frink.graphics

Class Point2DFloatList

java.lang.Object

frink.graphics.Point2DFloatList

public class Point2DFloatList
extends java.lang.Object

This is a list of Point2DFloat objects. It can represent a polygon for extrusion in VoxelArray.

Author:

Alan Eliasen, eliasen@mindspring.com

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	Point2DFloatList.CentroidAndArea This is a helper class that stores centroid and area (which share calculations and will be calculated together.

Field Summary

Fields

Modifier and Type	Field and Description
private BoundingBox2DFloat	boundingBox Bounding box of the shape.
private boolean	boundingBoxNeedsRecalculation A flag indicating if the BoundingBox needs recalculation.
private Point2DFloatList.CentroidAndArea	centroidAndArea The centroid and area, if we've calculated it.
private boolean	centroidNeedsRecalculation Flag indicating if the centroidAndArea needs recalculating.
java.util.Vector<Point2DFloat>	points The vector of points
private int	recalculateFrom The index to start recalculating the bounding box from.

Constructor Summary

Constructors

Constructor and Description
Point2DFloatList() Construct a point list with no initial points.

Method Summary

Modifier and Type	Method and Description
void	addPoint(float x, float y) Adds a point to this shape.
void	addPoint(Point2DFloat point) Adds a point to this shape.
private Point2DFloatList.CentroidAndArea	calculateCentroidAndArea() Calculate the centroid of the point list and the area, and caches it.
float	getArea() Calculates the area (if necessary) and returns it.
BoundingBox2DFloat	getBoundingBox() Returns the Bounding box of the object.
Point2DFloat	getCentroid() Calculates the centroid (if necessary) and returns it.
Point2DFloatList.CentroidAndArea	getCentroidAndArea() Calculates the centroid and area (if necessary) and returns it.
Point2DFloat	getPoint(int index) Gets the specified point.
int	getPointCount() Returns the number of points contained here.
boolean	isInside(float x, float y) Returns true if the specified point is inside the polygon using the even-odd rule.
static Point2DFloatList	makeRegularPolygon(int sides, float outerRadius, double startAngle) Constructs a regular polygon with the specified number of sides, outer radius, and starting angle specified in radians (0 radians points along the x-axis.) TODO: Make the angle as a Unit?
private void	recalculateBoundingBox() Recalculates the BoundingBox for this shape.
Point2DFloatList	rotateAround(float cx, float cy, double theta) Creates a version of this polygon rotated around (cx, cy, by the specified angle).
Point2DFloatList	scaleAround(float cx, float cy, float scale) Creates a version of this polygon scaled around (cx, cy).

Methods inherited from class java.lang.Object

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

Field Detail

points

public java.util.Vector<Point2DFloat> points

The vector of points

boundingBoxNeedsRecalculation

private boolean boundingBoxNeedsRecalculation

A flag indicating if the BoundingBox needs recalculation.

recalculateFrom

private int recalculateFrom

The index to start recalculating the bounding box from.

centroidAndArea

private Point2DFloatList.CentroidAndArea centroidAndArea

The centroid and area, if we've calculated it.

centroidNeedsRecalculation

private boolean centroidNeedsRecalculation

Flag indicating if the centroidAndArea needs recalculating.

boundingBox

private BoundingBox2DFloat boundingBox

Bounding box of the shape.

Constructor Detail

Point2DFloatList

public Point2DFloatList()

Construct a point list with no initial points.

Method Detail

addPoint

public void addPoint(float x,
                     float y)

Adds a point to this shape.

addPoint

public void addPoint(Point2DFloat point)

Adds a point to this shape.

getPointCount

public int getPointCount()

Returns the number of points contained here.

getPoint

public Point2DFloat getPoint(int index)

Gets the specified point.

getBoundingBox

public BoundingBox2DFloat getBoundingBox()

Returns the Bounding box of the object.

recalculateBoundingBox

private void recalculateBoundingBox()

Recalculates the BoundingBox for this shape.

getCentroid

public Point2DFloat getCentroid()

Calculates the centroid (if necessary) and returns it.

getArea

public float getArea()

Calculates the area (if necessary) and returns it.

getCentroidAndArea

public Point2DFloatList.CentroidAndArea getCentroidAndArea()

Calculates the centroid and area (if necessary) and returns it.

calculateCentroidAndArea

private Point2DFloatList.CentroidAndArea calculateCentroidAndArea()

Calculate the centroid of the point list and the area, and caches it. See: http://en.wikipedia.org/wiki/Polygon#Area_and_centroid

isInside

public boolean isInside(float x,
                        float y)

Returns true if the specified point is inside the polygon using the even-odd rule. See http://www.eecs.umich.edu/courses/eecs380/HANDOUTS/PROJ2/InsidePoly.html

scaleAround

public Point2DFloatList scaleAround(float cx,
                                    float cy,
                                    float scale)

Creates a version of this polygon scaled around (cx, cy).

rotateAround

public Point2DFloatList rotateAround(float cx,
                                     float cy,
                                     double theta)

Creates a version of this polygon rotated around (cx, cy, by the specified angle). Looking from a positive Z axis toward the origin, a positive angle gives a counterclockwise rotation.

makeRegularPolygon

public static Point2DFloatList makeRegularPolygon(int sides,
                                                  float outerRadius,
                                                  double startAngle)

Constructs a regular polygon with the specified number of sides, outer radius, and starting angle specified in radians (0 radians points along the x-axis.) TODO: Make the angle as a Unit?