engine/src/core/com/jme3/scene/debug/Grid.java

/*
 * Copyright (c) 2009-2010 jMonkeyEngine
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
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 *
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 * * Redistributions in binary form must reproduce the above copyright
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 *   may be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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package com.jme3.scene.debug;

import com.jme3.scene.Mesh;
import com.jme3.scene.Mesh.Mode;
import com.jme3.scene.VertexBuffer.Type;
import com.jme3.util.BufferUtils;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;

/**
 * Simple grid shape.
 * 
 * @author Kirill Vainer
 */
public class Grid extends Mesh {

    /**
     * Creates a grid debug shape.
     * @param xLines
     * @param yLines
     * @param lineDist 
     */
    public Grid(int xLines, int yLines, float lineDist){
        xLines -= 2;
        yLines -= 2;
        int lineCount = xLines + yLines + 4;

        FloatBuffer fpb = BufferUtils.createFloatBuffer(6 * lineCount);
        ShortBuffer sib = BufferUtils.createShortBuffer(2 * lineCount);

        float xLineLen = (yLines + 1) * lineDist;
        float yLineLen = (xLines + 1) * lineDist;
        int curIndex = 0;

        // add lines along X
        for (int i = 0; i < xLines + 2; i++){
            float y = (i) * lineDist;

            // positions
            fpb.put(0)       .put(0).put(y);
            fpb.put(xLineLen).put(0).put(y);

            // indices
            sib.put( (short) (curIndex++) );
            sib.put( (short) (curIndex++) );
        }

        // add lines along Y
        for (int i = 0; i < yLines + 2; i++){
            float x = (i) * lineDist;

            // positions
            fpb.put(x).put(0).put(0);
            fpb.put(x).put(0).put(yLineLen);

            // indices
            sib.put( (short) (curIndex++) );
            sib.put( (short) (curIndex++) );
        }

        fpb.flip();
        sib.flip();

        setBuffer(Type.Position, 3, fpb);
        setBuffer(Type.Index, 2, sib);
        
        setMode(Mode.Lines);

        updateBound();
        updateCounts();
    }
    
}