Readme.txt

Urho3D - cross-platform rendering and game engine
-------------------------------------------------

http://urho3d.github.io/

Licensed under the MIT license, see License.txt for details.


Credits
-------

Urho3D development, contributions and bugfixes by:
- Lasse Öörni (loorni@gmail.com, AgentC at GameDev.net)
- Wei Tjong Yao
- Aster Jian
- Colin Barrett
- Erik Beran
- Danny Boisvert
- Carlo Carollo
- Pete Chown
- Sebastian Delatorre (primitivewaste)
- Josh Engebretson
- Chris Friesen
- Alex Fuller
- Mika Heinonen
- Graham King
- Jason Kinzer
- Gunnar Kriik
- Ali Kämäräinen
- Pete Leigh
- Paul Noome
- David Palacios
- Alex Parlett
- Jordan Patterson
- Vladimir Pobedinsky
- Nick Royer
- Miika Santala
- Joshua Tippetts
- Daniel Wiberg
- Steven Zhang
- Firegorilla
- Magic.Lixin
- Mike3D
- OvermindDL1
- andmar1x
- amadeus_osa
- mightyCelu
- reattiva
- skaiware

Urho3D is greatly inspired by OGRE (http://www.ogre3d.org) and Horde3D
(http://www.horde3d.org). Additional inspiration & research used:
- Rectangle packing by Jukka Jylänki (clb)
  http://clb.demon.fi/projects/rectangle-bin-packing
- Tangent generation from Terathon
  http://www.terathon.com/code/tangent.html
- Fast, Minimum Storage Ray/Triangle Intersection by Möller & Trumbore
  http://www.graphics.cornell.edu/pubs/1997/MT97.pdf
- Linear-Speed Vertex Cache Optimisation by Tom Forsyth
  http://home.comcast.net/~tom_forsyth/papers/fast_vert_cache_opt.html
- Software rasterization of triangles based on Chris Hecker's
  Perspective Texture Mapping series in the Game Developer magazine
  http://chrishecker.com/Miscellaneous_Technical_Articles
- Networked Physics by Glenn Fiedler
  http://gafferongames.com/game-physics/networked-physics/
- Euler Angle Formulas by David Eberly
  http://www.geometrictools.com/Documentation/EulerAngles.pdf
- Red Black Trees by Julienne Walker
  http://eternallyconfuzzled.com/tuts/datastructures/jsw_tut_rbtree.aspx
- Comparison of several sorting algorithms by Juha Nieminen
  http://warp.povusers.org/SortComparison/
- NVIDIA FXAA II for Consoles by Timothy Lottes
  http://timothylottes.blogspot.com/2011/04/nvidia-fxaa-ii-for-console.html

Urho3D uses the following third-party libraries:
- AngelScript 2.28.1 (http://www.angelcode.com/angelscript/)
- Box2D 2.3.0 (http://box2d.org/)
- Bullet 2.82 (http://www.bulletphysics.org/)
- Civetweb (http://sourceforge.net/projects/civetweb/)
- FreeType 2.5.0 (http://www.freetype.org/)
- GLEW 1.9.0 (http://glew.sourceforge.net/)
- jo_jpeg 1.52 (http://www.jonolick.com/uploads/7/9/2/1/7921194/jo_jpeg.cpp)
- kNet (https://github.com/juj/kNet)
- libcpuid 0.2.0 (http://libcpuid.sourceforge.net/)
- Lua 5.1 (http://www.lua.org)
- LuaJIT 2.0.2 (http://www.luajit.org)
- LZ4 (http://code.google.com/p/lz4/)
- MojoShader (http://icculus.org/mojoshader/)
- Open Asset Import Library (http://assimp.sourceforge.net/)
- pugixml 1.0 (http://pugixml.org/)
- Recast/Detour (https://github.com/memononen/recastnavigation/)
- SDL 2.0.1 (http://www.libsdl.org/)
- StanHull (http://codesuppository.blogspot.com/2006/03/
  john-ratcliffs-code-suppository-blog.html)
- stb_image 1.29 (http://nothings.org/)
- stb_vorbis 0.99996 (http://nothings.org/)
- tolua++ 1.0.93 (http://www.codenix.com/~tolua)

DXT / ETC1 / PVRTC decompression code based on the Squish library and the Oolong
Engine.
Jack and mushroom models from the realXtend project. (http://www.realxtend.org)
Ninja model and terrain, water, smoke, flare and status bar textures from OGRE.
BlueHighway font from Larabie Fonts.
Anonymous Pro font by Mark Simonson.
NinjaSnowWar sounds by Veli-Pekka Tätilä.


Documentation
-------------

Urho3D classes have been sparsely documented using Doxygen notation. To
generate documentation into the "Docs" subdirectory, open the Doxyfile in the
"Docs" subdirectory with doxywizard and click "Run doxygen" from the "Run" tab.
Get Doxygen from http://www.doxygen.org & Graphviz from http://www.graphviz.org.
See section "Documentation build" below on how to automate documentation
generation as part of the build process.

The documentation is also available online at http://urho3d.github.io/documentation/


Building prerequisites
----------------------

Although all required third-party libraries are included as source code, there
are system-level dependencies that must be satisfied before Urho3D can be built
successfully:

- For Windows, the June 2010 DirectX SDK needs to be installed.

- For Linux, the following development packages need to be installed:
  libx11-dev, libxrandr-dev, libasound2-dev on Debian-based distros;
  libX11-devel, libXrandr-devel, alsa-lib-devel on RedHat-based distros.
  Also install the package libgl1-mesa-dev (Debian) or mesa-libGL-devel (RH)
  if your GPU driver does not include OpenGL headers & libs. Building as 32-bit 
  on a 64-bit system requires installing also the 32-bit versions of the 
  development libraries.

- For Raspberry Pi, the following development packages need to be installed:
  libraspberrypi0, libraspberrypi-dev, libasound2-dev, libudev-dev on Raspbian;
  raspberrypi-vc-libs, raspberrypi-vc-libs-devel, alsa-lib-devel, systemd-devel
  on Pidora. The first two packages which contain the Broadcom VideoCore IV
  libraries and development headers should normally come preinstalled.

- For Mac OS X, the Xcode developer tools package should include everything
  necessary.

- For Android, the Android SDK and Android NDK (minimum API level 9) need to be
  installed. Optionally, also install Eclipse ADT plugin for building and 
  deployment via Eclipse.

To run Urho3D, the minimum system requirements are:

- Windows: CPU with SSE instructions support, Windows XP or newer, DirectX 9.0c,
  GPU with Shader Model 2 support (Shader Model 3 recommended.)

- Linux & Mac OS X: CPU with SSE instructions support, GPU with OpenGL 2.0
  support, EXT_framebuffer_object and EXT_packed_depth_stencil extensions.

- Raspberry Pi: Model B revision 2.0 with at least 128 MB of 512 MB SDRAM
  allocated for GPU. OpenGL ES 2.0 capable GPU.

- Android: OS version 2.3 or newer, OpenGL ES 2.0 capable GPU.

- iOS: OpenGL ES 2.0 capable GPU.

SSE requirement can be eliminated by disabling the use of SSE instruction set,
see "Build options" below.


Desktop build process
---------------------

On desktop systems Urho3D uses CMake (http://www.cmake.org) to build. The
process has two steps:

1) Run CMake in the root directory with your preferred toolchain specified to
   generate the build files. You can use the provided batch files or shell
   scripts on the respective platform.
   
    Windows: cmake_vs2008.bat, cmake_vs2010.bat, cmake_vs2012.bat, or
             cmake_mingw.bat,
    Linux: cmake_gcc.sh or cmake_eclipse.sh,
    Mac OS X: cmake_gcc.sh or cmake_macosx.sh.

2) For Visual Studio, open Urho3D.sln from the Build directory and build the
   configuration(s) you like.
   
   For Eclipse, import the Eclipse's project generated by CMake into
   the workspace as a general project. Note that Eclipse requires CDT plugin to
   build C/C++ project.

   For GCC, execute make in the Build directory (by default, cmake_gcc.sh
   specifies to make a Release build).

   For Xcode, open Urho3D.xcodeproj and build.

If using MinGW to compile, DirectX headers may need to be acquired separately.
They can be copied to the MinGW installation eg. from the following package:
http://www.libsdl.org/extras/win32/common/directx-devel.tar.gz. These will
be missing some of the headers related to shader compilation, so a MinGW build 
will use OpenGL by default. To build in Direct3D9 mode, the MinGW-w64 port is 
necessary: http://mingw-w64.sourceforge.net/. Using it, Direct3D9 can be 
enabled with the CMake option -DUSE_OPENGL=0.

After the build is complete, the programs can be run from the Bin directory.
These include the Urho3D player application, which can run application scripts,
the tools, and C++ sample applications if they have been enabled.

To run the Urho3D player application from the Visual Studio debugger, set the 
Urho3DPlayer project as the startup project and enter its relative path and 
filename into Properties -> Debugging -> Command: ..\..\..\Bin\Urho3DPlayer.exe.
Additionally, entering -w into Debugging -> Command Arguments is highly
recommended. This enables startup in windowed mode: without it running into an
exception or breakpoint will be obnoxious as the mouse cursor will likely be
hidden. To actually make the Urho3DPlayer application do something useful, it
must be supplied with the name of the script file it should load and run. You
can try for example the following arguments: Scripts/NinjaSnowWar.as -w

To run from Eclipse on Linux, locate and select the Urho3DPlayer executable in
the Project Explorer. From the menu, choose "Run Configurations" to create a new
launch configuration for "C/C++ Application". Switch to "Arguments" tab, specify
the argument required by Urho3DPlayer executable.

To run from Xcode on Mac OS X, edit the Product Scheme to set "Run" setting
to execute "Urho3DPlayer" in the "Info" tab. In the "Arguments" tab, specify the
arguments required by Urho3DPlayer executable. Ensure the check boxes are ticked
on the argument entries that you want to be active.

CMake caches some internal variables to speed up the subsequent invocation of
the CMake build script. This is normally a good thing. However, there are cases
when this is not desirable, for instance when switching CMake generators or
after upgrading development software components. In such cases, it is recomended
to first clean the CMake cache by invoking cmake_clean.bat or cmake_clean.sh.


Android build process
---------------------

First, if you are building under Windows platform without MKLINK support then
copy Bin/Data and Bin/CoreData directories to the Source/Android/assets
directory (you can use the provided batch file CopyData.bat). This step is not
necessary for Windows with MKLINK support and non-Windows platforms because the
build script uses symbolic links for platforms that support it.

Set the ANDROID_NDK environment variable to point to your Android NDK. On 
Windows, ensure that make.exe from the Android NDK is included in the path and
is executable from the command line.

On Windows, execute cmake_android.bat. If MKLINK support is available, provide
build option "-DUSE_MKLINK=1" to generate out-of-source build. Then go to the
build directory Source/Android (or android-Build if out-of-source build) and
execute the following commands. On OS X or Linux, execute cmake_gcc.sh (the
ANDROID_NDK environment variable distinguishes from a normal desktop build) then
go to the android-Build directory (always an out-of-source build) and execute
the following commands.

- android update project -p . -t 1 (only needed on the first time,
                                    replace '-t 1' with desired target-id)
- make -j8 (replace '-j8' with the number of logical CPU cores of the 
            host/build system)
- ant debug

After the commands finish successfully, the APK should have been generated to
the build's "bin" subdirectory, from where it can be installed on a device or an
emulator. The command "ant installd" can be used for this.

For a release build, use the "ant release" command instead of "ant debug" and
follow the Android SDK instructions on how to sign your APK properly.

By default the Android package for Urho3D is com.googlecode.urho3d. For a real
application you must replace this with your own package name. The Urho3D
activity subclasses the SDLActivity from org.libsdl.app package, whose name
(or the JNI code from SDL library) does not have to be changed.

Note that the native code is built by default for armeabi-v7a ABI. To make your
program compatible also with old Android devices, build also an armeabi version
by executing the CMake batch file again with the parameter -DANDROID_ABI=armeabi
added, then execute make again in the build directory.

You can also build and deploy using Eclipse IDE with ADT plugin. To do that,
after setting the ANDROID_NDK environment variable then run cmake_eclipse.sh.
Import "Existing Android Code into Workspace" from the CMake generated Eclipse's
project found in the android-Build directory. Switch Eclipse IDE to use Java
Perspective. Update project properties to choose the desired Android API target
and that's it. Just choose "Run" to let ADT automatically build and deploy the
application to Android (virtual) device.


iOS build process
-----------------

Run cmake_ios.sh. This generates an Xcode project named Urho3D.xcodeproj.

Open the Xcode project and check the properties for the Urho3D project (topmost
in the Project Navigator.) In Architectures -> Base SDK, choose your iOS SDK
(CMake would automatically select latest iOS when generating the Xcode project).
In Code Signing, enter your developer identity as necessary.

The Urho3DPlayer target will actually build the application bundle and copy
resources from Bin/Data and Bin/CoreData directories. Edit its build scheme to
choose debug or release mode.

To run from Xcode on iPhone/iPad Simulator, edit the Product Scheme to set "Run"
destination setting to "iPhone Simulator" or "iPad Simulator", and executable
to "Urho3DPlayer.app".


Raspberry Pi build process
--------------------------

For native build on Raspberry Pi itself, use the similar process for Linux
Desktop build described above.

For cross-compiling build on another build/host machine, firstly set the
RASPI_TOOL environment variable to point to your Raspberry Pi Cross-Compiling
tool where all the arm-linux-gnueabihf-* executables are located. You can setup
the tool using crosstool-NG (http://crosstool-ng.org/) or just download one
from https://github.com/raspberrypi/tools. Secondly, set the RASPI_ROOT
environment variable to point to your Raspbian or Pidora system root. You must
install the Urho3D prerequisites software development packages for Raspberry Pi
(see "Building_Prerequisites") in the system root before attempting to do the
Urho3D cross-compiling build.

When running cmake_gcc.sh with RASPI_TOOL environment variable set, it tells
build script to generate additional raspi-Build directory for cross-compiling.
Go to this raspi-Build directory and proceed to execute make. After the build
is complete, the ARM executables can be found in Bin-CC output directory.

You can also build, deploy, run/debug (as C/C++ Remote Application) using
Eclipse IDE, if you run cmake_eclipse.sh to generate the project file. Import
the CMake generated Eclipse project in the raspi-Build directory into Eclipse's
workspace. Build the project as usual. Use the SCP_TO_TARGET build option to
automatically deploy the ARM executables to target Raspberry Pi as part of every
project build or configure Eclipse to perform a "download to target path" in the
Run/Debug configuration for C/C++ Remote Application. Either way, you have to
configure the Run/Debug configuration how to reach your target Raspberry Pi.


MinGW cross-compile build process
---------------------------------

It is possible to cross-compile Urho3D for Windows using a Linux system. The
process is largely the same as for the Linux Desktop build process described
above.

To cross-compile, the MinGW tool-chain (compiler, linker and w32api) needs to be
installed on the system. You will also need the DirectX header files, those can
be downloaded and installed from the following packet:
http://www.libsdl.org/extras/win32/common/directx-devel.tar.gz.

For activating the MinGW tool-chain, and to allow it to find the correct
compiler, the MINGW_PREFIX environment variable needs to be set when running
cmake_gcc.sh. This variable should be set to the prefix of the compiler name.
So, if for example your MinGW compiler is named i686-pc-mingw32-gcc, the
MINGW_PREFIX should read i686-pc. Most likely you also need to set MINGW_ROOT
environment variable to point to your mingw32 system root.

Running cmake_gcc.sh with the MINGW_PREFIX environment variable set, produces
an additional mingw-Build directory. Go to this directory and execute make to
start the build process. When the build is complete, the Windows executables can
be found in the mingw-Bin output directory.


Desktop 64bit build
-------------------

Currently CMake build configuration has been set to compile Urho3D as 32bit by
default. To enable 64bit build, run the provided cmake_xxxx.bat or cmake_xxxx.sh
by passing the option "-DENABLE_64BIT=1" explicitly. For Visual Studio on
Windows platform, this option also overrides CMake to use a 64bit solution
generator.


Library build
-------------

As of v1.31 (to be released), the build process first builds the Urho3D library
target (either static or shared). The library is then linked against by other
targets like tools and samples that reference Urho3D as one of the external
libraries. The Urho3D library type is defaulted to static, so the build process
would generate standalone executables as previous releases. The Urho3D library
type can be changed using "URHO3D_LIB_TYPE" build option.

To install the Urho3D library (or should we call it SDK), use the usual
'make install' command when using Makefile. There is an equivalent command in
Visual Studio and Xcode IDE to build 'install' target instead of the default
'all' target. This could be useful when you want your application to always link
against a 'stable' installed version of the Urho3D library, while keeping your
Urho3D project root tree in sync with origin/master. That is, install the newly
built library after you have tested the changes do not break your application
during development.

Refer to "Using Urho3D as external library" on how to setup your own project to
use Urho3D as external library.


Documentation build
-------------------

If ENABLE_DOCS build option is set then a normal (ALL) build would not only
build Urho3D software but also Urho3D documentation automatically. If it is not
then the documentation can be generated by manually invoking 'make doc' command
or its equivalent command in IDE.

The prerequisites are Doxygen and Graphviz. Tools to dump the AngelScript API
for the default scripting subsystem and the LuaScript API (when the LuaScript
subsystem is also enabled) will be built internally when all the tools are being
built.


Compiling Direct3D shaders
--------------------------

When building with the Windows 8 SDK, copy d3dcompiler_46.dll from
C:/Program Files (x86)/Windows Kits/8.0/bin/x86 to Urho3D Bin directory so that
Urho3D executables will run correctly.

Note that you can also force an OpenGL mode build on Windows by using the CMake
option in the table below; OpenGL does not depend on a separate shader compiler
DLL.


Build options
-------------

A number of build options can be defined explicitly when invoking the above
cmake_xxxx batch files or shell scripts.

|----------------------|-------------------------------------------------------|
|Defines               |Build Options                                          |
|----------------------|-------------------------------------------------------|
|-DENABLE_64BIT=1      |to enable 64bit build                                  |
|-DENABLE_LUA=1        |to enable additional Lua scripting support             |
|-DENABLE_LUAJIT=1     |to enable Lua Just-in-time compilation, implied        |
|                      | ENABLE_LUA (check its CMakeLists.txt for more options)|
|-DENABLE_SAFE_LUA=1   |to enable Lua C++ wrapper safety checks                |
|-DENABLE_SAMPLES=1    |to build the C++ sample applications                   |
|-DENABLE_TOOLS=1      |to build the tools (only useful for Raspberry Pi build |
|                      | because this option is already enabled by default for |
|                      | other Desktop platforms)                              |
|-DENABLE_DOCS=1       |to build the docs when building all the targets        |
|-DENABLE_ANGELSCRIPT=0|to disable AngelScript scripting support               |
|-DENABLE_SSE=0        |to disable SSE instruction set                         |
|-DENABLE_MINIDUMPS=0  |to disable minidumps on crash (VS only)                |
|-DENABLE_FILEWATCHER=0|to disable filewatcher support                         |
|-DENABLE_PROFILING=0  |to disable profiling support                           |
|-DENABLE_LOGGING=0    |to disable logging support                             |
|-DUSE_OPENGL=1        |to use OpenGL instead of Direct3D (only useful for VS  |
|                      | on Windows platform because this option is enabled by |
|                      | default for other platforms)                          | 
|-DUSE_MKLINK=1        |to use mklink command to create symbolic links (Windows|
|                      |  Vista and above only)                                |
|-DUSE_STATIC_RUNTIME=1|to use static C/C++ runtime libraries and eliminate the|
|                      |  need for runtime DLLs installation (VS only)         |
|-DSCP_TO_TARGET=<v>   |to automatically scp executables to target system      |
|                      | (non-Android cross-compiling build only), SSH digital |
|                      | key must be setup first for this to work, typical     |
|                      | value has a pattern of usr@tgt:remote-loc             |
|-DCMAKE_BUILD_TYPE=<v>|to tell CMake which build configuration to be          |
|                      | generated (Makefile generator only), possible values  |
|                      | are Release (default), Debug, and RelWithDebInfo      |
|-DURHO3D_LIB_TYPE=<v> |to specify Urho3D library type, possible values are    |
|                      | STATIC (default) and SHARED                           |
|-DANDROID_ABI=<v>     |to specify ABI for native code (Android build only),   |
|                      | possible values are armeabi-v7a (default) and armeabi |
|----------------------|-------------------------------------------------------|

Note that build option values specified via command line are cached by CMake.
The cached values will be used by CMake in the subsequent invocation. That is,
the same build options are not required to be specified again and again. Once a
non-default build option value is being cached, it can only be reverted back to
its default value by explicitly setting it via command line. That is, simply by
NOT passing the corresponding build option would not work. One way to revert all
the build options to their default values is by clearing the CMake cache by
calling cmake_clean.bat or cmake_clean.sh.


History
-------

V1.31   - Extensive build system improvements, especially for using Urho3D as
          a library in an external project.
        - LuaJIT support.
        - Improved Lua bindings, Lua coroutine support, automatic loading of
          compiled Lua scripts (.luc) if they exist.
        - HDR rendering, 3D textures, height fog and several new post process
          shaders.
        - Shader refactoring. Need for XML shader descriptions & ShaderCompiler
          tool removed.
        - Reflection / refraction rendering support.
        - 2D drawable components: StaticSprite2D, AnimatedSprite2D,
          ParticleEmitter2D.
        - ToolTip & MessageBox UI elements. UI logic improvements.
        - Optimized text rendering + dynamic population of font textures for
          improved batching.
        - AngelScript DelayedExecute for free functions, and event handling for
          any script object, not just ScriptInstances
        - Editor: added grid, toolbar, camera view presets, camera orbit,
          mouse wheel zoom, multiple viewports and orthographic camera.
        - Borderless window mode, possibility to change application icon.
        - SDL GameController support, raw key codes support.
        - Optimized shadow rendering on mobile devices. Low quality mode
          avoids dependent texture reads.
        - HttpRequest class runs in a background thread to avoid blocking.
        - Compressed package file support using the LZ4 library.
        - Cone parameters in SoundSource3D for directional attenuation.
        - Variant GetPtr() safety refactoring. Uses WeakPtr to store RefCounted
          subclasses. Use GetVoidPtr() to store unsafe arbitrary pointers.
        - Improved work queue completion events. Work items are now RefCounted
          to allow persisting them as necessary.
        - Allow to disable automatic execution of AngelScript & Lua from the 
          engine console.
        - Added shader variations, for example ambient occlusion texture and
          better emissive color support.
        - Added examples.
        - Update SDL to 2.0.1
        - Update AngelScript to 2.28.1.
        - Update FreeType to 2.5.0.
        - Fix partial texture updates, both Direct3D9 & OpenGL.
        - Fix long-standing audio click bug.
        - Fix kinematic rigidbodies to apply impulses correctly to dynamic
          bodies.
        - Plus many more improvements and bugfixes.

V1.3    - Lua scripting support.
        - Optional build as a single external library, static or dynamic.
        - Raspberry Pi support.
        - 64-bit build support.
        - HTTP client using the Civetweb library.
        - Enhanced CMake build scripts. Android build also uses CMake.
          Use out-of-source build on platform that supports it.
        - Rendering performance optimizations, optional StaticModelGroup
          component for culling and lighting several objects as one unit.
        - A set of sample applications implemented in C++, AngelScript and Lua.
        - Automatic Node/component handle member variable serialization for
          AngelScript script objects.
        - New UI theme.
        - Shadow & stroke effects in Text & Text3D.
        - Boolean shader uniforms.
        - Quick menu in the editor.
        - Material editor and preview in the editor.
        - Editable attributes for particle emitters.
        - Components are grouped into categories in the editor.
        - Update SDL to stable 2.0.0 release.
        - Several other improvements and bugfixes.

V1.23   - UI editing support in the editor.
        - Undo/redo in the editor.
        - Recast/Detour library integration for navigation mesh generation and
          pathfinding.
        - Open Asset Import Library update, enables FBX file support.
        - "Is Enabled" attribute in scene nodes and components for an uniform
          mechanism to temporarily disable unneeded audiovisual, physics or
          logic objects.
        - Script object public variables editing and serialization.
        - New components: Text3D and Sprite.
        - UI library functionality improvements.
        - sRGB texture and framebuffer support.
        - Switched to GLEW library for OpenGL extension handling.
        - Vegetation and lightmapping example shaders.
        - Engine configuration through a parameter map.
        - Lots of refactoring, code cleanup and bugfixes.

V1.22   - Configurable render path replaces hardcoded forward/prepass/deferred
          modes. Render path system also used for postprocessing now.
        - Threaded task priorities; long-running tasks (more than one frame) can
          coexist with the time-critical tasks.
        - Possibility to use also RGB normal maps.
        - CustomGeometry component, which allows geometry to be defined
          similarly to OpenGL immediate mode.
        - Elapsed time shader parameter for material animation.
        - Cubic environment mapping example shaders.
        - Separate physics collision start & end events.
        - Visual Studio 2012, Eclipse & Xcode build support.
        - Many bugfixes, including iOS 6 orientation & shadow mapping bugfixes,
          skinning on some Android devices.

V1.21   - Bugfixes and code cleanup.
        - External window support (experimental.)
        - UI elements refactored to use attributes for serialization.
        - Animation state editing and animation trigger events.
        - Scene update time scale can be modified.
        - Improved the delayed method call system.

V1.2    - Android and iOS support.
        - Decal rendering.
        - Terrain rendering.
        - Joystick input support.
        - Use SDL library for windowing and input on all platforms.
        - KTX and PVR image loading (for ETC1 & PVRTC compressed textures.)
        - Removed need for shader preprocessing; reorganized shaders to be more
          friendly to base custom shaders on.
        - Inbuilt geometry shapes in the editor.

V1.16   - Switched to Bullet physics library.
        - More physics constraint types.
        - Rendering and networking performance optimizations.
        - Use Squish library to implement software DXT decompression when not
          supported in hardware.

V1.15   - New deferred rendering pipeline.
        - Unicode support.
        - Live resource reloading in the editor (Windows only so far.)
        - More accurate frame timing.
        - Bugfixes to physics jittering and FBO performance issue on Linux.

V1.14   - Object (partial scene) load/save.
        - Post-processing.
        - Switched to pugixml library, scene load/save optimizations.
        - Bugfixes to rendertexture views and component attributes.

V1.13   - Task-based multithreading.
        - Vertex lighting option.
        - Forward and light pre-pass rendering pipelines.

V1.12   - Manipulator gizmo and multi-editing in the editor.
        - Switched to forward rendering exclusively, which is optimized to do
          more work in the vertex shader.
        - Zone system refactoring. Objects check the zone they belong to for
          per-zone light masking, ambient light and fog settings.
        - Scripting API fixes and improvements.

V1.11   - Bugfixes and performance optimizations.
        - Added GraphicsTest example from V1.0 (now called TestSceneOld.)
        - Added fallback mode, which is used if multiple render targets or
          hardware shadow maps are not available.

V1.1    - Object and scene model refactoring.
        - Automatic serialization of scene objects via attributes.
        - Added OpenGL and cross-platform support.
        - Switched to kNet library for networking.

V1.0    - Original release.