Element 14 Raspberry Pi User Manual page 31

Programming Minecraft Pi
Once you have launched the game then you can select Start Game
followed by Create New. This should take you into a randomly
generated world that you can start to modify with code.
You should still have your LX Terminal
windows open. If not then click on the LX
Terminal window again to open a command
line prompt. To do this you will need to
press escape to pause the game and allow
you to move the mouse out of the game
window. You can then launch another
terminal from the desktop. One way is to
have the programming terminal window
and the Minecraft Window side by side
Once you have your terminal launched
you need to go to the Python API
directory (programming tools) by typing
the following at the terminal window:
cd mcpi/api/python/mcpi
and then:
python
and pressing return.
Your terminal prompt should change to
Now we are ready to start programming.
The first thing we need to do is to
import the Minecraft library.
At the command prompt in the
terminal windows type:
import minecraft
Now we need to initialize it which will
create a connection to your game
and allow you to start modifying
the game world. So now type:
mc = minecraft.Minecraft.create()
You can now use the mc object you
have created to control the world. Let's
say hello to your Minecraft world:
So type at the terminal window:
mc.postToChat("Hello Minecraft
World!")
You should then see your message
come up on the chat window in your
game. Feel free to change this message
to what ever you want. You can use the
postToChat method to post all sorts of
information you want the player to see.
Raspberry Pi User Guide.indd 31
Congratulations, you have learned
to simply program Minecraft Pi.
Now on to a more advanced project,
that is Placing Block within your
game. To place a block let's type the
following at the command prompt:
import block
mc.setBlock(0, 10, 0, block.STONE)
The first line which imports block simply
allows us to use the block names when
we position them. The name "block.
STONE" can be changed to block.
LAVA, block.MELON or block.WATER.
The Minecraft Wikipage gives you
many other types of blocks to use.
minecraft.wikia.com/wiki/Category:Blocks
The second line calls setBlock and passes
in 3 numbers and the block type. These 3
numbers are the X, Y and Z coordinates in
.
>>>
the game world. Just like you would find
in maths, this coordinate system, called
Cartesian Coordinates, allows you to map
your blocks in a 3D world. From your player
start position X is left and right, with numbers
going down as you head left and up if you
head right. The Y coordinates are up and
down, with up increasing the number and
down decreasing the number. This leaves
the Z axis being forwards and backwards,
with forward increasing the number and
backwards decreasing. It's worth noting that
decreasing numbers go to a negative value.
Have a go at setting different coordinates for
blocks and see how they come out. If you
don't see a block then it means you either
put it very far away or it's underground. To
avoid blocks going too far away try and keep
the X, Y and Z values within 20 and -20.
You can view the source code for this
tutorial here: github.com/piprogramming/
Minecraft/blob/master/tutorial1.py
If you have the git-core package
installed then you can download it
using: git clone git://github.com/
piprogramming/Minecraft.git
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