Using Variables

In the last lesson, we learned how to make a large, hollow box area to use for the battle arena. There is one problem with our last mod, however.

Notice that we coded all the coordinates by hand, assuming our arena will always be 31x31x31. When we code things by hand instead of letting a computer do the calculations for us, we are hardcoding.

Why is hardcoding the coordinates a bad thing? If, later on, we decide our box is too big and want to resize it, we'll have to recalculate our from and to positions. If we need to resize the box again, we'll have to calculate the positions one more time.

Instead of hardcoding the coordinates, we should use a variable, size, that keeps track of how big the box will be. Then we can use size to calculate the coordinates using some simple math. If size is 30, then the to and from positions become:

X Y Z

From: -size / 2 -1 -size / 2

To: size / 2 size size / 2

It doesn't matter what we set size to be, the coordinates will always match the new box size.

To implement this concept, we will need code from the math category.

Test your mod. You should get the same result as before. Now adjust the value of size until you are satisfied with the scale of your battle arena.

Challenge

Since certain monsters in Minecraft burn when they are exposed to sunlight, you'll need to build the arena out of a different block. However, when you build the new arena, the inside of the arena will be completely dark.

You can just manually add torches, but remember that the point of these lessons is to let the code do most of the work.

Your challenge is to make the floor and ceiling of the battle arena glowstone so the player can see. Your code will look something like this:

Notice that you will have to use replace as your build setting for the floor and ceiling since you'll be destroying the current floor and ceiling. Your final result should look something like this.

Building the Arena - Part 2