SIO2 is a Free Open Source 3D Game Engine for iPhone and iPod Touch written in pure C using OpenGL|ES with a bit of Obj-C and C++ to glue things together with the iPhone & Bullet Physic.

Please find below a list of the current & future engine features and capabilities.

In addition SIO2 include the following libraries and functionalities embedded in the core where most of them have been modified to operate directly in memory for better performance:

OpenAL: For 3D positional sounds (FX) and ambient music.

Theora: For realtime MPEG4 (ogv) playback.

Ogg: For MP3 style playback.

LUA: As the default scripting language that includes all the SIO2 API + all the OpenGL ES API, and uses SWIG to generate the necessary C wrapper. All OpenGL ES & OpenAL instructions are also available from LUA as well as the specific SIO2 API.

libJPEG: For fast JPEG decompression.

Zlib: To create and compress the SIO2 fileformat (.sio2)

libPNG: For fast PNG decompression.

Bullet: For Rigid & Soft Body physic, as well as for collision detection, collision feedback, custom sensors and collision triggers.

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Architecture
* Optimized File Format
* Unique Package Approach
* OpenGL ES v1.1 Compatible
* Written in pure C

Tool Chain
* Built around Blender (WYSIWYG)
* Exporter & Optimizer
* Auto Texture Bake Script
* Animation Exporter

Real Time Physic
* Rigid Body
* Collision Detection
* Soft Body
* Particle System
* Fog

Texturing
* Multi-Texturing
* Texture Filtering
* Anisotropic Filtering
* Transparent
* Semi-Transparent

Multimedia & Special Effects
* Ambient & FX Sound
* Real 3D Stereo & Surround
* Realtime MP3 Playback
* Realtime MPEG 4 Playback

Scene Management
* Fast Sorting & Culling System
* Event & Trigger System
* Scripting Support (Level & UI)
* Network Support (TCP/IP)
* Touch Screen & Accelerometer

Lighting & Shadow
* Per-Vertex
* Light Mapping
* Projected Shadow
* Projected Geometry

Animation
* Full IPO Support
* Hybrid Skeletal Animation
* Keyframe Animation

System Requirements
* Mac OS X v10.5.6
* iPhone SDK v2.2.1

You can use SIO2 for free or commercial product, please read the SIO2 license agreement ( /SIO2_SDK/src/license/sio2.txt ). Basically the only thing that we are asking is that you mention SIO2 and/or our website somewhere in your project if its made available to the public in order to keep the SIO2 project alive.

For more information on SIO2 please check our website for more information: http://sio2interactive.com/TECHNOLOGY.html