我可以使用一些额外的眼睛来帮助我了解为什么我的纹理贴图在我的对象上是反转的。它向后打印——就像在镜子里看到它一样。我曾怀疑也许反转索引会有所帮助，但这只是改变了它的映射位置而没有反转反转。
public class MobiusBanner extends Applet {
public static void main(String[] args) {
new MainFrame(new MobiusBanner(), 800, 600);
}
@Override
public void init() {
GraphicsConfiguration gc = SimpleUniverse.getPreferredConfiguration();
Canvas3D canvas = new Canvas3D(gc);
this.setLayout(new BorderLayout());
this.add(canvas, BorderLayout.CENTER);
SimpleUniverse su = new SimpleUniverse(canvas);
su.getViewingPlatform().setNominalViewingTransform();
BranchGroup bg = createSceneGraph();
bg.compile();
su.addBranchGraph(bg);
}
private BranchGroup createSceneGraph() {
BranchGroup root = new BranchGroup();
Shape3D shape = new Shape3D();
shape.setGeometry(mobius().getIndexedGeometryArray());
//Scaling transform
Transform3D tr = new Transform3D();
tr.setScale(0.5);
//Spin transform group
TransformGroup spin = new TransformGroup();
spin.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
spin.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
root.addChild(spin);
//Set appearance
Appearance ap = createTextureAppearance();
ap.setPolygonAttributes(new PolygonAttributes(PolygonAttributes.POLYGON_FILL,
PolygonAttributes.CULL_BACK, 0));
//Set materials
Material mat = new Material();
mat.setLightingEnable(true);
mat.setShininess(30);
ap.setMaterial(mat);
//Overarching Transform group
TransformGroup tg = new TransformGroup(tr);
tg.addChild(shape);
spin.addChild(tg);
shape.setAppearance(ap);
//Set rotation
MouseRotate rotator = new MouseRotate(spin);
BoundingSphere bounds = new BoundingSphere();
rotator.setSchedulingBounds(bounds);
spin.addChild(rotator);
//Set translation
MouseTranslate translator = new MouseTranslate(spin);
translator.setSchedulingBounds(bounds);
spin.addChild(translator);
//Set zoom
MouseZoom zoom = new MouseZoom(spin);
zoom.setSchedulingBounds(bounds);
spin.addChild(zoom);
//Set background
Background background = new Background(1.0f, 1.0f, 1.0f);
background.setApplicationBounds(bounds);
root.addChild(background);
f//Set lighting
AmbientLight light = new AmbientLight(true, new Color3f(Color.BLACK));
light.setInfluencingBounds(bounds);
root.addChild(light);
PointLight ptlight = new PointLight(new Color3f(Color.white),
new Point3f(0.5f, 0.5f, 1f),
new Point3f(1f, 0.2f, 0f));
ptlight.setInfluencingBounds(bounds);
root.addChild(ptlight);
return root;
}//Close branchgroup method
//Create the Mobius shape
private GeometryInfo mobius() {
int m = 100; //number of row points
int n = 100; //number of col points
int p = 4 * ((m - 1) * (n - 1)); //faces * points per face
IndexedQuadArray iqa = new IndexedQuadArray(m * n,
GeometryArray.COORDINATES | GeometryArray.TEXTURE_COORDINATE_2, p);
Point3d[] vertices = new Point3d[m * n];
int index = 0;
//Create vertices
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
double u = i * (4 * (Math.PI)) / (m - 1);
double v = -0.3 + (j * (0.6 / (n - 1)));
double x = (1 + v * Math.cos(u / 2)) * Math.cos(u);
double y = (1 + v * Math.cos(u / 2)) * Math.sin(u);
double z = v * Math.sin(u / 2);
vertices[index] = new Point3d(x, y, z);
index++;
}//close nested for loop
}//close for loop
index = 0;
//set texture coordinates
TexCoord2f[] tex = new TexCoord2f[m * n];
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
tex[index] = new TexCoord2f();
tex[index] = new TexCoord2f(i * 1f / m, j * 1f / n);
index++;
}
}
iqa.setCoordinates(0, vertices);
iqa.setTextureCoordinates(0, 0, tex);
index = 0;
//set index for coordinates
int[] texIndices = new int[p];
for (int i = 0; i < m - 1; i++) {
for (int j = 0; j < n - 1; j++) {
iqa.setCoordinateIndex(index, i * m + j);
texIndices[index] = i * m + j;
index++;
iqa.setCoordinateIndex(index, i * m + j + 1);
texIndices[index] = i * m + j + 1;
index++;
iqa.setCoordinateIndex(index, (i + 1) * m + j + 1);
texIndices[index] = (i + 1) * m + j + 1;
index++;
iqa.setCoordinateIndex(index, (i + 1) * m + j);
texIndices[index] = (i + 1) * m + j;
index++;
}//close nested for loop
}//close for loop
iqa.setTextureCoordinateIndices(0, 0, texIndices);
//create geometry info and generate normals for shape
GeometryInfo gi = new GeometryInfo(iqa);
NormalGenerator ng = new NormalGenerator();
ng.generateNormals(gi);
return gi;
}
Appearance createTextureAppearance() {
Appearance ap = new Appearance();
BufferedImage bi = new BufferedImage(1024, 128,
BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = (Graphics2D) bi.getGraphics();
g2.setColor(Color.white);
g2.fillRect(0, 0, 1024, 128);
g2.setFont(new Font("Serif", Font.BOLD, 36));
g2.setColor(new Color(200, 0, 0));
g2.drawString("Mobius Strip", 0, 100);
ImageComponent2D image = new ImageComponent2D(ImageComponent2D.FORMAT_RGBA, bi);
Texture2D texture = new Texture2D(Texture.BASE_LEVEL, Texture.RGBA,
image.getWidth(), image.getHeight());
texture.setImage(0, image);
texture.setMagFilter(Texture.BASE_LEVEL_LINEAR);
ap.setTexture(texture);
//Combine Texture and Lighting
TextureAttributes textatt = new TextureAttributes();
textatt.setTextureMode(TextureAttributes.COMBINE);
ap.setTextureAttributes(textatt);
ap.setMaterial(new Material());
return ap;
}
}