com.openinventor.inventor.geo

Class SoGeoLOD

java.lang.Object

com.openinventor.inventor.Inventor

com.openinventor.inventor.misc.SoBase

com.openinventor.inventor.fields.SoFieldContainer

com.openinventor.inventor.nodes.SoNode

com.openinventor.inventor.nodes.SoGroup

com.openinventor.inventor.geo.SoGeoLOD

All Implemented Interfaces:

SafeDisposable

public class SoGeoLOD
extends SoGroup

Level-of-detail management for multi-resolution terrains. The SoGeoLOD node allows applications to build massive tiled, multi-resolution terrain models where the viewer progressively loads higher resolution detail as you fly into the terrain.

VRML X3D SPECIFICATION

This section describes the expected behavior of the node in a conforming X3D / VRML97 browser application. In some cases, the application is responsible for implementing portions of the expected behavior. Open Inventor viewer classes and IVF classes implement some of the application behaviors.

This section may reference portions of the X3D specification that are not present in this help file. The complete X3D spec is available at http://www.web3d.org.

The SoGeoLOD node provides a terrain-specialized form of the LOD node. It is a grouping node that specifies two different levels of detail for an object using a tree structure, where 0 to 4 children can be specified, and also efficiently manages the loading and unloading of these levels of detail. The level of detail is switched depending upon whether the user is closer or further than range meters from the geospatial coordinate center. The center field should be specified as described in 25.2.4 Specifying geospatial coordinates. The geoSystem field is used to define the spatial reference frame and is described in 25.2.3 Specifying a spatial reference frame. When the user is outside the specified range, only the geometry for rootUrl or rootNode are displayed. When the viewer enters the specified range, this geometry is replaced with the contents of the four children files defined by child1Url through child4Url. The four children files are loaded into memory only when the user is within the specified range. Similarly, these are unloaded from memory when the user leaves this range. Figure below illustrates this process. The child URLs shall be arranged in the same order as in the figure; i.e., child1Url represents the bottom-left quadtree child. It is valid to specify less than four child URLs; in which case, the SoGeoLOD should switch to the children nodes when all of the specified URLs have been loaded. This latter feature can support tree structures other than quadtrees, such as binary trees.

The rootUrl and rootNode fields provide two different ways to specify the geometry of the root tile. You may use one or the other. The rootNode field lets you include the geometry for the root tile directly within the X3D file; whereas the rootUrl field lets you specify a URL for a file that contains the geometry. The result of specifying a value for both of these fields is undefined.

File format/default:

GeoLOD {

center	0 0 0
child1Url	[]
child2Url	[]
child3Url	[]
child4Url	[]
geoSystem	["GD","WE"]
range	10
rootUrl	[]

}

Action behavior:

SoGLRenderAction, SoCallbackAction, SoGetBoundingBoxAction, SoRayPickAction, SoGetPrimitiveCountAction

Nested Class Summary

Nested classes/interfaces inherited from class com.openinventor.inventor.Inventor

Inventor.ConstructorCommand

Field Summary

Fields

Modifier and Type	Field and Description
SoSFVec3d	center Object-space center of the model.
SoSFString	child1Url First child url : bottom-left quadtree child.
SoSFString	child2Url Second child url : up-left quadtree child.
SoSFString	child3Url Third child url : up-right quadtree child.
SoSFString	child4Url Fourth child url : bottom-right quadtree child.
SoMFString	geoSystem Defines the spatial reference frame.
SoSFFloat	range World-space distance to use as switching criteria.
SoSFString	rootUrl Url of the file that contains the root tile geometry.

Fields inherited from class com.openinventor.inventor.nodes.SoGroup

boundingBoxIgnoring

Fields inherited from class com.openinventor.inventor.Inventor

VERBOSE_LEVEL, ZeroHandle

Constructor Summary

Constructors

Constructor and Description
SoGeoLOD() Constructor.
SoGeoLOD(int nChildren) Constructor that takes approximate number of children.

Method Summary

Methods inherited from class com.openinventor.inventor.nodes.SoGroup

addChild, findChild, getChild, getNumChildren, insertChild, removeAllChildren, removeChild, removeChild, replaceChild, replaceChild

Methods inherited from class com.openinventor.inventor.nodes.SoNode

affectsState, callback, copy, copy, distribute, doAction, getAlternateRep, getBoundingBox, getByName, getMatrix, getPrimitiveCount, getRenderUnitID, GLRender, GLRenderBelowPath, GLRenderInPath, GLRenderOffPath, grabEventsCleanup, grabEventsSetup, handleEvent, isBoundingBoxIgnoring, isOverride, pick, rayPick, search, setOverride, touch, write

Methods inherited from class com.openinventor.inventor.fields.SoFieldContainer

copyFieldValues, copyFieldValues, enableNotify, fieldsAreEqual, get, getAllFields, getEventIn, getEventOut, getField, getFieldName, hasDefaultValues, isNotifyEnabled, set, setToDefaults

Methods inherited from class com.openinventor.inventor.misc.SoBase

dispose, getEXTERNPROTO, getName, getPROTO, isDisposable, isSynchronizable, setName, setSynchronizable

Methods inherited from class com.openinventor.inventor.Inventor

getAddress, getNativeResourceHandle, startInternalThreads, stopInternalThreads

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

geoSystem

public final SoMFString geoSystem

Defines the spatial reference frame.
Valid values are:

• GC: Earth-fixed Geocentric with respect to the WGS84 ellipsoid.
• GD: Geodetic spatial reference frame.
  An optional second string may be used to specify the ellipsoid using one of the ellipsoid codes that are defined in X3D. If no ellipsoid is specified, then "WE" is assumed (the WGS84 ellipsoid).
• UTM: Universal Transverse Mercator
  One further required argument must be supplied for UTM in order to specify the zone number (1..60). This is given in the form "Zn", where n is the zone number. An optional argument of "S" may be supplied in order to specify that the coordinates are in the southern hemisphere (otherwise, northern hemisphere will be assumed).

child1Url

public final SoSFString child1Url

First child url : bottom-left quadtree child.

child2Url

public final SoSFString child2Url

Second child url : up-left quadtree child.

child3Url

public final SoSFString child3Url

Third child url : up-right quadtree child.

child4Url

public final SoSFString child4Url

Fourth child url : bottom-right quadtree child.

rootUrl

public final SoSFString rootUrl

Url of the file that contains the root tile geometry.

range

public final SoSFFloat range

World-space distance to use as switching criteria.

center

public final SoSFVec3d center

Object-space center of the model.

Constructor Detail

SoGeoLOD

public SoGeoLOD()

Constructor.

SoGeoLOD

public SoGeoLOD(int nChildren)

Constructor that takes approximate number of children.