Graphical Programming (1) Graphical Programming (2) Graphical ...

Graphical Programming (2)

Graphical Programming (1)

X-Windows  X-protocol, Xlib, window manager  OSF/Motif  widgets, widgets gadgets, gadgets window manager  MS MS--Windows  RenderMan  OpenGL  Direct3D 

programs to process and manipulate graphical objects and data  early standards: PHIGS PHIGS, GKS  2D, 3D graphics libraries  level of abstraction  low low--level API: OpenGL  scene graph API: Java3D 

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OpenInventor, VRML, X3D  scene graph oriented  engines, sensors, manipulators

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IRIS Performer

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Java3D

What is OpenGL?  OpenGL is a hardware hardware--independent interface to the graphics hardware OpenGL does not provide rendering context management functions or means to manage user input → Interface between OS and OpenGL needed:  WGL / Microsoft Windows  GLX / UNIX's X X--Windows (direct and indirect rendering)  GLUT / OS independent 3 / 24

E.Gröller, H. Doleisch, L. Mroz, S. Grimm

E.Gröller, H. Doleisch, L. Mroz, S. Grimm

Java Applet/Application

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Hierarchical structure

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Corresponds to logical structure of the scene

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Easy design and manipulation of complex scenes

Java 3D DirectX

Graphics Hardware E.Gröller, H. Doleisch, L. Mroz, S. Grimm

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Scenegraph

Java3D

OpenGL

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OpenGL / Windows System

Graphical Programming (3) 

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J3D--Scenegraph J3D content

The Renderer viewing

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Double buffering, RGB(A)

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Infinite loop: Traverse Graph

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Take care of transparency

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Regions of influence of fog, lights, sound

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Optimized for rendering (display list)

Node States - Capabilities  

Java3D Node Types

Node created: all operations legal Live:: Node inserted into scene Live - capabilities specify permitted operations p ((r / w / modify) y)

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Group nodes - addChild(...) 

BranchGroup - only detachable/relocable node - grouping of Shapes

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TransformGroup - transform applied to all children

setCapability(ALLOW_TRANSFORM_WRITE); setCapability( ALLOW_TRANSFORM_WRITE);

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Compiled (optional): Optimized by renderer - modifications restricted Capabilities fixed if live or compiled

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Hello3D! / Scenegraph

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Hello3D! / Constructor ... Canvas3D c=new Canvas3D(null); aWindow.add(c); BranchGroup content=createSceneGraph(); SimpleUniverse u=new SimpleUniverse(c); u.addBranchGraph(content);//now “live” ...

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Hello3D! Content

Java3D Node Types

Public BranchGroup createSceneGraph(){ BranchGroup objRoot=new BranchGroup(); Transform3D spin=new Transform3D(); Transform3D tmpspin=new Transform3D(); spin.rotX(Math.PI/4.0d); t tmpspin.rotY(Math.PI/5.0d); i tY(M th PI/5 0d) spin.mul(tmpspin); TransformGroup objTrans=new TransformGroup(spin); objRoot.addChild(objTrans); objTrans.addChild(new ColorCube()); return objRoot();} E.Gröller, H. Doleisch, L. Mroz, S. Grimm

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Shape3D - defines object within the scene Contains: Geometry - polygon related information  Attributes - material definition - rendering mode (wireframe, …) 

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Geometry Nodes

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Geometry Nodes Geometry definition:

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Helper Classes

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coordinates

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optional: normals

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optional: RGB(A) color

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optional: texture coord. (u/v[/w])

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for indexed types: indices

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Helper Classes  javax.vecmath javax.vecmath.* .*

- Tuple/Point/Vector Tuple/Point/Vector 2/3/4D d/float with corresponding operations - Matrix 3/4D d/float - Quaternion classes  javax.media.j3d.Transform3D - 4D matrix + helper func. func. for CG: orth//persp orth persp.. Projection, scale, rotate, translate, …

 com.sun.j3d.utils.*

- SimpleUniverse SimpleUniverse:: fast viewing model setup - Mouse Mouse--> Transform mapping for interactions - Simple geometrical Objects (cube, …)

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Appearance

Lighting

Defines attributes for rendering geometry of an object - polygon attributes: pts/wirefr./fill - culling - rendering attrib.: zz-buff., -blend. - transp./color (if not per vertex) - material (reflection coefficients) - texture images E.Gröller, H. Doleisch, L. Mroz, S. Grimm

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Behaviors

Ambient be t

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Directional (infinitely distant)

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PointLight (spot light)

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 Influence

transform. / geometry  Examples: - Mouse controlled navigation - Interpolator: timetime->value - ProximitySensor - Collision reaction - Picking: Click -> list of Shape3Ds below mouse 21 / 24

Viewing Model 

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Behaviors

“Events” for the scenegraph  Action executed if criteria met: - time triggered, kbd & mouse events, picking of objects, collision, frames elapsed  Boolean combination of criteria  Bounded area of relevance  processStimulus() E.Gröller, H. Doleisch, L. Mroz, S. Grimm

Light source nodes require Bounds delimiting the area of influence

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Java3D - Further Material

Supports multiple Canvas3D -> stereo rendering, (Cave!)

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Support for tracking tracking.

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Detailed description of viewer’s

Java 3D API specification documentation & tutorial: https://java3d.dev.java.net/

eyes/ears configuration

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