Java|Java 3D入门之基本图形功能附源码 Java3D入门之基本图形功能附源

坐标系
基本体组合的显示实例
三角面图形
三角扇图形
四边面图形

坐标系

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1、原点O在显示器的中间。
2、Z轴是指向屏幕之外的，也就是观察者。
3、由于观察者眼睛，即观察方向是指向Z轴的反方向，所以当定义好图形之后，光源的方向一定不能是指向Z轴的正方向，否则无法观察到图形。（根据光的反射）

基本体组合的显示实例

import java.applet.Applet; import java.awt.BorderLayout; import java.awt.GraphicsConfiguration; import javax.media.j3d.*; import javax.vecmath.Color3f; import javax.vecmath.Point3d; import javax.vecmath.Vector3f; import com.sun.j3d.utils.applet.MainFrame; import com.sun.j3d.utils.behaviors.mouse.MouseRotate; import com.sun.j3d.utils.behaviors.mouse.MouseTranslate; import com.sun.j3d.utils.behaviors.mouse.MouseZoom; import com.sun.j3d.utils.geometry.Box; import com.sun.j3d.utils.geometry.Sphere; import com.sun.j3d.utils.universe.SimpleUniverse; public class towprimitivedisplay extends Applet { public BranchGroup createBranchGroup() {//定义BranchGroupBranchGroup BranchGroupRoot = new BranchGroup (); //创建球心在坐标系原点球形范围BoundingSphere bounds = new BoundingSphere(new Point3d( 0.0,0.0,0.0),100.0); //定义背景颜色Color3f bgColor=new Color3f(.0f,.0f,.0f); Background bg=new Background(bgColor); bg.setApplicationBounds(bounds); BranchGroupRoot.addChild(bg); //定义平行光、颜色、照射方向与作用范围Color3f directionColor=new Color3f(1.f,1.f,1.f); Vector3f vec=new Vector3f(1.0f,-1.0f,-1.0f); DirectionalLight directionalLight= new DirectionalLight(directionColor,vec); directionalLight.setInfluencingBounds(bounds); BranchGroupRoot.addChild(directionalLight); //定义总的TransformGroup:transformgroupTransformGroup transformgroup=new TransformGroup(); //设置对该TransformGroup的读写能力transformgroup.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE); transformgroup.setCapability(TransformGroup.ALLOW_TRANSFORM_READ); //将该TransformGroup加入到BranchGroupRoot中BranchGroupRoot.addChild(transformgroup); //定义鼠标对场景的旋转、平移与放大功能MouseRotate mouserotate=new MouseRotate(); mouserotate.setTransformGroup(transformgroup); BranchGroupRoot.addChild(mouserotate); mouserotate.setSchedulingBounds(bounds); MouseZoom mousezoom=new MouseZoom(); mousezoom.setSchedulingBounds(bounds); BranchGroupRoot.addChild(mousezoom); mousezoom.setSchedulingBounds(bounds); MouseTranslate mousetranslate=new MouseTranslate(); mousetranslate.setTransformGroup(transformgroup); BranchGroupRoot.addChild(mousetranslate); mousetranslate.setSchedulingBounds(bounds); //定义两个三维型体的外观Appearance app1=new Appearance(); Material material1=new Material(); material1.setDiffuseColor(new Color3f(1.0f,.0f,0.0f)); app1.setMaterial(material1); Appearance app2=new Appearance(); Material material2=new Material(); material2.setDiffuseColor(new Color3f(0.0f,1.0f,0.0f)); app2.setMaterial(material2); //定义一个球体于一个长方体的大小、外观属性与坐标变换，并定义相应的TransformGroup：ta1、ta2TransformGroup tg1=new TransformGroup(); tg1.addChild(new Sphere(0.3f,app1)); Transform3D t=new Transform3D(); t.setTranslation(new Vector3f(0.f,-0.425f,0.f)); TransformGroup tg2=new TransformGroup(t); tg2.addChild(new Box(0.5f,0.05f,0.5f,app2)); //将定义好的两个TransformGroup(tg1、tg2)加入到总的transformgrouptransformgroup.addChild(tg1); transformgroup.addChild(tg2); //对BranchGroupRoot预编译BranchGroupRoot.compile(); //通过方法名返回BranchGroupRootreturn BranchGroupRoot; }public towprimitivedisplay(){//设置显示界面的相关参数setLayout(new BorderLayout()); //创建投影平面Canvas3DGraphicsConfiguration gc=SimpleUniverse.getPreferredConfiguration(); Canvas3D c=new Canvas3D(gc); //将投影平面上的图像显示在显示平面的中间add("Center",c); //设置SimpleUniverse，由系统选择视点在z轴的正向，观察方向沿z轴反向BranchGroup BranchGroupScene=createBranchGroup(); SimpleUniverse u=new SimpleUniverse(c); u.getViewingPlatform().setNominalViewingTransform(); //将BranchGroup:BranchGroupScene加入到SimpleUniverse:u中u.addBranchGraph(BranchGroupScene); }public static void main(String[] args){//通过MainFrame显示图像new MainFrame(new towprimitivedisplay(),300,300); }}

由于光源方向是：
Vector3f vec=new Vector3f(-1.f,-1.f,-1.0f); 即指向第七象限。所以结果是：

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如果改变光源方向：
Vector3f vec=new Vector3f(0.0f,0.0f,-1.0f); 光源指向Z轴反方向

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Vector3f vec=new Vector3f(-1.0f,0.0f,0.0f); 光源指向X轴反方向

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三角面图形以一维数组给出顶点的坐标值，从前向后一次以3个顶点形成一个三角形，并且上一个三角形与下一个三角形之间没有公共顶点。

import java.awt.BorderLayout; import java.awt.GraphicsConfiguration; import javax.media.j3d.Appearance; import javax.media.j3d.Background; import javax.media.j3d.BoundingSphere; import javax.media.j3d.BranchGroup; import javax.media.j3d.Canvas3D; import javax.media.j3d.DirectionalLight; import javax.media.j3d.PolygonAttributes; import javax.media.j3d.Shape3D; import javax.media.j3d.TransformGroup; import javax.media.j3d.TriangleArray; import javax.vecmath.Color3f; import javax.vecmath.Point3d; import javax.vecmath.Vector3f; import com.sun.j3d.utils.applet.MainFrame; import com.sun.j3d.utils.behaviors.mouse.MouseRotate; import com.sun.j3d.utils.behaviors.mouse.MouseTranslate; import com.sun.j3d.utils.behaviors.mouse.MouseZoom; import com.sun.j3d.utils.universe.SimpleUniverse; import java.applet.Applet; public class DisplayTriangles extends Applet { public BranchGroup createBranchGroup() {BranchGroup BranchGroupRoot = new BranchGroup(); BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0), 100.0); Color3f bgColor = new Color3f(1.0f, 1.0f, 1.0f); Background bg = new Background(bgColor); bg.setApplicationBounds(bounds); BranchGroupRoot.addChild(bg); Color3f directionalColor = new Color3f(1.f, 0.f, 0.f); Vector3f vec = new Vector3f(0.f, 0.f, -1.0f); DirectionalLight directionalLight = new DirectionalLight(directionalColor, vec); directionalLight.setInfluencingBounds(bounds); BranchGroupRoot.addChild(directionalLight); TransformGroup transformgroup = new TransformGroup(); transformgroup.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE); transformgroup.setCapability(TransformGroup.ALLOW_TRANSFORM_READ); BranchGroupRoot.addChild(transformgroup); MouseRotate mouserotate = new MouseRotate(); mouserotate.setTransformGroup(transformgroup); BranchGroupRoot.addChild(mouserotate); mouserotate.setSchedulingBounds(bounds); MouseZoom mousezoom = new MouseZoom(); mousezoom.setTransformGroup(transformgroup); BranchGroupRoot.addChild(mousezoom); mousezoom.setSchedulingBounds(bounds); MouseTranslate mousetranslate = new MouseTranslate(); mousetranslate.setTransformGroup(transformgroup); BranchGroupRoot.addChild(mousetranslate); mousetranslate.setSchedulingBounds(bounds); transformgroup.addChild(new TriangleArrays()); BranchGroupRoot.compile(); return BranchGroupRoot; } public DisplayTriangles() {setLayout(new BorderLayout()); GraphicsConfiguration gc = SimpleUniverse.getPreferredConfiguration(); Canvas3D c = new Canvas3D(gc); add("Center", c); BranchGroup BranchGroupScene = createBranchGroup(); SimpleUniverse u = new SimpleUniverse(c); u.getViewingPlatform().setNominalViewingTransform(); u.addBranchGraph(BranchGroupScene); } public static void main(String[] args) {new MainFrame(new DisplayTriangles(), 300, 300); }}//outsideclassclass TriangleArrays extends Shape3D { public TriangleArrays() {int vCount = 12; float vertexes[] = { -0.6f,0.9f,0.0f,-0.6f,-0.9f,0.2f,-0.4f, 0.9f, -0.2f, -0.2f, -0.9f, 0.2f, 0.0f, 0.9f,-0.2f,0.0f, -0.9f, 0.2f, 0.2f, 0.7f, 0.0f,0.2f, -0.9f, 0.3f,0.5f, 0.8f, -0.3f,0.6f, -.9f, 0.0f,0.8f, 0.9f, 0.2f,0.8f, -0.8f, 0.3f }; float colors[] = { 0.0f,0.5f,1.0f,0.0f,0.5f,1.0f,0.0f,0.8f,.0f,1.0f,0.0f,0.3f,0.0f,1.0f,0.5f,0.9f,1.0f,0.0f,0.5f,0.0f,1.0f,0.0f,0.5f,1.0f,1.0f,0.5f,0.0f,1.0f,0.0f,0.5f,1.0f,0.8f,0.0f,1.0f,0.5f,0.0f}; TriangleArray trianglearray = new TriangleArray(vCount, TriangleArray.COORDINATES | TriangleArray.COLOR_3); trianglearray.setCoordinates(0, vertexes); trianglearray.setColors(0, colors); PolygonAttributes polygonattributes = new PolygonAttributes(); //polygonattributes.setCullFace(PolygonAttributes.CULL_NONE); //polygonattributes.setCullFace(PolygonAttributes.CULL_FRONT); polygonattributes.setCullFace(PolygonAttributes.CULL_BACK); Appearance app = new Appearance(); app.setPolygonAttributes(polygonattributes); this.setGeometry(trianglearray); this.setAppearance(app); }}

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三角扇图形以第一个顶点为公用顶点，依次与其余顶点分别连接形成三角形。其中给定的定点数至少为3个。

class ShapeTriangleFanArray extends Shape3D { public ShapeTriangleFanArray() {int vertexesCount = 12; int stripCount[] = new int[1]; //int stripCount[]=new int[2]; //int stripCount[]=new int[3]; float vertexes[] = { .0f, 0.9f, 0.0f, -1.f, -0.8f, 0.f, -0.8f, -0.6f, -0.2f, -0.6f, -0.9f, 0.2f,-0.4f, -0.8f,-0.2f, 0.f, -0.8f, 0.2f, 0.2f, -0.5f, 0.0f, 0.4f, -0.6f, -0.5f, 0.6f, -0.8f, -0.3f, 0.8f, -0.9f, -0.2f,0.9f, -0.7f, -0.2f, 1.1f, -0.8f, -0.3f }; float colors[] = { 0.0f, 0.5f, 1.0f, 0.0f, 0.5f, 1.0f, 0.0f, 0.8f, .0f, 1.0f, 0.0f, 0.3f, 0.0f, 1.0f, 0.5f,0.9f, 1.0f, 0.0f, 0.5f, 0.0f, 1.0f, 0.0f, 0.5f, 1.0f, 1.0f, 0.5f, 0.0f, 1.0f, 0.0f, 0.5f, 1.0f, 0.8f,0.0f, 1.0f, 0.5f, 0.0f }; stripCount[0] = 12; //stripCount[1]=4; //stripCount[2]=4; TriangleFanArray triangleFanarray = new TriangleFanArray(vertexesCount,TriangleFanArray.COORDINATES | TriangleFanArray.COLOR_3, stripCount); triangleFanarray.setCoordinates(0, vertexes); triangleFanarray.setColors(0, colors); PolygonAttributes polygonattributes = new PolygonAttributes(); polygonattributes.setCullFace(PolygonAttributes.CULL_NONE); Appearance app = new Appearance(); app.setPolygonAttributes(polygonattributes); this.setGeometry(triangleFanarray); this.setAppearance(app); }}

int stripCount[]; 数组表示生成的三角扇个数
eg：总共十二个顶点
new stripCount[1]，表示生成一个扇区。所以stripCount[0]=12，这一个扇区有十二个点。
该程序，用顶点颜色插值生成线与面颜色，这种颜色无需光照，也能显示。

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四边面图形以顶点坐标数组中给出的一维顶点数组，从前向后依次以4个顶点形成一个四边形面，并且相邻两个四边形面之间没有公用顶点。给定的总的顶点数必须是4的倍数。

class ShapeQuadArray extends Shape3D {public ShapeQuadArray() {int vertexCount=12; float vertexes[]={ -0.8f,0.9f,0.0f, -0.8f,-0.8f,0.f,-0.6f,-0.8f,0.f, -0.6f,0.9f,0.f,-0.4f,0.9f,0.f,-0.4f,-0.7f,-0.9f,0.4f,-0.8f,0.f,0.4f,0.8f,0.0f,0.5f,0.8f,0.f,0.6f,-0.8f,0.0f,0.8f,-0.7f,0.f,0.8f,0.8f,0.f}; float colors[]={0.0f,0.5f,1.0f,0.0f,0.5f,1.0f,0.0f,0.8f,.0f,1.0f,0.0f,0.3f,0.0f,1.0f,0.5f,0.9f,1.0f,0.0f,0.5f,0.0f,1.0f,0.0f,0.5f,1.0f,1.0f,0.5f,0.0f,1.0f,0.0f,0.5f,1.0f,0.8f,0.0f,1.0f,0.5f,0.0f }; QuadArray quadarray=new QuadArray(vertexCount,QuadArray.COORDINATES|QuadArray.COLOR_3); quadarray.setCoordinates(0,vertexes); quadarray.setColors(0,colors); PolygonAttributes polygonattributes=new PolygonAttributes(); polygonattributes.setCullFace(PolygonAttributes.CULL_NONE); //polygonattributes.setCullFace(PolygonAttributes.CULL_BACK); //polygonattributes.setCullFace(PolygonAttributes.CULL_FRONT); Appearance app=new Appearance(); app.setPolygonAttributes(polygonattributes); this.setGeometry(quadarray); this.setAppearance(app); }}