openRender

openRender is a photorealistic renderer that uses a Pixar's RenderMan-like interface. Originally based on Pixie by Okan Arikan, this project continues to evolve as an open-source rendering solution.

Table of Contents

• About
• Features
• Installation
• Dependencies
• Building
• Usage
• Project Structure
• Contributing
• License
• Authors

About

openRender is a sophisticated photorealistic renderer that implements a RenderMan-compliant interface. It is designed to be compatible with RenderMan Interface Bytestream (RIB) files and supports a wide range of rendering techniques including ray tracing, Reyes-style rendering, and advanced shading.

Features

• RenderMan-compliant interface supporting RIB files
• Advanced shading language support
• Multiple rendering backends (Reyes, ray tracing)
• Support for various image formats (TIFF, PNG, Radiance RGBE)
• Multi-threaded rendering
• Network rendering capabilities
• Procedural geometry support
• Extensive texture mapping options
• OpenEXR support for high dynamic range output

Installation

Prerequisites

• C++20 compliant compiler (GCC 10+, Clang 10+, or MSVC 2019+)
• CMake 3.15 or higher
• Git

Dependencies

• libtiff: Image format support (http://www.libtiff.org)
• flex/bison: Parser generation (available on Unix platforms by default)
• fltk: GUI support for the interactive viewer (http://www.fltk.org)
• OpenEXR: High dynamic range image support (http://www.openexr.com)

Building

Unix/Linux/macOS

# Clone the repository
git clone https://github.com/juvenal/openrender.git
cd openrender

# Create build directory
mkdir build && cd build

# Configure with CMake
cmake .. -DCMAKE_BUILD_TYPE=Release

# Compile (using multiple cores)
make -j$(nproc || sysctl -n hw.ncpu)

# Optionally install
sudo make install

Windows

Using Visual Studio or similar IDE:

1. Open CMake GUI or use command line
2. Set source directory to openrender root
3. Set build directory (e.g., openrender/build)
4. Click "Configure" and select your generator (Visual Studio, Ninja, etc.)
5. Click "Generate"
6. Build using your IDE or run cmake --build . --config Release

Alternatively, using command line:

mkdir build
cd build
cmake .. -G "Visual Studio 16 2019" -A x64
cmake --build . --config Release

CMake Options

• USE_FLEX_BISON: Use flex and bison to regenerate parsers (default: ON)
• BUILD_SHOW: Build the show program (default: ON)
• INSTALL_SELFCONTAINED: Build for a self-contained setup (default: ON)

Usage

Basic Rendering

# Render a RIB file
./build/src/orender scene.rib

# Render with multiple threads
./build/src/orender -t:4 scene.rib

# Render specific frame range
./build/src/orender -f 1:10 scene.rib

Network Rendering

# Start a render server
./build/src/orender -r

# Render on network servers
./build/src/orender -s server1:port1,server2:port2 scene.rib

Project Structure

├── CMake/                 # CMake modules
├── doc/                  # Documentation
├── docs/                 # Additional documentation
├── examples/             # Example scenes
├── geometry/             # Geometry examples
├── man/                  # Manual pages
├── shaders/              # Default shaders
├── specs/                # Specification documents
├── src/                  # Source code
│   ├── common/           # Common utilities
│   ├── dsotest/          # DSO test utilities
│   ├── file/             # File I/O operations
│   ├── framebuffer/      # Framebuffer implementations
│   ├── gui/              # GUI components
│   ├── openexr/          # OpenEXR support
│   ├── orender/          # Main renderer executable
│   ├── oshader/          # Shader compiler
│   ├── oshow/            # Interactive viewer
│   ├── otexmake/         # Texture processing tools
│   ├── precomp/          # Precomputation tools
│   ├── rgbe/             # Radiance RGBE support
│   ├── ri/               # RenderMan interface implementation
│   ├── sdr/              # Shader runtime
│   ├── sdrinfo/          # Shader info utility
│   └── ...
├── tests/                # Unit tests
├── textures/             # Sample textures
├── CMakeLists.txt        # Main CMake build file
├── COMPILING.txt         # Compilation instructions
├── README.md             # This file
├── COPYING               # License information
└── ...

Contributing

We welcome contributions to openRender! Please feel free to submit pull requests, create issues for bugs and feature requests, or contribute to documentation.

Development Guidelines

• Follow C++20 standards
• Maintain compatibility with existing RIB files
• Write unit tests for new functionality
• Update documentation as needed

License

openRender is licensed under the GNU Lesser General Public License v2.1 (LGPL-2.1). See the COPYING file for details.

Authors

Current Maintainer

• Juvenal A. Silva Jr. [email protected]

Original Creator

• Okan Arikan - Original Pixie renderer

Historical Contributors

The original Pixie project contributors include:

• Okan Arikan (Head developer)
• George Harker
• Gary Oliver & Kirk Bailey
• Bruce Walter
• Moritz Moeller
• Jordan Smith
• Mayur Patel
• Ashton Edwin-Kent
• Eliot Mack
• Raphael Sebbe

For a complete list of contributors, see the AUTHORS file.

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openRender continues the legacy of the original Pixie renderer, extending its capabilities while maintaining compatibility with the RenderMan interface.