OnTopGlobeAnnotation.java

/*******************************************************************************
 * Copyright 2012 Geoscience Australia
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/
package au.gov.ga.earthsci.worldwind.common.util;

import gov.nasa.worldwind.geom.Position;
import gov.nasa.worldwind.geom.Vec4;
import gov.nasa.worldwind.render.DrawContext;
import gov.nasa.worldwind.render.GlobeAnnotation;

/**
 * A {@link GlobeAnnotation} subclass which modifies the setDepthFunc function
 * to ensure that the annotation is always drawn on top of everything else.
 * 
 * @author Michael de Hoog (michael.dehoog@ga.gov.au)
 */
public class OnTopGlobeAnnotation extends GlobeAnnotation
{
	public OnTopGlobeAnnotation(String text, Position position)
	{
		super(text, position);
	}

	@Override
	protected void setDepthFunc(DrawContext dc, Vec4 screenPoint)
	{
		//passing 0 for the screenPoint's z-coordinate causes the glDepthFunc to always pass
		screenPoint = new Vec4(screenPoint.x, screenPoint.y, 0.0, screenPoint.w);
		super.setDepthFunc(dc, screenPoint);
	}
}