vgp.tutor.linear
Class PjLinear

java.lang.Object
  |
  +--jv.object.PsObject
        |
        +--jv.project.PjProject
              |
              +--vgp.tutor.linear.PjLinear

All Implemented Interfaces:

java.lang.Cloneable, PsTimeListenerIf, PsUpdateIf, PvPickListenerIf, java.io.Serializable

public class PjLinear

extends PjProject

Simple interactive linear algebra applet performs vector calculations on two vectors and shows the result vector.

The result vector has 3D coordinates because of the possible cross product mode. Nevertheless, the dimension of the two argument vectors has been chosen 2D since then the vectors always lie in the xy-plane in the display, even if the camera is in perspective mode. This makes the dragging of the argument vectors in cross product mode more intuitive. Note, the method computeResult() may be simplified a little if one chooses 3D coordinates for all vectors.

Version:

04.03.01, 1.20 revised (kp) Converted into a tutorial, and moved to vgp.tutor.
26.11.00, 1.10 revised (kp) Use global instead of local polygon colors.
22.10.00, 1.00 created (kp)

Author:

Konrad Polthier

See Also:

Serialized Form

Field Summary

protected int	m_mode Computation mode, possibly values are MODE_... constants.
protected PgPolygon	m_result The result vector is a single polygon.
protected PgPolygonSet	m_vectors Two argument vectors are represented as two lines of a polygon set determined by their endpoints.
static int	MODE_ADD Summation mode, result is sum of two argument vectors.
static int	MODE_CROSS Cross product mode, result is cross product of two argument vectors.
static int	MODE_SUB Difference mode, result is difference of two argument vectors.

Fields inherited from class jv.project.PjProject

m_anim, m_bAutoFit, m_display, m_displayList, m_geometry, m_parm, m_rootGeometry

Fields inherited from class jv.object.PsObject

HAS_CONFIG_PANEL, HAS_INFO_PANEL, HAS_MATERIAL_PANEL, INSPECTOR_INFO, INSPECTOR_INFO_EXT, IS_DELETED, IS_FIXED, IS_SELECTED, IS_USED, m_infoPanel, m_name, m_panelList, m_parent, m_tag, m_updateList, NUM_TAGS

Constructor Summary

PjLinear()
Constructors creates two argument vectors and a result vector.

Method Summary

void	computeResult(int mode) Perform vector arithmetic on two argument vectors to compute the result vector.
int	getMode() Get the current computation mode, possibly values are MODE_... constants.
void	init() Initialize all instance variables of this project.
int	setMode(int mode) Set the current computation mode, possibly values are MODE_... constants.
void	start() Method is invoked during loading of a project in JavaView.
boolean	update(java.lang.Object event) Perform recomputations whenever a child has changed.

Methods inherited from class jv.project.PjProject

addDisplay, addGeometry, addGeometry, dispose, dragDisplay, dragInitial, dragVertex, fitDisplays, getAnimation, getDisplay, getDisplays, getGeometry, getGeometry, getNumGeometries, getParameter, getViewer, hasAnimation, hasDisplay, isEnabledAutoFit, markVertices, pickDisplay, pickInitial, pickVertex, removeDisplay, removeGeometries, removeGeometry, selectDisplay, selectGeometry, setAnimation, setDisplay, setEnabledAutoFit, setParameter, setTime, setViewer, stop, unmarkVertices

Methods inherited from class jv.object.PsObject

addInspector, addUpdateListener, clearTag, clone, clone, clone, copy, getFather, getInfoPanel, getInspector, getName, getNumObjects, hasInspector, hasTag, hasUpdateListener, instanceOf, instanceOf, removeInspector, removeUpdateListener, setName, setParent, setTag, toString, updatePanels

Methods inherited from class java.lang.Object

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

Methods inherited from interface jv.anim.PsTimeListenerIf

getName

Methods inherited from interface jv.project.PvPickListenerIf

getName

Methods inherited from interface jv.object.PsUpdateIf

getFather, getName, setParent

Field Detail

MODE_ADD

public static final int MODE_ADD

Summation mode, result is sum of two argument vectors.

MODE_SUB

public static final int MODE_SUB

Difference mode, result is difference of two argument vectors.

MODE_CROSS

public static final int MODE_CROSS

Cross product mode, result is cross product of two argument vectors.

m_vectors

protected PgPolygonSet m_vectors

Two argument vectors are represented as two lines of a polygon set determined by their endpoints. The base point of both vectors is identical, namely, the first vertex of the polygon set. The second and third vertex of the polygon set are the endpoints of both vertices.

m_result

protected PgPolygon m_result

The result vector is a single polygon. The base point of this vector is kept equal to the base point of the two argument vectors, and its endpoint is computed from the two argument vectors depending on the current mode, i.e. either the sum, difference or cross product.

m_mode

protected int m_mode

Computation mode, possibly values are MODE_... constants.

Constructor Detail

PjLinear

public PjLinear()

Constructors creates two argument vectors and a result vector. Initializations of instance variables should be performed within the init() method to allow resetting the project later by simply calling the init() method.

Method Detail

init

public void init()

Initialize all instance variables of this project. This method is invoked during the construction of this project and whenever this project is resetted. Therefore, allocations of instance variables should be performed in the constructor of the project.

Overrides:

init in class PjProject

start

public void start()

Description copied from class: PjProject

Method is invoked during loading of a project in JavaView.

If a project has an animation object, then the animation panel is shown when the project's this start() method is invoked during loading of the project. Use setAnimation(PsAnimation) to register an animation.

If auto fit is enabled then scenery is scaled to fit in each display.

Overrides:

start in class PjProject

Following copied from class: jv.project.PjProject

See Also:

PvViewerIf.start(), #isEnabledAutoFit(boolean)

getMode

public int getMode()

Get the current computation mode, possibly values are MODE_... constants.

setMode

public int setMode(int mode)

Set the current computation mode, possibly values are MODE_... constants. Method also recomputes the result vector and initiates a redraw.

computeResult

public void computeResult(int mode)

Perform vector arithmetic on two argument vectors to compute the result vector. This method could be made simpler if one uses 3D coordinates for argument vectors too.

update

public boolean update(java.lang.Object event)

Perform recomputations whenever a child has changed. Here the two argument vectors have registered this class as parent, therefore, we are able to catch their update events and recompute the result vectors if they have changed. Method is usually invoked from the children.

Overrides:

update in class PsObject

Following copied from interface: jv.object.PsUpdateIf

Parameters:

event - carries a lot of information

Returns:

true if event has been handled, otherwise false

See Also:

PsObject, PsUpdateIf.getFather(), PsUpdateIf.setParent(PsUpdateIf)