org.j3d.aviatrix3d
Class AccumulationBufferState

java.lang.Object
  org.j3d.aviatrix3d.SceneGraphObject
      org.j3d.aviatrix3d.BufferState
          org.j3d.aviatrix3d.AccumulationBufferState

All Implemented Interfaces:

java.lang.Comparable, BufferStateRenderable, Renderable

public class AccumulationBufferState
extends BufferState
implements BufferStateRenderable

Describes attributes used when interacting with the accumulation buffer.

Including this state class in the global setup automatically enables the accumulation buffer. It also has a slightly special status in that, unlike the other buffer types, the state is executed at the end of the rendering pass rather than at the beginning. That is because accumulation buffers are used to take the current colour buffer and copy it into the accumulation buffer using one of a set of functions (or copy the accumulation buffer back to the colour buffer in the case of GL_RETURN).

The default setup for this class is:

• Function: RETURN
• Value: 1.0

Internationalisation Resource Names

• invalidAccFunctionMsg: Error message when the given function type does not match one of the available types.

Version:

$Revision: 2.5 $

Author:

Justin Couch

Field Summary

static int	FUNCTION_ACCUMULATE Take the current buffer colours multiply them by value and then add with the accumulation buffer.
static int	FUNCTION_ADD Add the value to the current accumulation buffer values.
static int	FUNCTION_LOAD Replace the values in the accumulation buffer with the current colours
static int	FUNCTION_MULTIPLY Multiply the contents of the current buffer by the value.

Fields inherited from class org.j3d.aviatrix3d.BufferState

lastParent, liveCount, parentList

Fields inherited from class org.j3d.aviatrix3d.SceneGraphObject

alive, LISTENER_SET_TIMING_ERR_PROP, updateHandler

Fields inherited from interface org.j3d.aviatrix3d.rendering.BufferStateRenderable

ACCUMULATION_BUFFER, COLOR_BUFFER, DEPTH_BUFFER, GENERAL_BUFFER, STENCIL_BUFFER

Constructor Summary

AccumulationBufferState()
Constructs a state set with default values.

Method Summary

boolean	checkClearBufferState() Check to see if this buffer should be cleared at the start of this run.
void	clearBufferState(javax.media.opengl.GL gl) Restore all state to the default values and copy the buffer to the colour buffer.
int	compareTo(AccumulationBufferState abs) Compares this object with the specified object for order.
int	compareTo(java.lang.Object o) Compares this object with the specified object for order.
boolean	equals(AccumulationBufferState abs) Compares this object with the specified object to check for equivalence.
boolean	equals(java.lang.Object o) Compare this object for equality to the given object.
int	getAccumFunction() Get the current operation used when accumulating colour values.
float	getAlpha() Get the current alpha channel clear value
float	getBlue() Get the current blue channel clear value
int	getBufferBitMask() Get the GL buffer bit flag that this state class represents.
int	getBufferType() Get the type of buffer this state represents.
float	getGreen() Get the current green channel clear value
float	getRed() Get the current red channel clear value
float	getValue() Get the value operand used with some of the function types.
void	setAccumFunction(int func) Set the operation that should be performed when accumulating colour values into the accumulation buffer.
void	setBufferState(javax.media.opengl.GL gl) Issue ogl commands needed for this buffer to set the initial state, including the initial enabling.
void	setClearBufferState(boolean clear) Set the flag for whether the buffer state should be cleared when this state object is executed.
void	setClearColor(float red, float green, float blue, float alpha) Set the value that each of the colour channels should be cleared to.
void	setValue(float val) Set the value that accompanies some of the operation types.
void	updateBufferState(javax.media.opengl.GL gl) Issue ogl commands needed for this component to change the state, assuming that it is already enabled.

Methods inherited from class org.j3d.aviatrix3d.BufferState

addParent, getParents, numParents, removeParent

Methods inherited from class org.j3d.aviatrix3d.SceneGraphObject

checkForCyclicChild, checkForCyclicParent, dataChanged, getAppUpdateWriteTimingMessage, getBoundsWriteTimingMessage, getDataWriteTimingMessage, getUserData, isLive, setLive, setUpdateHandler, setUserData

Methods inherited from class java.lang.Object

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

Field Detail

FUNCTION_ACCUMULATE

public static final int FUNCTION_ACCUMULATE

Take the current buffer colours multiply them by value and then add with the accumulation buffer.

See Also:

Constant Field Values

FUNCTION_LOAD

public static final int FUNCTION_LOAD

Replace the values in the accumulation buffer with the current colours

See Also:

Constant Field Values

FUNCTION_ADD

public static final int FUNCTION_ADD

Add the value to the current accumulation buffer values.

See Also:

Constant Field Values

FUNCTION_MULTIPLY

public static final int FUNCTION_MULTIPLY

Multiply the contents of the current buffer by the value. Note that for this function, the value is clamped to [-1, 1] by OpenGL.

See Also:

Constant Field Values

Constructor Detail

AccumulationBufferState

public AccumulationBufferState()

Constructs a state set with default values.

Method Detail

getBufferType

public int getBufferType()

Get the type of buffer this state represents.

Specified by:

getBufferType in interface BufferStateRenderable

Returns:

One of the _BUFFER constants

getBufferBitMask

public int getBufferBitMask()

Get the GL buffer bit flag that this state class represents. Used for bulk clearing all the states at once.

Specified by:

getBufferBitMask in interface BufferStateRenderable

Returns:

The bit state constant for Stencil Buffers

checkClearBufferState

public boolean checkClearBufferState()

Check to see if this buffer should be cleared at the start of this run. If it should be, add the bit mask from this state to the global list.

Specified by:

checkClearBufferState in interface BufferStateRenderable

Returns:

true if the state should be cleared

setBufferState

public void setBufferState(javax.media.opengl.GL gl)

Issue ogl commands needed for this buffer to set the initial state, including the initial enabling.

Specified by:

setBufferState in interface BufferStateRenderable

Parameters:

gl - The gl context to draw with

updateBufferState

public void updateBufferState(javax.media.opengl.GL gl)

Issue ogl commands needed for this component to change the state, assuming that it is already enabled.

Specified by:

updateBufferState in interface BufferStateRenderable

Parameters:

gl - The gl context to draw with

clearBufferState

public void clearBufferState(javax.media.opengl.GL gl)

Restore all state to the default values and copy the buffer to the colour buffer.

Specified by:

clearBufferState in interface BufferStateRenderable

Parameters:

gl - The gl context to draw with

compareTo

public int compareTo(java.lang.Object o)
              throws java.lang.ClassCastException

Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.

Specified by:

compareTo in interface java.lang.Comparable

Parameters:

o - The objec to be compared

Returns:

-1, 0 or 1 depending on order

Throws:

java.lang.ClassCastException - The specified object's type prevents it from being compared to this Object

equals

public boolean equals(java.lang.Object o)

Compare this object for equality to the given object.

Specified by:

equals in interface Renderable

Overrides:

equals in class java.lang.Object

Parameters:

o - The object to be compared

Returns:

True if these represent the same values

setClearBufferState

public void setClearBufferState(boolean clear)
                         throws InvalidWriteTimingException

Set the flag for whether the buffer state should be cleared when this state object is executed.

Parameters:

clear - True if the buffer should be cleared when this is the first state to be used in the current operation

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data update callback method

setAccumFunction

public void setAccumFunction(int func)
                      throws java.lang.IllegalArgumentException,
                             InvalidWriteTimingException

Set the operation that should be performed when accumulating colour values into the accumulation buffer. This should be one of the FUNCTION_ constants at the top of this class.

Parameters:

func - One of the FUNCTION_ constants

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data update callback method

java.lang.IllegalArgumentException - The operation value was not one of the valid types.

getAccumFunction

public int getAccumFunction()

Get the current operation used when accumulating colour values.

Returns:

One of the FUNCTION_ constants

setValue

public void setValue(float val)
              throws java.lang.IllegalArgumentException,
                     InvalidWriteTimingException

Set the value that accompanies some of the operation types. Consult the docs for individual functions for how the value may be used.

Parameters:

val - An arbitrary value defined by the user

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data update callback method

java.lang.IllegalArgumentException

getValue

public float getValue()

Get the value operand used with some of the function types.

Returns:

Any arbitrary value set by the user

setClearColor

public void setClearColor(float red,
                          float green,
                          float blue,
                          float alpha)
                   throws InvalidWriteTimingException

Set the value that each of the colour channels should be cleared to. The values are automatically clamped by OpenGL to the range [-1,1].

Parameters:

red - The red channel clear value

green - The green channel clear value

blue - The blue channel clear value

alpha - The alpha channel clear value

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data update callback method

getRed

public float getRed()

Get the current red channel clear value

Returns:

The current red channel clear value [-1,1]

getGreen

public float getGreen()

Get the current green channel clear value

Returns:

The current green channel clear value [-1,1]

getBlue

public float getBlue()

Get the current blue channel clear value

Returns:

The current blue channel clear value [-1,1]

getAlpha

public float getAlpha()

Get the current alpha channel clear value

Returns:

The current alpha channel clear value [-1,1]

compareTo

public int compareTo(AccumulationBufferState abs)

Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.

Parameters:

abs - The attributes instance to be comabsred

Returns:

-1, 0 or 1 depending on order

equals

public boolean equals(AccumulationBufferState abs)

Compares this object with the specified object to check for equivalence.

Parameters:

abs - The attributes instance to be compared

Returns:

true if the objects represent identical values