CubicPy

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CubicPy - A 3D programming learning app for placing and building physics objects with code

Call it “CubicPy” - or simply “CuPy” for short!

Application Description

CubicPy is an application that allows you to place objects in 3D space using Python code and build worlds that operate with realistic physics simulations. You can freely place boxes, spheres, and other objects to create structures and learn programming while experiencing physical laws such as gravity and collisions.

CubicPy Sample Animation Gif

The constructed objects and structures can be observed undergoing realistic collapse processes by tilting the ground or removing objects using physics simulations. You can also change the gravity factor to observe physical behavior under different gravitational environments. Additionally, you can set initial velocity vectors for objects and launch them.

Installation

pip install cubicpy

Using the cubicpy Command

After installation, you can easily run from the command line:

# Run a randomly selected sample code
cubicpy

# Display help
cubicpy --help
cubicpy -h

# Display sample list
cubicpy --list
cubicpy -l

# Run a specific sample
cubicpy --example cube_tower_sample
cubicpy -e cube_tower_sample

# Run your own Python file
cubicpy your_body_data_script.py

# Run with modified gravity factor (specifies the power of 10 to multiply gravity by)
cubicpy --gravity 0.01 --example cube_tower_sample
cubicpy -g 0.01 -e cube_tower_sample

# Run with custom window size (1280x720)
cubicpy -e cube_tower_sample -w 1280,720
cubicpy --window-size 1280,720 -e cube_tower_sample

# Run with specific camera lens type (perspective or orthographic)
cubicpy -e cube_tower_sample -c orthographic
cubicpy --camera-lens orthographic -e cube_tower_sample

# Run in websocket mode
cubicpy -e cube_tower_sample --external
cubicpy -e cube_tower_sample -x

# Run in websocket mode with specific room
cubicpy -e cube_tower_sample --external --room 1000
cubicpy -e cube_tower_sample -x -m 1000

# Run with custom restitution coefficient (0-1)
cubicpy -e cube_tower_sample --restitution 0.8
cubicpy -e cube_tower_sample -r 0.8

# Run with custom friction coefficient (0-1)
cubicpy -e cube_tower_sample --friction 0.5
cubicpy -e cube_tower_sample -f 0.5

Sample Code Examples

Creating a Tower of Boxes (cube_tower_sample.py)

Sample cube tower

# Create an array of object data
body_data = []

# Stack 10 levels of cubes
for i in range(10):
    body_data.append({
        'type': 'cube',
        'pos': (0, 0, i),  # Position: x, y, z
        'scale': (1, 1, 1),  # Size: width, depth, height
        'color': (i/10, 0, 1-i/10),  # Color: red, green, blue (0-1)
        'mass': 1  # Mass (optional)
    })

Launching Objects with Initial Velocity Vectors

# Create a projectile
body_data.append({
    'type': 'sphere',
    'pos': (5, 5, 2),  # Position: x, y, z
    'scale': (1, 1, 1),  # Size
    'color': (1, 0, 0),  # Red color
    'mass': 5,  # Mass
    'velocity': (10, -5, 3)  # Initial velocity vector: x, y, z direction
})

Other Samples for Command Mode

Additional sample code can be found in the “codes” directory. Run with cubicpy your_file.py command.

Object Definition Details (for cubicpy command)

Details of object definitions to add to the body_data list:

Parameter Description Required Default Value
type Object type: ‘cube’, ‘sphere’, ‘cylinder’ Required -
pos Position coordinates (x, y, z) Required -
scale Size (width, depth, height) Optional (1, 1, 1)
color Color (red, green, blue) - values from 0 to 1 Optional (0.5, 0.5, 0.5)
mass Mass (0: fixed object) Optional 1
color_alpha Transparency (0: transparent to 1: opaque) Optional 1
hpr Rotation degree angles (heading, pitch, roll) Optional (0, 0, 0)
base_point Position reference point Optional 0
remove Removed Object Optional False
vec Initial velocity vector (x, y, z) Optional (0, 0, 0)

※ base_point can be set to the following values:

Building Worlds with the cubicpy Command

  1. Create a Python file in the format of the sample
  2. Run it with the cubicpy your_file.py command

Sample Code for API Mode

Sample api mode

from cubicpy import CubicPyApp

# Instantiate
app = CubicPyApp(gravity_factor=0.01)

# Adding individual objects
# Add objects using API
app.add_cube(position=(0, 0, 0), scale=(1, 1, 1), color=(1, 0, 0))
app.add_sphere(position=(2, 0, 0),  scale=(1, 1, 1), color=(0, 1, 0))
app.add_cylinder(position=(4, 0, 0),  scale=(1, 1, 1), color=(0, 0, 1))

# Add an object with initial velocity vector
app.add_sphere(
    position=(5, 5, 2),
    scale=(1, 1, 1),
    color=(1, 0, 0),
    mass=5,
    vec=(10, -5, 3)  # Will be launched when space key is pressed
)

# Adding multiple objects (loop)
for i in range(10):
    app.add_cube(
        position=(0, 5, i),
        color=(i/10, 0, 1-i/10)
    )

# Adding body_data for compatibility with cubicpy command
body_data = []
for i in range(10):
    body_data.append({
        'type': 'cube',
        'pos': (0, 10, i),
        'scale': (1, 1, 1),
        'color': (i / 10, 0, 1 - i / 10),
        'mass': 1,
        'color_alpha': 1,
    })

app.from_body_data(body_data)

# Run simulation
app.run()

Other Samples for API Mode

Additional sample code can be found in the “api_codes” directory. Run with python your_file.py command.

API Mode Method Details

CubicPyApp Class

CubicPyApp(code_file=None, gravity_factor=1, window_size=(900, 600), camera_lens='perspective'
    restitution=0.5, friction=0.5)

Object Addition Methods

Adding a Box

add_cube(position=(0, 0, 0), scale=(1, 1, 1), color=(0.5, 0.5, 0.5), mass=1, color_alpha=1, hpr=(0, 0, 0), base_point=0, remove=False, vec=(0, 0, 0))

Adding a Sphere

add_sphere(position=(0, 0, 0), scale=(1, 1, 1), color=(0.5, 0.5, 0.5), mass=1, color_alpha=1, hpr=(0, 0, 0), base_point=0, remove=False, vec=(0, 0, 0))

Adding a Cylinder

add_cylinder(position=(0, 0, 0), scale=(1, 1, 1), color=(0.5, 0.5, 0.5), mass=1, color_alpha=1, hpr=(0, 0, 0), base_point=0, remove=False, vec=(0, 0, 0))

Generic Object Addition

add(obj_type, **kwargs)

Building Objects from body_data List

from_body_data(body_data)

Text Display API Methods

You can display text on the application screen.

set_top_left_text(text)

Displays text at the top-left corner of the screen.

set_bottom_left_text(text)

Displays text at the bottom-left corner of the screen.

Coordinate Transformation Methods

CubicPy provides coordinate transformation methods that work similarly to Processing, allowing you to place objects relative to different coordinate systems. These methods make complex object positioning much easier.

List of Transformation Methods

push_matrix()   # Saves the current transformation state to the stack and creates a new transformation node
pop_matrix()    # Restores the transformation state from the stack
translate(x, y, z)    # Moves to the specified position
rotate_hpr(h, p, r)   # Rotates using HPR (Heading-Pitch-Roll)
reset_matrix()   # Resets all transformations

Usage Example

Here’s an example that places three towers at different positions using coordinate transformations:

from cubicpy import CubicPyApp

# Instantiate
app = CubicPyApp(gravity_factor=1, window_size=(1800, 1200))

# First tower (placed at the origin)
for i in range(10):
    app.add_cube(
        position=(0, 0, i),
        color=(i / 10, 0, 1 - i / 10)
    )

# First transformation
app.push_matrix()
app.translate(5, 5, 0)  # Move coordinate system to position (5,5,0)

# Second tower (placed relative to position (5,5,0))
for i in range(10):
    app.add_cube(
        position=(0, 0, i),  # This position is relative to the new coordinate system
        color=(i / 10, 1 - i / 10, 0)
    )

# Second transformation
app.push_matrix()
app.translate(5, 5, 0)  # Move another (5,5,0) (total of (10,10,0) from original origin)
app.rotate_hpr(45, 10, 0)  # Rotate 45 degrees around Y-axis, 10 degrees around X-axis

# Third tower (placed relative to the newest coordinate system with rotation applied)
for i in range(10):
    app.add_cube(
        position=(0, 0, i),  # This position is relative to the latest coordinate system
        color=(0, i / 10, 1 - i / 10)
    )

# Return from second transformation
app.pop_matrix()

# Return from first transformation
app.pop_matrix()

# Run simulation
app.run()

How Coordinate Transformations Work

Coordinate transformations are managed using a stack structure:

  1. When you call push_matrix(), the current transformation state is saved to the stack and a new transformation node is created
  2. You modify the coordinate system using translate() or rotate_hpr()
  3. Objects you add are placed relative to the current coordinate system
  4. When you call pop_matrix(), you return to the previous coordinate system
  5. reset_matrix() clears the entire stack and returns to the initial state

This functionality makes it easy to build complex structures using relative coordinates. For example, it’s useful when you want to place different parts of a house (walls, roof, windows) in relative positions and then move the entire house.

Important Notes

World Operation Methods

run()  # Build and run the world
reset()  # Reset the world
launch_objects()  # Launch objects with initial velocity vectors (also triggered by space key)

Building Worlds with API Mode

  1. Create a CubicPyApp instance in your Python script
  2. Add objects using methods like add_cube(), add_sphere(), etc.
  3. Call the run() method to build and run the world
  4. If needed, use the reset() method to rebuild
  5. Run with python your_script.py

Application Controls

WebSocket Mode

CubicPy can receive object data via WebSocket from external applications. This allows for real-time interaction between CubicPy and other applications.

Establish WebSocket communication using the room name displayed in the top-left corner of the screen.

Starting WebSocket Server

To start CubicPy in WebSocket mode, use the following command:

cubicpy --external

cubicpy -x

Example: Sending Data from Voxelamming Client

You can send data to CubicPy from a Voxelamming client application. Here’s an example using Python:

Websocket mode

# Import Voxelamming class from voxelamming package
from voxelamming import Voxelamming

# Specify the room name displayed in the CubicPy application
room_name = "1000"
# Create an instance of Voxelamming class
vox = Voxelamming(room_name)

# Set voxel size
vox.set_box_size(1)
# Set voxel placement interval
vox.set_build_interval(0.01)

# Set position and color for voxel placement
for i in range(100):
    vox.create_box(-1, i, 0, r=0, g=1, b=1, alpha=1)
    vox.create_box(0, i, 0, r=1, g=0, b=0, alpha=1)
    vox.create_box(1, i, 0, r=1, g=1, b=0, alpha=1)
    vox.create_box(2, i, 0, r=0, g=1, b=1, alpha=1)

# Set positions for voxel removal
for i in range(50):
    vox.remove_box(0, i * 2 + 1, 0)
    vox.remove_box(1, i * 2, 0)

# Send voxel data to the application
vox.send_data("main")
# vox.close_connection()

Installation and Running

# Install voxelamming package
$ pip install voxelamming
$ pip install --upgrade voxelamming

# Run the sample
$ cd sample/python
$ python main.py
# or
$ python3 main.py

Other Sample Codes for Websocket Mode

Additional sample codes are available in the “websocket_codes” directory. Supported languages include Python, JavaScript, Ruby, Swift, and Scratch3.

For more details, please refer to the Voxelamming official website:

Voxelamming official

Requirements

These dependencies are automatically installed with pip install cubicpy.

About the Font

This application uses “PixelMplus” font, which is a TrueType font designed to recreate the appearance of 8-bit gaming console bitmap fonts.

License Information

PixelMplus font is provided under the M+ FONT LICENSE. This license allows free use, copying, and redistribution with or without modification, including for commercial purposes (without warranty).

For more information and font downloads, please visit: https://github.com/itouhiro/PixelMplus

Released under the MIT License. See the LICENSE file for details.

Contribution

Bug reports and feature improvement suggestions are welcome via GitHub Issues or Pull Requests. New sample creation and documentation improvements are also welcome.

Development and Release Process

Testing CLI mode

Before releasing a new version to PyPI, test cli.py on local file.

PYTHONPATH=$PYTHONPATH:. python cubicpy/cli.py

Testing Before Release

Before releasing a new version to PyPI, it’s important to run the tests to ensure everything works correctly:

# Install development dependencies
pip install pytest

# Run all tests
pytest

# Run specific test file
pytest tests/test_physics.py

Publishing to PyPI

After confirming that all tests pass, you can publish the package to PyPI:

# Install build tools
pip install build twine

# Build the package
python -m build

# Upload to PyPI (requires PyPI account and token)
python -m twine upload dist/*

For more information about PyPI tokens, see the PyPI documentation.

Have fun learning programming with CubicPy!

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