Whether you’re building a classic RPG or a puzzle game, tile-based rendering is one of the most efficient ways to create large, structured game worlds. Instead of drawing every pixel manually, we divide the world into a grid of “tiles.”
In this tutorial, we’ll learn how to translate a 2D Python list into a visual game map using Processing.py.
The Concept: The Data Map
At its heart, a game level is just data. We can represent a grid of tiles using a 2D list (a list of lists). In this example:
* 0 represents Grass (Green)
* 1 represents Water (Blue)
# Our 5x5 game map
game_map = [
[0, 0, 0, 0, 0],
[0, 1, 1, 1, 0],
[0, 1, 0, 1, 0],
[0, 1, 1, 1, 0],
[0, 0, 0, 0, 0]
]
Rendering the Grid
To turn this data into a visual map, we need to loop through the rows and columns. The position of each tile on the screen is calculated by multiplying its grid index by the tile size.
The Math
If a tile is at row r and column c, and our tiles are 50 pixels wide:
* x = c * 50
* y = r * 50
The Python Implementation
TILE_SIZE = 50
def setup():
size(250, 250)
noLoop() # We only need to draw the map once
def draw():
background(255)
# Iterate through rows
for r in range(len(game_map)):
# Iterate through columns in each row
for c in range(len(game_map[r])):
tile_type = game_map[r][c]
# Determine color based on tile type
if tile_type == 0:
fill(34, 139, 34) # Forest Green
elif tile_type == 1:
fill(30, 144, 255) # Dodger Blue
# Draw the tile
# Notice x is column (c) and y is row (r)
rect(c * TILE_SIZE, r * TILE_SIZE, TILE_SIZE, TILE_SIZE)
Why use Tile Maps?
- Memory Efficiency: You only need to store a few integers per tile, rather than high-resolution images of the entire world.
- Easy Collision Detection: If you know your character is at pixel (120, 85), you can easily calculate exactly which tile they are standing on by dividing by
TILE_SIZE. - Level Editors: It’s very easy to create a tool that allows you to “paint” levels by changing numbers in a grid.
Going Further
Once you have the basic grid working, you can replace the simple rect() calls with image() calls to use actual sprites for your grass and water.
In our next post, we’ll look at how to generate these maps randomly so you never play the same level twice!
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Written by
Abdur-Rahmaan Janhangeer
Chef
Python author of 7+ years having worked for Python companies around the world
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