com.luciad.view.lightspeed.geometry

LuciadFusionClass TLspFrustum

java.lang.Object

com.luciad.view.lightspeed.geometry.TLspFrustum

public class TLspFrustum
extends Object

Describes a view frustum: a volume delimited by six planes. A frustum can represent the volume of space that is visible in an ILspView, and can hence be used to perform culling of invisible objects. To this effect, this class contains overlap tests for the frustum with shapes such as points and bounds.

The figure below shows a schematic view of a frustum. The frustum itself is defined by the thick lines. With relation to a scene that is drawn in an ILspView, all objects that are located inside the volume defined by those thick lines, will appear on the screen. All the objects that are outside these bounds will be culled.

Since:

2012.0

Method Summary

Modifier and Type	Method and Description
static TLspFrustum	createFromModelViewProjectionMatrix(double[][] aMVPMatrix) Creates a frustum, based on the given modelview/projection matrix.
static TLspFrustum	createFromViewRectangle(Rectangle aViewRectangle, ALspViewXYZWorldTransformation aViewXYZWorldTransformation) Creates a frustum, based on the given rectangle in view coordinates and the given view to world transformation.
ILcdBounds	getBounds() Gets the bounds of the frustum.
List<ILcdPoint>	getCorners() Gets the 8 corners of this frustum.
double[][]	getPlanes() Gets the 6 planes that bounds this frustum.
double[]	getPlaneSFCT(int aIndex, double[] aCoefficientsSFCT) Returns the plane equation coefficients for a particular side of the frustum.
boolean	isBoundsVisible(ILcdBounds aBounds) Checks whether the given bounds (in world coordinates) are visible in this frustum.
boolean	isPointVisible(ILcdPoint aPoint) Checks whether the given point (in world coordinates) is visible in this frustum.
String	toString() Returns a textual representation of this frustum.

Methods inherited from class java.lang.Object

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

Method Detail

createFromModelViewProjectionMatrix

public static TLspFrustum createFromModelViewProjectionMatrix(double[][] aMVPMatrix)

Creates a frustum, based on the given modelview/projection matrix. The matrix is specified in row major order, i.e. it is to be indexed as aMVPMatrix[row][column].

Parameters:

aMVPMatrix - the combined modelview and projection matrices for which to determine the frustum planes

Returns:

a frustum, based on the given modelview/projection matrix.

Throws:

IllegalArgumentException - when the given matrix is null.

createFromViewRectangle

public static TLspFrustum createFromViewRectangle(Rectangle aViewRectangle,
                                                  ALspViewXYZWorldTransformation aViewXYZWorldTransformation)

Creates a frustum, based on the given rectangle in view coordinates and the given view to world transformation.

Parameters:

aViewRectangle - the rectangle around which to fit a frustum

aViewXYZWorldTransformation - the view to world transform for which to determine the frustum

Returns:

a frustum, based on the given rectangle in view coordinates and the given view to world transformation.

Throws:

IllegalArgumentException - when the given rectangle or view to world transformation are null

toString

public String toString()

Returns a textual representation of this frustum.

Overrides:

toString in class Object

Returns:

a String containing the textual representation of this frustum

isBoundsVisible

public boolean isBoundsVisible(ILcdBounds aBounds)

Checks whether the given bounds (in world coordinates) are visible in this frustum.

A bounds is visible if it intersects the volume defined by this frustum.

Parameters:

aBounds - the bounds to be tested

Returns:

true if the bounds are visible

Throws:

IllegalArgumentException - when the given bounds are null

isPointVisible

public boolean isPointVisible(ILcdPoint aPoint)

Checks whether the given point (in world coordinates) is visible in this frustum.

Parameters:

aPoint - the point to be tested

Returns:

true if the point is visible

Throws:

IllegalArgumentException - when the given point is null

getPlaneSFCT

public double[] getPlaneSFCT(int aIndex,
                             double[] aCoefficientsSFCT)

Returns the plane equation coefficients for a particular side of the frustum. Given the plane equation Ax + By + Cz + D = 0, this method returns the values of A, B, C and D in an array.

If aCoefficientsSFCT is not null and has at least four elements, it receives the coefficients. Otherwise, a new array is allocated. This method returns the array into which the coefficients were written.

Parameters:

aIndex - the index of the plane to be retrieved (between 0 and 5, inclusive)

aCoefficientsSFCT - if not null, receives the plane equation coefficients in its first four elements

Returns:

the array containing the plane equation coefficients

Throws:

IllegalArgumentException - when the given index is not in range [0, 5] or when aCoefficientsSFCT is not null and aCoefficientsSFCT.length < 4

getPlanes

public double[][] getPlanes()

Gets the 6 planes that bounds this frustum.

The result array should not be modified. To adapt the frustum, please create a new one using createFromModelViewProjectionMatrix or createFromViewRectangle.

Returns:

A double array containing the plane equations' coefficients

getCorners

public List<ILcdPoint> getCorners()

Gets the 8 corners of this frustum.

The result list and points should not be modified. To adapt the frustum, please use computeFromModelViewProjectionMatrix(double[][]) or computeFromViewRectangle(java.awt.Rectangle, com.luciad.view.lightspeed.camera.ALspViewXYZWorldTransformation).

Returns:

the eight corner points that define this frustum

getBounds

public ILcdBounds getBounds()

Gets the bounds of the frustum.

Returns:

the bounds of the frustum.