trace-racer

A toy ray-tracer written in Python. The implementation loosely follows the Ray Tracing in One Weekend series.

Below is an image of the latest render from the code:

This image took 2.5 hr to render which is slow, given the low render resolution and sampling level. The ray tracer was written in Python and Numpy so there is some implicit overhead.

Quick Start

Installation Guide

1. Ensure that you have Python 3.11 or above installed on your computer.
2. Open up the command terminal and navigate to the directory you want to install trace-racer in via cd commands.
3. Clone the repo by entering the command:

git clone https://github.com/biinnnggggg/trace-racer.git

5. Install the necessary dependencies by running

pip install numpy, PIL

How to use

1. Describe world to render in main.py and run the file. An example and render is given below:

if __name__ == '__main__':
    #...
    # Create world
    world = HittableList()

    # Materials
    material_ground = Lambertian(np.array([0.8, 0.8, 0.35]))
    material_blue = Lambertian(np.array([0.1, 0.2, 0.5]))
    material_powderblue = Lambertian(np.array([0.7, 0.9, 0.92]))
    #... add materials here...

    # Objects
    spheres = [
        Sphere(np.array([0.0, -100.5, -1.0]), 100.0, material_ground),
        Sphere(np.array([0.0, 0.0, -1.2]), 0.5, material_powderblue),
        Sphere(np.array([4.8, 0.0, 1.2]), 0.5, material_powderblue),
        Sphere(np.array([-1.0, 0.0, -1.0]), 0.5, material_glass),
        Sphere(np.array([-1.0, 0.0, -1.0]), 0.45, material_bubble),
        Sphere(np.array([1.4, 0.0, -0.8]), 0.5, material_glass),
        Sphere(np.array([1.4, 0.0, -0.8]), 0.45, material_bubble),        
        Sphere(np.array([0.75, 0.0, 0.75]), 1, material_reflectless),
        Sphere(np.array([-3.5, 1.3, -0.8]), 1.75, material_reflect),
        Sphere(np.array([-0.5, 0.0, -3.0]), 0.5, material_red),
        Sphere(np.array([-1.25, 0.0, 0.5]), 0.5, material_red),\
        # ... add objects here
    ]

    # Add objects to world
    for sphere in spheres:
        world.add(sphere)

    # Logger?
    logger = Output('log')

    # Change camera settings here...
    Camera.aspect_ratio = 16 / 9 
    Camera.image_width = 720
    Camera.samples_per_pixel = 100
    Camera.max_depth = 30

    Camera.vfov = 100
    Camera.look_from = np.array([-2.0, 2.0, 1.0])
    Camera.look_at   = np.array([0.0, 0.0, -1.0])
    Camera.vup       = np.array([0.0, 1.0, 0.0])

    Camera.defocus_angle = 3.0
    Camera.focus_dist = 3.4
    ...

2. The render output should be saved as data/output.png and render log can be found in main.log

Upcoming features

1. Positionable camera
2. Blur, field of view, depth of field,...
3. Textures
4. More unit tests, and preliminary integration testing
5. Cubes and polyhedrons
6. Description language

Resources I used along the way:

• https://docs.python-guide.org/writing/structure/
• https://docs.python-guide.org/writing/tests/
• https://docs.python.org/3/library/logging.html
• https://stackoverflow.com/questions/33189208/vs-for-a-power-of-2-operation
• https://www.youtube.com/watch?v=TrqK-atFfWY - different ways of optimising ray tracers e.g. bounding volume, BVH, ...
• https://angms.science/doc/RM/randUnitVec.pdf - how to generate uniform unit vectors in Rn efficiently using normal distribution sampling.