Difference between revisions of "Getting Started"

From OpenGL Wiki
Jump to navigation Jump to search
m
 
(172 intermediate revisions by 44 users not shown)
Line 1: Line 1:
So you want to take advantage of the power of the OpenGL API? If you are visiting this page because a game or software implements the OpenGL API, you need to install the appropriate graphic driver which enables usage of the functionality provided.
+
So you want to take advantage of the power of the OpenGL API? If you are visiting this page because a game or software uses the OpenGL API, you need to install the appropriate graphic driver which enables usage of the functionality provided.
  
 
To program using the OpenGL API, you need the driver and the development package (depends on platform and programming language). More platform-specific details are described in the sections below.
 
To program using the OpenGL API, you need the driver and the development package (depends on platform and programming language). More platform-specific details are described in the sections below.
  
__TOC__
+
== FAQ ==
 +
{{main|FAQ}}
 +
 +
This Wiki maintains a FAQ page for OpenGL.
  
== Windows ==
+
== Downloading OpenGL ==
  
If you are running Windows 98/Me/NT/2000/XP/2003, the OpenGL library has already been installed on your system.
+
In all three major desktop platforms (Linux, macOS, and Windows), OpenGL more or less comes with the system. However, you ''will'' need to ensure that you have downloaded and installed a recent driver for your graphics hardware.
Win95A did not come with GL, so Microsoft has made this available at: [ftp://ftp.microsoft.com/softlib/mslfiles/opengl95.exe Windows OpenGL library].
 
  
Remember that GL is a system component on Windows. DO NOT modify or copy opengl32.dll from one OS to another.
+
=== Windows ===
The filename is <code>opengl32.dll</code> and is either in <code>WINDOWS\SYSTEM</code>, <code>WINNT\SYSTEM32</code> or <code>WINDOWS\SYSTEM32</code>. This also means that you do not have to ship a copy of the library with your application since it will already be available on the system.
 
  
The standard Windows <code>OpenGL32.dll</code> library alone will not provide you with hardware acceleration for OpenGL. In order to get hardware acceleration, you will need to install the latest drivers for your graphics card:
+
Appropriate Windows driver websites:
* [http://www.3dlabs.com 3Dlabs]
+
 
* [http://www.ati.com ATI]
+
* [http://support.amd.com/en-us/download AMD/ATI]
* [http://www.intel.com Intel]
+
* [https://downloadcenter.intel.com/ Intel]
* [http://www.nvidia.com NVidia]
+
* [http://www.nvidia.com/Download/index.aspx NVidia]
  
 
Some sites also distribute beta versions of graphics drivers, which may give you access to bug fixes or new functionality before an official driver release from the manufacturer:
 
Some sites also distribute beta versions of graphics drivers, which may give you access to bug fixes or new functionality before an official driver release from the manufacturer:
* [http://www.3dchipset.com 3DChipset]
 
 
* [http://www.guru3d.com Guru3D]
 
* [http://www.guru3d.com Guru3D]
  
GLU is also included in the system folder as <code>glu32.dll</code>
+
Without drivers, you will default to a software version of OpenGL 1.1 (on Win98, ME, and 2000), a Direct3D wrapper that supports OpenGL 1.1 (WinXP), or a Direct3D wrapper that supports OpenGL 1.1 (Windows Vista and Windows 7). None of these options are particularly fast, so installing drivers is always a good idea.
This is also a system component. Updated DLL should be placed in your program's folder. You can get a GLU's source code from [http://www.mesa3d.org MESA3D]. You can get precompiled lib from [http://www.geocities.com/vmelkon/glu.html vmelkon's GLU]; The current version is 1.3.
 
 
 
Other libraries like GLUT, freeGLUT, QT, etc are not part of the OS. These should be downloaded from the net. [http://www.opengl.org/resources/libraries/ GLUT and OpenGL Utility Libraries]
 
 
 
Windows 95, 98, Me, 2000 support OpenGL version 1.1 as a software rasterizer implemented in <code>opengl32.dll</code>. There is no support for hardware acceleration therefore installing drivers is necessary. Windows XP supports OpenGL version 1.1 as a Direct3D wrapper in <code>opengl32.dll</code>. Since performance will be lousy, installing drivers is a good idea. On Windows 2003, you aren't suppose to use it as a desktop machine, but it is similar to Win 2000. Windows Vista will support OpenGL version 1.4 as a Direct3D wrapper. ''Always'' install drivers.
 
 
 
=== 64 bits Windows versions ===
 
If you are running the 64 bit version of Windows Vista or perhaps you are running Windows XP x64, you might be wondering if there is a <code>OpenGL64.dll</code> file. The answer is no, there isn't. On both of these Operating Systems, <code>Windows\System32</code> contains all the 64 bit DLLs. It contains the <code>OpenGL32.dll</code> which is actually a 64 bit dll.
 
  
For 32 bit programs, Windows detects the exe as a 32 bit program and instead of using System32 files, it uses Windows\SysWOW64 which actually contains the 32 bit DLLs. WOW means '''W'''indows '''O'''n '''W'''indows which is a backwards-compatibility layer.
+
If your system does not contain a GPU, or the GPU vendor delivers graphics drivers providing OpenGL support that's so old as to be useless to you, you might want to consider installing the Mesa3D OpenGL library on your system. See this wiki link for details:
  
To find your Windows' System32 directory, go to: Start, Run... and type in <code>%WINDIR%\System32</code>. The system will redirect you to the default System32 directory automatically; this is also true for the 32 bits versions of Windows.
+
* [[Platform specifics: Windows#Installing Mesa3D on Windows|Installing Mesa3D on Windows]]
  
== Linux ==
+
=== Linux ===
  
Graphics on Linux is almost exclusively implemented using the X windows system. Supporting OpenGL on Linux involves using GLX extensions to the X Server. There is a standard Application Binary Interface defined for OpenGL on Linux that gives application compatability for OpenGL for a range of drivers. In addition the Direct Rendering Infrastucture (DRI) is a driver framework that allows drivers to be written and interoperate within a standard framework to easily support hardware acceleration, the DRI is included in of XFree86 4.0 but may need a card specific driver to be configured after installation.
+
Graphics on Linux is almost exclusively implemented using the X Window system. Supporting OpenGL on Linux involves using GLX extensions to the X Server. There is a standard Application Binary Interface defined for OpenGL on Linux that gives application compatibility for OpenGL for a range of drivers. In addition the Direct Rendering Infrastructure (DRI) is a driver framework that allows drivers to be written and interoperate within a standard framework to easily support hardware acceleration, the DRI is included in of XFree86 4.0 but may need a card specific driver to be configured after installation.
These days, XFree86 has been rejected in favor of XOrg due to the change in the license of XFree86, so many developers left Xfree86 and joined the XOrg group. Popular Linux distros come with XOrg now. Developers
+
These days, XFree86 has been rejected in favor of XOrg due to the change in the license of XFree86, so many developers left Xfree86 and joined the XOrg group. Popular Linux distros come with XOrg now.
  
 
Vendors have different approaches to drivers on Linux, some support Open Source efforts using the DRI, and others support closed source frameworks but all methods support the standard ABI that will allow correctly written OpenGL applications to run on Linux.
 
Vendors have different approaches to drivers on Linux, some support Open Source efforts using the DRI, and others support closed source frameworks but all methods support the standard ABI that will allow correctly written OpenGL applications to run on Linux.
  
 +
* [http://support.amd.com/en-us/download/linux AMD/ATI]
 +
* [https://01.org/linuxgraphics Intel]
 
* [http://www.nvidia.com/object/unix.html Nvidia]
 
* [http://www.nvidia.com/object/unix.html Nvidia]
 
* [http://www.faqs.org/docs/Linux-mini/Nvidia-OpenGL-Configuration.html Nvidia HOWTO (old)]
 
* [http://www.faqs.org/docs/Linux-mini/Nvidia-OpenGL-Configuration.html Nvidia HOWTO (old)]
* [https://support.ati.com/ics/support/KBAnswer.asp?questionID=3380 ATI]
 
  
 
For more information on developing OpenGL applications on Linux, see [[Platform specifics: Linux]]
 
For more information on developing OpenGL applications on Linux, see [[Platform specifics: Linux]]
  
Linux comes with Mesa libraries, which implements the OpenGL API as a software rasterizer. Most Linux distros don't come with hardware acceleration. Some Linux distributions may include support for hardware acceleration. Also, some GPUs have Open Source drivers developed by the community even though a close source driver may be available from the manufacturer.
+
=== macOS ===
 +
 
 +
Unlike other platforms, where the Operating System and OpenGL implementations are often updated separately, OpenGL updates are included as part of macOS system updates. To obtain the latest OpenGL on macOS, users should upgrade to the latest OS release, which can be found at [https://www.apple.com/macos/ Apple.com].
 +
 
 +
For developers, a default installation of macOS does not include any OpenGL headers, nor does it include other necessary development tools. These are installed by a separate developer tools package called Xcode. This installer includes the OpenGL headers, compilers (gcc), debuggers (gdb), Apple's Xcode IDE, and a number of performance tools useful for OpenGL application development.
 +
 
 +
* [http://developer.apple.com/library/mac/#documentation/GraphicsImaging/Conceptual/OpenGL-MacProgGuide/opengl_intro/opengl_intro.html OpenGL Information]
 +
* [http://developer.apple.com/technology/xcode.html Download Xcode]
 +
 
 +
For more information on developing OpenGL applications on macOS, see [[Platform specifics: macOS]].
 +
 
 +
== Writing an OpenGL Application ==
 +
 
 +
The first step is to pick your language. Bindings for OpenGL exist in many languages, from C# and Java to Python and Lua. Some languages have multiple sets of OpenGL bindings, none of them being official. All of them are ultimately based on the C/C++ bindings.
  
== Mac OS X ==
+
If you are not using C/C++, you must download and install a package or library for your chosen language that includes the OpenGL bindings. Some come pre-installed, but others have separate downloads.
Every version of Mac OS X has shipped with OpenGL runtime libraries pre-installed. Users who want to run OpenGL applications do not need to install or configure anything.
 
  
Unlike other platforms, where the Operating System and OpenGL implementations are often updated separately, OpenGL updates are usually included as part of Mac OS X system updates. To obtain the latest OpenGL on Mac OS X, users should upgrade to the latest OS release, which can be found at: [http://www.apple.com/macosx/upgrade/softwareupdates.html].
+
If you are using C/C++, then you must first set up a build environment (Visual Studio project, GNU makefile, CMake file, etc) that can link to OpenGL. Under Windows, you need to statically link to a library called OpenGL32.lib (note that you still link to OpenGL32.lib if you're building a 64-bit executable. The "32" part is meaningless). Visual Studio, and most Windows compilers, come with this library.
  
For developers, a default installation of Mac OS X does not include any OpenGL headers, nor does it include other necessary development tools.  These are installed by a separate developer tools package [http://developer.apple.com/tools/download/].  This installer includes the OpenGL headers, compilers (gcc), debuggers (gdb), Apple's Xcode IDE, and a number of performance tools useful for OpenGL application development.
+
On Linux, you need to link to libGL. This is done with a command-line parameter of "-lGL".
  
For more information on developing OpenGL applications on Mac OS X, see [[Platform specifics: Mac OS X]].
+
=== Initialization ===
  
== OpenGL 2.0 and extensions ==
+
Before you can actually use OpenGL in a program, you must first initialize it. Because OpenGL is platform-independent, there is not a standard way to initialize OpenGL; each platform handles it differently. Non-C/C++ language bindings can also handle these differently.
If you will be programming for Windows, typically compilers comes with a standard OpenGL 1.1 <code>.h</code> and <code>.lib</code>.
 
For Linux and others, you might want to borrow the same idea (getting function pointers for the GL functions)
 
To access higher OpenGL functions, you would have to get the function pointers.
 
For example, in C or C++, this is what you would do
 
  
Download <code>glext.h</code> and <code>wglext.h</code> from [http://www.opengl.org/registry/ The Extensions Registry]
+
There are two phases of OpenGL initialization. The first phase is the creation of an [[OpenGL Context]]; the second phase is to load all of the necessary functions to use OpenGL. Some non-C/C++ language bindings merge these into one.
  
Put it in your compiler's GL folder.
+
==== OpenGL Context Creation ====
  
<pre>
+
An OpenGL context represents all of OpenGL. Creating one is very platform-specific, as well as language-binding specific.
include <GL/gl.h>
 
include <GL/glext.h>
 
include <GL/wglext.h>
 
  
extern PFNGLACTIVETEXTUREPROC glActiveTexture;  //Put this in a .h so that you can include the header in all your other .cpp
+
If you are using the C/C++ language binding for OpenGL, then you are strongly advised to use a [[Related_toolkits_and_APIs#Context/Window_Toolkits|window toolkit]] for managing this task. These libraries create a window, attach an OpenGL context to this window, and manage basic input for that window. Once you are comfortable with OpenGL, you can then start learning how to [[Creating an OpenGL Context|do this manually]].
PFNGLACTIVETEXTUREPROC glActiveTexture;    //Declare your function pointer in a .cpp file
 
</pre>
 
  
Once you create a GL context, you can use wglGetProcAddress to get a pointer to the function.
+
Most non-C/C++ language bindings will provide you with a language-specific mechanism for creating a context.
  
glActiveTexture = (PFNGLACTIVETEXTUREPROC) wglGetProcAddress("glActiveTexture");
+
==== Getting Functions ====
  
This would be tedious if you had to do this for all the functions and it's is even more work if you want to detect a certain OpenGL API version, then load all the core functions. Then, detect if a certain extension is present, then load all the functions.
+
If you are using a non-C/C++ language binding, then the maintainer of that binding will already handle this as part of context creation. If you are using C/C++, read on.
  
There exists a few libraries out there that will get the function pointers for you. All you have to do is create an OpenGL rendering context and call the library's init function. The recent version of GLee doesn't require a call to its init function.
+
In order to use OpenGL, you must get OpenGL API functions. For most libraries you are familiar with, you simply #include a header file, make sure a library is linked into your project or makefile, and it all works. OpenGL doesn't work that way.
  
Examples are :
+
For reasons that are ultimately irrelevant to this discussion, you must manually load functions via a platform-specific API call. This boilerplate work is done with various [[OpenGL Loading Library|OpenGL loading libraries]]; these make this process smooth. You are ''strongly'' advised to use one.
*[http://glew.sourceforge.net GLEW - The GL Extension Wrangler Library]
 
*[http://elf-stone.com/glee.php GLEE - GL Easy Extension library]
 
  
== How to make your first OpenGL Program ==
+
If you want to do it manually however, there is a [[Load OpenGL Functions|guide as to how to load functions manually]]. You still should use an extension loader.
The first thing to do is chose a programming language. It could be C++, C++ Managed, Visual Basic, Visual Basic .NET, Pascal, Java, Ada, x86 assembly, etc.
 
  
The second thing is to chose a compiler. It could be MS Visual C++, DevC++, Delphi, Masm, etc. Remember that OpenGL is an API, so as long as you have the language bindings for your compiler, you can do OpenGL programming.
+
== Using OpenGL ==
  
Typically, a compiler comes with the binding files. For example, if you have a C++ compiler, it will come with <code>gl.h</code> and <code>opengl32.lib</code>. It may even come with <code>glu.h</code> and <code>glu32.lib</code>, <code>glut.h</code> and <code>glut32.lib</code>.
+
OpenGL is a rendering library. What OpenGL does not do is retain information about an "object". All OpenGL sees is a ball of triangles and a bag of state with which to render them. It does not remember that you drew a line in one location and a sphere in another.
  
If you don't have your binding files, you will need to figure out where to download them from. Microsoft releases their Windows Platform SDK which contains these files and most likely you don't need it because your compiler came with the files.
+
Because of that, the general way to use OpenGL is to draw everything you need to draw, then show this image with a platform-dependent buffer swapping command. If you need to update the image, you draw everything again, even if you only need to update part of the image. If you want to animate objects moving on the screen, you need a loop that constantly clears and redraws the screen.
  
You might want to use SDL, GLUT, freeGLUT, or some other wrapper that takes care of creating a GL window for you and destroying for you. It makes it easier for someone who just wants to learn the OpenGL API syntax.
+
There are techniques for only updating a portion of the screen. And you can use OpenGL with these techniques. But OpenGL itself doesn't do it internally; ''you'' must remember where you drew everything. You must figure out what needs updating and clear only that part of the screen. And so forth
  
Assuming you know how to program in your language of choice, now all you need is to learn OpenGL. There are many online tutorials. Just search for <code>opengl+tutorial</code> in your favorite search engine.
+
There are many [[#Tutorials_and_How_To_Guides|tutorials and other materials]] available for learning how to use OpenGL, both on this wiki and online.
  
 
== OpenGL Viewers==
 
== OpenGL Viewers==
 
These are programs that you install and run, and they give you information specific to the OpenGL API your system implements, like the version offered by your system, the vendor, the renderer, the extension list, supported viewport size, line size, point size, plus many other details. Some might include a benchmark. Some are standalone benchmarks.
 
These are programs that you install and run, and they give you information specific to the OpenGL API your system implements, like the version offered by your system, the vendor, the renderer, the extension list, supported viewport size, line size, point size, plus many other details. Some might include a benchmark. Some are standalone benchmarks.
  
* [http://www.delphi3d.net/hardware/index.php Download GLInfo2 (Windows)]
+
* [http://www.ozone3d.net/gpu_caps_viewer/ GPU Caps Viewer (Windows XP, Vista 32)]
* [http://www.realtech-vr.com/glview/index.html OpenGL Extension Viewer (Windows, Windows x64 and MacOS X)]
+
* [http://realtech-vr.com/admin/glview OpenGL Extension Viewer (Windows, Windows x64 and macOS)]: This one comes with a database containing information about what extensions are implemented by hardware other than your own
* [http://www.glbenchmark.com/index.jsp OpenGL ES benchmark tool (Linux, Symbian, Windows Mobile)]
+
* [http://www.saschawillems.de/?page_id=771 OpenGL hardware capability viewer (Windows, Linux, macOS)]
* [http://www.devbump.com/story.php?title=Fur_Rendering_Benchmark_-_A_Small_and_Handy_OpenGL_Utility Fur rendering benchmark (Windows)]
+
* [http://www.ozone3d.net/benchmarks/fur/ FurMark benchmarking application (Windows)]
* [http://www.futuremark.com/download/ Futuremark's GL ES benchmark]
+
 
 +
== Tutorials and How To Guides ==
 +
User contributed tutorials and getting started guides
 +
 
 +
* OpenGL 3.0 and above:
 +
** [https://nicolbolas.github.io/oldtut/index.html Learning Modern 3D Graphics Programming Through OpenGL]
 +
** [http://ogldev.atspace.co.uk/ OpenGL Step by Step] (using C++, FreeGLUT and GLEW)
 +
** [http://openglbook.com/ OpenGLBook.com] Free online OpenGL 4.0 book (OpenGL 3.3 code provided wherever possible) using freeglut and GLEW
 +
** [http://www.spieleprogrammierung.net/ Spiele Programmierung Windows OpenGL 3 Tutorials And Articles], Beginner to Advanced in German
 +
** [http://www.swiftless.com/opengltuts/opengl4tuts.html Swiftless OpenGL 4 Tutorials]
 +
** [http://www.opengl-tutorial.org opengl-tutorial.org] OpenGL 3.3 and later Tutorials
 +
*** [http://www.opengl-tutorial.org/beginners-tutorials/ Basics]
 +
*** [http://www.opengl-tutorial.org/intermediate-tutorials/ Intermediate]
 +
** [http://tomdalling.com/blog/category/modern-opengl/ Modern OpenGL Tom Dalling]
 +
** [http://www.learnopengl.com www.learnopengl.com]: Easy-to-understand modern OpenGL tutorials aimed at beginners
 +
** [https://www.youtube.com/watch?v=W3gAzLwfIP0&index=1&list=PLlrATfBNZ98foTJPJ_Ev03o2oq3-GGOS2 TheChernoProject (Youtube)]: High Quality video series for learning modern OpenGL
 +
** [https://open.gl/introduction Open.gl/introduction]: Learn OpenGL basics
 +
** [https://www.codeproject.com/Tips/1231444/GPGPU-D-Fourier-Transform GPGPU-D-Fourier-Transform]: Introduction to compute shader via 1D Fourier Transform
 +
** [https://bitbucket.org/asif_bahrainwala/opengl_notepad/src/master/ A simple text editor using OpenGL]: Showcasing use of vertex & Fragment shader to render text
 +
** A simple walk through using GLFW: https://bitbucket.org/asif_bahrainwala/walkthrough/src/main/
 +
 
 +
* Pre-OpenGL 3.0:
 +
** [http://www.glprogramming.com/red/ The OpenGL Programming Guide, also called the Red Book] Covers OpenGL version 1.1.
 +
** [http://duriansoftware.com/joe/An-intro-to-modern-OpenGL.-Chapter-1:-The-Graphics-Pipeline.html DurianSoftware.com], Intro to Modern OpenGL ([http://www.fevrierdorian.com/blog/post/2010/10/04/Une-introduction-à-l-OpenGL-Moderne-Chapitre-1%3A-Le-Pipeline-Graphique en français])
 +
** [http://www.xmission.com/~nate/opengl.html GLUT], Tutorials
 +
** [http://www.MarekKnows.com MarekKnows.com], Game development video tutorials, OpenGL, shaders, physics, math, C++, 3D modeling, network, audio etc
 +
** [http://nehe.gamedev.net NeHe], OpenGL Tutorials
 +
** [http://www.songho.ca/opengl/index.html SongHo OpenGL tutorials]
 +
** Swiftless Tutorials [http://www.swiftless.com/opengltuts.html OpenGL 1 & 2],
 +
** [http://lazyfoo.net/tutorials/OpenGL/index.php Lazy Foo's OpenGL Tutorial], Covers OpenGL 2D in both OpenGL 2.1 and modern OpenGL
 +
* [[Code Resources]]: These are small snippets of code from the web that have been useful in the past. Most of them use deprecated functionality.
 +
 
 +
By Topic
 +
* Shadow Mapping
 +
** [http://www.opengl-tutorial.org/intermediate-tutorials/tutorial-16-shadow-mapping/ opengl-tutorial.org, Tutorial 16 : Shadow mapping] PCF, shadow-acne/peter-panning, stratisfied sampling. GL3.3.
 +
** [http://www.paulsprojects.net/tutorials/smt/smt.html paulsprojects.net] GL1.5.
 +
** [http://fabiensanglard.net/shadowmapping/index.php ShadowMapping with GLSL] shadow-acne, resolution, backfaces, border-issues. GL2+
 +
 
 +
== Development Tools ==
 +
* [https://renderdoc.org/ RenderDoc] - free, stand-alone graphics debugger. Supports only the OpenGL 3.2+ Core Profile. Works on both Windows and Linux.
 +
* [https://developer.nvidia.com/nvidia-nsight-visual-studio-edition Nsight Visual Studio Edition] - Nsight 3.0 support OpenGL 4.2 Debugging and Profiling, along with Shader Debugging and Pixel History
 +
* [http://deleaker.com/ Deleaker] - Deleaker for Visual Studio finds OpenGL leaks
 +
 
 +
== See Also ==
 +
 
 +
* [[OpenGL Reference]]: All of the OpenGL {{current version}} functions and what they do.
 +
* [[Related toolkits and APIs]]: For utilities that make using OpenGL easier.
 +
* [[Language bindings]]
  
 
== External Links ==
 
== External Links ==
* '''Tutorials'''
+
 
** [http://nehe.gamedev.net NeHe], OpenGL Tutorials
+
* '''Reference Documentation'''
** [http://www.xmission.com/~nate/opengl.html GLUT], Tutorials
+
** [https://www.khronos.org/registry/OpenGL/index_gl.php The Khronos OpenGL Registry]
** [http://www.delphi3d.net Delphi3D.net], Delphi programming and OpenGL
 
 
* '''Implementations'''
 
* '''Implementations'''
 
** [http://www.mesa3d.org The Mesa 3D Graphics Library], a software renderer based on the OpenGL API.
 
** [http://www.mesa3d.org The Mesa 3D Graphics Library], a software renderer based on the OpenGL API.
 
* '''Engines'''
 
* '''Engines'''
 
** [http://www.ogre3d.org Ogre 3D engine]
 
** [http://www.ogre3d.org Ogre 3D engine]
** [http://www.geocities.com/SiliconValley/Bay/6525 3DS loader, keyframes]
+
** [http://visualizationlibrary.org Visualization Library]
 
* '''Demos'''
 
* '''Demos'''
 
** [http://www.sulaco.co.za/ Delphi OpenGL Demos]
 
** [http://www.sulaco.co.za/ Delphi OpenGL Demos]
** [http://www.humus.ca/ Humus.ca] many demos, advanced
+
** [http://www.g-truc.net G-Truc Creation]: [http://www.g-truc.net/project-0026.html OpenGL 2.1 - 4.1 Code samples]
** [http://www.flipcode.com Flipcode] many demos
+
** [http://www.humus.name/ Humus.name] many demos, advanced
** [http://local.wasp.uwa.edu.au/~pbourke/ Paul Bourke] many demos and explanations, advanced
+
* '''Vendor SDKs'''
* '''Theory and General Graphics Programming'''
+
** [http://www.opengl.org/sdk/ OpenGL SDK projects and OpenGL man pages]
** [http://www.magic-software.com Magic Software] algorithms, intersection test
+
** [http://developer.nvidia.com nVidia's SDK, examples and many pdf]
** [http://freespace.virgin.net/hugo.elias/graphics/x_posure.htm Light Exposure Theory]
+
** [http://developer.amd.com/ AMD/ATI's examples and many pdf]
** [http://scriptionary.com/ Scriptionary.com] Graphics Programming related both OpenGL and Direct3D
 
 
* '''Other'''
 
* '''Other'''
 
** [http://www.3dcafe.com/ 3D models]
 
** [http://www.3dcafe.com/ 3D models]
 +
** [http://www.opengl.org/sdk/docs/tutorials/TyphoonLabs/ http://www.opengl.org/sdk/docs/tutorials/TyphoonLabs/]
 +
** [http://www.opencsg.org http://www.opencsg.org], Constructive Solid Geometry, boolean operations with geometry
 +
** [http://www.gamedev.net/forum/25-opengl/ GameDev.net], The Gamedev OpenGL Forums
 +
** [http://gpwiki.org http://gpwiki.org] A Wiki about Game Programming, also has GL code snippets and other APIs
 +
  
 
[[Category:General OpenGL]]
 
[[Category:General OpenGL]]

Latest revision as of 15:58, 25 April 2021

So you want to take advantage of the power of the OpenGL API? If you are visiting this page because a game or software uses the OpenGL API, you need to install the appropriate graphic driver which enables usage of the functionality provided.

To program using the OpenGL API, you need the driver and the development package (depends on platform and programming language). More platform-specific details are described in the sections below.

FAQ

This Wiki maintains a FAQ page for OpenGL.

Downloading OpenGL

In all three major desktop platforms (Linux, macOS, and Windows), OpenGL more or less comes with the system. However, you will need to ensure that you have downloaded and installed a recent driver for your graphics hardware.

Windows

Appropriate Windows driver websites:

Some sites also distribute beta versions of graphics drivers, which may give you access to bug fixes or new functionality before an official driver release from the manufacturer:

Without drivers, you will default to a software version of OpenGL 1.1 (on Win98, ME, and 2000), a Direct3D wrapper that supports OpenGL 1.1 (WinXP), or a Direct3D wrapper that supports OpenGL 1.1 (Windows Vista and Windows 7). None of these options are particularly fast, so installing drivers is always a good idea.

If your system does not contain a GPU, or the GPU vendor delivers graphics drivers providing OpenGL support that's so old as to be useless to you, you might want to consider installing the Mesa3D OpenGL library on your system. See this wiki link for details:

Linux

Graphics on Linux is almost exclusively implemented using the X Window system. Supporting OpenGL on Linux involves using GLX extensions to the X Server. There is a standard Application Binary Interface defined for OpenGL on Linux that gives application compatibility for OpenGL for a range of drivers. In addition the Direct Rendering Infrastructure (DRI) is a driver framework that allows drivers to be written and interoperate within a standard framework to easily support hardware acceleration, the DRI is included in of XFree86 4.0 but may need a card specific driver to be configured after installation. These days, XFree86 has been rejected in favor of XOrg due to the change in the license of XFree86, so many developers left Xfree86 and joined the XOrg group. Popular Linux distros come with XOrg now.

Vendors have different approaches to drivers on Linux, some support Open Source efforts using the DRI, and others support closed source frameworks but all methods support the standard ABI that will allow correctly written OpenGL applications to run on Linux.

For more information on developing OpenGL applications on Linux, see Platform specifics: Linux

macOS

Unlike other platforms, where the Operating System and OpenGL implementations are often updated separately, OpenGL updates are included as part of macOS system updates. To obtain the latest OpenGL on macOS, users should upgrade to the latest OS release, which can be found at Apple.com.

For developers, a default installation of macOS does not include any OpenGL headers, nor does it include other necessary development tools. These are installed by a separate developer tools package called Xcode. This installer includes the OpenGL headers, compilers (gcc), debuggers (gdb), Apple's Xcode IDE, and a number of performance tools useful for OpenGL application development.

For more information on developing OpenGL applications on macOS, see Platform specifics: macOS.

Writing an OpenGL Application

The first step is to pick your language. Bindings for OpenGL exist in many languages, from C# and Java to Python and Lua. Some languages have multiple sets of OpenGL bindings, none of them being official. All of them are ultimately based on the C/C++ bindings.

If you are not using C/C++, you must download and install a package or library for your chosen language that includes the OpenGL bindings. Some come pre-installed, but others have separate downloads.

If you are using C/C++, then you must first set up a build environment (Visual Studio project, GNU makefile, CMake file, etc) that can link to OpenGL. Under Windows, you need to statically link to a library called OpenGL32.lib (note that you still link to OpenGL32.lib if you're building a 64-bit executable. The "32" part is meaningless). Visual Studio, and most Windows compilers, come with this library.

On Linux, you need to link to libGL. This is done with a command-line parameter of "-lGL".

Initialization

Before you can actually use OpenGL in a program, you must first initialize it. Because OpenGL is platform-independent, there is not a standard way to initialize OpenGL; each platform handles it differently. Non-C/C++ language bindings can also handle these differently.

There are two phases of OpenGL initialization. The first phase is the creation of an OpenGL Context; the second phase is to load all of the necessary functions to use OpenGL. Some non-C/C++ language bindings merge these into one.

OpenGL Context Creation

An OpenGL context represents all of OpenGL. Creating one is very platform-specific, as well as language-binding specific.

If you are using the C/C++ language binding for OpenGL, then you are strongly advised to use a window toolkit for managing this task. These libraries create a window, attach an OpenGL context to this window, and manage basic input for that window. Once you are comfortable with OpenGL, you can then start learning how to do this manually.

Most non-C/C++ language bindings will provide you with a language-specific mechanism for creating a context.

Getting Functions

If you are using a non-C/C++ language binding, then the maintainer of that binding will already handle this as part of context creation. If you are using C/C++, read on.

In order to use OpenGL, you must get OpenGL API functions. For most libraries you are familiar with, you simply #include a header file, make sure a library is linked into your project or makefile, and it all works. OpenGL doesn't work that way.

For reasons that are ultimately irrelevant to this discussion, you must manually load functions via a platform-specific API call. This boilerplate work is done with various OpenGL loading libraries; these make this process smooth. You are strongly advised to use one.

If you want to do it manually however, there is a guide as to how to load functions manually. You still should use an extension loader.

Using OpenGL

OpenGL is a rendering library. What OpenGL does not do is retain information about an "object". All OpenGL sees is a ball of triangles and a bag of state with which to render them. It does not remember that you drew a line in one location and a sphere in another.

Because of that, the general way to use OpenGL is to draw everything you need to draw, then show this image with a platform-dependent buffer swapping command. If you need to update the image, you draw everything again, even if you only need to update part of the image. If you want to animate objects moving on the screen, you need a loop that constantly clears and redraws the screen.

There are techniques for only updating a portion of the screen. And you can use OpenGL with these techniques. But OpenGL itself doesn't do it internally; you must remember where you drew everything. You must figure out what needs updating and clear only that part of the screen. And so forth

There are many tutorials and other materials available for learning how to use OpenGL, both on this wiki and online.

OpenGL Viewers

These are programs that you install and run, and they give you information specific to the OpenGL API your system implements, like the version offered by your system, the vendor, the renderer, the extension list, supported viewport size, line size, point size, plus many other details. Some might include a benchmark. Some are standalone benchmarks.

Tutorials and How To Guides

User contributed tutorials and getting started guides

By Topic

Development Tools

  • RenderDoc - free, stand-alone graphics debugger. Supports only the OpenGL 3.2+ Core Profile. Works on both Windows and Linux.
  • Nsight Visual Studio Edition - Nsight 3.0 support OpenGL 4.2 Debugging and Profiling, along with Shader Debugging and Pixel History
  • Deleaker - Deleaker for Visual Studio finds OpenGL leaks

See Also

External Links