com.sun.j3d.utils.compression

Class CommandStream

java.lang.Object

com.sun.j3d.utils.compression.CommandStream

 class CommandStream
extends java.lang.Object

This class is used to build the bit-level compression command stream which is the final result of the compression process. It defines the bit representations of the compression commands and provides a mechanism for the interleaving and forwarding of command headers and bodies required by the geometry compression specification.

Field Summary

Fields

Modifier and Type	Field and Description
private int	bitOffset
private int	byteOffset
private byte[]	bytes
(package private) static int	COLOR_TABLE
private long	lastBody
private int	lastBodyLength
(package private) static int	MESH_B_R
(package private) static int	NORMAL_TABLE
(package private) static int	POSITION_TABLE
(package private) static int	SET_COLOR
(package private) static int	SET_NORM
(package private) static int	SET_STATE
(package private) static int	SET_TABLE
(package private) static int	V_NO_OP
(package private) static int	VERTEX

Constructor Summary

Constructors

Constructor and Description
CommandStream() Create an empty CommandStream with a default initial size.
CommandStream(int initSize) Create an empty CommandStream with the given initial size.

Method Summary

Methods

Modifier and Type	Method and Description
private void	addByte(int b, int bitCount)
(package private) void	addCommand(int header, int headerLength, long body, int bodyLength) Add a compression command to this instance.
private void	addLong(long l, int bitCount)
(package private) void	clear() Mark the CommandStream as empty so that its storage will be reused.
(package private) void	end() Add a no-op and the last command body.
(package private) int	getByteCount() Get the number of bytes in the compression command stream.
(package private) byte[]	getBytes() Get the bytes composing the compression command stream.

Methods inherited from class java.lang.Object

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

Field Detail

SET_NORM

static final int SET_NORM

See Also:

Constant Field Values

SET_COLOR

static final int SET_COLOR

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Constant Field Values

VERTEX

static final int VERTEX

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Constant Field Values

MESH_B_R

static final int MESH_B_R

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Constant Field Values

SET_STATE

static final int SET_STATE

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Constant Field Values

SET_TABLE

static final int SET_TABLE

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Constant Field Values

V_NO_OP

static final int V_NO_OP

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Constant Field Values

POSITION_TABLE

static final int POSITION_TABLE

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Constant Field Values

COLOR_TABLE

static final int COLOR_TABLE

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Constant Field Values

NORMAL_TABLE

static final int NORMAL_TABLE

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Constant Field Values

bytes

private byte[] bytes

byteOffset

private int byteOffset

bitOffset

private int bitOffset

lastBody

private long lastBody

lastBodyLength

private int lastBodyLength

Constructor Detail

CommandStream

CommandStream()

Create an empty CommandStream with a default initial size.

CommandStream

CommandStream(int initSize)

Create an empty CommandStream with the given initial size.

Parameters:

initSize - initial capacity of CommandStream in bytes

Method Detail

clear

void clear()

Mark the CommandStream as empty so that its storage will be reused.

addCommand

void addCommand(int header,
              int headerLength,
              long body,
              int bodyLength)

Add a compression command to this instance.

A compression command includes an 8-bit header and can range up to 72 bits in length. The command with the maximum length is a 2-bit color command with a 6-bit tag in the header, followed by four 16-bit color components of data.

A subcommand is either a position, normal, or color, though in practice a position subcommand can only be part of a vertex command. Normal and color subcommands can be parts of separate global normal and color commands as well as parts of a vertex command.

A subcommand includes a 6-bit header. Its length is 2 bits less than the length of the corresponding command.

Parameters:

header - contains compression command header bits, right-justified within the bits of the int

headerLength - number of bits in header, either 8 for commands or 6 for subcommands

body - contains the body of the compression command, right-justified within the bits of the long

bodyLength - number of bits in the body

addByte

private void addByte(int b,
           int bitCount)

addLong

private void addLong(long l,
           int bitCount)

end

void end()

Add a no-op and the last command body. Pad out with additional no-ops to a 64-bit boundary if necessary. A call to this method is required in order to create a valid compression command stream.

getByteCount

int getByteCount()

Get the number of bytes in the compression command stream.

Returns:

size of compressed data in bytes

getBytes

byte[] getBytes()

Get the bytes composing the compression command stream.

Returns:

reference to array of bytes containing the compressed data