com.threerings.media.util
Class ArcPath

java.lang.Object
  com.threerings.media.util.TimedPath
      com.threerings.media.util.ArcPath

All Implemented Interfaces:

Path

public class ArcPath
extends TimedPath

The line path is used to cause a pathable to go from point A to point B along the arc of an ellipse in a certain number of milliseconds.

Field Summary

protected Point	_center The center of our ellipse.
protected double	_delta Our starting and delta angles.
protected int	_orient The method to be used to orient the pathable.
protected int	_orientOffset An orientation offset used when orienting our pathable.
protected double	_sangle Our starting and delta angles.
protected Point	_tpos A temporary point used when computing our position along the path.
protected double	_xradius Our ellipse radii.
protected double	_yradius Our ellipse radii.
static int	FINE An orientation constant indicating that the fine (sixteen) directions should be used to orient the pathable being made to follow this path.
static int	NONE An orientation indicating that the pathable should not be oriented as it moves along the path.
static int	NORMAL An orientation constant indicating that the normal (eight) directions should be used to orient the pathable being made to follow this path.

Fields inherited from class com.threerings.media.util.TimedPath

_duration, _startStamp

Constructor Summary

ArcPath(Point start, double xradius, double yradius, double sangle, double delta, long duration, int orient)
Creates an arc path that will animate a pathable from the specified starting position along an ellipse defined by the supplied parameters.

Method Summary

static void	computePosition(Point center, double xradius, double yradius, double angle, Point pos) Computes the position of an entity along the path defined by the supplied parameters assuming that it must finish the path in the specified duration (in millis) and has been traveling the path for the specified number of elapsed milliseconds.
Point	getEndPos() Returns the position of the end of the path.
Path	getTranslatedInstance(int x, int y) Return a copy of the path, translated by the specified amounts.
void	paint(Graphics2D gfx) Paint this path on the screen (used for debugging purposes only).
void	setOrientOffset(int offset) Sets the offset that is applied to the pathable whenever it is oriented.
boolean	tick(Pathable pable, long timestamp) Called to request that this path update the position of the specified pathable based on the supplied timestamp information.
protected void	toString(StringBuilder buf) An extensible method for generating a string representation of this instance.

Methods inherited from class com.threerings.media.util.TimedPath

fastForward, init, toString, wasRemoved

Methods inherited from class java.lang.Object

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

Field Detail

NORMAL

public static final int NORMAL

An orientation constant indicating that the normal (eight) directions should be used to orient the pathable being made to follow this path.

See Also:

Constant Field Values

FINE

public static final int FINE

An orientation constant indicating that the fine (sixteen) directions should be used to orient the pathable being made to follow this path.

See Also:

Constant Field Values

NONE

public static final int NONE

An orientation indicating that the pathable should not be oriented as it moves along the path.

See Also:

Constant Field Values

_center

protected Point _center

The center of our ellipse.

_xradius

protected double _xradius

Our ellipse radii.

_yradius

protected double _yradius

Our ellipse radii.

_sangle

protected double _sangle

Our starting and delta angles.

_delta

protected double _delta

Our starting and delta angles.

_orient

protected int _orient

The method to be used to orient the pathable.

_orientOffset

protected int _orientOffset

An orientation offset used when orienting our pathable.

_tpos

protected Point _tpos

A temporary point used when computing our position along the path.

Constructor Detail

ArcPath

public ArcPath(Point start,
               double xradius,
               double yradius,
               double sangle,
               double delta,
               long duration,
               int orient)

Creates an arc path that will animate a pathable from the specified starting position along an ellipse defined by the supplied parameters. The pathable will travel the specified number of radians along the arc of that ellipse. A positive number of radians indicates counter-clockwise travel along the circle, a negative number, clockwise rotation.

Parameters:

start - the starting point for the pathable.

xradius - the length of the x radius.

yradius - the length of the y radius.

sangle - the starting angle.

delta - the angle through which the pathable should be moved.

duration - the number of milliseconds during which to effect the animation.

orient - an orientation code indicating how the pathable should be oriented when following the path, either NORMAL, or FINE.

Method Detail

getTranslatedInstance

public Path getTranslatedInstance(int x,
                                  int y)

Return a copy of the path, translated by the specified amounts.

setOrientOffset

public void setOrientOffset(int offset)

Sets the offset that is applied to the pathable whenever it is oriented. This offset is in clockwise units whose granularity is specified by the NORMAL or FINE setting supplied to the path at construct time. The intent here is to allow arc paths to be applied that don't orient the pathable in the direction they are traveling but instead in some fixed offset from that direction.

getEndPos

public Point getEndPos()

Returns the position of the end of the path.

tick

public boolean tick(Pathable pable,
                    long timestamp)

Description copied from interface: Path

Called to request that this path update the position of the specified pathable based on the supplied timestamp information. A path should record its initial timestamp and determine the progress of the pathable along the path based on the time elapsed since the pathable began down the path.

Parameters:

pable - the pathable whose position should be updated.

timestamp - the timestamp associated with this frame.

Returns:

true if the pathable's position was updated, false if the path determined that the pathable should not move at this time.

paint

public void paint(Graphics2D gfx)

Description copied from interface: Path

Paint this path on the screen (used for debugging purposes only).

toString

protected void toString(StringBuilder buf)

Description copied from class: TimedPath

An extensible method for generating a string representation of this instance.

Overrides:

toString in class TimedPath

computePosition

public static void computePosition(Point center,
                                   double xradius,
                                   double yradius,
                                   double angle,
                                   Point pos)

Computes the position of an entity along the path defined by the supplied parameters assuming that it must finish the path in the specified duration (in millis) and has been traveling the path for the specified number of elapsed milliseconds.