Open Shading Language 1.14 Documentation

Editor: Larry Gritz, OSL Chief Architect

Open Shading Language (OSL) is a small but rich language for programmable shading in advanced renderers and other applications, ideal for describing materials, lights, displacement, and pattern generation.

Quick Links: GitHub repository / Developer mail list / BSD License

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Contents

Introduction

• Copyright Notice

The OSL Language Specification

• 1. Introduction
  • 1.1. How OSL is different from other shading languages
  • 1.2. Acknowledgments
• 2. The Big Picture
  • 2.1. A shader is code that performs a discrete task
  • 2.2. Shader instances
  • 2.3. Shader groups, layers, and connections
  • 2.4. Geometric primitives
  • 2.5. Attribute state and shader assignments
  • 2.6. Shader execution state: parameter binding and global variables
  • 2.7. Surface and volume shaders compute closures
  • 2.8. Integrators
  • 2.9. Units
• 3. Lexical structure
  • 3.1. Characters
  • 3.2. Identifiers
  • 3.3. Comments
  • 3.4. Keywords and reserved words
  • 3.5. Preprocessor
• 4. Gross syntax, shader types, parameters
  • 4.1. Shader types
  • 4.2. Shader parameters
  • 4.3. Shader metadata
• 5. Data types
  • 5.1. int
  • 5.2. float
  • 5.3. color
  • 5.4. Point-like types: point, vector, normal
  • 5.5. matrix
  • 5.6. string
  • 5.7. void
  • 5.8. Arrays
  • 5.9. Structures
  • 5.10. Closures
• 6. Language Syntax
  • 6.1. Scoping
  • 6.2. Variable declarations and assignments
  • 6.3. Expressions
  • 6.4. Control flow: if, while, do, for
  • 6.5. Functions
  • 6.6. Global variables
• 7. Standard Library Functions
  • 7.1. Basic math functions
  • 7.2. Geometric functions
  • 7.3. Color functions
  • 7.4. Matrix functions
  • 7.5. Pattern generation
  • 7.6. Derivatives and area operators
  • 7.7. Displacement functions
  • 7.8. String functions
  • 7.9. Texture
  • 7.10. Material Closures
  • 7.11. Renderer state and message passing
  • 7.12. Dictionary Lookups
  • 7.13. Miscellaneous
• 8. Formal Language Grammar
  • 8.1. Lexical elements
  • 8.2. Overall structure
  • 8.3. Declarations
  • 8.4. Statements
  • 8.5. Expressions
• 9. Describing shader groups
• 10. Glossary