The OpenGL® Shading Language Language Version: 4.50 Document Revision: 7 09-May-2017 Editor: John Kessenich, Google Version 1.1 Authors: John Kessenich, Dave Baldwin, Randi Rost Copyright (c) 2008-2017 The Khronos Group Inc. All Rights Reserved. This specification is protected by copyright laws and contains material proprietary to the Khronos Group, Inc. It or any components may not be reproduced, republished, distributed, transmitted, displayed, broadcast, or otherwise exploited in any manner without the express prior written permission of Khronos Group. You may use this specification for implementing the functionality therein, without altering or removing any trademark, copyright or other notice from the specification, but the receipt or possession of this specification does not convey any rights to reproduce, disclose, or distribute its contents, or to manufacture, use, or sell anything that it may describe, in whole or in part. 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All other product names, trademarks, and/or company names are used solely for identification and belong to their respective owners. ii Table of Contents 1 Introduction.................................................................................................................................1 1.1 Acknowledgments................................................................................................................2 1.2 Changes................................................................................................................................3 1.2.1 Changes from Revision 6 of GLSL Version 4.50.........................................................3 1.2.2 Changes from Revision 5 of GLSL Version 4.50.........................................................4 1.2.3 Changes from Revision 3 of GLSL Version 4.50.........................................................4 1.2.4 Summary of Changes from Revision 9 of GLSL Version 4.40....................................5 1.3 Overview..............................................................................................................................6 1.4 Error Handling......................................................................................................................6 1.5 Typographical Conventions..................................................................................................7 1.6 Deprecation..........................................................................................................................7 2 Overview of OpenGL Shading....................................................................................................8 2.1 Vertex Processor...................................................................................................................8 2.2 Tessellation Control Processor.............................................................................................8 2.3 Tessellation Evaluation Processor........................................................................................9 2.4 Geometry Processor.............................................................................................................9 2.5 Fragment Processor..............................................................................................................9 2.6 Compute Processor...............................................................................................................9 3 Basics........................................................................................................................................11 3.1 Character Set and Phases of Compilation..........................................................................11 3.2 Source Strings....................................................................................................................12 3.3 Preprocessor.......................................................................................................................12 3.4 Comments..........................................................................................................................18 3.5 Tokens................................................................................................................................19 3.6 Keywords............................................................................................................................19 3.7 Identifiers...........................................................................................................................21 3.8 Definitions..........................................................................................................................21 3.8.1 Static Use....................................................................................................................22 3.8.2 Dynamically Uniform Expressions and Uniform Control Flow.................................22 4 Variables and Types...................................................................................................................24 4.1 Basic Types.........................................................................................................................24 4.1.1 Void.............................................................................................................................28 4.1.2 Booleans.....................................................................................................................28 4.1.3 Integers.......................................................................................................................28 4.1.4 Floating-Point Variables.............................................................................................30 4.1.5 Vectors........................................................................................................................31 4.1.6 Matrices......................................................................................................................31 4.1.7 Opaque Types.............................................................................................................32 iii 4.1.7.1 Samplers.............................................................................................................32 4.1.7.2 Images.................................................................................................................32 4.1.7.3 Atomic Counters.................................................................................................33 4.1.8 Structures....................................................................................................................33 4.1.9 Arrays..........................................................................................................................34 4.1.10 Implicit Conversions................................................................................................38 4.1.11 Initializers.................................................................................................................39 4.2 Scoping...............................................................................................................................41 4.3 Storage Qualifiers...............................................................................................................44 4.3.1 Default Storage Qualifier............................................................................................45 4.3.2 Constant Qualifier......................................................................................................45