cubicpy 0.1.22

A Python library for creating 3D basic shape models and animations with Physics.

CubicPy

日本語 | English

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.

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

Sample Code Examples

Creating a Tower of Boxes (cube_tower_sample.py)

# 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
})

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:

• 0: The corner nearest to the origin is the reference
• 1: The center of the bottom surface is the reference
• 2: The center of gravity is the reference

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

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()

API Mode Method Details

CubicPyApp Class

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

• code_file: Path to Python file to execute (optional)
• gravity_factor: Gravity factor (optional, default: 1)
• window_size: Window size (optional, default: (900, 600))
• camera_lens: Camera lens type ('perspective' or 'orthographic', optional, default: 'perspective')

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))

• position: Position coordinates (x, y, z)
• scale: Size (width, depth, height)
• color: Color (red, green, blue) - values from 0 to 1
• mass: Mass (0: fixed object)
• color_alpha: Transparency (0: transparent to 1: opaque)
• hpr: Rotation degree angles (heading, pitch, roll)
• base_point: Position reference point
• remove: Removed object (Boolean)
• vec: Initial velocity vector (x, y, z) - applied when space key is pressed

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))

• Parameters are the same as add_cube

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))

• Parameters are the same as add_cube

Generic Object Addition

add(obj_type, **kwargs)

• obj_type: Type of object ('cube', 'sphere', 'cylinder')
• **kwargs: Object parameters (the following keyword arguments can be used)
  • position or pos: Position coordinates
  • scale: Size
  • color: Color
  • mass: Mass
  • color_alpha: Transparency
  • hpr: Rotation degree angles (heading, pitch, roll)
  • base_point: Position reference
  • remove: Removed Object - can be deleted with the X key
  • vec: Initial velocity vector - applied when space key is pressed

Building Objects from body_data List

from_body_data(body_data) 

• body_data: List of object definitions (dictionaries) as used by the cubicpy command

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.

• text: The text to display

set_bottom_left_text(text)

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

• text: The text to display

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

• Always use push_matrix() and pop_matrix() in pairs
• Pay attention to the order of pop_matrix() calls when creating multiple layers
• Use reset_matrix() to reset the state during debugging

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

• Arrow keys: Change camera angle
• SHIFT + W/S/A/D/Q/E: Move camera target point
• Mouse wheel: Zoom in/out (perspective mode) or change display range (orthographic mode)
• W/S/A/D: Tilt the ground
• F/G: Change gravity strength
• R: Reset (also resets camera position and target point)
• Z: Toggle debug display
• X: Remove selected objects one by one
• Space key: Launch objects with velocity vectors (vec)
• ESC: Exit

Requirements

• Python 3.9 or higher
• Panda3D
• NumPy

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

Copyright

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 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.

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Have fun learning programming with CubicPy!