de.grogra.rgg

Class AvoidIntersection

java.lang.Object

de.grogra.rgg.AvoidIntersection

All Implemented Interfaces:

VolumeListener, Options

public class AvoidIntersection
extends java.lang.Object
implements Options, VolumeListener

Instances of AvoidIntersection helps to detected potential intersection by using rays (Line). Before something grow in a certain direction, this helps to check if objects lies in the near environment of the growing-direction.

Example to use:
AvoidIntersection ai = new AvoidIntersection(100);
ai.look(node);

The node gets a new direction.

Author:

Stephan Rogge

Field Summary

Fields

Modifier and Type	Field and Description
static int	FRIENDLY_HIT
static int	NO_HIT
static int	UNFRIENDLY_HIT

Constructor Summary

Constructors

Constructor and Description
AvoidIntersection() Create an instance of AvoidIntersection with 100 rays.
AvoidIntersection(int RayCount) Create an instance of AvoidIntersection with RayCount rays.

Method Summary

Methods

Modifier and Type	Method and Description
void	addFavorNode(Node node) Adds node to the list of favorNodes.
void	beginGroup(java.lang.Object object, boolean asNode) This method is invoked by a SceneVisitor when subsequent volumes shall be grouped into a single compound object.
void	endGroup() This method is invoked by a SceneVisitor when the current group ends.
java.lang.Object	get(java.lang.String key, java.lang.Object defaultValue) Returns the option value for the option identified by key.
boolean	look(Null node, float distance) This method works exactly like look(Null, float, float, boolean).
boolean	look(Null node, float distance, float strength, boolean showLines) This methods compute based on a intersection test with rays a new direction for node.
void	prepareScene() This method prepare the whole scene, may for a new intersection-computation.
void	setDistance2Surface(float distance) This method sets the distance of tangential plane to all nodes in favorNodes.
void	setFavorNodeType(java.lang.Class<?> className) To get more or less tangential directions to certain objects (called as favor nodes), we have mark them.
void	setLayerVisible(int id, boolean visible) Set layer # id to visible (true) or invisible (false).
void	setPrepareScene() This method sets the prepareScene flag.
void	setRange(float width, float height) For explanation see setRange(float, float, float).
void	setRange(float width, float height, float predictedLength) Set the width and height of the space which has to be test on intersection.
void	volumeCreated(java.lang.Object object, boolean asNode, Volume volume) This method is invoked by a SceneVisitor when a volume is created as representation of the geometry of object.

Methods inherited from class java.lang.Object

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

Field Detail

FRIENDLY_HIT

public static final int FRIENDLY_HIT

See Also:

Constant Field Values

NO_HIT

public static final int NO_HIT

See Also:

Constant Field Values

UNFRIENDLY_HIT

public static final int UNFRIENDLY_HIT

See Also:

Constant Field Values

Constructor Detail

AvoidIntersection

public AvoidIntersection()

Create an instance of AvoidIntersection with 100 rays.

AvoidIntersection

public AvoidIntersection(int RayCount)

Create an instance of AvoidIntersection with RayCount rays.

Parameters:

RayCount - Number of rays.

Method Detail

addFavorNode

public void addFavorNode(Node node)

Adds node to the list of favorNodes. Ray intersection with this node is marked as friendly. So a direction is calculated which is approximate tangential to the surface at the point where the intersection was computed.

Parameters:

node -

beginGroup

public void beginGroup(java.lang.Object object,
              boolean asNode)

Description copied from interface: VolumeListener

This method is invoked by a SceneVisitor when subsequent volumes shall be grouped into a single compound object. The group extends until the corresponding invocation of VolumeListener.endGroup(). These invocations may be nested, i.e., there may be groups within groups.

Each group starts at object in the graph. If object has a geometric representation itself, the corresponding invocation of VolumeListener.volumeCreated(java.lang.Object, boolean, de.grogra.vecmath.geom.Volume) may be either immediately before of after beginGroup.

Specified by:

beginGroup in interface VolumeListener

Parameters:

object - the object of the graph which represents the root of the group

asNode - is object a node or an edge?

See Also:

VolumeListener.endGroup()

endGroup

public void endGroup()

Description copied from interface: VolumeListener

This method is invoked by a SceneVisitor when the current group ends.

Specified by:

endGroup in interface VolumeListener

See Also:

VolumeListener.beginGroup(java.lang.Object, boolean)

get

public java.lang.Object get(java.lang.String key,
                   java.lang.Object defaultValue)

Description copied from interface: Options

Returns the option value for the option identified by key. If no special value for the option is defined, defaultValue is returned.

Specified by:

get in interface Options

Parameters:

key - identifier for option

defaultValue - default value of option

Returns:

value of option named key

look

public boolean look(Null node,
           float distance)

This method works exactly like look(Null, float, float, boolean). Expect that the strength of changing the direction is set to 1 and no rays were visualized.

Parameters:

node - For this node the environment has to be checked and a new direction could be the result.

distance - The distance is used as length for the rays. Thats a limitation for the near environment.

Returns:

Iff every ray has an unfriendly intersection with objects, this method return false otherwise true.

look

public boolean look(Null node,
           float distance,
           float strength,
           boolean showLines)

This methods compute based on a intersection test with rays a new direction for node. The area in front of node is defined by setRange(float, float, float) and by distance. Iff a new direction is calculated a transformation node which approximate the new direction by the given value of strength is put into the graph. Depending on objects which is involved in intersections the new direction could be tangential to the surface of an favor node a try get away from this object.

Parameters:

node - For this node the environment has to be checked and a new direction could be the result.

distance - The distance is used as length for the rays. Thats a limitation for the near environment.

strength - Iff a new direction is calculated, this parameter sets the strength of changing a direction.

showLines - To visualize what is going on in front of node, set this parameter true.

Returns:

Iff every ray has an unfriendly intersection with objects, this method return false otherwise true.

prepareScene

public void prepareScene()

This method prepare the whole scene, may for a new intersection-computation. This is necessary, when something in the scene has changed. The method look(Null node, float size, float distance) invoke this automatically.

setDistance2Surface

public void setDistance2Surface(float distance)

This method sets the distance of tangential plane to all nodes in favorNodes.

Parameters:

distance - Distance to surface

setFavorNodeType

public void setFavorNodeType(java.lang.Class<?> className)

To get more or less tangential directions to certain objects (called as favor nodes), we have mark them. This can be done by implementing an interface. This interface is className.

Parameters:

className - Interface type which is implemented by some objects of the scene.

setLayerVisible

public void setLayerVisible(int id,
                   boolean visible)

Set layer # id to visible (true) or invisible (false).

Parameters:

id - Layer id

visible - Layer visible or not.

setPrepareScene

public void setPrepareScene()

This method sets the prepareScene flag. When the method prepareScene() is invoked, an octree will re-computed.

setRange

public void setRange(float width,
            float height)

For explanation see setRange(float, float, float).

Parameters:

width - Width of the tested space.

height - Height of the tested space.

setRange

public void setRange(float width,
            float height,
            float predictedLength)

Set the width and height of the space which has to be test on intersection. With predictedLength the origin of all rays is shift along the direction line of the originNode.

Parameters:

width - Width of the tested space.

height - Height of the tested space.

predictedLength - Distance of shifting the ray origin.

volumeCreated

public void volumeCreated(java.lang.Object object,
                 boolean asNode,
                 Volume volume)

Description copied from interface: VolumeListener

This method is invoked by a SceneVisitor when a volume is created as representation of the geometry of object. By storing the information provided by the parameters, the link from graph objects (nodes and edges) to volumes can be established.

Specified by:

volumeCreated in interface VolumeListener

Parameters:

object - an object of the graph

asNode - is object a node or an edge?

volume - the volume which has been created as geometrical representation of object