https://github.com/anders94/render.js
A Node.js raytracing renderer with RenderMan RIB format support, implemented in pure JavaScript.
https://github.com/anders94/render.js
Last synced: 16 days ago
JSON representation
A Node.js raytracing renderer with RenderMan RIB format support, implemented in pure JavaScript.
- Host: GitHub
- URL: https://github.com/anders94/render.js
- Owner: anders94
- Created: 2025-11-04T04:26:08.000Z (7 months ago)
- Default Branch: main
- Last Pushed: 2026-01-10T03:54:14.000Z (5 months ago)
- Last Synced: 2026-01-10T23:25:07.886Z (5 months ago)
- Language: JavaScript
- Homepage:
- Size: 213 KB
- Stars: 10
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# Render.js: A Raytracing Renderer
A Node.js raytracing renderer with RenderMan RIB format support, implemented in pure JavaScript.
## Sample Output
*Example render showing multi-colored spheres with reflections, realistic lighting, and antialiasing*
## Features
- **Pure JavaScript Implementation**: No external dependencies, runs entirely in Node.js
- **Multi-Threaded Rendering**: Automatic CPU detection and parallel processing using worker threads
- **RenderMan RIB Support**: Parse and render RenderMan RIB format files
- **Advanced Antialiasing**: Stratified sampling with quality presets
- **Core Raytracing**: Full raytracing pipeline with reflection support
- **Lighting Models**: Phong/Blinn-Phong shading with multiple light sources
- **Geometry Primitives**: Spheres, planes, triangles, and NURBS surfaces
- **Material System**: Support for different surface materials (plastic, metal, matte)
- **Gamma Correction**: Proper color space handling
- **PPM Image Output**: Generates standard PPM image files
## Installation
```bash
git clone https://github.com/anders94/render.js.git
cd render.js
```
Note: there are no dependancies so `npm install` is not necessary.
## Quick Start
```bash
# Run the raytracer with example scene
npm start
# Run tests to verify everything works
npm test
# Render a high-quality example
npm run render:example
# Try the NURBS examples
node src/renderer.js --rib examples/nurbs_center.rib --aa medium
node src/renderer.js --rib examples/nurbs_complex.rib --width 800 --height 600 --aa high
```
## Usage
### Basic Usage (Default Scene)
```bash
node src/renderer.js
```
### Render from RIB File
```bash
# Basic sphere scene
node src/renderer.js --rib examples/simple.rib
# NURBS surface examples
node src/renderer.js --rib examples/nurbs_center.rib
node src/renderer.js --rib examples/nurbs_simple.rib
```
### Custom Resolution and Quality
```bash
# Using manual sample count
node src/renderer.js --width 800 --height 600 --samples 4 --output my_render.ppm
# Using quality presets (recommended)
node src/renderer.js --width 800 --height 600 --aa high --output my_render.ppm
# With custom gamma correction
node src/renderer.js --aa medium --gamma 1.8 --output linear.ppm
# Multi-threaded high quality rendering
node src/renderer.js --width 800 --height 600 --aa high --threads 8
```
## Command Line Options
- `--rib `: Render from RIB file
- `--width `: Image width (default: 400)
- `--height `: Image height (default: 300)
- `--samples `: Samples per pixel for anti-aliasing (default: 1)
- `--aa `: Antialiasing quality preset: none, low, medium, high, ultra
- `--gamma `: Gamma correction value (default: 2.2)
- `--no-stratified`: Disable stratified sampling (use random sampling)
- `--single-threaded`: Disable multi-threading (use single thread)
- `--threads `: Number of threads to use (default: auto-detect)
- `--output `: Output filename (default: output.ppm)
- `--help`: Show help message
### Antialiasing Quality Levels
- `none`: No antialiasing (1 sample per pixel) - fastest
- `low`: Light antialiasing (4 samples per pixel) - good performance
- `medium`: Good quality (9 samples per pixel) - balanced quality/speed
- `high`: High quality (16 samples per pixel) - better quality
- `ultra`: Maximum quality (25 samples per pixel) - best quality
## RIB Format Support
The renderer supports a subset of RenderMan RIB commands:
### Supported Commands
- `WorldBegin` / `WorldEnd`
- `AttributeBegin` / `AttributeEnd`
- `TransformBegin` / `TransformEnd`
- `Translate x y z`
- `Rotate angle x y z`
- `Scale sx sy sz`
- `Color [r g b]`
- `Surface "material"`
- `Sphere radius zmin zmax thetamax`
- `Polygon` (converted to triangles)
- `NuPatch` (NURBS surfaces with full B-spline evaluation)
- `LightSource "type"`
### Supported Surface Materials
- `plastic`: Standard plastic material with moderate reflection
- `metal`: Highly reflective metallic material
- `matte`: Non-reflective diffuse material
### NURBS Surface Support
The renderer includes full support for Non-Uniform Rational B-Spline (NURBS) surfaces via the `NuPatch` command:
- **Complete B-spline evaluation** using Cox-de Boor recursion algorithm
- **Arbitrary degree surfaces** with custom knot vectors
- **Tessellation-based ray intersection** for reliable rendering
- **Multi-threaded NURBS rendering** with proper serialization
- **Standard RenderMan syntax** compatibility
Example NURBS syntax:
```rib
NuPatch 3 3 "0 0 0 1 1 1" 0 1 3 3 "0 0 0 1 1 1" 0 1 "P" [
-1.0 -1.0 -3.0 0.0 -1.0 -3.0 1.0 -1.0 -3.0
-1.0 0.0 -3.0 0.0 0.0 -3.0 1.0 0.0 -3.0
-1.0 1.0 -3.0 0.0 1.0 -3.0 1.0 1.0 -3.0
]
```
## Testing
The raytracer includes a comprehensive testing framework that validates output using deterministic seeding:
```bash
# Run all tests
npm test
# Generate reference images for tests
npm run test:references
# Clean test output files
npm run test:clean
# Compare two images manually
npm run image:diff image1.ppm image2.ppm
```
### Test Features
- **Bit-for-bit comparison** of rendered images with reference images
- **Multi-threading validation** ensures single and multi-threaded renders are identical
- **Deterministic seeding** for reproducible test results
- **Automatic reference generation** when references don't exist
- **Comprehensive reporting** with detailed failure analysis
## Architecture
The renderer is built with a modular architecture:
- **math.js**: Vector math, matrices, rays, and color utilities
- **geometry.js**: Geometric primitives and scene management
- **rib-parser.js**: RenderMan RIB file parser
- **raytracer.js**: Core raytracing engine and camera system
- **multi-threaded-raytracer.js**: Multi-threading implementation with worker threads
- **random.js**: Deterministic random number generator for reproducible results
- **image-output.js**: Image file generation (PPM format)
- **renderer.js**: Main application and command-line interface
## Example RIB File
```rib
##RenderMan RIB-Structure 1.1
version 3.03
Format 400 300 1
Projection "perspective" "fov" [45]
WorldBegin
LightSource "distantlight" 1 "from" [1 1 1] "to" [0 0 0]
AttributeBegin
Color [0.8 0.2 0.2]
Surface "plastic"
Sphere 0.5 -0.5 0.5 360
AttributeEnd
WorldEnd
```
## Performance Notes
- Rendering time increases significantly with resolution and sample count
- **Multi-Threading:**
- Multi-threaded rendering is enabled by default and automatically uses *all available CPU cores*
- Performance improvement scales with CPU core count (typically 2-8x faster)
- Use `--threads N` and `--seed` to seed the random number generation for debugging or comparison
- **Antialiasing Options:**
- `--aa none`: Fastest, aliased edges
- `--aa low`: 4x slower than none, removes most aliasing
- `--aa medium`: 9x slower, good quality for most scenes
- `--aa high`: 16x slower, high quality for final renders
- `--aa ultra`: 25x slower, maximum quality
- **Stratified vs Random Sampling:**
- Stratified sampling (default) provides better quality and more even noise distribution
- Random sampling (`--no-stratified`) may be faster but with more noise
### Performance Tips
- Use multi-threading for production renders (enabled by default)
- Start with `--aa medium` for quality/speed balance
- Use lower resolutions for testing and development
- Consider `--threads N` where N is slightly less than your CPU cores for better system responsiveness
## Viewing Output
PPM files can be viewed with most image viewers or converted to other formats:
```bash
# Convert to PNG using ImageMagick
convert output.ppm output.png
# View directly (on macOS)
open output.ppm
```