Irrlicht is an open source graphic engine (the difference between a graphic and a game engine is that the latter includes a set of engines that manage graphics, physics, sound, input system, artificial inteligence, networking, memory, scene graphs, among other features; it INCLUDES the graphic engine as one of its features). But in the case of Irrlicht, it comes with a few more features than common graphics engine, since it also includes some modules made by the Irrlicht community that come be downloaded, whereby you can make games easily; like a sound engine, a physics engine, etc.

The Irrlicht Engine is a cross-platform high performance realtime 3D engine written in C++. It features a powerful high level API for creating complete 3D and 2D applications such as games or scientific visualizations. It comes with an excellent documentation and integrates all state-of-the-art features for visual representation such as dynamic shadows, particle systems, character animation, indoor and outdoor technology, and collision detection. All this is accessible through a well designed C++ interface, which is extremely easy to use.

You can download it from here:

http://irrlicht.sourceforge.net/downloads.html

Tool set: To make developing your games or applications using the Irrlicht engine more easy, there are some free tools to download from external pages. Theses tools and libraries are completely independent of the Irrlicht engine, but are written by the people behind this engine and are designed with Irrlicht compatibility in mind.

http://irrlicht.sourceforge.net/toolset.html

Some of it features include:

• High performance realtime 3D rendering using Direct3D and OpenGL.
• Platform independent. Runs on Windows, Linux, OSX, Solaris, and others.
• Huge built-in and extensible material library with vertex, pixel, and geometry shader support.
• Seamless indoor and outdoor mixing through highly customizeable scene management.
• Character animation system with skeletal and morph target animation.
• Particle effects, billboards, light maps, environment mapping, stencil buffer shadows, and lots of other special effects.
• Several language bindings which make the engine available to other languages such as C#, VisualBasic, Delphi, Java.
• Two platform and driver independent fast software renderers included. They have different properties (speed vs. quality) and feature everything needed: perspective correct texture mapping, bilinear filtering, sub pixel correctness, z-buffer, gouraud shading, alpha-blending and transparency, fast 2D drawing, and more.
• Powerful, customizeable, and easy to use 2D GUI System with Buttons, Lists, Edit boxes.
• 2D drawing functions like alpha blending, color key based blitting, font drawing, and mixing 3D with 2D graphics.
• Clean, easy to understand, and well documented API with lots of examples and tutorials.
• Written in pure C++ and totally object oriented.
• Direct import of common mesh file formats: Maya (.obj), 3DStudio (.3ds), COLLADA (.dae), Blitz3D (.b3d), Milkshape (.ms3d), Quake 3 levels (.bsp), Quake2 models (.md2), Microsoft DirectX (.X)
• Direct import of Textures: Windows Bitmap (.bmp), Portable Network Graphics (.png), Adobe Photoshop (.psd), JPEG File Interchange Format (.jpg), Truevision Targa (.tga), ZSoft Painbrush (.pcx)
• Fast and easy collision detection and response.
• Optimized fast 3D math and container template libraries.
• Directly reading from (compressed) archives. (.zip, .pak, .pk3, .npk)
• Integrated fast XML parser.
• Unicode support for easy localisation.
• Works with Microsoft VisualStudio, Metrowerks Codewarrior, Bloodshed Dev-C++, Code::Blocks, XCode, and gcc 3.x-4.x.
• The engine is open source and totally free. You can debug it, fix bugs and even change things you do not like. And you do not have to publish your changes: The engine is licensed under the zlib licence, not the GPL or the LGPL.
   

Materials and Shaders

To be able to create realistic environments quickly, there are lots of common built in materials available in the engine. Some materials are based on the fixed function pipeline (light mapped geometry for example) and some are relying on the programmable pipeline (normal mapped/parallax per pixel lighted materials for example) todays 3d hardware is offering. It is possible to mix these types of materials in a scene without problems and when using a material which needs features the hardware is not able to do, the engine provides fall back materials. However, if the built in materials are not enough, it is possible to add new materials to Irrlicht at runtime, without the need of modifying/recompiling the engine. Currently supported shader languages for this are:

• Pixel and Vertex Shaders 1.1 to 3.0
• ARB Fragment and Vertex Programs
• HLSL
• GLSL

Special Effects

There are lots of common special effects available in the Irrlicht Engine. They are not difficult to use, in most cases the programmer only has to switch them on. The engine is constantly extended with new effects, here is list of effects which are currently implemented:

• Animated water surfaces
• Dynamic lights
• Dynamic shadows using the stencil buffer
• Geo mip-mapped terrain
• Billboards
• Bump mapping
• Parallax mapping
• Transparent objects
• Light maps
• Customizeable Particle systems for snow, smoke, fire, ...
• Sphere mapping
• Texture animation
• Skyboxes and skydomes
• Fog
• Volume Light

Scene Management

Rendering in the Irrlicht Engine is done using a hierarchical scene graph. Scene nodes are attached to each other and follow each others movements, cull their children to the viewing frustum, and are able to do collision detection. A scene node can for example be a camera, an indoor or outdoor level, a skeletal animated character, animated water, a geomipmap terrain, or something completely different.

In this way, the Irrlicht engine can seamlessly mix indoor and outdoor scenes together, gives the programmer full control over anything which is going on in the scene. It is very easily extensible because the programmer is able to add his own scene nodes, meshes, texture loaders, GUI elements, and so on.

The geometry creator gives easy access to simple gemetrical bodies, such as cylinder, cube, etc. Objects can be renderes as polygons, wireframe, or points, using triangles, lines, point and point sprite primitives.

Character Animation
 

Currently there are two types of character animation implemented:

• Morph target animation: Meshes are linearly interpolated from one frame to the next. This is what is done in the Quake game series, and how the Irrlicht engine does it when importing .md2 and .md3 files.
• Skeletal animation: A skin is manipulated by animated joints. The Irrlicht Engine will do this when loading .ms3d, .x, and .b3d files. It is easily possible to attach objects to parts of the animated model. It is, e.g., possible to attach a weapon to the hand of a model, which will be moved as the hand moves, with only one line of code.

The programmer doesn't need to know about all this, if he doesn't want to. All he has to do is to load the files into the engine and let it animate and draw them.

Supported Render Features
 

Irrlicht supports all general render features needed for high quality rendering of materials and effects. Besides a few exceptions, all features are supported in all hardware accelerated APIs, and some are supported by the software renderers as well. The following list contains all supported render features of the current version of the Irrlicht Engine. Please ask for extending this set to certain features required.

• Predefined materials
  •  Solid
  • Solid with alpha blending 2nd texture
  • Light maps with configurable pre-multiplication and additional dynamic light support
  • Detail map
  • Sphere map
  • Environment reflection
  • Transparency by adding the texture
  • Transparency by using the texture alpha
  • Transparency by using the texture alpha without blending
  • Transparency by using the vertex alpha
  • Normal maps
  • Parallax maps
  • Flexible blend mode rendering 
• Material Colors (ambient, diffuse, emissive, specular)
• Shininess
• Line thickness (only OpenGL)
• ZBuffer write/test modes
• Per mesh anti-aliasing settings
• Alpha to Coverage
• Color masking
• Vertex colors with configurable interpretation
• Wireframe/Point cloud rendering
• Gouraud/Flat shading
• Lighting mode configurable
• Backface/Frontface culling
• Fog enabling per mesh
• Automatic normals normalization
• Texture coordinates repeat/clamp modes
• Per texture filtering (bilinear, trilinear, anisotropic)
• Texture LOD Bias
• Texture matrices
• Arbitrary number of multi-textures

Screenshots