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Qt3DInDepth

QtDeveloperDays,Berlin,7thOctober2014

PresentedbySeanHarmer&PaulLemire

BasedonQt3Dwip/newapiBranch

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Topics

Topics

Topics

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Topics

WhatisQt3D?

WhatisQt3D?

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Backtobasics

WhatshouldQt3Ddo?WhatshouldQt3Ddo?

WhatisQt3D?

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IdeasforQt3D

Graphics

3D/2D

Meshes

Materials

Shaders

Shadows

Ambientocclusion

Highdynamicrange

Deferredrendering

ThatcooltechniqueIreadabout...

WhatisQt3D?

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Whatdoesthatmean?

Whatdoesthatmeanforus?

Manytechniquesinpopularuse

Applicationdependent

Newtechniquesbeingdeveloped

Weneedtobeflexibleandextensible

WhatisQt3D?

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Requirement

Flexiblerenderer

EventuallybecametheFrameGraph

Data-drivenrendererconfguration

Moreonthislater

WhatisQt3D?

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Whatelse?

Beyondgraphics?

3Dpositionalaudio

Physicssimulation

Collisiondetection

Particles

Animation

Skeletal

Morphtargets

Pathfinding

Artificalintelligence

Fluidsimulation(liquids,smoke,etc)

Picking

Objectspawning

...

WhatisQt3D?

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What?Youwantmore?

...andifit'snottoomuchtrouble...

MakeitscalableacrossNCPUs/cores

Makeiteasytoextendandintegrate

WhatisQt3D?

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Topics

Designchallengesandmotivations

Designchallengesandmotivations

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Howtoproceed?

HowdowecomeupwithanHowdowecomeupwithanarchitecturetosatisfythatarchitecturetosatisfythatlot?lot?

Designchallengesandmotivations

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Analysis

Let'strytoanalyseasimpleandfamiliarexample

SpaceInvaders!

Designchallengesandmotivations

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ObjectModel

Designchallengesandmotivations

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Youwanttodowhat?

Designchallengesandmotivations

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Bubbleup

Designchallengesandmotivations

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Bubbleupsomemore

Designchallengesandmotivations

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Thedreadeddiamondofdeath

Designchallengesandmotivations

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Mixinclasses

Designchallengesandmotivations

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Allmixedup

Designchallengesandmotivations

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Problemswithinheritance

Inheritance:

Deepandwidehierarchies

Difficulttocomprehend

Difficulttomaintain

Deeperclasseshardertomodify

Onedimensionaltaxonomies

Eachlevelinhierarchyclassifiesbasedonasinglecriteria

Taxonomyissetinstone

Oftenhackedaroundleadingtomoreconfusion

Designchallengesandmotivations

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Problemswithinheritancecont'd

Inheritance:

Sharedcharacteristicstendtobubbleup

Leadstolargebaseclasses

Subclassesusingonlysomefeatures

Lotsofbloat

Multipleinheritance

Dreadeddiamondpattern

VerydifficulttodesignaMIscheme...

...thatworksandisunderstandable

Mix-inclasses

LimitedformofMI

Stepintherightdirection

Stillstatic

Designchallengesandmotivations

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Wheretothen?

Ifinheritanceisnogood,howabout...

AggregationorComposition

Has-aHas-aratherthanis-ais-a

Dynamicatruntime

Noneedtopreempteverypossiblecombination

Extensiblevianewaggregatedtypes

Objectsaresimplybagsofbuildingblocks

Designchallengesandmotivations

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EntityComponentSystem

Anentityentityisanemptyobject

Gaindatabyaggregatingcomponentscomponents

AspectsAspectsoperateonentitiestogivebehaviour

Designchallengesandmotivations

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EntityComponentSystemcont'd

Designchallengesandmotivations

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Qt3D'sECS

QObjectneedsextending

QNode

Communicateswithaspects

UniqueIDs

QEntity

QComponent

Mesh

Material

Transform

Collider

Yourcomponenttypehere...

QAbstractAspect

RendererAspect

PhysicsAspect

...

Designchallengesandmotivations

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ObjectModel

Designchallengesandmotivations

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Done?

Sowe'realldone,right?

Ha-ha-ha-ha-ha.No.

Weneedafewmorepieces...

Designchallengesandmotivations

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Qt3DAchitecture

Designchallengesandmotivations

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Topics

HowQt3Dworks

HowQt3Dworks

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Qt3DAchitecture-Howitworks

Let'sseehowsometypicalinteractionsoccur...

HowQt3Dworks

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Jobs

HowQt3Dworks

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Jobs

HowQt3Dworks

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Jobs

HowQt3Dworks

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Jobs

HowQt3Dworks

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Jobs

HowQt3Dworks

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PropertyChange

HowQt3Dworks

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PropertyChange

HowQt3Dworks

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PropertyChange

HowQt3Dworks

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PropertyChange

HowQt3Dworks

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AspectPropertyChange

HowQt3Dworks

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AspectPropertyChange

HowQt3Dworks

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AspectPropertyChange

HowQt3Dworks

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AspectPropertyChange

HowQt3Dworks

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AspectPropertyChange

HowQt3Dworks

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Sub-TreeAdded

HowQt3Dworks

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Sub-TreeAdded

HowQt3Dworks

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Sub-TreeAdded

HowQt3Dworks

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Sub-TreeAdded

HowQt3Dworks

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Sub-TreeAdded

HowQt3Dworks

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Sub-TreeAdded

HowQt3Dworks

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AspectAddsaSub-Tree

HowQt3Dworks

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Sub-TreeAdded

HowQt3Dworks

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Sub-TreeAdded

HowQt3Dworks

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Sub-TreeAdded

HowQt3Dworks

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Sub-TreeAdded

HowQt3Dworks

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Topics

Whatdoesthismakepossible?

Whatdoesthismakepossible?

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Whatcanwedo?

Qt3DwillprovideadefaultRendereraspectandInputaspect

Futurereleaseshaveplanned

Physicsaspect

Skeletalanimationaspect

OpenAL3DAudioaspect

Userscanextendwiththeirowncustomaspects

Whatdoesthismakepossible?

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Giveussomeexamples

Data-drivenRenderer-TheFrameGraph

C++rendererimplementationisgeneric

ConvertsfromRenderCommandstoOpenGLcalls

GenerationofRenderCommandsiscontrolledbydata

FrameGraphcomponent

TreeofFrameGraphItemscontrolsstateandEntityfiltering

SceneGraphofEntitiestorender

Whatdoesthismakepossible?

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RendertoTextureFramegraph

Whatdoesthismakepossible?

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RendertoTextureFramegraph

Whatdoesthismakepossible?

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RendertoTextureFramegraph

Whatdoesthismakepossible?

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Topics

Thefuture

Thefuture

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Whatnext?

LotsofAPIpolishing

Testing

Examples

Documentation

???

Profit

Thefuture

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Doesitwork?

Lot'smorestuffwehaven'tdiscussedtoday

Let'sseesomeactualexamples

Thefuture

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That'scool!Canwehelp?

Canwehelp?

Pleasedo!

Qt3Dwip/newapibranch

#qt-3donirc

Developmenteffort,ideas,sponsorshipallverywelcome

Thefuture

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Thankyou!

Questions?Questions?

Thefuture