de.grogra.vecmath.geom
Class CSGDifference

java.lang.Object
  de.grogra.vecmath.geom.VolumeBase
      de.grogra.vecmath.geom.CompoundVolume
          de.grogra.vecmath.geom.CSGDifference

All Implemented Interfaces:

Volume

public class CSGDifference
extends CompoundVolume

An instance of this class represents the difference of a list of volumes. The difference consists of all points which are contained in the first volume of CompoundVolume.volumes, but not in one or more of the remaining volumes.

Author:

Ole Kniemeyer

Field Summary

Fields inherited from class de.grogra.vecmath.geom.CompoundVolume

volumes

Constructor Summary

CSGDifference()
Creates a new CSGDifference whose list of volumes is empty.

CSGDifference(Volume a, Volume b)
Creates a new CSGDifference whose list of volumes is set to [a, b].

Method Summary

boolean	computeIntersections(Line line, int which, IntersectionList list, Intersection excludeStart, Intersection excludeEnd) Computes intersections between the boundary surface of this object and the specified line.
boolean	contains(Tuple3d point, boolean open) Determines if the given point lies within this object.
void	getExtent(Tuple3d min, Tuple3d max, Variables temp) Computes the extent of this volume, i.e., an axis-aligned bounding box between min and max.
Volume	operator$sub(Volume v) This operator method creates the difference between a and b.

Methods inherited from class de.grogra.vecmath.geom.CompoundVolume

boxContainsBoundary, computeNormal, computeTangents, computeUV

Methods inherited from class de.grogra.vecmath.geom.VolumeBase

addConvexIntersections, getId, operator$and, operator$com, operator$or, setId

Methods inherited from class java.lang.Object

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

Constructor Detail

CSGDifference

public CSGDifference()

Creates a new CSGDifference whose list of volumes is empty.

CSGDifference

public CSGDifference(Volume a,
                     Volume b)

Creates a new CSGDifference whose list of volumes is set to [a, b].

Method Detail

computeIntersections

public boolean computeIntersections(Line line,
                                    int which,
                                    IntersectionList list,
                                    Intersection excludeStart,
                                    Intersection excludeEnd)

Description copied from interface: Volume

Computes intersections between the boundary surface of this object and the specified line. The intersections are added to list in ascending order of distance (i.e., of Intersection.parameter), where the parameter has to lie between line.start and line.end. Implementations of this method must not clear or modify the existing intersections in list.

The parameter which has to be one of Intersection.ALL, Intersection.CLOSEST, Intersection.ANY. It determines if all intersections have to be added to the list, only the closest (minimal value of Intersection.parameter), or an arbitrary of the set of all intersections. Only in case of ALL, the return value of this method is precise.

If specific intersection points should be excluded from the list of computed intersections, they have to be specified in excludeStart and excludeEnd. The intersection point of excludeStart has to be the starting point of line, the intersection point of excludeEnd has to be the end point of line. The exclusion of intersections is a useful feature for ray-tracing, e.g., when a ray is re-emitted at an intersection point in another direction.

Parameters:

line - a line

which - one of Intersection.ALL, Intersection.CLOSEST, Intersection.ANY, this determines which intersections have to be added to list

list - the intersections are added to this list

excludeStart - intersection at start point which shall be excluded, or null

excludeEnd - intersection at end point which shall be excluded, or null

Returns:

true iff the beginning of the line lies within the volume (i.e., if the line starts within the volume or enters the volume at the starting point); however note that the returned value is valid only if which == Intersection.ALL

contains

public boolean contains(Tuple3d point,
                        boolean open)

Description copied from interface: Volume

Determines if the given point lies within this object. If open is true, the interior of the volume is considered (the largest open set contained in the volume, i.e., excluding the boundary), otherwise the closure of the volume.

Parameters:

point - a point in global world coordinates

open - consider open or closed set

Returns:

true iff point is an element of the set

getExtent

public void getExtent(Tuple3d min,
                      Tuple3d max,
                      Variables temp)

Description copied from interface: Volume

Computes the extent of this volume, i.e., an axis-aligned bounding box between min and max.

Parameters:

min - minimum coordinates of bounding box are placed in here

max - maximum coordinates of bounding box are placed in here

temp - has to be provided by the invoker, may be used in implementations

operator$sub

public Volume operator$sub(Volume v)

Description copied from interface: Volume

This operator method creates the difference between a and b.

Specified by:

operator$sub in interface Volume

Overrides:

operator$sub in class VolumeBase

Parameters:

v - the volume to be subtracted

Returns:

the difference between this volume and b

See Also:

CSGDifference