The OpenGL
R
Graphics System:
A Specification
(Version 3.3 (Compatibility Profile) - March 11,
2010)
Mark Segal
Kurt Akeley
Editor (version 1.1): Chris Frazier
Editor (versions 1.2-3.3): Jon Leech
Editor (version 2.0): Pat Brown
Copyright
c
2006-2010 The Khronos Group Inc. All Rights Reserved.
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Contents
1 Introduction 1
1.1 Formatting of the OpenGL Specification . . . . . . . . . . . . . . 1
1.1.1 Formatting of the Compatibility Profile . . . . . . . . . . 1
1.1.2 Formatting of Optional Features . . . . . . . . . . . . . . 1
1.1.3 Formatting of Changes . . . . . . . . . . . . . . . . . . . 1
1.2 What is the OpenGL Graphics System? . . . . . . . . . . . . . . 2
1.3 Programmer’s View of OpenGL . . . . . . . . . . . . . . . . . . 2
1.4 Implementor’s View of OpenGL . . . . . . . . . . . . . . . . . . 2
1.5 Our View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.6 The Deprecation Model . . . . . . . . . . . . . . . . . . . . . . . 3
1.7 Companion Documents . . . . . . . . . . . . . . . . . . . . . . . 3
1.7.1 OpenGL Shading Language . . . . . . . . . . . . . . . . 3
1.7.2 Window System Bindings . . . . . . . . . . . . . . . . . 4
2 OpenGL Operation 5
2.1 OpenGL Fundamentals . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.1 Floating-Point Computation . . . . . . . . . . . . . . . . 7
2.1.2 16-Bit Floating-Point Numbers . . . . . . . . . . . . . . 8
2.1.3 Unsigned 11-Bit Floating-Point Numbers . . . . . . . . . 9
2.1.4 Unsigned 10-Bit Floating-Point Numbers . . . . . . . . . 9
2.1.5 Fixed-Point Data Conversions . . . . . . . . . . . . . . . 10
2.2 GL State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2.1 Shared Object State . . . . . . . . . . . . . . . . . . . . . 13
2.3 GL Command Syntax . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4 Basic GL Operation . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.5 GL Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.6 Begin/End Paradigm . . . . . . . . . . . . . . . . . . . . . . . . 18
2.6.1 Begin and End . . . . . . . . . . . . . . . . . . . . . . . 22
2.6.2 Polygon Edges . . . . . . . . . . . . . . . . . . . . . . . 29
i
CONTENTS ii
2.6.3 GL Commands within Begin / End . . . . . . . . . . . . 29
2.7 Vertex Specification . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.8 Vertex Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.8.1 Packed Vertex Data Formats . . . . . . . . . . . . . . . . 43
2.8.2 Drawing Commands . . . . . . . . . . . . . . . . . . . . 44
2.9 Buffer Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.9.1 Creating and Binding Buffer Objects . . . . . . . . . . . 52
2.9.2 Creating Buffer Object Data Stores . . . . . . . . . . . . 54
2.9.3 Mapping and Unmapping Buffer Data . . . . . . . . . . . 56
2.9.4 Effects of Accessing Outside Buffer Bounds . . . . . . . 61
2.9.5 Copying Between Buffers . . . . . . . . . . . . . . . . . 61
2.9.6 Vertex Arrays in Buffer Objects . . . . . . . . . . . . . . 62
2.9.7 Array Indices in Buffer Objects . . . . . . . . . . . . . . 62
2.9.8 Buffer Object State . . . . . . . . . . . . . . . . . . . . . 63
2.10 Vertex Array Objects . . . . . . . . . . . . . . . . . . . . . . . . 63
2.11 Rectangles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
2.12 Fixed-Function Vertex Transformations . . . . . . . . . . . . . . 65
2.12.1 Matrices . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
2.12.2 Normal Transformation . . . . . . . . . . . . . . . . . . . 71
2.12.3 Generating Texture Coordinates . . . . . . . . . . . . . . 73
2.13 Fixed-Function Vertex Lighting and Coloring . . . . . . . . . . . 76
2.13.1 Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
2.13.2 Lighting Parameter Specification . . . . . . . . . . . . . . 81
2.13.3 ColorMaterial . . . . . . . . . . . . . . . . . . . . . . . 82
2.13.4 Lighting State . . . . . . . . . . . . . . . . . . . . . . . . 85
2.13.5 Color Index Lighting . . . . . . . . . . . . . . . . . . . . 85
2.13.6 Clamping or Masking . . . . . . . . . . . . . . . . . . . 86
2.14 Vertex Shaders . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
2.14.1 Shader Objects . . . . . . . . . . . . . . . . . . . . . . . 87
2.14.2 Program Objects . . . . . . . . . . . . . . . . . . . . . . 89
2.14.3 Vertex Attributes . . . . . . . . . . . . . . . . . . . . . . 91
2.14.4 Uniform Variables . . . . . . . . . . . . . . . . . . . . . 95
2.14.5 Samplers . . . . . . . . . . . . . . . . . . . . . . . . . . 111
2.14.6 Varying Variables . . . . . . . . . . . . . . . . . . . . . . 112
2.14.7 Shader Execution . . . . . . . . . . . . . . . . . . . . . . 115
2.14.8 Required State . . . . . . . . . . . . . . . . . . . . . . . 122
2.15 Geometry Shaders . . . . . . . . . . . . . . . . . . . . . . . . . . 123
2.15.1 Geometry Shader Input Primitives . . . . . . . . . . . . . 124
2.15.2 Geometry Shader Output Primitives . . . . . . . . . . . . 125
2.15.3 Geometry Shader Variables . . . . . . . . . . . . . . . . . 126
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2.15.4 Geometry Shader Execution Environment . . . . . . . . . 126
2.16 Coordinate Transformations . . . . . . . . . . . . . . . . . . . . 131
2.16.1 Controlling the Viewport . . . . . . . . . . . . . . . . . . 132
2.17 Asynchronous Queries . . . . . . . . . . . . . . . . . . . . . . . 133
2.18 Conditional Rendering . . . . . . . . . . . . . . . . . . . . . . . 135
2.19 Transform Feedback . . . . . . . . . . . . . . . . . . . . . . . . 136
2.20 Primitive Queries . . . . . . . . . . . . . . . . . . . . . . . . . . 139
2.21 Flatshading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
2.22 Primitive Clipping . . . . . . . . . . . . . . . . . . . . . . . . . . 142
2.22.1 Color and Associated Data Clipping . . . . . . . . . . . . 144
2.23 Final Color Processing . . . . . . . . . . . . . . . . . . . . . . . 145
2.24 Current Raster Position . . . . . . . . . . . . . . . . . . . . . . . 146
3 Rasterization 150
3.1 Discarding Primitives Before Rasterization . . . . . . . . . . . . 152
3.2 Invariance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
3.3 Antialiasing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
3.3.1 Multisampling . . . . . . . . . . . . . . . . . . . . . . . 154
3.4 Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
3.4.1 Basic Point Rasterization . . . . . . . . . . . . . . . . . . 157
3.4.2 Point Rasterization State . . . . . . . . . . . . . . . . . . 161
3.4.3 Point Multisample Rasterization . . . . . . . . . . . . . . 161
3.5 Line Segments . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
3.5.1 Basic Line Segment Rasterization . . . . . . . . . . . . . 162
3.5.2 Other Line Segment Features . . . . . . . . . . . . . . . . 165
3.5.3 Line Rasterization State . . . . . . . . . . . . . . . . . . 168
3.5.4 Line Multisample Rasterization . . . . . . . . . . . . . . 168
3.6 Polygons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
3.6.1 Basic Polygon Rasterization . . . . . . . . . . . . . . . . 169
3.6.2 Stippling . . . . . . . . . . . . . . . . . . . . . . . . . . 171
3.6.3 Antialiasing . . . . . . . . . . . . . . . . . . . . . . . . . 172
3.6.4 Options Controlling Polygon Rasterization . . . . . . . . 172
3.6.5 Depth Offset . . . . . . . . . . . . . . . . . . . . . . . . 173
3.6.6 Polygon Multisample Rasterization . . . . . . . . . . . . 174
3.6.7 Polygon Rasterization State . . . . . . . . . . . . . . . . 175
3.7 Pixel Rectangles . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
3.7.1 Pixel Storage Modes and Pixel Buffer Objects . . . . . . . 176
3.7.2 The Imaging Subset . . . . . . . . . . . . . . . . . . . . 177
3.7.3 Pixel Transfer Modes . . . . . . . . . . . . . . . . . . . . 178
3.7.4 Transfer of Pixel Rectangles . . . . . . . . . . . . . . . . 189
OpenGL 3.3 (Compatibility Profile) - March 11, 2010
