在java3d中面部着色
使用java3d，我怎样才能在每个顶点基础上而不是在每个基础上进行着色？
我试着了解java3d但是我生产的Shape3d看起来并不像预期的那样。 我想用不同的颜色着色不同的三角形，但我不知道如何做到这一点。
纹理看起来像是一种矫枉过正，更重要的是，我根本没有掌握这一部分。 据我所见，材料在一个完整的GeometryArray上工作，所以这里没有好处。 每个顶点颜色都不会起作用。
我喜欢这个解决方案。 “每顶点颜色”实际上是每个顶点参考，因此每个顶点的每个面都可以有不同的颜色。
这是一个工作示例（遗憾的是不是很小）：
package examples; import javax.media.j3d.Alpha; import javax.media.j3d.AmbientLight; import javax.media.j3d.Appearance; import javax.media.j3d.BoundingSphere; import javax.media.j3d.Bounds; import javax.media.j3d.BranchGroup; import javax.media.j3d.DirectionalLight; import javax.media.j3d.GeometryArray; import javax.media.j3d.IndexedTriangleArray; import javax.media.j3d.Node; import javax.media.j3d.PolygonAttributes; import javax.media.j3d.RotationInterpolator; import javax.media.j3d.Shape3D; import javax.media.j3d.Transform3D; import javax.media.j3d.TransformGroup; import javax.media.j3d.View; import javax.media.j3d.ViewPlatform; import javax.vecmath.Color3f; import javax.vecmath.Point3d; import javax.vecmath.Vector3f; import com.sun.j3d.utils.geometry.GeometryInfo; import com.sun.j3d.utils.geometry.NormalGenerator; import com.sun.j3d.utils.universe.MultiTransformGroup; import com.sun.j3d.utils.universe.SimpleUniverse; import com.sun.j3d.utils.universe.ViewingPlatform; public class Example { public static void main(final String[] args) { new Example(); } public Example() { final SimpleUniverse universe = new SimpleUniverse(); final BranchGroup group = new BranchGroup(); final TransformGroup tg = new TransformGroup(); final BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0), 100.0); final Node blob = createMonster(); { //to enable rotation tg.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE); tg.setCapability(TransformGroup.ALLOW_TRANSFORM_READ); } // Create rotation to see all sides of the object final Transform3D btrans = new Transform3D(); btrans.rotX(1); final Transform3D ztrans = new Transform3D(); ztrans.rotZ(-1); btrans.mul(ztrans); final RotationInterpolator ri = createRotation(tg, bounds, btrans, 7000); tg.addChild(ri); tg.addChild(blob); // group.addChild(tg); // addLight(group, new Color3f(1f, 1f, 0f), new Vector3f(4.0f, +7.0f, -12.0f)); addLight(group, new Color3f(1f, 1f, 1f)); // final ViewingPlatform viewingPlatform = universe.getViewingPlatform(); final ViewPlatform view = viewingPlatform.getViewPlatform(); view.setViewAttachPolicy(View.NOMINAL_SCREEN); viewingPlatform.setNominalViewingTransform(); final MultiTransformGroup mtg = viewingPlatform.getMultiTransformGroup(); final TransformGroup vtg = mtg.getTransformGroup(0); final Transform3D t1 = btrans; vtg.getTransform(t1); t1.setScale(2); vtg.setTransform(t1); group.compile(); // add the group of objects to the Universe universe.addBranchGraph(group); } private Node createMonster() { final Shape3D child = createShape(); final Appearance fillAppNode = new Appearance(); final PolygonAttributes pAtt = new PolygonAttributes(); // avoid trouble with clockwise faces pAtt.setCullFace(PolygonAttributes.CULL_NONE); pAtt.setBackFaceNormalFlip(true); fillAppNode.setPolygonAttributes(pAtt); child.setAppearance(fillAppNode); return child; } private Shape3D createShape() { final Point3d[] points = new Point3d[] {// new Point3d(-1, 1, 0), // new Point3d(1, 1, 0), // new Point3d(1, -1, 0), // new Point3d(-1, -1, 0), // new Point3d(0, 0, 1), // }; final int[] idxs = new int[] {// the triangle faces 0, 1, 2,// 2, 3, 0,// 1, 0, 4,// 1, 2, 4,// 2, 3, 4,// 3, 0, 4 }; final IndexedTriangleArray ita = new IndexedTriangleArray(points.length, GeometryArray.COORDINATES | GeometryArray.COLOR_3, idxs.length); ita.setCoordinates(0, points); ita.setCoordinateIndices(0, idxs); //per vertex colors really are per vertex reference //so each vertex can have a different color for each of its faces final Color3f[] colors = new Color3f[] {// new Color3f(1, 0, 1),// new Color3f(0, 1, 0),// new Color3f(0, 0, 1),// new Color3f(1, 1, 0),// new Color3f(1, 1, 1),// }; ita.setColors(0, colors); ita.setColorIndices(0, idxs); ita.setColorIndices(0, new int[] { 0, 0, 0, 1, 1, 1 }); // final GeometryInfo gi = new GeometryInfo(ita); //also generate normal vectors so that the surface can be light final NormalGenerator normalGenerator = new NormalGenerator(); normalGenerator.generateNormals(gi); final GeometryArray geometryArray = gi.getGeometryArray(); return new Shape3D(geometryArray); } private RotationInterpolator createRotation(final TransformGroup objScale, final Bounds bounds, final Transform3D btrans, final long milis) { final Alpha alpha = new Alpha(-1, Alpha.INCREASING_ENABLE, 0, 0, milis, 0, 0, 0, 0, 0); final RotationInterpolator ri = new RotationInterpolator(alpha, objScale, btrans, 0.0f, (float) Math.PI * 2.0f); ri.setSchedulingBounds(bounds); return ri; } private void addLight(final BranchGroup group, final Color3f light1Color, final Vector3f ligthDirection) { { final BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0), 100.0); final DirectionalLight light1 = new DirectionalLight(light1Color, ligthDirection); light1.setInfluencingBounds(bounds); group.addChild(light1); } } private void addLight(final BranchGroup group, final Color3f light1Color) { { final BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0), 100.0); final AmbientLight light1 = new AmbientLight(light1Color); light1.setInfluencingBounds(bounds); group.addChild(light1); } } } 您必须分别绘制每个面，为每个面指定一种颜色。 例如：
Appearance polygon1Appearance = new Appearance(); // set your color here QuadArray polygon1 = new QuadArray (4, QuadArray.COORDINATES); polygon1.setCoordinate(0, new Point3f (0f, 0f, 0f)); polygon1.setCoordinate(1, new Point3f (2f, 0f, 0f)); polygon1.setCoordinate(2, new Point3f (2f, 3f, 0f)); polygon1.setCoordinate(3, new Point3f (0f, 3f, 0f)); objRoot.addChild(new Shape3D(polygon1, polygon1Appearance));