Simulation Engines TDA571|DIT030 Practical System Development fileIDC | Interaction Design Collegium Course contents (once more) Introduction to simulation engines and practical information

Simulation Engines TDA571|DIT030 Practical System Development

Tommaso Piazza

Monday, November 1, 2010

IDC | Interaction Design Collegium

Todays Topics

Development Tools Libraries Documentation Performance and optimization Short Ogre3D primer

Focus on Software Engineering



Administrative Stuff

Check the webpage for updates Any new arrivals? Student Representatives The groups Group meetings



Course Information (once more)

Examination in this course consists of a group project. The course has no written exam

A passing grade requires the following: An approved written suggestion for an individual extension of the

simulation engine A passing grade on your group's project report A passing grade on your group's project presentation A passing grade on your personal project report A verbal presentation of a course subject

The course is divided in two parts. One part is 2 points and represents each student's individual effort and the other is 3 points and represents the project group's collaborative effort. Possible grades are failure, 3, 4 and 5 at Chalmers or U, G and VG at Göteborgs Universitet. Grading is individual and is based on the above mentioned subjects as well as the project supervisor's judgement.



Important Dates Mon, 1 Nov 24.00

Extension suggestions should be handed in to project supervisors

Mon, 8 Nov Approval of extension suggestions

Week 3-7 Individual presentations of themes from project members

Mon, 10 Jan 24.00 Group reports and individual reports should be handed in

Exam week Project presentations

Failing to keep a deadline without a proper explanation in good time before the deadline will result in a failing grade!



Course contents (once more)

Introduction to simulation engines and practical information Software engineering, architecture and design Multimedia and scenegraphs 3D graphics AI and network Physics Input and collision detections, misc. Project demos:

Project Deliveries

Extension suggestion, group project repot, individual report Demonstrations

Extension demonstration, project demonstration No written exam



The project (repeated)

This course is based on the group project 5 students per group Individually

Responsible for their own theme Suggesting an extension to the simulation engine within their theme Implementing their extension Verbally present their theme and extension to the rest of their group Write an individual report and project diary

Groups Design and implement a tech demo that utilizes all of the extensions

that have been created by the group members Write a project report Verbally present the project to the rest of the class



Form Groups (once more)

Form groups of 5 people (no exceptions unless absolutely necessary!)

Write down the name and email of everyone in your group Themes

Software Engineering 3D graphics Multimedia AI and network Physics (Misc)

First individual presentation November 8th!



How to group-work and share with me All students are required a Google Account

concerned about your data? http://www.dataliberation.org/

Sharing Documents (Google Docs) The group report and any tech demo presentation must be created and shared by the

group head to me ([email protected]) and all group members The group head will create a folder named as follow simEngines-g# (ex. simEngines-g1)

and share it with me Inside the folder there will be two files named as follow simEngines-g#-GroupReport (ex.

simEngines-g6-GroupReport) and simEngines-g#-GroupPresentation (ex. simEngines-g2-GroupPresentation)

For individual reports, extension suggestions and presentation it is enough to create the documents and share them with me without creating a folder. Naming conventions are simEngines-g#-YourName-Report|Extension|Presentation (ex. simEngines-g7-TommasoPiazza-Report, simEngines-g7-TommasoPiazza-Extension, simEngines-g7-TommasoPiazza-Presentation)

Sharing Code (Google Code) http://code.google.com/hosting/createProject - Created by the group head invite all group members and me Version control system is SVN. License is up to you


http://www.dataliberation.org

http://www.dataliberation.org

mailto:[email protected]

mailto:[email protected]

http://code.google.com/hosting/createProject

http://code.google.com/hosting/createProject


Development Tools Compilers

C++ (G++, Hp aC++, Intel C++ Compiler, Visual C++ ...) Debuggers

Find bugs (GDB, IDB,Visual Studio Debugger...) Profilers

Analyze performance (Valgrind, Google Perf-Tools, VTune, GlowCode ...) Source code management

Storage and version control (CVS, SVN, Mercurial, GIT...) UML-editors

Software design and code generation ( ArgoUML, Umbrello, StarUML ...) IDEs

MSVS, Eclipse, Netbeans, Code:Blocks, Xcode ...


http://en.wikipedia.org/wiki/ArgoUML

http://en.wikipedia.org/wiki/ArgoUML


Compilers Microsoft Visual C++ Integrated in Microsoft Visual Studio 2008 Will be used in this course Downloadable through Academic Alliance

http://my.chl.chalmers.se/wiki/view/chl/MicrosoftAcademy/ http://msdn60.e-academy.com/elms/Storefront/Home.aspx?campus=dth_hsg


http://my.chl.chalmers.se/wiki/view/chl/MicrosoftAcademy/

http://my.chl.chalmers.se/wiki/view/chl/MicrosoftAcademy/

http://msdn60.e-academy.com/elms/Storefront/Home.aspx?campus=dth_hsg

http://msdn60.e-academy.com/elms/Storefront/Home.aspx?campus=dth_hsg


Build Tools

Integrated in Visual Studio Alternatives Make CMake Jam SCons Ant (Java) Maven (Java)



Source Code Management

SVN - Subversion Successor of CVS (Concurrent Version System) Cross platform Atomic commits (Interrupted commit operations

would otherwise cause repository inconsistency or corruption), biggest difference with CVS

Variety of access protocols Locally file:///path/ Remote WebDAV http://host/path or https://host/path SVN protocol svn://host/path or svn+ssh://host/path


http://host/path

http://host/path

https://host/path

https://host/path


Subversion (1) Traceability and safety All changes are saved Each commit is a revision

Decentralization Multiple developers can work on the same code copy-modify-merge solution

Code from multiple developers is automatically unified



Subversion (2)

Copyright © 2002, 2003, 2004 Ben Collins-Sussman, Brian W. Fitzpatrick, C. Michael Pilato, http://svnbook.red-bean.com/en/1.0/index.html



Subversion (3)

Client/Server Central storage Multiple local checkouts

Workflow Update / Checkout (Solve conflicts) Change code Commit



Subversion (4) Stand Alone Clients Command line version RapidSVN TortoiseSVN

Plugins for most IDEs Visual Studio

Visual SVN AnkhSVN

Eclipse Subclipse Subvervise



Libraries Do not reinvent the wheel! Reuse code as much as

possible In the group project, you are

not expected to write all code yourself. You are allowed to use external libraries.


Graphic Libraries



OpenGL

Open Graphics Library Industry standard for 2D and 3D

graphics OpenGL was developed by Silicon

Graphics Inc. (SGI) in 1992, led the creation of the OpenGL architectural review board (OpenGL ARB)

On the 31st July, 2006 it was announced at SIGGRAPH that control of the OpenGL specification would be passed to the Khronos Group


http://en.wikipedia.org/wiki/SIGGRAPH

http://en.wikipedia.org/wiki/SIGGRAPH


OpenGL (2)

OpenGL is multiplatform Embedded version OpenGL ES

“Glue”-layers for window handling GLX on Unix/Linux WGL on Windows CGL on Mac OS X

Programmable shaders with GLSL



DirectX/Direct3D

Started in 1995 by Microsoft Collection of APIs for a lot of

different multimedia Feature rich and good performance Fast to adapt new technologies Good standard libraries Arguably more cumbersome than OpenGL Programmable shaders with HLSL



XNA (XNA's Not Acronymed)

A set of tools with a managed runtime environment that facilitates computer games development

Write once, run on (almost) any Microsoft platform. Common language runtime

.NET based VM Very accessible for new developers XNA Game Studio Express

Windows & XBOX 360 C# (officially supported) Free



Open SG

Open Source API for scenegraphs (collection of nodes in a tree describing a scene)

Realtime applications Mostly for VR However, the design is

interesting for game engines


Sound Libraries



OpenAL

Open Source library for audio Has grown rapidly Multiplatform Primarily used on stationary computers Windows, Mac, Linux but available also for Xbox and Xbox 360 and

iPhone Used in: Battlefield 2, Unreal Tournament, Quake 4, etc.



FMOD

Library for sound Multiplatform PC, Wii, Xbox, Xbox 360, Ps3, iPhone, etc.

Support for most audio formats Free for non-commercial use Batman: Arkham Asylum, Far Cry, Guitar Hero, LittleBigPlanet,

Call of Duty 4, Forza Motorsport, Starcraft 2 ....


http://en.wikipedia.org/wiki/Call_of_Duty_4

http://en.wikipedia.org/wiki/Call_of_Duty_4

Phsycs Libraries



ODE

Open Source physics engine Multiplatform Mostly used in hobby productions but also a

few commercial Stalker, Call of Juarez, Bloodrayne 2



Newton

Free physics engine Not open source but free to use Used in the Swedish independent game

Penumbra.



PhysX

Industry standard physics engine

Nowadays, the binary SDK is free

Connects to physics hardware

Used in lots of next-gen titles Unreal 3 engine, Mass Effect,

GRAW, Mirror’s Edge...


http://www.nzone.com/object/nzone_mirrorsedge_home.html

http://www.nzone.com/object/nzone_mirrorsedge_home.html


Havok

The other industry standard physics engine Commercially available, free for non

commercial use Has packages for physics driven character

behaviors and animation in addition to the physics engine.

Used in major titles Half-life 2, Halo 3, etc.



Bullet 3D

Multiplatform (Playstation 3, XBox 360, Nintendo Wii, PC and iPhone) Open Source Modular extendible C++ design with hot-swap of most components Optimized back-ends with multi-threaded support for Playstation 3 Cell SPU, CUDA,

OpenCL and other platforms Features

Discrete and continuous collision detection (CCD)

Swept collision queries

Ray casting with custom collision filtering

Generic convex support (using GJK), capsule, cylinder, cone, sphere, box and non-convex triangle meshes.

Rigid body dynamics including constraint solvers, generic constraints, ragdolls, hinge, ball-socket

Support for constraint limits and motors

Soft body support including cloth, rope and deformable

Bullet is integrated into Blender 3D and provides a Maya Plugin Supports import and export into COLLADA 1.4 Physics format

Support for dynamic deformation of non-convex triangle meshes, by refitting the acceleration structures

Halo 3, Free realms, Trial HD...


Graphical User Interface Libraries



CEGUI

Open Source GUI system Object oriented architecture with interfaces and

events Integrated into Ogre3D LGPL, so free to use



Microsoft Foundation Classes (MFC)

Graphical interface for Windows Based largely on inheritance and polymorphism Large amount of classes and arguably hard to

work with Succeeded by Windows Presentation

Foundation in .NET 3.0 designed to remove dependencies on the aging GDI built on DirectX clear separation between the user interface and the

programming logic



GTK+

Multiplatform GUI toolkit Used primarily in Linux/Unix environments Nowadays available in Windows as well

Initially developed for The Gimp which is an Open Source image editor

Alternatives to GTK are Qt and Motif



Scaleform

Commercially available Used in countless number of games Flash based Flash Videos Animated Textures Audio support ...

Editor for quickly building UIs Even full mini games

http://www.scaleform.com/


http://www.scaleform.com

http://www.scaleform.com

Networking Libraries



Open TNL

Torque Network Layer Originally a part of the Torque engine Open Source version of TNL and is intended for

non-commercial use



RakNet Free for non-commercial use Multiplatform Used by mayor game developers Extensively documented Features

Lobby system Object replication system Secure connections Robust communication layer RPC Voice Communication NAT PunchThrough

Video Tutorial of Features http://www.rakkarsoft.com/raknet/

manual/RakNetMajorFeatures.html


http://www.rakkarsoft.com/raknet/manual/RakNetMajorFeatures.html






Tool Libraries



Boost

General C++ library Contains lots of useful stuff Smart pointers Regex Threading Etc...

Practically a part of standard C++



Break

http://xkcd.com


http://xkcd.com

http://xkcd.com


Performance and optimization

Optimization techniques and measuring performance could be a course of its own

Optimize with extreme prejudice Optimization is a time-consuming task Put your effort into optimizing the critical parts of

the code and leave the rest to the compiler




High-level and inner loops Optimizing functions that are called just a few times

is meaningless Optimize inner loops Optimize high-level functionality. Switching

algorithms can boost performance a lot more than low-level optimizations

Use a profiler Identifies bottlenecks Often, bottlenecks are not where you would expect

them to be




Beware of virtual functions Calling virtual functions in C++ requires looking up

function pointers in the virtual function table of a class

Do not use in inner loops Use assembly only when absolutely necessary Assembly is rarely portable Try tweaking your compiler first

Read Zen of Code Optimization by Michael Abrash for tips



Documentation

Your role as a software engineer Engineers write documentation Reports Documentation for code and implementations

Extra important for a reusable simulation engine

Badly documented projects will automatically fail this course!



Documenting a simulation engine

A simulation engine should be documented in at least the following ways Requirements

Functional and non-functional requirements on the engine or the extensions made to it. Functional requirements are the features that the engine is actually capable of, whereas non-functional ones describe its properties.

Functional requirements may be calculations, technical details, data manipulation and processing and other specific functionality that define what a system is supposed to accomplish.

Non-functional requirements (also known as quality requirements), impose constraints on the design or implementation (such as performance requirements, security, or reliability)

Analysis The conceptual model of your game engine, including the high-level concepts and

their associations.

Design Class and interaction diagrams

Implementation Api reference (source code documentation).



Doxygen

Documentation system C/C++, Java, etc.

Inspired by Javadoc Generates both HTML and offline manuals

/** * This is a documentation string. * * @param i first parameter * @param j second parameter * @return description of return value. */int foo(int i, int j);



Content Creation Tools

Code is our thing, but not necessarily everyone else's

Simulation engines, and the projects they are used with, require extremely functional content pipelines



World Editors

Large difference between outdoor and indoor environments

Outdoor environments are mostly based on heightmaps

Objects often placed on heightmap in 2½D



World Editors: Examples

Terragen Generates and renders fairly

impressive procedural terrain FreeWorld 3D

Terrain editor geared towards with game development with support for Ogre3D

CryEngine Sandbox The engine used in FarCry

has exceptional tools for working with outdoor scenes



Level editors

Geared towards indoor scenery Nowadays, thin line between

level editors and outdoor scene editors

Commonly released along with the games they were built for

Similar to regular 3D modeling tools, but simplified

A science of its own, check the web for lots and lots of information



Level Editors: Examples

Hammer Used with the Source engine

(Half-life) Radiant

Editor for the Quake3 and now Doom3 engine

UnrealEd Official editor for the Unreal

engine Sandbox

Official editor for the CryEngine



3D modeling

3D Studio Max Most popular

Maya Popular with animatos

Lightwave 3D Powerful but not as common

Softimage Modern and flexible but not

as common Blender

Free and surprisingly able



Integrate 3D modeling software

Programmers are rarely 3D artists as well Need to translate data from 3D modeling

application to simulation engine Often, special tools need to be written in native

APIs Alternatively rely on standard export formats FBX, Collada, Obj, 3ds, etc



Example: Maya API

Maya Embedded Lanuage, MEL API for C/C++ access Fairly usable (in contrast to the Max SDK)

• 3D graphical manipulators• geometry shapes• dynamic fields• particle emitters• node and plug locking• custom model views• user defined transformations• motion capture servers• manipulators• any other type of custom node

• MEL commands• file translators (e.g. exporters for game engines, or third party renderers)• drawing in OpenGL• inverse-kinematic solvers• shaders, lights, textures hardware shaders• procedural animation• simulators (e.g. Maya Cloth was written entirely using the API)• user-defined deformations



Ogre3D



Ogre showcase



Ogre showcase



Ogre showcase



Ogre showcase



Ogre showcase



Ogre showcase



Ogre3D

Ogre is not a complete simulation engine It is primarily a renderer

“I realise this approach means that as of today, it’s not as fastto develop a game with OGRE than it is with another all-in-oneengine. [...] My philosophy is to build a flexible graphics componentwhich can be used in the maximum number of situations, and to makeit easy to integrate with other components - not to build an enginethat can be used to make a small number of game variants. [...]You’ll find it a lot harder to extend an engine which is designed tohandle only a small subset of scene types, with strongly integratedfeatures designed from a certain perspective. [...]”



Ogre3D is not...

Commercial It is freely available for use even in commercial projects

Closed source Ogre3D is Open Source with full access to all underlying source code

Finished Open Source applications are never finished and undergo constant

improvements. Ogre3D has reached v1.0 though and is reasonably stable.

Bug-Free Connected to the previous item

A complete simulation engine Only provides 3D functionality and rudimentary input

Completely documented Be prepared to get your hands dirty! I mean it!



Ogre3D contains

Windows, MacOS & Linux support Direct3D and OpenGL support Material and shader system with support for CG, HLSL and GLSL Texture and mesh loading Skeletal and morph animation Scene management with support for many different types of

scenes Shadow rendering Compositor system for post processing effects Particle systems Resource management Lots of other stuff...



What completes the gaps?

Sound OpenAL, FMOD

Collision / Physics OpCode, Bullet,

PhysX, ODE, Newton AI

OpenSteer, FFLL

Network OpenTNL, ZoidCom, RakNet

GUI CEGUI, Flash

Scripting Lua, Python, GameMonkey,

Ruby



Get started with Ogre3D

Install a compiler of your choice (for this course, preferably Visual Studio)

Plenty of tutorials, demos, help texts at www.ogre3d.org

Read the documentation (RTFM)


http://www.ogre3d.org/

http://www.ogre3d.org/


Where to get help

Do not hesitate to ask, but I will not be able to assist in every possible case

Visit these places Official website http://www.ogre3d.org Forums http://www.ogre3d.org/phpBB2/ Wiki http://www.ogre3d.org/wiki IRC irc://freenode/ogre3d



Conclusion

There is a lot to think about when it comes to simulation engines

These lectures will not cover specific or practical details. Find those on your own. Do not be afraid to ask questions though.

Please help each other with help in installing the SDKs to get started and so forth
