3维空间曲线

JME3提供了Curve类，用于生成曲线网格。利用它可以很容易绘制3维空间曲线。

package com.ruanko.jme3;

import java.util.Random;

import com.jme3.app.SimpleApplication;
import com.jme3.material.Material;
import com.jme3.math.ColorRGBA;
import com.jme3.math.FastMath;
import com.jme3.math.Vector3f;
import com.jme3.scene.Geometry;
import com.jme3.scene.debug.Arrow;
import com.jme3.scene.debug.Grid;
import com.jme3.scene.shape.Curve;
import com.jme3.system.AppSettings;

/**
 * 3维空间曲线
 * @author [e-mail]
 */
public class ThreeDCurve extends SimpleApplication {
	private Geometry curveGeom;// 曲线A

	private Vector3f camLocVctr = new Vector3f(100.0f, 32.0f, 0.0f);

	//
	public static void main(String[] args) {
		ThreeDCurve app = new ThreeDCurve();
		
		// 初始化应用程序
		AppSettings settings = new AppSettings(true);
		settings.setHeight(768);
		settings.setWidth(1024);
		app.setSettings(settings);
		app.setShowSettings(false);
		app.start();
	}

	@Override
	public void simpleInitApp() {
		this.setDisplayFps(false);
		this.setDisplayStatView(false);
		
		// 背景色
		viewPort.setBackgroundColor(ColorRGBA.White);
		
		// 摄像机初始位置
		cam.setLocation(camLocVctr);
		cam.lookAt(Vector3f.ZERO, cam.getUp());
		flyCam.setMoveSpeed(100.0f);
		
		// 显示3维坐标系
		showNodeAxes(250);

		// 生成坐标系网格
		Geometry g = new Geometry("wireFrameDebugGrid1", new Grid(100, 100, 5.0f));// 5WU
		Material m = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
		m.getAdditionalRenderState().setWireframe(true);
		m.setColor("Color", ColorRGBA.LightGray);
		g.setMaterial(m);
		g.center().move(Vector3f.ZERO);// 中心坐标
		rootNode.attachChild(g);

		// 生成一个有100个顶点的曲线
		Vector3f[] points = new Vector3f[100];
		for (float i = 0; i < 100; i++) {
			// 这里利用三角函数生成顶点。
			// 随便写的，可以改掉。
			points[(int) i] = new Vector3f(i, i + 10
					* FastMath.sin(i / 10 * FastMath.PI), i + 10
					* FastMath.sin(i / 25 * FastMath.PI));
		}

		Curve curve = new Curve(points, 1);// 曲线A
		curveGeom = new Geometry("曲线A", curve);

		// 设置材质
        Material mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
        mat.setColor("Color", ColorRGBA.Red);
		curveGeom.setMaterial(mat);
		rootNode.attachChild(curveGeom);
	}

	@Override
	public void simpleUpdate(float tpf) {
		
		/////// 下面的代码会重新生成曲线A的所有顶点 ///////////
		Random rand = new Random();
		Vector3f[] points = new Vector3f[100];
		float base = rand.nextFloat() * 10;
		for (int i = 0; i < 100; i++) {
			// 这里利用三角函数生成顶点。
			// 随便写的，可以改掉。
			float x = i + base;
			float y = i + rand.nextFloat() * 10
					* FastMath.sin(i / 10 * FastMath.PI);
			float z = i + rand.nextFloat() * 10 + rand.nextFloat() * 10
					* FastMath.sin(i / 25 * FastMath.PI);
			points[i] = new Vector3f(x, y, z);
		}
		///////////////////////////////////
		
		// 刷新曲线A
		Curve curve = new Curve(points, 1);// 曲线A
		curveGeom.setMesh(curve);
		curveGeom.updateModelBound();
	}

	public void showNodeAxes(float axisLen) {
		// 
		Vector3f v = new Vector3f(axisLen, 0, 0);
		Arrow a = new Arrow(v);
		Material mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
		mat.setColor("Color", ColorRGBA.Red);
		Geometry geom = new Geometry(rootNode.getName() + "XAxis", a);
		geom.setMaterial(mat);
		rootNode.attachChild(geom);

		//
		v = new Vector3f(0, axisLen, 0);
		a = new Arrow(v);
		mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
		mat.setColor("Color", ColorRGBA.Green);
		geom = new Geometry(rootNode.getName() + "YAxis", a);
		geom.setMaterial(mat);
		rootNode.attachChild(geom);

		//
		v = new Vector3f(0, 0, axisLen);
		a = new Arrow(v);
		mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
		mat.setColor("Color", ColorRGBA.Blue);
		geom = new Geometry(rootNode.getName() + "ZAxis", a);
		geom.setMaterial(mat);
		rootNode.attachChild(geom);
	}
}

效果