Package edu.cnu.mdi.mdi3D.item3D

Class LabelSet3D

java.lang.Object

edu.cnu.mdi.mdi3D.item3D.Item3D

edu.cnu.mdi.mdi3D.item3D.LabelSet3D

public class LabelSet3D
extends Item3D

Draws screen-space text labels for a set of 3D points.

This item projects each 3D point into window coordinates using Panel3D.project(GL2, float, float, float, float[]) and then renders the corresponding label in pixel coordinates via JOGL's TextRenderer.

This keeps label size constant regardless of zoom and avoids any need for 3D text geometry. Label visibility policy (e.g., globe front-hemisphere) is optional and controlled by a pluggable LabelSet3D.LabelCull.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	LabelSet3D.LabelCull	Functional interface for optional per-label visibility tests.

Field Summary

Fields inherited from class edu.cnu.mdi.mdi3D.item3D.Item3D

_panel3D, FILLALPHA, FILLCOLOR, FONT, LINE_WIDTH, LINEALPHA, LINECOLOR, TEXT_COLOR

Constructor Summary

Constructors

Constructor	Description
LabelSet3D(Panel3D panel3D, float[] coords, String[] labels)	Create a label set for 3D points.

Method Summary

Modifier and Type	Method	Description
protected void	dispose(com.jogamp.opengl.GLAutoDrawable drawable)	Releases the lazily-created TextRenderer and its GPU texture atlas.
void	draw(com.jogamp.opengl.GLAutoDrawable drawable)	The custom drawing method
static LabelSet3D.LabelCull	frontHemisphereCull(float cx, float cy, float cz)	Returns a culling policy that keeps labels on the visible hemisphere of a sphere.
void	setClipToViewport(boolean clip)	If enabled, labels must project into the viewport and have depth in [0,1].
void	setCoords(float[] coords)	Update coordinates (e.g., if points move).
void	setCull(LabelSet3D.LabelCull cull)	Install (or clear) an optional culling strategy.
void	setLabels(String[] labels)	Update labels.
void	setPixelOffset(int dx, int dy)	Set pixel offsets applied to each label after projecting.

Methods inherited from class edu.cnu.mdi.mdi3D.item3D.Item3D

addChild, defaultProperties, disposeItem, drawItem, get, getChildren, getColor, getFillAlpha, getFillColor, getFloat, getFont, getFont, getInt, getLineAlpha, getLineColor, getLineWidth, getPanel3D, getParent, getSortPoint, getString, getTextColor, isVisible, put, removeChild, setAlphaOfColor, setFillAlpha, setFillColor, setFont, setLineAlpha, setLineColor, setLineWidth, setTextColor, setVisible

Methods inherited from class java.lang.Object

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

Constructor Details

LabelSet3D

public LabelSet3D(Panel3D panel3D,
 float[] coords,
 String[] labels)

Create a label set for 3D points.

Parameters:

panel3D - owner panel

coords - point coords as [x1,y1,z1,...]

labels - per-point labels (same count as points)

Method Details

setCull

public void setCull(LabelSet3D.LabelCull cull)

Install (or clear) an optional culling strategy.

Parameters:

cull - strategy, or null to disable extra culling

setPixelOffset

public void setPixelOffset(int dx,
 int dy)

Set pixel offsets applied to each label after projecting.

Parameters:

dx - pixels right

dy - pixels up

setClipToViewport

public void setClipToViewport(boolean clip)

If enabled, labels must project into the viewport and have depth in [0,1].

Parameters:

clip - true to clip labels to viewport

setCoords

public void setCoords(float[] coords)

Update coordinates (e.g., if points move).

Parameters:

coords - [x1,y1,z1,...]

setLabels

public void setLabels(String[] labels)

Update labels.

Parameters:

labels - per-point labels

dispose

protected void dispose(com.jogamp.opengl.GLAutoDrawable drawable)

Releases the lazily-created TextRenderer and its GPU texture atlas.

Overrides:

dispose in class Item3D

Parameters:

drawable - the OpenGL drawable being disposed

draw

public void draw(com.jogamp.opengl.GLAutoDrawable drawable)

Description copied from class: Item3D

The custom drawing method

Specified by:

draw in class Item3D

Parameters:

drawable - the OpenGL drawable

frontHemisphereCull

public static LabelSet3D.LabelCull frontHemisphereCull(float cx,
 float cy,
 float cz)

Returns a culling policy that keeps labels on the visible hemisphere of a sphere.

This is a geometric hemisphere test for a sphere whose center is given in world coordinates. It does not require the sphere to be centered at (0,0,0).

Implementation details:

• Transforms the sphere center C and the point P into eye space using the provided modelview.
• Computes N = P - C (outward normal direction).
• Computes V = -C (vector from center to camera at origin in eye space).
• Accepts if N · V > 0.

Parameters:

cx - sphere center world x

cy - sphere center world y

cz - sphere center world z

Returns:

a culling strategy for the front hemisphere of that sphere