org.cell2d.space

Class Viewport<T extends CellGame,U extends SpaceState<T,U,?>>

java.lang.Object

org.cell2d.space.Viewport<T,U>

Type Parameters:

T - The type of CellGame that uses this Viewport's SpaceStates

U - The type of SpaceState that uses this Viewport

public class Viewport<T extends CellGame,U extends SpaceState<T,U,?>>
extends java.lang.Object

A Viewport represents a rectangular region of the screen through which the space of the SpaceState to which it is assigned can be viewed. The center of a Viewport's rectangular field of view in a SpaceState is the center of a SpaceObject called the Viewport's camera. To render the region of its SpaceState in its field of view, a Viewport's camera must be assigned to the same SpaceState as it. One pixel in a Viewport's rendering region on the screen is equal to one fracunit in its SpaceState.

While a Viewport is rendering visuals, the Graphics context to which it is rendering can only be drawn on within the Viewport's rendering region. When drawn to the Graphics context, shapes and Drawables will automatically be clipped so that they do not extend beyond the rendering region.

HUDs may be assigned to Viewports to render visuals in front of the Viewport's own. Only one HUD may be assigned to a given Viewport in this capacity at once. A Viewport's HUD uses the region of the screen that the Viewport occupies as its rendering region.

See Also:

SpaceState.setViewport(int, org.cell2d.space.Viewport), HUD

Constructor Summary

Constructors

Constructor and Description
Viewport(long x1, long y1, long x2, long y2) Constructs a Viewport that occupies the specified region of the screen.

Method Summary

Modifier and Type	Method and Description
int	getBottom() Returns the difference of the y-coordinates in pixels of this Viewport's bottom edge and the position of its camera on the screen.
long	getBottomEdge() Returns the y-coordinate of the bottom edge of this Viewport's field of view in a SpaceState.
SpaceObject	getCamera() Returns this Viewport's camera, or null if it has none.
T	getGame() Returns the CellGame of the SpaceState to which this Viewport is assigned, or null if it is not assigned to a SpaceState.
U	getGameState() Returns the SpaceState to which this Viewport is assigned, or null if it is not assigned to one.
long	getHeight() Returns this Viewport's height in fracunits on the screen.
HUD	getHUD() Returns the HUD that is assigned to this Viewport, or null if there is none.
int	getLeft() Returns the difference of the x-coordinates in pixels of this Viewport's left edge and the position of its camera on the screen.
long	getLeftEdge() Returns the x-coordinate of the left edge of this Viewport's field of view in a SpaceState.
int	getRight() Returns the difference of the x-coordinates in pixels of this Viewport's right edge and the position of its camera on the screen.
long	getRightEdge() Returns the x-coordinate of the right edge of this Viewport's field of view in a SpaceState.
java.awt.Point	getScreenPoint(CellVector spacePoint) Returns the point in pixels on the screen that corresponds to the specified point in a SpaceState as seen through this Viewport.
java.awt.Point	getScreenPoint(long x, long y) Returns the point in pixels on the screen that corresponds to the specified point in a SpaceState as seen through this Viewport.
CellVector	getSpacePoint(int x, int y) Returns the point in a SpaceState, as seen through this Viewport, that corresponds to the specified point in pixels in this Viewport's on-screen rendering region.
int	getTop() Returns the difference of the y-coordinates in pixels of this Viewport's top edge and the position of its camera on the screen.
long	getTopEdge() Returns the y-coordinate of the top edge of this Viewport's field of view in a SpaceState.
long	getWidth() Returns this Viewport's width in fracunits on the screen.
long	getX1() Returns the x-coordinate in fracunits of this Viewport's left edge on the screen.
long	getX2() Returns the x-coordinate in fracunits of this Viewport's right edge on the screen.
long	getY1() Returns the y-coordinate in fracunits of this Viewport's top edge on the screen.
long	getY2() Returns the y-coordinate in fracunits of this Viewport's bottom edge on the screen.
boolean	rectangleIsVisible(long x1, long y1, long x2, long y2) Returns whether any part of the specified rectangular region of a SpaceState's space is visible through this Viewport.
void	setCamera(SpaceObject camera) Sets this Viewport's camera to the specified SpaceObject, or to none if the specified SpaceObject is null.
void	setHUD(HUD hud) Sets the HUD that is assigned to this Viewport to the specified one.
boolean	setX1(long x1) Sets the x-coordinate in fracunits of this Viewport's left edge on the screen to the specified value, if doing so would not cause this Viewport's width to be negative.
boolean	setX2(long x2) Sets the x-coordinate in fracunits of this Viewport's right edge on the screen to the specified value, if doing so would not cause this Viewport's width to be negative.
boolean	setY1(long y1) Sets the y-coordinate in fracunits of this Viewport's top edge on the screen to the specified value, if doing so would not cause this Viewport's height to be negative.
boolean	setY2(long y2) Sets the y-coordinate in fracunits of this Viewport's bottom edge on the screen to the specified value, if doing so would not cause this Viewport's height to be negative.

Methods inherited from class java.lang.Object

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

Constructor Detail

Viewport

public Viewport(long x1,
                long y1,
                long x2,
                long y2)

Constructs a Viewport that occupies the specified region of the screen.

Parameters:

x1 - The x-coordinate in pixels of this Viewport's left edge on the screen

y1 - The y-coordinate in pixels of this Viewport's top edge on the screen

x2 - The x-coordinate in pixels of this Viewport's right edge on the screen

y2 - The y-coordinate in pixels of this Viewport's bottom edge on the screen

Method Detail

getGame

public final T getGame()

Returns the CellGame of the SpaceState to which this Viewport is assigned, or null if it is not assigned to a SpaceState.

Returns:

This Viewport's SpaceState's CellGame

getGameState

public final U getGameState()

Returns the SpaceState to which this Viewport is assigned, or null if it is not assigned to one.

Returns:

The SpaceState to which this Viewport is assigned

getCamera

public final SpaceObject getCamera()

Returns this Viewport's camera, or null if it has none.

Returns:

This Viewport's camera

setCamera

public final void setCamera(SpaceObject camera)

Sets this Viewport's camera to the specified SpaceObject, or to none if the specified SpaceObject is null.

Parameters:

camera - The new camera

getHUD

public final HUD getHUD()

Returns the HUD that is assigned to this Viewport, or null if there is none.

Returns:

This Viewport's HUD

setHUD

public final void setHUD(HUD hud)

Sets the HUD that is assigned to this Viewport to the specified one. If there is already an HUD assigned to this Viewport, it will be removed. If the specified HUD is null, the current HUD will be removed if there is one, but it will not be replaced with anything.

Parameters:

hud - The HUD to add

getX1

public final long getX1()

Returns the x-coordinate in fracunits of this Viewport's left edge on the screen.

Returns:

The x-coordinate in fracunits of this Viewport's left edge

setX1

public final boolean setX1(long x1)

Sets the x-coordinate in fracunits of this Viewport's left edge on the screen to the specified value, if doing so would not cause this Viewport's width to be negative.

Parameters:

x1 - The new x-coordinate in fracunits of this Viewport's left edge

Returns:

Whether the change occurred

getY1

public final long getY1()

Returns the y-coordinate in fracunits of this Viewport's top edge on the screen.

Returns:

The y-coordinate in fracunits of this Viewport's top edge

setY1

public final boolean setY1(long y1)

Sets the y-coordinate in fracunits of this Viewport's top edge on the screen to the specified value, if doing so would not cause this Viewport's height to be negative.

Parameters:

y1 - The new y-coordinate in fracunits of this Viewport's top edge

Returns:

Whether the change occurred

getX2

public final long getX2()

Returns the x-coordinate in fracunits of this Viewport's right edge on the screen.

Returns:

The x-coordinate in fracunits of this Viewport's right edge

setX2

public final boolean setX2(long x2)

Sets the x-coordinate in fracunits of this Viewport's right edge on the screen to the specified value, if doing so would not cause this Viewport's width to be negative.

Parameters:

x2 - The new x-coordinate in fracunits of this Viewport's right edge

Returns:

Whether the change occurred

getY2

public final long getY2()

Returns the y-coordinate in fracunits of this Viewport's bottom edge on the screen.

Returns:

The y-coordinate in fracunits of this Viewport's bottom edge

setY2

public final boolean setY2(long y2)

Sets the y-coordinate in fracunits of this Viewport's bottom edge on the screen to the specified value, if doing so would not cause this Viewport's height to be negative.

Parameters:

y2 - The new y-coordinate in fracunits of this Viewport's bottom edge

Returns:

Whether the change occurred

getWidth

public final long getWidth()

Returns this Viewport's width in fracunits on the screen.

Returns:

This Viewport's width in fracunits

getHeight

public final long getHeight()

Returns this Viewport's height in fracunits on the screen.

Returns:

This Viewport's height in fracunits

getLeft

public final int getLeft()

Returns the difference of the x-coordinates in pixels of this Viewport's left edge and the position of its camera on the screen.

Returns:

This Viewport's left-side difference

getRight

public final int getRight()

Returns the difference of the x-coordinates in pixels of this Viewport's right edge and the position of its camera on the screen.

Returns:

This Viewport's right-side difference

getTop

public final int getTop()

Returns the difference of the y-coordinates in pixels of this Viewport's top edge and the position of its camera on the screen.

Returns:

This Viewport's top-side difference

getBottom

public final int getBottom()

Returns the difference of the y-coordinates in pixels of this Viewport's bottom edge and the position of its camera on the screen.

Returns:

This Viewport's bottom-side difference

getLeftEdge

public final long getLeftEdge()
                       throws java.lang.NullPointerException

Returns the x-coordinate of the left edge of this Viewport's field of view in a SpaceState.

Returns:

The x-coordinate of this Viewport's field of view's left edge

Throws:

java.lang.NullPointerException - if this Viewport has no camera

getRightEdge

public final long getRightEdge()
                        throws java.lang.NullPointerException

Returns the x-coordinate of the right edge of this Viewport's field of view in a SpaceState.

Returns:

The x-coordinate of this Viewport's field of view's right edge

Throws:

java.lang.NullPointerException - if this Viewport has no camera

getTopEdge

public final long getTopEdge()
                      throws java.lang.NullPointerException

Returns the y-coordinate of the top edge of this Viewport's field of view in a SpaceState.

Returns:

The y-coordinate of this Viewport's field of view's top edge

Throws:

java.lang.NullPointerException - if this Viewport has no camera

getBottomEdge

public final long getBottomEdge()
                         throws java.lang.NullPointerException

Returns the y-coordinate of the bottom edge of this Viewport's field of view in a SpaceState.

Returns:

The y-coordinate of this Viewport's field of view's bottom edge

Throws:

java.lang.NullPointerException - if this Viewport has no camera

getSpacePoint

public final CellVector getSpacePoint(int x,
                                      int y)

Returns the point in a SpaceState, as seen through this Viewport, that corresponds to the specified point in pixels in this Viewport's on-screen rendering region. If the specified point is not in this Viewport's rendering region or this Viewport has no camera, this method will return null.

Parameters:

x - The x-coordinate of the screen point

y - The y-coordinate of the screen point

Returns:

The SpaceState point that corresponds to the specified screen point

getScreenPoint

public final java.awt.Point getScreenPoint(CellVector spacePoint)

Returns the point in pixels on the screen that corresponds to the specified point in a SpaceState as seen through this Viewport. If the specified point is not visible through this Viewport, this method will return null.

Parameters:

spacePoint - The SpaceState point

Returns:

The screen point that corresponds to the specified SpaceState point as seen through this Viewport

getScreenPoint

public final java.awt.Point getScreenPoint(long x,
                                           long y)

Returns the point in pixels on the screen that corresponds to the specified point in a SpaceState as seen through this Viewport. If the specified point is not visible through this Viewport, this method will return null.

Parameters:

x - The x-coordinate of the SpaceState point

y - The y-coordinate of the SpaceState point

Returns:

The screen point that corresponds to the specified SpaceState point as seen through this Viewport

rectangleIsVisible

public final boolean rectangleIsVisible(long x1,
                                        long y1,
                                        long x2,
                                        long y2)

Returns whether any part of the specified rectangular region of a SpaceState's space is visible through this Viewport.

Parameters:

x1 - The x-coordinate of the region's left edge

y1 - The y-coordinate of the region's top edge

x2 - The x-coordinate of the region's right edge

y2 - The y-coordinate of the region's bottom edge

Returns:

Whether the specified rectangular region of a SpaceState's space is visible through this Viewport