3, apples will be worth 1 point each. If you turn the speed all the way up and the forgiveness all the way down, you'll get a value of 2 points per apple. The speed is weighted more heavily than the forgiveness, so crank up that speed and soften up those walls.

Updates

Every time you open the workbook, it will check for a text file on Amazon's S3 that has a version number and the URL to the latest workbook, should I ever update the thing.

Download

You can find the workbook at https://s3.amazonaws.com/aaronfrancis/snake/snake.xlsm. The code is wide open so feel free to look at it and offer any suggestions! I will probably put it on GitHub before too long.