maspack.geometry

Class OBB

java.lang.Object

maspack.geometry.BVNode

maspack.geometry.OBB

All Implemented Interfaces:

IsRenderable

public class OBB
extends BVNode

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	OBB.Method Method used to generate an OBB from a set of boundables

Field Summary

Fields

Modifier and Type	Field and Description
static double	defaultTolerance

Fields inherited from interface maspack.render.IsRenderable

TRANSPARENT, TWO_DIMENSIONAL

Constructor Summary

Constructors

Constructor and Description
OBB()
OBB(double wx, double wy, double wz)
OBB(double wx, double wy, double wz, RigidTransform3d X)
OBB(MeshBase mesh)
OBB(Vector3d widths, RigidTransform3d X)

Method Summary

Modifier and Type	Method and Description
boolean	containsPoint(Point3d pnt) Returns true if this bounding volume contains a prescribed point.
double	distanceAlongLine(Point3d origin, Vector3d dir, double min, double max) Code is modified from "An Efficient and Robust Ray-Box Intersection Algorithm", Amy Williams, Steve Barrus, R.
double	distanceToPoint(Point3d pnt) Returns the distance of a point to this bounding volume, or 0 if the point is on or inside it.
void	getCenter(Vector3d center) Returns a center point for this bounding volume.
Vector3d	getHalfWidths() Gets the half-widths for this OBB.
void	getHalfWidths(Vector3d halfWidths) Sets the half-widths for this OBB.
double	getRadius() Returns an approximate "radius" for this bounding volume.
void	getSortedAxes(Vector3d[] axes) Returns the axes of the box, sorted in order from largest to smallest.
RigidTransform3d	getTransform() Returns the transform associated with this OBB.
void	getTransform(RigidTransform3d XObbToRef) Gets the transform associated with this OBB.
void	getWidths(Vector3d widths) Gets the widths for this OBB.
boolean	intersectsLine(double[] lam, Point3d origin, Vector3d dir, double min, double max) Returns true if this bounding volume intersects a line.
boolean	intersectsLineSegment(Point3d p1, Point3d p2) Returns true if this bounding volume intersects a line segment.
boolean	intersectsPlane(Vector3d n, double d) Returns true if this bounding volume intersects a plane described by
boolean	intersectsSphere(Point3d pnt, double r) Returns true if this bounding volume intersects a sphere.
boolean	isContained(Boundable[] boundables, double tol) Returns true if an entire set of elements is contained within this bounding volume.
void	prerender(RenderList list) Called prior to rendering to allow this object to update the internal state required for rendering (such as by caching rendering coordinates).
void	render(Renderer renderer, int flags) Render this object using the functionality of the supplied Renderer.
void	scale(double s) Scales this bounding volume node by the indicated scale factor s.
void	set(Boundable[] elems, int num, double margin, OBB.Method method)
void	set(MeshBase mesh, double margin, OBB.Method method) Sets this OBB to contain the points for a mesh.
void	set(Point3d[] pnts, double margin, OBB.Method method)
void	setHalfWidths(Vector3d hw)
void	setTransform(RigidTransform3d XObbToRef) Sets the transform associated with this OBB.
void	setWidths(double wx, double wy, double wz) Sets the widths for this OBB.
void	setWidths(Vector3d widths) Sets the widths for this OBB.
boolean	update(double margin) Update node
void	updateBounds(Vector3d pmin, Vector3d pmax) Update the minimum and maximum points for this object.
boolean	updateForPoint(Point3d p, double margin) Update the half-widths of this node to accommodate a single point p within a prescribed margin.

Methods inherited from class maspack.geometry.BVNode

addChild, getDepth, getElements, getFirstChild, getNext, getNumber, getNumElements, getParent, getRenderHints, isLeaf, numChildren, setElements, setNumber, setParent, updateFor

Methods inherited from class java.lang.Object

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

Field Detail

defaultTolerance

public static double defaultTolerance

Constructor Detail

OBB

public OBB()

OBB

public OBB(double wx,
           double wy,
           double wz,
           RigidTransform3d X)

OBB

public OBB(double wx,
           double wy,
           double wz)

OBB

public OBB(Vector3d widths,
           RigidTransform3d X)

OBB

public OBB(MeshBase mesh)

Method Detail

getRadius

public double getRadius()

Description copied from class: BVNode

Returns an approximate "radius" for this bounding volume. This does not have to be precise, but should reflect roughly the maximum distance of the volume boundary from it's center.

Specified by:

getRadius in class BVNode

Returns:

approximate radius of the volume

getCenter

public void getCenter(Vector3d center)

Description copied from class: BVNode

Returns a center point for this bounding volume.

Specified by:

getCenter in class BVNode

Parameters:

center - returns to center point

setWidths

public void setWidths(double wx,
                      double wy,
                      double wz)

Sets the widths for this OBB. These are the extents of the OBB along each of its principal axes.

Parameters:

wx - new width value for the 'x' principal axis

wy - new width value for the 'y' principal axis

wz - new width value for the 'z' principal axis

setHalfWidths

public void setHalfWidths(Vector3d hw)

setWidths

public void setWidths(Vector3d widths)

Sets the widths for this OBB. These are the extents of the OBB along each of its principal axes.

Parameters:

widths - specifies new width values for this OBB

getWidths

public void getWidths(Vector3d widths)

Gets the widths for this OBB. These are the extents of the OBB along each of its principal axes.

Parameters:

widths - returns the width values for this OBB

getHalfWidths

public void getHalfWidths(Vector3d halfWidths)

Sets the half-widths for this OBB. These are 1/2 the extents of the OBB along each of its principal axes.

Parameters:

halfWidths - returns the half-width values for this OBB

getHalfWidths

public Vector3d getHalfWidths()

Gets the half-widths for this OBB. These are 1/2 the extents of the OBB along each of its principal axes.

Returns:

half-width values for this OBB (should not be modified).

setTransform

public void setTransform(RigidTransform3d XObbToRef)

Sets the transform associated with this OBB. This is the transform that maps from the coordinate from of the OBB into world coordinates.

Parameters:

XObbToRef - new transform value

getTransform

public void getTransform(RigidTransform3d XObbToRef)

Gets the transform associated with this OBB. This is the transform that maps from the coordinate from of the OBB into world coordinates.

Parameters:

XObbToRef - returns the transform value

getTransform

public RigidTransform3d getTransform()

Returns the transform associated with this OBB. The returned result should not be modified.

Returns:

transform associated with this OBB.

set

public void set(MeshBase mesh,
                double margin,
                OBB.Method method)

Sets this OBB to contain the points for a mesh. It does this by computing the OBB using the faces of the convex hull of the mesh points.

Parameters:

mesh - mesh to fit the OBB to

margin - extra distance by with the OBB should be grown. If less than 0, a default margin is computed.

method - method used to compute the OBB

set

public void set(Point3d[] pnts,
                double margin,
                OBB.Method method)

getSortedAxes

public void getSortedAxes(Vector3d[] axes)

Returns the axes of the box, sorted in order from largest to smallest.

set

public void set(Boundable[] elems,
                int num,
                double margin,
                OBB.Method method)

containsPoint

public boolean containsPoint(Point3d pnt)

Description copied from class: BVNode

Returns true if this bounding volume contains a prescribed point.

Specified by:

containsPoint in class BVNode

Parameters:

pnt - point to be tested

Returns:

true if this bounding volume contains pnt.

intersectsSphere

public boolean intersectsSphere(Point3d pnt,
                                double r)

Description copied from class: BVNode

Returns true if this bounding volume intersects a sphere. By specifying a negative value for the radius, the method can be used as a test to see if the center point is located a certain distance within the bounding volume.

Specified by:

intersectsSphere in class BVNode

Parameters:

pnt - center point of the sphere

r - radius of the sphere

Returns:

true if this bounding volume intersects the sphere

intersectsLine

public boolean intersectsLine(double[] lam,
                              Point3d origin,
                              Vector3d dir,
                              double min,
                              double max)

Description copied from class: BVNode

Returns true if this bounding volume intersects a line. The line is described by a point and a direction, such that points x along the line can be described by a parameter s according to

 x = origin + s dir
 

The line can be given finite bounds by specifying maximum and minimum bounds for s.

Specified by:

intersectsLine in class BVNode

Parameters:

lam - if non-null, returns the lower and upper values of s that define the intersection region

origin - originating point for the line

dir - direction of the line

min - minimum s value for the line, or -infinity if there is no minimum value

max - maximum s value for the line, or +infinity if there is no maximum value

Returns:

true if this bounding volume intersects the line

updateForPoint

public boolean updateForPoint(Point3d p,
                              double margin)

Update the half-widths of this node to accommodate a single point p within a prescribed margin.

Parameters:

p - point to accommodate

margin - extra space margin

update

public boolean update(double margin)

Description copied from class: BVNode

Update node

Parameters:

margin - supplied margin around boundary

Returns:

true if node was modified

isContained

public boolean isContained(Boundable[] boundables,
                           double tol)

Description copied from class: BVNode

Returns true if an entire set of elements is contained within this bounding volume. This method is mainly intended for diagnostic purposes.

Specified by:

isContained in class BVNode

Parameters:

boundables - set of boundable elements to check

tol - specifies the minimum amount by which each element must be inside

distanceToPoint

public double distanceToPoint(Point3d pnt)

Description copied from class: BVNode

Returns the distance of a point to this bounding volume, or 0 if the point is on or inside it.

Specified by:

distanceToPoint in class BVNode

Parameters:

pnt - point to check distance for

Returns:

distance of pnt to this volume

distanceAlongLine

public double distanceAlongLine(Point3d origin,
                                Vector3d dir,
                                double min,
                                double max)

Code is modified from "An Efficient and Robust Ray-Box Intersection Algorithm", Amy Williams, Steve Barrus, R. Keith Morley, Peter Shirley, University of Utah.

Specified by:

distanceAlongLine in class BVNode

Parameters:

origin - originating point for the line

dir - direction of the line

min - minimum s value for the line, or -infinity if there is no minimum value

max - maximum s value for the line, or +infinity if there is no maximum value

Returns:

distance of the point to the volume along the line

updateBounds

public void updateBounds(Vector3d pmin,
                         Vector3d pmax)

Description copied from interface: IsRenderable

Update the minimum and maximum points for this object. In an x-y-z coordinate system with x directed to the right and y directed upwards, the minimum and maximum points can be thought of as defining the left-lower-far and right-upper-near corners of a bounding cube. This method should only reduce the elements of the minimum point and increase the elements of the maximum point, since it may be used as part of an iteration to determine the bounding cube for several different objects.

Parameters:

pmin - minimum point

pmax - maximum point

render

public void render(Renderer renderer,
                   int flags)

Description copied from interface: IsRenderable

Render this object using the functionality of the supplied Renderer.

Parameters:

renderer - provides the functionality used to perform the rendering.

flags - flags that may be used to control different aspects of the rendering. Flags are defined in Renderer and currently include Renderer.HIGHLIGHT and Renderer.SORT_FACES.

prerender

public void prerender(RenderList list)

Description copied from interface: IsRenderable

Called prior to rendering to allow this object to update the internal state required for rendering (such as by caching rendering coordinates). The object may add internal objects to the list of objects being rendered, by calling

list.addIfVisible (obj);

for each of the objects in question.

Parameters:

list - list of objects to be rendered

intersectsLineSegment

public boolean intersectsLineSegment(Point3d p1,
                                     Point3d p2)

Description copied from class: BVNode

Returns true if this bounding volume intersects a line segment.

Specified by:

intersectsLineSegment in class BVNode

Parameters:

p1 - first segment end point

p2 - second segment end point

Returns:

true if this bounding volume intersects the line segment.

intersectsPlane

public boolean intersectsPlane(Vector3d n,
                               double d)

Description copied from class: BVNode

Returns true if this bounding volume intersects a plane described by

 n^T x = d
 

Specified by:

intersectsPlane in class BVNode

Parameters:

n - normal direction of the plane

d - dot product offset

Returns:

true if this bounding volume intersects the plane

scale

public void scale(double s)

Scales this bounding volume node by the indicated scale factor s. This can be used to enlarge a volume to accommodate a margin.

Parameters:

s - scaling factor