OGRE

For other uses, see Ogre (disambiguation).

OGRE

Developer(s)	The OGRE Team
Stable release	1.7.3 (Cthugha) / May 8, 2011; 6 months ago (2011-05-08)
Written in	C++
Platform	Cross-platform
Type	3D graphics engine
License	MIT[1]
Website	http://www.ogre3d.org/

Screenshot from the official OGRE Demos pack, from "Fresnel Reflections and Refractions" benchmark. Rendering options: 1600*1200 pixel resolution, OpenGL renderer, 16x FSAA and 32-bit color depth.

OGRE (Object-Oriented Graphics Rendering Engine) is a scene-oriented, flexible 3D rendering engine (as opposed to a game engine) written in C++ designed to make it easier and intuitive for developers to produce applications utilizing hardware-accelerated 3D graphics. The class library abstracts the details of using the underlying system libraries like Direct3D and OpenGL and provides an interface based on world objects and other high level classes.

OGRE has a very active community, and was SourceForge's project of the month in March 2005.^[2] It has been used in some commercial games such as Ankh, Torchlight and Garshasp.

1.0.0 ("Azathoth") was released in February 2005. The current release in the 1.x.y series is 1.7.3 ("Cthugha"), released on May 8th, 2011. Released under the terms of the MIT License^[1] and previously under a modified GNU Lesser General Public License (LGPL), the engine is free software. The modification to this license allows users to statically link the library under the same terms as dynamic linking, though a distinction made by the LGPL.

General information

As its name states, OGRE is "just" a rendering engine. As such, its main purpose is to provide a general solution for graphics rendering. Though it also comes with other facilities (vector and matrix classes, memory handling, etc.), they are considered supplemental. It is not an all-in-one solution in terms of game development or simulation as it doesn't provide audio or physics support, for instance.

Generally, this is thought of as the main drawback of OGRE, but it could also be seen as a feature of the engine. The choice of OGRE as a graphics engine allows developers the freedom to use whatever physics, input, audio and other libraries they want and allows the OGRE development team to focus on graphics rather than distribute their efforts amongst several systems. OGRE explicitly supports the OIS, SDL and CEGUI libraries, and includes the Cg toolkit.

As of version 1.7.0 Ogre is released under the terms of the MIT License^[1]. Earlier versions of OGRE was published under a dual license (one being LGPL, the other one called OGRE Unrestricted License (OUL)), to make it possible to be chosen for console development as well, because for most of the publishers copyleft license terms are unacceptable.

Features

OGRE has an object-oriented design with a plugin architecture that allows easy addition of features, thus making it highly modular.

OGRE is a scene graph based engine, with support for a wide variety of scene managers, most notably octree, BSP and a Paging Landscape scene manager, along with a beta-stage portal-based scene manager under ongoing development.

OGRE is fully multi-platform, with OpenGL and Direct3D support. It can render the same content on different platforms without the content creator having to take into consideration the different capabilities of each platform. This reduces the complexity of deploying a game on multiple systems. Currently pre-compiled binaries exist for Linux, Mac OS X, and all major versions of Windows.

OGRE also supports Vertex and Fragment programs along with custom shaders written in GLSL, HLSL, Cg and assembler.

The landscape scene manager has support for Progressive LOD, which can be automatically or manually created.

The animation engine has full support for hardware weighted multiple bone skinning, which can be fixed across several poses for full pose mixing.

OGRE also has a compositing manager with a scripting language and full screen Video post-processing for effects such as HDR, blooming, saturation, brightness, blurring and noise. A particle system with extensible rendering and customizable effectors and emitters.

The libraries also feature memory debugging and loading resources from archives.

There are content exporter tools available for most 3D modelers around including 3D Studio Max, Maya, Blender, LightWave, Milkshape, Sketchup and more.

A full overview of the features provided by OGRE can be found the OGRE3d website.^[3]

Google Summer of Code

OGRE got 6 slots in Google Summer of Code 2006 to enhance the existing engine and add new features to it. These entries were:

• Tool for one-step solution for artists
• RmOgreExporter (v2), FxOgreExporter
• Instancing, Crowd Rendering
• Extending, Demo-ing, and Documenting the Shadow Mapping System
• Scene Management
• Billboard Clouds

In the following years, many other Google Summer of Code projects have been realized for the Ogre engine.^[4]

Version naming

The version branch names, Hastur for 0.15.x, Azathoth for 1.0.x, Dagon for 1.1.x and 1.2.x, Eihort for 1.3.x and 1.4.x, Shoggoth for 1.5.x and 1.6.x, have been named after members of an ancient race of fearsome deities called the Great Old Ones in the Cthulhu mythology of H. P. Lovecraft.

Release history

A brief history of OGRE, and its milestones:

Around 1999

Sinbad realises that his 'DIMClass' project, a project to make an easy to use object-oriented Direct3D library, has become so abstracted that it really doesn't need to be based on Direct3D any more. Begins planning a more ambitious library which could be API and platform independent.

February 25, 2000 

Sourceforge project registered, OGRE name coined. No development starts due to other commitments but much pondering occurs.

February 2005

Ogre v1.0.0 "Azathoth" Final Released - resource system overhaul, hardware pixel buffers, HDR, CEGui, XSI exporter

March 2005

Ogre is 'Project of the Month' on Sourceforge

November 4, 2005

Ankh is released as the first commercial product using Ogre

May 7, 2006

Ogre 1.2 "Dagon" is officially released

March 25, 2007 

Ogre 1.4 "Eihort" is officially released

August 28, 2008 

Ogre 1.6 "Shoggoth" is officially released (Currently 1.6.5 Stable Release)

February 28, 2010 

Ogre 1.7 "Cthugha" is officially released (Currently 1.7.3 Stable Release)

OGRE ports and wrappers

There exist a number of OGRE bindings to other languages and frameworks including Perl, PureBasic, Python-Ogre for Python, Ogre.rb for Ruby, Ogre4j for Java and OgreDotNet, GMOGRE for Game Maker and MOGRE for .NET.

Axiom Engine^[5] is a C# port of OGRE. It is open-source and cross-platform, for .NET and Mono.^[6] It provides complete abstraction from the 3D API, supports OpenGL, DirectX and XNA, contains a scene graph model and provides support for complex shaders.^[7] Multiverse Network is a project which uses Axiom.

The are also some free level editors for Ogre, like Ogitor^[8]

Games using OGRE

Open-source games

• WorldForge Ember 3D client
• Rigs of Rods
• Awakened
• Walabers Trampoline
• Facade
• Trinity Reign
• Summoning Wars

Games with proprietary licenses

• Ankh
• Ankh: Heart of Osiris
• Earth Eternal
• Garshasp: The Monster Slayer
• Jack Keane
• Motorm4x
• Next Life
• Nimbus
• Pacific Storm
• Raindrop
• Roblox
• Snakeworlds
• The Dead Linger (TDL)
• Torchlight
• Venetica
• Zero Gear
• Zombie Driver

See also

	Free software portal
	Video games portal

• 3D computer graphics software
• CEGUI The unofficial GUI toolkit for OGRE.
• Irrlicht Engine
• OpenSceneGraph
• SpeedTree
• Visualization Library

References

1. ^ ^{a b c} OGRE3d.org
2. ^ "SourceForge: Project of the Month". http://sourceforge.net/potm/potm-2005-03.php. 
3. ^ OGRE3d.org
4. ^ "OGRE’s Latest Release Features Google Summer of Code Projects". http://google-opensource.blogspot.com/2010/03/ogres-latest-release-features-google.html. 
5. ^ Axiom3d.net
6. ^ Kordic, Vedran (2005). Cutting Edge Robotics. pIV pro literatur Verlag Robert Mayer-Scholz. p. 53. 
7. ^ "Axiom list of features". http://axiom3d.net/wiki/index.php/Axiom_Features. Retrieved 26 November 2008. 
8. ^ Ogitor home site

• Felix Kerger, OGRE 3D 1.7 Beginner's Guide, Packt Publishing, 2010 - ISBN 1849512485
• Gregory Junker, Pro OGRE 3D programming, Apress, 2006, ISBN 1590597109

External links

• Official website
• Steve Streeting's Blog, Founder of OGRE 3D
• Why Ogre3D make you want to use it?
• Flickr album with many screenshots of Ogre projects