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We've coded up the majority of this game now already.

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All that's left to do is to define the two situations where we might get game

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over.

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And that is detecting collision with wall and detecting collision with tail.

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So let's tackle the easier one first. We want the snake

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once it gets past a certain point

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that's very close to the four walls to trigger the game over sequence.

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So we know that we have a 600 by 600 screen and the X and Y axis go to 300 and

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-300 at all four sides.

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So if we create a boundary box that say 280 here,

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280 here, -280 and -280,

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then as soon as the snake head touches that position,

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then once it zoomed past it,

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then we can say that the snake has pretty much hit the wall.

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Now this number is not perfect,

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it's just what I found to work after doing a lot of testing.

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And this is the case with a lot of games, you have to test it, run it,

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see if it works the way you want it to. But let's go ahead and add a comment,

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detect collision with a wall,

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and let's create our if statement.

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So what we want to say is if the snake.head has a X coordinate that is

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greater than 280, so it's gone too far to the right,

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or if it has a X coordinate that is less than -280,

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so it's gone too far to the left,

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or if it has a Y coordinate

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that's greater than 280, so too far to the top,

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or if it has a Y coordinate that is less than -280

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so it's gone too far to the bottom, if any of these four situations occur

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then it basically means that the snake has hit the wall.

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So what do we want to happen when the snake hits the wall? Well,

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we want to change this game_is_on to false because what that's going to allow us

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to do is to exit the while loop and basically

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end the snake movement and end the game.

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Let's go ahead and test this out.

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So let's let the snake hit the wall and you can see it no longer continues

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moving forward. But for the user, this might be a little bit confusing.

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It doesn't seem like it's actually game over. It seems like it's just crushed.

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So let's go ahead into our scoreboard

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which does a lot of the writing and let's create a new function

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which is going to be called game_over.

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And this game_over function is going to simply just write some texts,

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not the score, but instead

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it's just going to write 'GAME OVER' onto the screen using the same alignment and

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the same font. But instead of it at the position

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which we initially defined which is right at the top,

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let's go ahead and get it to go to the center, which is at (0, 0).

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So now when the snake hits the wall,

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not only does the snake stop moving,

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but we're also going to get the scoreboard to trigger the game over a sequence.

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So that means when it hits the wall, game over shows up in the middle of the

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screen, and you can still see the score that was written previously

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because we don't actually hit clear before we write this game over.

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And this means that the user can see that the game is over, the snake has stopped

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moving, and they can see their final score.

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So let's try to score some points. And once I've done that,

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I'm gonna hit a wall and it's game over and I can see that my score was 2.