Difference between revisions of "Getting Started"

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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.
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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 ==
 
== FAQ ==
 
{{main|FAQ}}
 
{{main|FAQ}}
  
Besides the OpenGL Wiki FAQ linked above, there is an [http://www.opengl.org/resources/faq/ older FAQ]
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This Wiki maintains a FAQ page for OpenGL. There is an [http://www.opengl.org/resources/faq/ older FAQ] available, but information in it is more likely to be out of date.
 +
 
 +
== Downloading OpenGL ==
  
== Windows ==
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In all three major desktop platforms (Linux, MacOS X, 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.
  
If you are running Windows 98/Me/NT/2000/XP/2003/Vista, the OpenGL library has already been installed on your system.
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=== Windows ===
  
Remember that GL is a system component on Windows. DO NOT modify or copy OpenGL32.dll from one OS to another.
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Appropriate Windows driver websites:
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. The second reason to install new drivers is to have the latest version of GL on your system (the max version supported by your GPU):
 
 
* [http://support.amd.com/us/gpudownload/Pages/index.aspx AMD/ATI]
 
* [http://support.amd.com/us/gpudownload/Pages/index.aspx AMD/ATI]
 
* [http://www.intel.com/support/graphics/detect.htm Intel]
 
* [http://www.intel.com/support/graphics/detect.htm Intel]
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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.
 
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.
  
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]
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=== Linux ===
  
=== 64 bits Windows versions ===
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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 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.
If you are running a 64 bit version of Windows, you might be wondering if there is a <code>OpenGL64.dll</code> file. The answer is no, there isn't. On all versions of Windows, <code>Windows\System32</code> contains all the 64 bit DLLs. It contains the <code>OpenGL32.dll</code> which is actually a 64 bit dll.
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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.
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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.
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== Linux ==
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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.
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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. Developers  
  
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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.
 
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.
  
== Mac OS X ==
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=== Mac OS X ===
All versions of Mac OS X ship with OpenGL runtime libraries pre-installed. Users who want to run OpenGL applications do not need to install or configure anything.
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Unlike other platforms, where the Operating System and OpenGL implementations are often updated separately, OpenGL updates are 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/ Apple.com].
 
Unlike other platforms, where the Operating System and OpenGL implementations are often updated separately, OpenGL updates are 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/ Apple.com].
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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 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 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 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/opengl OpenGL Information]
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* [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]
 
* [http://developer.apple.com/technology/xcode.html Download Xcode]
  
 
For more information on developing OpenGL applications on Mac OS X, see [[Platform specifics: Mac OS X]].
 
For more information on developing OpenGL applications on Mac OS X, see [[Platform specifics: Mac OS X]].
  
== Accessing OpenGL functions ==
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== Writing an OpenGL Application ==
  
The OpenGL ABI (application binary interface) is frozen to version GL 1.1 on Windows, and GL 1.2 on Linux. This means that you can not link directly to any function provided by newer versions of GL.
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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.
  
So how do you use newer features? The answer is to get function pointers for those features at runtime (the same method for getting function pointers for extensions).  
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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.
  
{{note|The following shows how to do this process manually. There are a number of automatic [[Extension Loading Library|extension loading libraries]], and you are encouraged to use them.}}
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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.
  
If you will be programming for Windows, typically compilers comes with a standard OpenGL 1.1 header (gl.h) and the library file (opengl32.lib). To gain access to more recent versions or extension functions, you will need to use glext.h and either wglext.h (for windows) or glxext.h (for linux). These define function pointers for all extensions and versions of OpenGL 1.2 and above.
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On Linux, you need to link to libGL. This is done with a command-line parameter of "-lGL".
  
Download glext.h and wglext.h/glxext.h from [http://www.opengl.org/registry/ The Extensions Registry]. You can put these files directly under the compiler's "GL" folder, or you can put them in some other folder that will be in your project's include path. As long as you can find them. The example code will assume that they are in the "GL" folder.
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=== Initialization ===
  
<source lang="cpp">
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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.
include <GL/gl.h>
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include <GL/glext.h>
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include <GL/wglext.h>
+
  
PFNGLACTIVETEXTUREPROC glActiveTexture;   //Declare a OpenGL function pointer in a .cpp file
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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.
</source>
+
  
PFNGLACTIVETEXTUREPROC is a typedef defined in glext.h that represents a function pointer to this particular OpenGL function. Every OpenGL core function (in a version 1.2 or greater) and every OpenGL extension function has a typedef. They all begin with PFN, followed by the function name in ALL CAPS, followed by PROC.
+
==== OpenGL Context Creation ====
  
If you wish to expose this function pointer to other .cpp files, you will need to put the following in a header file that those .cpp files include:
+
An OpenGL context represents all of OpenGL. Creating one is very platform-specific, as well as language-binding specific.
  
<source lang="cpp">
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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]].
//Some header file.
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include <GL/gl.h>
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include <GL/glext.h>
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include <GL/wglext.h>
+
  
extern PFNGLACTIVETEXTUREPROC glActiveTexture;
+
Most non-C/C++ language bindings will provide you with a language-specific mechanism for creating a context.
</source>
+
  
After creating an OpenGL context, and ''only after creating an OpenGL context'', you may use wglGetProcAddress (or glXGetProcAddress for *nix systems) to get the function pointer.
+
==== Getting Functions ====
  
<source lang="cpp">
+
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.
glActiveTexture = (PFNGLACTIVETEXTUREPROC)wglGetProcAddress("glActiveTexture");
+
</source>
+
  
This must be done for each function you intend to use that is not a core OpenGL 1.1 function and there are plenty of functions. You will have hundreds of lines of code just calling wglGetProcAddress. Or you can use an [[Extension Loading Library|extension loading library]] and not have to worry about it.
+
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.
  
We should also state that you should always check the GL version supported to make sure the system supports your program. For more info
+
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://www.opengl.org/wiki/FAQ#How_do_I_tell_what_version_of_OpenGL_I.27m_using.3F
+
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.
  
== OpenGL 3.0 and Above ==
+
== Using OpenGL ==
OpenGL 3.0 adds many features to the core of OpenGL. It also brings with it a [[Deprecation|deprecation model]] that previous versions of OpenGL did not have. Before OpenGL 3.0, anything that became core had to remain in the specification permanently. The deprecation model allows OpenGL versions to announce that certain features may be removed from the core in later versions.
+
  
The OpenGL specification now is broken into two specifications: [[Core_And_Compatibility_in_Contexts|core and compatibility]]. Compatibility provides full backwards compatibility with GL 2.1 and below, while Core does not. A new context creation model exists; it is the only way to create core contexts of OpenGL 3.1 and above.
+
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.
  
Part of this new API is a specification of exactly what version of OpenGL you want. So if you ask for a GL 3.1 context, you are telling the system that you expect that any entrypoints version 3.1 removed from earlier versions will not be available, and that any entrypoints 3.1 added to new versions will be available. The new API can fail if the implementation simply does not implement that version of OpenGL.
+
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.
  
More detailed instructions for [[Creating an OpenGL Context]] are available.
+
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.
  
== OpenGL specifications ==
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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.
* [http://www.opengl.org/registry/doc/glspec41.core.20100725.pdf OpenGL 4.1 Core Profile Specification]
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* [http://www.opengl.org/registry/doc/GLSLangSpec.4.10.6.clean.pdf OpenGL Shading Language 4.1 Specification]
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* [http://www.opengl.org/registry/doc/glspec33.core.20100311.pdf OpenGL 3.3 Core Profile Specification]
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* [http://www.opengl.org/registry/doc/GLSLangSpec.3.30.6.clean.pdf OpenGL Shading Language 3.3 Specification]
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+
== How to make your first OpenGL Program ==
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The first thing to do is chose a programming language. It could be C, C++, C#, Visual Basic, Pascal, Perl, Java, Ada, x86 assembly, etc. As long as a language has an OpenGL binding for your chosen language, you may use it.
+
 
+
The second thing is to chose a compiler. It could be MS Visual C++, Code::Blocks, 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.
+
 
+
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>.
+
 
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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.
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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.
+
 
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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 or visit some of the [[Getting_started#Tutorials_and_How_To_Guides| tutorials listed here]].
+
  
 
== OpenGL Viewers==
 
== OpenGL Viewers==
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* [http://www.ozone3d.net/gpu_caps_viewer/ GPU Caps Viewer (Windows XP, Vista 32)]
 
* [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)]
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* [http://www.realtech-vr.com/glview/index.html OpenGL Extension Viewer (Windows, Windows x64 and MacOS X)]: 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)]
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* [http://www.ozone3d.net/benchmarks/fur/ FurMark benchmarking application (Windows)]
* [http://www.devbump.com/story.php?title=Fur_Rendering_Benchmark_-_A_Small_and_Handy_OpenGL_Utility Fur rendering benchmark (Windows)]
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* [http://www.futuremark.com/download/ Futuremark's GL ES benchmark]
+
  
 
== Tutorials and How To Guides ==
 
== Tutorials and How To Guides ==
 
User contributed tutorials and getting started guides
 
User contributed tutorials and getting started guides
  
* [[Tutorials]]: Tutorials hosted on this wiki.
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* OpenGL 3.0 and above:
* [http://nehe.gamedev.net NeHe], OpenGL Tutorials
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** [http://www.siteduzero.com/tutoriel-3-421558-developpez-vos-jeux-video-3d-avec-opengl-3-1.html Develop with OpenGL 3.1 from scratch (Français)]
* [http://www.leolol.com/tutorials/graphics_tutorials.html LeoLoL], OpenGL Tutorials for Java (JOGL)
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** [http://www.arcsynthesis.org/gltut Learning Modern 3D Graphics Programming Through OpenGL].
* [http://www.xmission.com/~nate/opengl.html GLUT], Tutorials
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** [http://ogldev.atspace.co.uk/ OpenGL Step by Step] (using C++, FreeGLUT and GLEW)
* [http://www.lighthouse3d.com lighthouse3d.com], GL 2.0, GLSL, tutorials
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** [http://openglbook.com/ OpenGLBook.com] Free online OpenGL 4.0 book (OpenGL 3.3 code provided wherever possible) using freeglut and GLEW
* [http://www.marek-knows.com marek-knows.com], Non-free Game Engine development video tutorials, OpenGL, Physics, Math, C++, 3D modeling etc
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** [http://www.spieleprogrammierung.net/ Spiele Programmierung Windows OpenGL 3 Tutorials And Articles], Beginner to Advanced in German
* [http://openglbook.com/ OpenGLBook.com] Free online OpenGL 4.0 book (OpenGL 3.3 code provided wherever possible) using freeglut and GLEW
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** [http://www.swiftless.com/opengltuts/opengl4tuts.html Swiftless OpenGL 4 Tutorials]
* [http://www.arcsynthesis.org/gltut Learning Modern 3D Graphics Programming Through OpenGL].
+
** [http://www.opengl-tutorial.org opengl-tutorial.org] OpenGL 3.3 and later Tutorials
* [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.opengl-tutorial.org/beginners-tutorials/ Basics]
* [http://www.spieleprogrammierung.net/ Windows OpenGL 3 Tutorials And Articles], Beginner to Advanced in German
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*** [http://www.opengl-tutorial.org/intermediate-tutorials/ Intermediate]
* [http://www.levelbylevel.com/blog/opengl-c-and-glut-using-codeblocks-and-mingw-updated/ Setting up OpenGL, C++ & GLUT on Windows 7], Beginner tutorial
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** [http://tomdalling.com/blog/category/modern-opengl/ Modern OpenGL Tom Dalling]
* Swiftless Tutorials [http://www.swiftless.com/opengltuts.html OpenGL 1 & 2], [http://www.swiftless.com/opengltuts/opengl4tuts.html OpenGL 4]
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** [http://github.prideout.net/modern-opengl-prezo/ Modern OpenGL 2012 (PDF file)] by The Little Grashopper
* [http://www.g-truc.net G-Truc Creation]: [http://www.g-truc.net/project-0026.html OpenGL 2.1 - 4.1 Code samples]
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* Pre-OpenGL 3.0:
* [http://gpwiki.org/index.php/Template:OpenGL:Tutorials OpenGL Tutorials at GPWiki]
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** [http://www.glprogramming.com/red/ The OpenGL Programming Guide, also called the Red Book] Covers OpenGL version 1.1.
* [http://www.siteduzero.com/tutoriel-3-421558-developpez-vos-jeux-video-3d-avec-opengl-3-1.html Develop with OpenGL 3.1 from scratch (Français)]
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** [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://gpwiki.org/index.php/Template:OpenGL:Tutorials GPWiki OpenGL Tutorials]
 +
** [http://www.leolol.com/tutorials/graphics_tutorials.html LeoLoL], OpenGL Tutorials for Java (JOGL)
 +
** [http://www.lighthouse3d.com lighthouse3d.com], GL 2.0, GLSL, 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.levelbylevel.com/blog/opengl-c-and-glut-using-codeblocks-and-mingw-updated/ Setting up OpenGL, C++ & GLUT on Windows 7], Beginner tutorial
 +
** 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.
  
Deferred Shading Tutorials
 
  
* [http://www.codinglabs.net/tutorial_def_rendering_1.aspx Deferred Rendering]
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By Topic
* [http://www.gamerendering.com/category/rendering-methods/page/2/ Deferred Lighting]
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* Deferred Shading Tutorials
 +
** [http://www.codinglabs.net/tutorial_def_rendering_1.aspx Deferred Rendering]
 +
** [http://www.gamerendering.com/category/rendering-methods/page/2/ Deferred Lighting]
 +
* 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 ==
 
== Development Tools ==
 
* [http://www.gremedy.com/ gDEBugger] - OpenGL, OpenGL ES and OpenCL Debugger, Profiler and Memory Analyzer For Windows, Linux, Mac OS X and iPhone
 
* [http://www.gremedy.com/ gDEBugger] - OpenGL, OpenGL ES and OpenCL Debugger, Profiler and Memory Analyzer For Windows, Linux, Mac OS X and iPhone
 +
* [http://developer.amd.com/tools/hc/gDEBugger/Pages/default.aspx AMD gDEBugger] - After Graphic Remedy became a subsidiary of AMD in 2011, the new line of gDEBugger was released as a Visual Studio plugin and has since been re-released as a stand-alone application for Windows and Linux.
 +
 +
{{warning|AMD's version of gDEBugger will not do any OpenCL kernel debugging without AMD hardware installed!}}
  
 
== See Also ==
 
== 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.
 
* [[Related toolkits and APIs]]: For utilities that make using OpenGL easier.
 
* [[Language bindings]]
 
* [[Language bindings]]
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* '''Reference Documentation'''
 
* '''Reference Documentation'''
** [http://www.opengl.org/documentation/specs/ The OpenGL specification page]
 
 
** [http://www.opengl.org/documentation/glsl/ The OpenGL Shading Language specification page]
 
** [http://www.opengl.org/documentation/glsl/ The OpenGL Shading Language specification page]
 
** [http://www.opengl.org/registry/ The extension registry]
 
** [http://www.opengl.org/registry/ The extension registry]
Line 194: Line 169:
 
** [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.g-truc.net G-Truc Creation]: [http://www.g-truc.net/project-0026.html OpenGL 2.1 - 4.1 Code samples]
 
** [http://www.humus.name/ Humus.name] many demos, advanced
 
** [http://www.humus.name/ Humus.name] many demos, advanced
** [http://www.flipcode.com Flipcode] many demos
 
 
** [http://local.wasp.uwa.edu.au/~pbourke/ Paul Bourke] many demos and explanations, advanced
 
** [http://local.wasp.uwa.edu.au/~pbourke/ Paul Bourke] many demos and explanations, advanced
 
** [http://es.g0dsoft.com/?page_id=236 OpenGL Code Samples] modern OpenGL code samples and demos
 
** [http://es.g0dsoft.com/?page_id=236 OpenGL Code Samples] modern OpenGL code samples and demos
 +
** [http://oglplus.org/html/examples.html OGLplus Examples] OpenGL 3 and higher code examples
 
* '''Theory and General Graphics Programming'''
 
* '''Theory and General Graphics Programming'''
** [http://www.magic-software.com Magic Software] algorithms, intersection test
 
 
** [http://freespace.virgin.net/hugo.elias/graphics/x_posure.htm Light Exposure Theory]
 
** [http://freespace.virgin.net/hugo.elias/graphics/x_posure.htm Light Exposure Theory]
 
* '''Vendor SDKs'''
 
* '''Vendor SDKs'''
 
** [http://www.opengl.org/sdk/ OpenGL SDK projects and OpenGL man pages]
 
** [http://www.opengl.org/sdk/ OpenGL SDK projects and OpenGL man pages]
 
** [http://developer.nvidia.com nVidia's SDK, examples and many pdf]
 
** [http://developer.nvidia.com nVidia's SDK, examples and many pdf]
** [http://ati.amd.com/developer/index.html AMD/ATI's examples and many pdf]
+
** [http://developer.amd.com/ AMD/ATI's examples and many pdf]
 
* '''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.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.opencsg.org http://www.opencsg.org], Constructive Solid Geometry, boolean operations with geometry
** [http://www.gamedev.net/community/forums/showfaq.asp?forum_id=25#q11a http://www.gamedev.net/community/forums/showfaq.asp?forum_id=25#q11a], The Gamedev FAQ
+
** [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
 
** [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]]

Revision as of 17:25, 15 February 2013

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. There is an older FAQ available, but information in it is more likely to be out of date.

Downloading OpenGL

In all three major desktop platforms (Linux, MacOS X, 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.

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 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

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

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.

Mac OS X

Unlike other platforms, where the Operating System and OpenGL implementations are often updated separately, OpenGL updates are 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 Apple.com.

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 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 Mac OS X, see Platform specifics: Mac OS X.

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

  • gDEBugger - OpenGL, OpenGL ES and OpenCL Debugger, Profiler and Memory Analyzer For Windows, Linux, Mac OS X and iPhone
  • AMD gDEBugger - After Graphic Remedy became a subsidiary of AMD in 2011, the new line of gDEBugger was released as a Visual Studio plugin and has since been re-released as a stand-alone application for Windows and Linux.
Warning: AMD's version of gDEBugger will not do any OpenCL kernel debugging without AMD hardware installed!

See Also

External Links