Panda3D
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BamWriter Class Reference

This is the fundamental interface for writing binary objects to a Bam file, to be extracted later by a BamReader. More...

Inheritance diagram for BamWriter:
BamEnums

Public Member Functions

 __init__ (const BamWriter)
 
 __init__ (DatagramSink target)
 
 flush ()
 Ensures that all data written thus far is manifested on the output stream. More...
 
BamEnums::BamEndian getFileEndian ()
 Returns the endian preference indicated by the Bam file currently being written. More...
 
int getFileMajorVer ()
 Returns the major version number of the Bam file currently being written. More...
 
int getFileMinorVer ()
 Returns the minor version number of the Bam file currently being written. More...
 
const Filename getFilename ()
 If a BAM is a file, then the BamWriter should contain the name of the file. More...
 
bool getFileStdfloatDouble ()
 Returns true if the file will store all "standard" floats as 64-bit doubles, or false if they are 32-bit floats. More...
 
BamEnums::BamTextureMode getFileTextureMode ()
 Returns the BamTextureMode preference indicated by the Bam file currently being written. More...
 
TypedWritable getRootNode ()
 Returns the root node of the part of the scene graph we are currently writing out. More...
 
DatagramSink getTarget ()
 Returns the current target of the BamWriter as set by set_target() or the constructor. More...
 
bool hasObject (const TypedWritable obj)
 Returns true if the object has previously been written (or at least requested to be written) to the bam file, or false if we've never heard of it before. More...
 
bool init ()
 Initializes the BamWriter prior to writing any objects to its output stream. More...
 
 setFileMinorVer (int minor_ver)
 Changes the minor .bam version to write. More...
 
 setFileTextureMode (BamEnums::BamTextureMode file_texture_mode)
 Changes the BamTextureMode preference for the Bam file currently being written. More...
 
 setRootNode (TypedWritable root_node)
 Sets the root node of the part of the scene graph we are currently writing out. More...
 
 setTarget (DatagramSink target)
 Changes the destination of future datagrams written by the BamWriter. More...
 
bool writeObject (const TypedWritable obj)
 Writes a single object to the Bam file, so that the BamReader::read_object() can later correctly restore the object and all its pointers. More...
 
- Public Member Functions inherited from BamEnums
 __init__ ()
 
 __init__ (const BamEnums)
 

Public Attributes

BamEnums::BamEndian file_endian
 Returns the endian preference indicated by the Bam file currently being written. More...
 
bool file_stdfloat_double
 Returns true if the file will store all "standard" floats as 64-bit doubles, or false if they are 32-bit floats. More...
 
BamEnums::BamTextureMode file_texture_mode
 Returns the BamTextureMode preference indicated by the Bam file currently being written. More...
 
const Filename filename
 If a BAM is a file, then the BamWriter should contain the name of the file. More...
 
TypedWritable root_node
 Returns the root node of the part of the scene graph we are currently writing out. More...
 
DatagramSink target
 Returns the current target of the BamWriter as set by set_target() or the constructor. More...
 

Additional Inherited Members

- Public Types inherited from BamEnums
enum  BamEndian { BE_bigendian = 0, BE_littleendian = 1, BE_native = 1 }
 
enum  BamObjectCode {
  BOC_push = 0, BOC_pop = 1, BOC_adjunct = 2, BOC_remove = 3,
  BOC_file_data = 4
}
 
enum  BamTextureMode {
  BTM_unchanged = 0, BTM_fullpath = 1, BTM_relative = 2, BTM_basename = 3,
  BTM_rawdata = 4
}
 

Detailed Description

This is the fundamental interface for writing binary objects to a Bam file, to be extracted later by a BamReader.

A Bam file can be thought of as a linear collection of objects. Each object is an instance of a class that inherits, directly or indirectly, from TypedWritable. The objects may include pointers to other objects; the BamWriter automatically manages these (with help from code within each class) and writes all referenced objects to the file in such a way that the pointers may be correctly restored later.

This is the abstract interface and does not specifically deal with disk files, but rather with a DatagramSink of some kind, which simply accepts a linear stream of Datagrams. It is probably written to a disk file, but it might conceivably be streamed directly to a network or some such nonsense.

Bam files are most often used to store scene graphs or subgraphs, and by convention they are given filenames ending in the extension ".bam" when they are used for this purpose. However, a Bam file may store any arbitrary list of TypedWritable objects; in this more general usage, they are given filenames ending in ".boo" to differentiate them from the more common scene graph files.

See also BamFile, which defines a higher-level interface to read and write Bam files on disk.

Member Function Documentation

◆ __init__() [1/2]

__init__ ( const  BamWriter)

◆ __init__() [2/2]

__init__ ( DatagramSink  target)

◆ flush()

flush ( )

Ensures that all data written thus far is manifested on the output stream.

◆ getFileEndian()

BamEnums::BamEndian getFileEndian ( )

Returns the endian preference indicated by the Bam file currently being written.

This does not imply that every number is stored using the indicated convention, but individual objects may choose to respect this flag when recording data.

◆ getFileMajorVer()

int getFileMajorVer ( )

Returns the major version number of the Bam file currently being written.

◆ getFileMinorVer()

int getFileMinorVer ( )

Returns the minor version number of the Bam file currently being written.

◆ getFilename()

const Filename getFilename ( )

If a BAM is a file, then the BamWriter should contain the name of the file.

This enables the writer to convert pathnames in the BAM to relative to the directory containing the BAM.

◆ getFileStdfloatDouble()

bool getFileStdfloatDouble ( )

Returns true if the file will store all "standard" floats as 64-bit doubles, or false if they are 32-bit floats.

This isn't runtime settable; it's based on the compilation flags of the version of Panda that generated this file.

◆ getFileTextureMode()

BamEnums::BamTextureMode getFileTextureMode ( )

Returns the BamTextureMode preference indicated by the Bam file currently being written.

Texture objects written to this Bam file will be encoded according to the specified mode.

◆ getRootNode()

TypedWritable getRootNode ( )

Returns the root node of the part of the scene graph we are currently writing out.

This is used for determining what to make NodePaths relative to.

◆ getTarget()

DatagramSink getTarget ( )

Returns the current target of the BamWriter as set by set_target() or the constructor.

◆ hasObject()

bool hasObject ( const TypedWritable  obj)

Returns true if the object has previously been written (or at least requested to be written) to the bam file, or false if we've never heard of it before.

◆ init()

bool init ( )

Initializes the BamWriter prior to writing any objects to its output stream.

This includes writing out the Bam header.

This returns true if the BamWriter successfully initialized, false otherwise.

◆ setFileMinorVer()

setFileMinorVer ( int  minor_ver)

Changes the minor .bam version to write.

This should be called before init(). Each Panda version has only a fairly narrow range of versions it is able to write; consult the .bam documentation for more information.

◆ setFileTextureMode()

setFileTextureMode ( BamEnums::BamTextureMode  file_texture_mode)

Changes the BamTextureMode preference for the Bam file currently being written.

Texture objects written to this Bam file will be encoded according to the specified mode.

◆ setRootNode()

setRootNode ( TypedWritable  root_node)

Sets the root node of the part of the scene graph we are currently writing out.

NodePaths written to this bam file will be relative to this node.

◆ setTarget()

setTarget ( DatagramSink  target)

Changes the destination of future datagrams written by the BamWriter.

This also implicitly calls init() if it has not already been called.

◆ writeObject()

bool writeObject ( const TypedWritable  obj)

Writes a single object to the Bam file, so that the BamReader::read_object() can later correctly restore the object and all its pointers.

This implicitly also writes any additional objects this object references (if they haven't already been written), so that pointers may be fully resolved.

This may be called repeatedly to write a sequence of objects to the Bam file, but typically (especially for scene graph files, indicated with the .bam extension), only one object is written directly from the Bam file: the root of the scene graph. The remaining objects will all be written recursively by the first object.

Returns true if the object is successfully written, false otherwise.

Member Data Documentation

◆ file_endian

BamEnums::BamEndian file_endian

Returns the endian preference indicated by the Bam file currently being written.

This does not imply that every number is stored using the indicated convention, but individual objects may choose to respect this flag when recording data.

◆ file_stdfloat_double

bool file_stdfloat_double

Returns true if the file will store all "standard" floats as 64-bit doubles, or false if they are 32-bit floats.

This isn't runtime settable; it's based on the compilation flags of the version of Panda that generated this file.

◆ file_texture_mode

BamEnums::BamTextureMode file_texture_mode

Returns the BamTextureMode preference indicated by the Bam file currently being written.

Texture objects written to this Bam file will be encoded according to the specified mode.

◆ filename

const Filename filename

If a BAM is a file, then the BamWriter should contain the name of the file.

This enables the writer to convert pathnames in the BAM to relative to the directory containing the BAM.

◆ root_node

TypedWritable root_node

Returns the root node of the part of the scene graph we are currently writing out.

This is used for determining what to make NodePaths relative to.

◆ target

DatagramSink target

Returns the current target of the BamWriter as set by set_target() or the constructor.