org.scijava.java3d.loaders.objectfile

Class ObjectFile

java.lang.Object

org.scijava.java3d.loaders.objectfile.ObjectFile

All Implemented Interfaces:

Loader

public class ObjectFile
extends Object
implements Loader

The ObjectFile class implements the Loader interface for the Wavefront .obj file format, a standard 3D object file format created for use with Wavefront's Advanced Visualizer (tm) and available for purchase from Viewpoint DataLabs, as well as other 3D model companies. Object Files are text based files supporting both polygonal and free-form geometry (curves and surfaces). The Java 3D .obj file loader supports a subset of the file format, but it is enough to load almost all commonly available Object Files. Free-form geometry is not supported.

The Object File tokens currently supported by this loader are:

v float float float

A single vertex's geometric position in space. The first vertex listed in the file has index 1, and subsequent vertices are numbered sequentially.

vn float float float

A normal. The first normal in the file is index 1, and subsequent normals are numbered sequentially.

vt float float

A texture coordinate. The first texture coordinate in the file is index 1, and subsequent normals are numbered sequentially.

f int int int . . .

or

f int/int int/int int/int . . .

or

f int/int/int int/int/int int/int/int . . .

A polygonal face. The numbers are indexes into the arrays of vertex positions, texture coordinates, and normals respectively. There is no maximum number of vertices that a single polygon may contain. The .obj file specification says that each face must be flat and convex, but if the TRIANGULATE flag is sent to the ObjectFile constructor, each face will be triangulated by the Java 3D Triangulator, and therefore may be concave. A number may be omitted if, for example, texture coordinates are not being defined in the model. Numbers are normally positive indexes, but may also be negative. An index of -1 means the last member added to the respective array, -2 is the one before that, and so on.

g name

Faces defined after this token will be added to the named group. These geometry groups are returned as separated Shape3D objects attached to the parent SceneGroup. Each named Shape3D will also be in the Hashtable returned by Scene.getNamedObjects(). It is legal to add faces to a group, switch to another group, and then add more faces to the original group by reissuing the same name with the g token. If faces are added to the model before the g token is seen, the faces are put into the default group called "default."

s int

or

s off

If the vn token is not used in the file to specify vertex normals for the model, this token may be used to put faces into groups for normal calculation ("smoothing groups") in the same manner as the 'g' token is used to group faces geometrically. Faces in the same smoothing group will have their normals calculated as if they are part of the same smooth surface. To do this, we use the Java 3D NormalGenerator utility with the creaseAngle parameter set to PI (180 degrees - smooth shading, no creases) or to whatever the user has set the creaseAngle. Faces in group 0 or 'off' use a creaseAngle of zero, meaning there is no smoothing (the normal of the face is used at all vertices giving the surface a faceted look; there will be a crease, or "Hard Edge," between each face in group zero). There is also an implied hard edge between each smoothing group, where they meet each other.

If neither the vn nor the s token is used in the file, then normals are calculated using the creaseAngle set in the contructor. Normals are calculated on each geometry group separately, meaning there will be a hard edge between each geometry group.

usemtl name

The current (and subsequent) geometry groups (specified with the 'g' token) have applied to them the named material property. The following set of material properties are available by default:

     amber           amber_trans       aqua            aqua_filter
     archwhite       archwhite2        bflesh          black
     blondhair       blue_pure         bluegrey        bluetint
     blugrn          blutan            bluteal         bone
     bone1           bone2             brass           brnhair
     bronze          brown             brownlips       brownskn
     brzskin         chappie           charcoal        deepgreen
     default         dkblue            dkblue_pure     dkbrown
     dkdkgrey        dkgreen           dkgrey          dkorange
     dkpurple        dkred             dkteal          emerald
     fgreen          flaqua            flblack         flblonde
     flblue_pure     flbrown           fldkblue_pure   fldkdkgrey
     fldkgreen       fldkgreen2        fldkgrey        fldkolivegreen
     fldkpurple      fldkred           flesh           fleshtransparent
     flgrey          fllime            flltbrown       flltgrey
     flltolivegreen  flmintgreen       flmustard       florange
     flpinegreen     flpurple          flred           fltan
     flwhite         flwhite1          flyellow        glass
     glassblutint    glasstransparent  gold            green
     greenskn        grey              hair            iris
     jetflame        lavendar          lcdgreen        lighttan
     lighttan2       lighttan3         lighttannew     lightyellow
     lime            lips              ltbrown         ltgrey
     meh             metal             mintgrn         muscle
     navy_blue       offwhite.cool     offwhite.warm   olivegreen
     orange          pale_green        pale_pink       pale_yellow
     peach           periwinkle        pink            pinktan
     plasma          purple            red             redbrick
     redbrown        redorange         redwood         rubber
     ruby            sand_stone        sapphire        shadow
     ship2           silver            skin            sky_blue
     smoked_glass    tan               taupe           teeth
     violet          white             yellow          yellow_green
     yellowbrt       yelloworng
   

mtllib filename

Load material properties from the named file. Materials with the same name as the predefined materials above will override the default value. Any directory path information in (filename) is ignored. The .mtl files are assumed to be in the same directory as the .obj file. If they are in a different directory, use Loader.setBasePath() (or Loader.setBaseUrl() ). The format of the material properties files are as follows:

newmtl name

Start the definition of a new named material property.

Ka float float float

Ambient color.

Kd float float float

Diffuse color.

Ks float float float

Specular color.

illum (0, 1, or 2)

0 to disable lighting, 1 for ambient & diffuse only (specular color set to black), 2 for full lighting.

Ns float

Shininess (clamped to 1.0 - 128.0).

map_Kd filename

Texture map. Supports .rgb, .rgba, .int, .inta, .sgi, and .bw files in addition to those supported by TextureLoader.

Field Summary

Fields

Modifier and Type	Field and Description
static int	RESIZE Flag sent to constructor.
static int	REVERSE Flag sent to constructor.
static int	STRIPIFY Flag sent to contructor.
static int	TRIANGULATE Flag sent to constructor.

Fields inherited from interface org.scijava.java3d.loaders.Loader

LOAD_ALL, LOAD_BACKGROUND_NODES, LOAD_BEHAVIOR_NODES, LOAD_FOG_NODES, LOAD_LIGHT_NODES, LOAD_SOUND_NODES, LOAD_VIEW_GROUPS

Constructor Summary

Constructors

Constructor and Description
ObjectFile() Default constructor.
ObjectFile(int flags) Constructor.
ObjectFile(int flags, float radians) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
String	getBasePath() Return the path where files associated with this .obj file (like material files) are located.
URL	getBaseUrl() Return the URL where files associated with this .obj file (like material properties files) will be found.
int	getFlags() Get the parameters currently defined for loading the model.
Scene	load(Reader reader) The Object File is loaded from the already opened file.
Scene	load(String filename) The Object File is loaded from the .obj file specified by the filename.
Scene	load(URL url) The object file is loaded off of the web.
void	setBasePath(String pathName) Set the path where files associated with this .obj file are located.
void	setBaseUrl(URL url) For an .obj file loaded from a URL, set the URL where associated files (like material properties files) will be found.
void	setFlags(int flags) Set parameters for loading the model.

Methods inherited from class java.lang.Object

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

Field Detail

RESIZE

public static final int RESIZE

Flag sent to constructor. The object's vertices will be changed so that the object is centered at (0,0,0) and the coordinate positions are all in the range of (-1,-1,-1) to (1,1,1).

See Also:

Constant Field Values

TRIANGULATE

public static final int TRIANGULATE

Flag sent to constructor. The Shape3D object will be created by using the GeometryInfo POLYGON_ARRAY primitive, causing them to be Triangulated by GeometryInfo. Use this if you suspect concave or other non-behaving polygons in your model.

See Also:

Constant Field Values

REVERSE

public static final int REVERSE

Flag sent to constructor. Use if the vertices in your .obj file were specified with clockwise winding (Java 3D wants counter-clockwise) so you see the back of the polygons and not the front. Calls GeometryInfo.reverse().

See Also:

Constant Field Values

STRIPIFY

public static final int STRIPIFY

Flag sent to contructor. After normals are generated the data will be analyzed to find triangle strips. Use this if your hardware supports accelerated rendering of strips.

See Also:

Constant Field Values

Constructor Detail

ObjectFile

public ObjectFile(int flags,
          float radians)

Constructor.

Parameters:

flags - The constants from above or from org.scijava.java3d.loaders.Loader, possibly "or'ed" (|) together.

radians - Ignored if the vn token is present in the model (user normals supplied). Otherwise, crease angle to use within smoothing groups, or within geometry groups if the s token isn't present either.

ObjectFile

public ObjectFile(int flags)

Constructor. Crease Angle set to default of 44 degrees (see NormalGenerator utility for details).

Parameters:

flags - The constants from above or from org.scijava.java3d.loaders.Loader, possibly "or'ed" (|) together.

ObjectFile

public ObjectFile()

Default constructor. Crease Angle set to default of 44 degrees (see NormalGenerator utility for details). Flags set to zero (0).

Method Detail

load

public Scene load(String filename)
           throws FileNotFoundException,
                  IncorrectFormatException,
                  ParsingErrorException

The Object File is loaded from the .obj file specified by the filename. To attach the model to your scene, call getSceneGroup() on the Scene object passed back, and attach the returned BranchGroup to your scene graph. For an example, see j3d-examples/ObjLoad/ObjLoad.java.

Specified by:

load in interface Loader

Throws:

FileNotFoundException

IncorrectFormatException

ParsingErrorException

load

public Scene load(URL url)
           throws FileNotFoundException,
                  IncorrectFormatException,
                  ParsingErrorException

The object file is loaded off of the web. To attach the model to your scene, call getSceneGroup() on the Scene object passed back, and attach the returned BranchGroup to your scene graph. For an example, see j3d-examples/ObjLoad/ObjLoad.java.

Specified by:

load in interface Loader

Throws:

FileNotFoundException

IncorrectFormatException

ParsingErrorException

load

public Scene load(Reader reader)
           throws FileNotFoundException,
                  IncorrectFormatException,
                  ParsingErrorException

The Object File is loaded from the already opened file. To attach the model to your scene, call getSceneGroup() on the Scene object passed back, and attach the returned BranchGroup to your scene graph. For an example, see j3d-examples/ObjLoad/ObjLoad.java.

Specified by:

load in interface Loader

Throws:

FileNotFoundException

IncorrectFormatException

ParsingErrorException

setBaseUrl

public void setBaseUrl(URL url)

For an .obj file loaded from a URL, set the URL where associated files (like material properties files) will be found. Only needs to be called to set it to a different URL from that containing the .obj file.

Specified by:

setBaseUrl in interface Loader

getBaseUrl

public URL getBaseUrl()

Return the URL where files associated with this .obj file (like material properties files) will be found.

Specified by:

getBaseUrl in interface Loader

setBasePath

public void setBasePath(String pathName)

Set the path where files associated with this .obj file are located. Only needs to be called to set it to a different directory from that containing the .obj file.

Specified by:

setBasePath in interface Loader

getBasePath

public String getBasePath()

Return the path where files associated with this .obj file (like material files) are located.

Specified by:

getBasePath in interface Loader

setFlags

public void setFlags(int flags)

Set parameters for loading the model. Flags defined in Loader.java are ignored by the ObjectFile Loader because the .obj file format doesn't include lights, fog, background, behaviors, views, or sounds. However, several flags are defined specifically for use with the ObjectFile Loader (see above).

Specified by:

setFlags in interface Loader

getFlags

public int getFlags()

Get the parameters currently defined for loading the model. Flags defined in Loader.java are ignored by the ObjectFile Loader because the .obj file format doesn't include lights, fog, background, behaviors, views, or sounds. However, several flags are defined specifically for use with the ObjectFile Loader (see above).

Specified by:

getFlags in interface Loader