Taichi Voxel Challenge: Tiny White Boat & Giant Yellow Duck

(Win "Committee's Pick" award in Taichi Voxel Challange 2022, 5/111)

Figure: result of main.py.

Figure: animation result of rubberduck.py.

Figure: a 360-degree animation result of rubberduck.py.

Blog (In Chinese 中文)：https://zhuanlan.zhihu.com/p/516533880

My API Extension

You can find the use of these extensional APIs in rubberduck.py

Use right mouse button to rotate view

1. GUI Widgets

• sene.add_text(your_text)

  scene.add_text("direct light")

• scene.add_slider(name_of_slider, var, range_min, range_max)

  Use list to pass reference of var.

  duck_z=[11.2]
  scene.add_slider("duck z", duck_z,-64.,64.)

• scene.add_color_picker(name_of_color_picker, var)

  Use list to pass reference of var.

  sky_col = [(135,206,235)] 
  scene.add_color_picker("sky color", sky_col)

• scene.add_callback_button(name_of_callback, callback_func, callback_args_ref)

  scene.add_callback_button("re-light / re-wave", relight, (sky_col,))
  scene.add_callback_button("reset scene", create_scene, ())

• scene.display_camera_info()

2. Scene Management

• scene.reset_part_of_scene

  Clear the voxels with "resetable" attributes equal to 1.

  Reason to add this api is that the creation of duck and boat in the scene is time-consuming, while the creation of wave and splash requires little time.

  So to adjust the appearence of waves for debugging, we only need to reset the voxels of waves, where we can set the voxels of waves as "resetable = 1", while the voxels of duck and boat as "resetable = 0".

  You can set this attribute in set_voxel

  (method) set_voxel: (idx: Any, mat: Any, color: Any, resetable: int = 1) -> None

• scene.reset_all_scene

  Clear all voxels.

3. Camera, Screenshot, etc.

• scene.set_camera(cam_pos, lookat)

• scene.save_screeshot(path)

  scene.save_screeshot(f"./rot_anim/{i:03d}.png")

How to create animation or 360-degree animation

First, generate a sequence of images, then use ti video -f your_framerate to generate video.

Here I introduce how to generate images.

1. A simple fixed-view animation

def animate():
    scene.set_camera((-3.168, 0.929, -1.915),(-1.46, 0.2557, -0.876))
    n_frame = 40
    for i in range(n_frame):
        if i == 0:
            # arguments are the y-axis offset of duck & boat
            create_scene(0, 0) 
        elif i == 8:
            create_scene(1, 0)
        elif i == 16:
            create_scene(1, -1)
        elif i == 24:
            create_scene(0, 0)
        elif i == 32:
            create_scene(-1, 1)
        else:
            scene.reset_part_of_scene()
            relight()
        scene.save_screeshot(f"./anim/{i:03d}.png")

2. A 360-degree Animation

import numpy as np 
from numpy.linalg import norm
def rot360_animate():
    #####################
    # replace with your create scene code / function 
    create_scene(0, 0) 
    #####################
    
    lookat = (0, -0.3, 0)
    init_pos = (-3.168, 0.929, -1.915)
    rot_center = (lookat[0], init_pos[1], lookat[2])
    radius = norm(np.array(init_pos) - np.array(rot_center))

    n_frame = 100
    for i in range(n_frame):
        theta = (2 * np.pi / n_frame) * i
        cam_pos = np.array(rot_center) + radius * np.array([np.sin(theta), 0., np.cos(theta)])
        print(f"cam_pos = {cam_pos}")
        scene.set_camera(cam_pos, lookat)
        
        #############################
        # or scene.reset_all_scene() then create new scene based on your need
        scene.reset_part_of_scene()
        relight()
        #############################

        scene.save_screeshot(f"./rot_anim/{i:03d}.png")

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We invite you to create your voxel artwork, by putting your Taichi code in main.py!

Rules:

• You can only import two modules: taichi (pip installation guide below) and scene.py (in the repo).
• The code in main.py cannot exceed 99 lines. Each line cannot exceed 120 characters.

The available APIs are:

• scene = Scene(voxel_edges, exposure)
• scene.set_voxel(voxel_id, material, color)
• material, color = scene.get_voxel(voxel_id)
• scene.set_floor(height, color)
• scene.set_directional_light(dir, noise, color)
• scene.set_background_color(color)

Remember to call scene.finish() at last.

Taichi lang documentation: https://docs.taichi.graphics/

Modifying files other than main.py is not allowed.

Installation

Make sure your pip is up-to-date:

pip3 install pip --upgrade

Assume you have a Python 3 environment, simply run:

pip3 install -r requirements.txt

to install the dependencies of the voxel renderer.

Quickstart

python3 example1.py  # example2/3/.../7/8.py

Mouse and keyboard interface:

• Drag with your left mouse button to rotate the camera.
• Press W/A/S/D/Q/E to move the camera.
• Press P to save a screenshot.

More examples

Show your artwork

Please put your artwork at the beginning of this README file. Replacing the demo.jpg file with your creation will do the job.