Python programming for Minecraft Pi

Minecraft Pi comes with the Python programming interface. This means that it's possible to script the action of a character in the game using Python. In this section, we will learn how to use Python programming to script the character actions as well as create amazing effects in the Minecraft world.

Start Minecraft Pi and create the world. Once it's done, while the game is running, free the mouse by pressing the Tab key and opening lxterminal. Create the /home/pi/book/chapter02 directory. Navigate to the directory and write the following code in the prog1.py file:

import mcpi.minecraft as minecraft

mc = minecraft.Minecraft.create()

mc.postToChat("Hello Minecraft World!")

The preceding program first imports the Minecraft Pi Python API. The second statement creates the connection to Minecraft, and the third statement posts the message to the game chat.

Run the preceding code; the following is its output:

Let's take a look at some of the most important functions of the Minecraft Pi Python API.

We can see the player's current coordinates in the game window in the top-left corner of the window. We can retrieve these coordinates with getPos(). The following is the code to retrieve the player character's current coordinates and print them:

import mcpi.minecraft as minecraft
mc = minecraft.Minecraft.create()
cur_pos = mc.player.getPos()
print cur_pos.x ; print cur_pos.y ; print cur_pos.z

This will print the current coordinates to the screen. Alternatively, the following syntax can be used to achieve this:

import mcpi.minecraft as minecraft
mc = minecraft.Minecraft.create()
cur_x , cur_y , cur_z = mc.player.getPos()
print cur_x ; print cur_y ; print cur_z

The setPos() function can be used to set the character's position. We need to pass the desired coordinates of the character to this function, as follows:

import mcpi.minecraft as minecraft
mc = minecraft.Minecraft.create()
cur_x , cur_y , cur_z = mc.player.getPos()
mc.player.setPos(cur_x+10, cur_y, cur_z)

The preceding code will displace the character by 10 blocks in the x axis.

The following code will set the character position 100 blocks higher than the current position, and as a result, the character will start falling:

mc.player.setPos(cur_x, cur_y + 100 , cur_z)

We can place the blocks of our choice with the setBlock() function. We need to pass the coordinates of the block (the first three arguments) and the type of the block (the fourth argument) we need to set to this function as follows:

import mcpi.minecraft as minecraft
import mcpi.block as block
mc = minecraft.Minecraft.create()
cur_x , cur_y , cur_z = mc.player.getPos()
mc.setBlock(cur_x + 1 , cur_y , cur_z , block.ICE.id )

You will find an ice block placed in front of you. If you do not find the block, then try to look around; it will be just beside or behind you.

Some blocks (such as wool and wood) have additional properties. We can pass this additional property as the fifth argument to the function for the wool and wood block types. The following code creates a column of a wool block with all the possible colors:

import mcpi.minecraft as minecraft
import mcpi.block as block
mc = minecraft.Minecraft.create()
cur_x , cur_y , cur_z = mc.player.getPos()

for i in range (0 , 15):
  mc.setBlock(cur_x + 1 , cur_y + i , cur_z , block.WOOL.id, i )

Run the preceding code and check the output for yourself.

We can use setBlocks() to place multiple blocks for a given volume. The following example places multiple gold blocks:

import mcpi.minecraft as minecraft
import mcpi.block as block
mc = minecraft.Minecraft.create()
cur_x , cur_y , cur_z = mc.player.getPos()

mc.setBlocks(cur_x + 1 , cur_y + 1 , cur_z + 1 , cur_x + 6 , cur_y + 6 , cur_z  + 6 , block.GOLD_BLOCK.id )

We can also use mathematical equations to draw geometric shapes in the game world. Now we know that setBlock() is used to place a single block. We can use this function in a single for loop to create a line of blocks. Calling this function in a double for loop will set a two-dimensional geometric shape. We can further extend this by introducing one more for loop. This will create a three-dimensional shape. The following code places a golden sphere near the player's position. We will place the gold block in the positions where the coordinates satisfy the equation of the sphere with a radius of 10 blocks:

import mcpi.minecraft as minecraft
import mcpi.block as block

mc = minecraft.Minecraft.create()

r = 10

cur_x , cur_y , cur_z = mc.player.getPos()

for x in range(r*-1,r):
  for y in range(r*-1, r):
    for z in range(r*-1,r):
      if x**2 + y**2 + z**2 < r**2:
        mc.setBlock(cur_x + x, cur_y + ( y + 20 ) , cur_z - ( z + 20 ) , block.GOLD_BLOCK)

The following is the output of the preceding program:

The following code places a gold block below the player's current position until the execution of the code is terminated by pressing Ctrl + C:

import mcpi.minecraft as minecraft
import mcpi.block as block
import time

mc = minecraft.Minecraft.create()

while 1:
  cur_x, cur_y , cur_z = mc.player.getPos()
  mc.setBlock(cur_x,cur_y-1,cur_z,block.GOLD_BLOCK.id)
  time.sleep(0.1)

The following is the output of the preceding code:

Now, we will conclude the chapter with some explosions. We can place a TNT block near us. It can be activated by left-clicking while holding the sword in hand. It will explode in a few seconds. The explosion will destroy some blocks in the blast radius:

cur_x, cur_y , cur_z = mc.player.getPos()
mc.setBlocks(cur_x+1,cur_y,cur_z, block.TNT.id,1)
This can be made more spectacular by placing multiple TNT blocks, as follows:
import mcpi.minecraft as minecraft
import mcpi.block as block

mc = minecraft.Minecraft.create()

cur_x, cur_y , cur_z = mc.player.getPos()
mc.setBlocks(cur_x+1,cur_y,cur_z,cur_x+4,cur_y+3,cur_z+3,block.TNT.id,1)

Once blocks are placed, activate the TNT block by the sword. The following is the screenshot of an explosion after activating the TNT blocks placed by the preceding code: