introduction to java 3d

department of computer scienceand engineering

INTRODUCTION TO JAVA 3DINTRODUCTION TO JAVA 3D

Martin Martin ČČadíkadíkCzech Technical University in Prague, Czech RepublicCzech Technical University in Prague, Czech Republic

November 27, 2002

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ContentContent

OverviewOverview Scene graphScene graph Java 3D classesJava 3D classes Simple applicationSimple application Describing objectsDescribing objects Groups, transformsGroups, transforms Behaviors, interpolators, pickingBehaviors, interpolators, picking Lighting, SoundLighting, Sound

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What Is Java3D?What Is Java3D?

APIAPI– Applications or AppletsApplications or Applets– ““Write once, run anywhere”Write once, run anywhere”

• platform independent (IBM AIX, HP-UX, Linux, SGI IRIX, Solaris/Sparc, platform independent (IBM AIX, HP-UX, Linux, SGI IRIX, Solaris/Sparc, Windows)Windows)

• display environmentsdisplay environments

– higher level APIhigher level API• objects instead of verticesobjects instead of vertices

• content instead of rendering processcontent instead of rendering process

– scalablescalable– scene graph - basedscene graph - based

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Java3D - OverviewJava3D - Overview

JavaJava– JREJRE

– SDKSDK

Java 3DJava 3D– JREJRE

– SDKSDK

– OpenGLOpenGL

– DirectXDirectX

Code examples in distributiCode examples in distributionon

ApplicationsApplications– scientific visualization, scientific visualization,

animation, web design, animation, web design, simulations, virtual world simulations, virtual world construction (CAVE), training, construction (CAVE), training, games, design automationgames, design automation

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Java3D Scene GraphJava3D Scene Graph

VirtualUniverseVirtualUniverse– to contain all 3D datato contain all 3D data

– typically one per applicationtypically one per application

– SimpleUniverseSimpleUniverse

– Locale Locale objectobject

ViewView– describes how to view 3D describes how to view 3D

contentcontent

– multiple views per universemultiple views per universe

– View PlatformView Platform (movable) (movable)

Content BranchContent Branch– describes 3D contentdescribes 3D content

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Java 3D RendererJava 3D Renderer

Canvas 3DCanvas 3D– surface onto which a surface onto which a View View rendersrenders

– one canvas per viewone canvas per view

– there can be multiple canvases per appthere can be multiple canvases per app

while (true) { Process input if (exit request)break Check for collisions Perform behaviors Start playing sounds Traverse scene graph and render objects }Cleanup

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Java 3D ClassesJava 3D Classes

javax.media.j3d packagejavax.media.j3d packagejavax.media.j3d.VirtualUniverse (java.lang.Object)

Enumeration getAllLocales( )

javax.media.j3d.Locale

VirtualUniverse getVirtualUniverse( ) void addBranchGraph( Branchgroup branchGroup )

removeBranchGraph( Branchgroup branchGroup ) void Enumeration getAllBranchGraphs( )

javax.media.j3d.SceneGraphObject

Capabilities (read/write transforms, geometry Capabilities (read/write transforms, geometry coords...)coords...)

javax.media.j3d.Node

javax.media.j3d.NodeComponent

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Java 3D ClassesJava 3D Classes

javax.media.j3d.Node– Shapes, Groups, Sounds, Lights, etc.

– parent nodeparent node

– location (local, VWorld transform)location (local, VWorld transform)

– bounding volume (automatical computation)bounding volume (automatical computation)

javax.media.j3d.NodeComponent– attributesattributes– Shape geometry, Shape appearance, Shape texture, etc.

javax.vecmath packagejavax.vecmath packagejavax.vecmath.Tuple3d

Vector3d

Point3d, Color3d, etc.

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Coordinate System, ElementsCoordinate System, Elements

Coordinate systemCoordinate system– Right-handedRight-handed

• +X is to the right+X is to the right• ++Y is upY is up• +Z is towards the viewer+Z is towards the viewer

– Angles in radiansAngles in radians

– Distance in metersDistance in meters

Elements in a GeometryElements in a Geometry– CoordinatesCoordinates

– NormalsNormals

– ColorsColors

– TextureCoordinatesTextureCoordinates

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Simple Java3D ApplicationSimple Java3D Application

Construct view branchConstruct view branch– Canvas3DCanvas3D

– SimpleUniverseSimpleUniverse• VirtualUniverse, Locale, VirtualUniverse, Locale,

BranchGroup, TransformGroup, BranchGroup, TransformGroup, ViewPlatform, ViewViewPlatform, View

Construct content branchConstruct content branch– BranchGroupBranchGroup

– TransformGroupTransformGroup

– Shape3D, Light, Sound...Shape3D, Light, Sound...

– BehaviorBehavior

SimpleApp3DSimpleApp3D– codecode

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ShapeShape3D3D

Fundamental mean of describing objectFundamental mean of describing objectjavax.media.j3d.Shape3D (Leaf)

Geometry Geometry void setGeometry(Geometry geometry)

AppearanceAppearancevoid setAppearance(Appearance appearance)

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GeometryGeometry

javax.media.j3d.Geometry (NodeComponent)

GeometryArrayGeometryArray– LineArray, PointArray, TriangleArray, QuadArrayLineArray, PointArray, TriangleArray, QuadArray– Indexed~Indexed~– Stripped versionsStripped versions

Text3DText3Djavax.media.j3d.Text3D

– exampleexample

RasterRaster– raster imageraster image

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AppearanceAppearance

javax.media.j3d.Appearance (NodeComponent)

Specifies how to render Specifies how to render GeometryGeometry sibling sibling– Color (intrinsic) and shading (flat, Gouraud)Color (intrinsic) and shading (flat, Gouraud)

• ColoringAttributes• Material

– TransparencyTransparency• TransparencyAttributes

– Line, point, polygon attributesLine, point, polygon attributes• LineAttributes, PointAttributes,

PolygonAttributes

– Rendering controlRendering control– Texture mappingTexture mapping

– exampleexample

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Loading contentLoading content

LoaderLoader– creates scene graph elements creates scene graph elements

from a filefrom a file

com.sun.j3d.loaders– only the interface included in only the interface included in

Java 3DJava 3D

UsageUsage– import loaderimport loader

– create loader objectcreate loader object

– Scene Scene variablevariable

– load fileload file

– insert insert Scene Scene into the scene into the scene graphgraph

Available loadersAvailable loaders– 3DS, COB, DEM, DXF, IOB, 3DS, COB, DEM, DXF, IOB,

LWS, NFF, OBJ, PDB, PLAY, LWS, NFF, OBJ, PDB, PLAY, SLD, VRT, VTK, WRLSLD, VRT, VTK, WRL

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GroupingGrouping

exactly one parent, arbitrary childrenexactly one parent, arbitrary childrenjavax.media.j3d.Group (Node)

BranchGroup, OrderedGroup, SharedGroup (Link), Switch, TransformGroup

child rendering order determines Java 3Dchild rendering order determines Java 3D– can perform sorting for better rendering efficiencycan perform sorting for better rendering efficiency

BranchGroupsBranchGroups– can be attached to can be attached to Locale Locale ---->> it makes it it makes it live live --> constrains by --> constrains by

capabilitiescapabilities– can be compiledcan be compiled

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TransformingTransforming

world coordinate systemworld coordinate systemTransformGroup

– new coordinate system relative to new coordinate system relative to parentparent

transformation accumulate as graph is traversedtransformation accumulate as graph is traversed

Transform3D (Object)– 4 x 4 matrix of doubles - 4 x 4 matrix of doubles - Matrix4d– translate, rotate, scale, sheartranslate, rotate, scale, shear– must be affine (no perspective)must be affine (no perspective)– helper methodshelper methods

• setIdentity, rotX.., setScale, setTranslation, setRotation, etc.

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Texture mappingTexture mapping

Appearance nodeAppearance nodeTexture2D (abstract Texture (NodeComponent))

- image textures, example- image textures, example

Texture3D - volume textures- volume textures

Texture formatTexture format– IntensityIntensity– Luminance, AlphaLuminance, Alpha– RGB, RGBARGB, RGBA

TextureAttributes (NodeComponent)– Mode: Blend, Decal, Modulate, ReplaceMode: Blend, Decal, Modulate, Replace– TransformTransform– Perspective correctionPerspective correction

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BehaviorsBehaviors

javax.media.j3d.Behavior

code to run (code to run (processStimulus)) wakeup conditionswakeup conditions

– frame or milliseconds have elapsedframe or milliseconds have elapsed– AWT eventAWT event– transform changetransform change– collision, view platform or sensor is closecollision, view platform or sensor is close

scheduling boundsscheduling bounds– activation radius intersects scheduling boundsactivation radius intersects scheduling bounds– runs only when necessaryruns only when necessary– common errorcommon error - forgetting scheduling bounds - forgetting scheduling bounds

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InterpolatorsInterpolators

javax.media.j3d.Interpolator

simple behaviorssimple behaviors– vary a parameter from starting to ending valuevary a parameter from starting to ending value– Time-to-Alpha mapping Time-to-Alpha mapping (Alpha (Object) <0,1>)– Alpha-to-Value mappingAlpha-to-Value mapping

• transforms, colors, switchestransforms, colors, switches

– Target (f.e. TransformGroup)Target (f.e. TransformGroup)

PositionInterpolator,

RotationInterpolator,

ColorInterpolatorm, etc.

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Input devicesInput devices

– joysticksjoysticks– 6DOF devices (Magellan, Ultrasonic tracker...)6DOF devices (Magellan, Ultrasonic tracker...)– buttonsbuttons– real / virtualreal / virtual

javax.media.j3d.InputDevice interface– implementation maps physical detectors onto implementation maps physical detectors onto Sensor objectobject

(process input, return Sensor)(process input, return Sensor)

javax.media.j3d.Sensor (Object)– SensorRead objectobject

• time-stamptime-stamp

• 6DOF value, button state6DOF value, button state

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Picking featuresPicking features

– selecting Shapesselecting Shapes– interaction methodsinteraction methods– designed for speed (Bounds)designed for speed (Bounds)

Pick methods (Node)Pick methods (Node)– take take PickShape (PickPoint, PickRay, PickSegment)– return return SceneGraph objectsobjects– f.e.: f.e.: pickAll, pickAllSorted, pickClosest

– example

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Lighting the environmentLighting the environment

javax.media.j3d.Light

Types of lightsTypes of lights– ambient - ambient - AmbientLight– directional - directional - DirectionalLight– point - point - PointLight

• attenuationattenuation

– spot - spot - SpotLight

Light attributesLight attributes– on/offon/off

– colorcolor

– bounding volume and scopebounding volume and scope• by default universal scopeby default universal scope

– again: again: common errorcommon error - forgetting - forgetting scheduling boundsscheduling bounds

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SoundsSounds

javax.media.j3d.Sound

SoundsSounds– triggeredtriggered

– continuouscontinuous

Sound typesSound types– background - background - BackgroundSound– point - point - PointSound

• attenuatedattenuated

– cone - cone - ConeSound• attenuatedattenuated

Sound propertiesSound properties– sound data sound data (MediaContainer)

• AIF, AU, WAVAIF, AU, WAV

– looping parameterslooping parameters

– playback priorityplayback priority

– scheduling boundsscheduling bounds

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MiscMisc

BackgroundBackgroundjavax.media.j3d.Background

FogFog– exponential, linearexponential, linearjavax.media.j3d.Fog

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AccelerationAcceleration

Performance GuidePerformance Guide– capability bitscapability bits– compilationcompilation– bounds, activation radiusbounds, activation radius– geometry by referencegeometry by reference– unordered renderingunordered rendering

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NewsNews

FastScript 3DFastScript 3D– open sourceopen source– web applets using Java3D via JavaScript and HTMLweb applets using Java3D via JavaScript and HTML– Java, Java3D requiredJava, Java3D required– fs.jarfs.jar

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Java 3DJava 3D

Thank youThank youfor your attentionfor your attention

introduction to java 3d

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