glTF is a format for distribution of 3D models optimized for being used in software
This page hosts a formal specification of GL Transmission Format, binary container using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for Java generated by Kaitai Struct depends on the Java runtime library. You have to install it before you can parse data.
The Java runtime library is published in the Maven Central Repository. Refer to the artifact page for instructions how to add it into your project with the build tool that you use.
Parse a local file and get structure in memory:
GltfBinary data = GltfBinary.fromFile("path/to/local/file.glb");
Or parse structure from a byte array:
byte[] someArray = new byte[] { ... };
GltfBinary data = new GltfBinary(new ByteBufferKaitaiStream(someArray));
After that, one can get various attributes from the structure by invoking getter methods like:
data.header() // => get header
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
import io.kaitai.struct.ByteBufferKaitaiStream;
import io.kaitai.struct.KaitaiStruct;
import io.kaitai.struct.KaitaiStream;
import java.io.IOException;
import java.util.Map;
import java.util.HashMap;
import java.util.ArrayList;
import java.util.Arrays;
import java.nio.charset.Charset;
/**
* glTF is a format for distribution of 3D models optimized for being used in software
* @see <a href="https://github.com/KhronosGroup/glTF/tree/2354846/specification/2.0#binary-gltf-layout">Source</a>
*/
public class GltfBinary extends KaitaiStruct {
public static GltfBinary fromFile(String fileName) throws IOException {
return new GltfBinary(new ByteBufferKaitaiStream(fileName));
}
public enum ChunkType {
BIN(5130562),
JSON(1313821514);
private final long id;
ChunkType(long id) { this.id = id; }
public long id() { return id; }
private static final Map<Long, ChunkType> byId = new HashMap<Long, ChunkType>(2);
static {
for (ChunkType e : ChunkType.values())
byId.put(e.id(), e);
}
public static ChunkType byId(long id) { return byId.get(id); }
}
public GltfBinary(KaitaiStream _io) {
this(_io, null, null);
}
public GltfBinary(KaitaiStream _io, KaitaiStruct _parent) {
this(_io, _parent, null);
}
public GltfBinary(KaitaiStream _io, KaitaiStruct _parent, GltfBinary _root) {
super(_io);
this._parent = _parent;
this._root = _root == null ? this : _root;
_read();
}
private void _read() {
this.header = new Header(this._io, this, _root);
this.chunks = new ArrayList<Chunk>();
{
int i = 0;
while (!this._io.isEof()) {
this.chunks.add(new Chunk(this._io, this, _root));
i++;
}
}
}
public static class Header extends KaitaiStruct {
public static Header fromFile(String fileName) throws IOException {
return new Header(new ByteBufferKaitaiStream(fileName));
}
public Header(KaitaiStream _io) {
this(_io, null, null);
}
public Header(KaitaiStream _io, GltfBinary _parent) {
this(_io, _parent, null);
}
public Header(KaitaiStream _io, GltfBinary _parent, GltfBinary _root) {
super(_io);
this._parent = _parent;
this._root = _root;
_read();
}
private void _read() {
this.magic = this._io.readBytes(4);
if (!(Arrays.equals(magic(), new byte[] { 103, 108, 84, 70 }))) {
throw new KaitaiStream.ValidationNotEqualError(new byte[] { 103, 108, 84, 70 }, magic(), _io(), "/types/header/seq/0");
}
this.version = this._io.readU4le();
this.length = this._io.readU4le();
}
private byte[] magic;
private long version;
private long length;
private GltfBinary _root;
private GltfBinary _parent;
public byte[] magic() { return magic; }
/**
* Indicates the version of the Binary glTF container format.
* For this specification, should be set to 2.
*/
public long version() { return version; }
/**
* Total length of the Binary glTF, including Header and all Chunks, in bytes.
*/
public long length() { return length; }
public GltfBinary _root() { return _root; }
public GltfBinary _parent() { return _parent; }
}
public static class Chunk extends KaitaiStruct {
public static Chunk fromFile(String fileName) throws IOException {
return new Chunk(new ByteBufferKaitaiStream(fileName));
}
public Chunk(KaitaiStream _io) {
this(_io, null, null);
}
public Chunk(KaitaiStream _io, GltfBinary _parent) {
this(_io, _parent, null);
}
public Chunk(KaitaiStream _io, GltfBinary _parent, GltfBinary _root) {
super(_io);
this._parent = _parent;
this._root = _root;
_read();
}
private void _read() {
this.lenData = this._io.readU4le();
this.type = GltfBinary.ChunkType.byId(this._io.readU4le());
{
ChunkType on = type();
if (on != null) {
switch (type()) {
case JSON: {
this._raw_data = this._io.readBytes(lenData());
KaitaiStream _io__raw_data = new ByteBufferKaitaiStream(_raw_data);
this.data = new Json(_io__raw_data, this, _root);
break;
}
case BIN: {
this._raw_data = this._io.readBytes(lenData());
KaitaiStream _io__raw_data = new ByteBufferKaitaiStream(_raw_data);
this.data = new Bin(_io__raw_data, this, _root);
break;
}
default: {
this.data = this._io.readBytes(lenData());
break;
}
}
} else {
this.data = this._io.readBytes(lenData());
}
}
}
private long lenData;
private ChunkType type;
private Object data;
private GltfBinary _root;
private GltfBinary _parent;
private byte[] _raw_data;
public long lenData() { return lenData; }
public ChunkType type() { return type; }
public Object data() { return data; }
public GltfBinary _root() { return _root; }
public GltfBinary _parent() { return _parent; }
public byte[] _raw_data() { return _raw_data; }
}
public static class Json extends KaitaiStruct {
public static Json fromFile(String fileName) throws IOException {
return new Json(new ByteBufferKaitaiStream(fileName));
}
public Json(KaitaiStream _io) {
this(_io, null, null);
}
public Json(KaitaiStream _io, GltfBinary.Chunk _parent) {
this(_io, _parent, null);
}
public Json(KaitaiStream _io, GltfBinary.Chunk _parent, GltfBinary _root) {
super(_io);
this._parent = _parent;
this._root = _root;
_read();
}
private void _read() {
this.data = new String(this._io.readBytesFull(), Charset.forName("UTF-8"));
}
private String data;
private GltfBinary _root;
private GltfBinary.Chunk _parent;
/**
* This is where GLB deviates from being an elegant format.
* To parse the rest of the file, you have to parse the JSON first.
*/
public String data() { return data; }
public GltfBinary _root() { return _root; }
public GltfBinary.Chunk _parent() { return _parent; }
}
public static class Bin extends KaitaiStruct {
public static Bin fromFile(String fileName) throws IOException {
return new Bin(new ByteBufferKaitaiStream(fileName));
}
public Bin(KaitaiStream _io) {
this(_io, null, null);
}
public Bin(KaitaiStream _io, GltfBinary.Chunk _parent) {
this(_io, _parent, null);
}
public Bin(KaitaiStream _io, GltfBinary.Chunk _parent, GltfBinary _root) {
super(_io);
this._parent = _parent;
this._root = _root;
_read();
}
private void _read() {
this.data = this._io.readBytesFull();
}
private byte[] data;
private GltfBinary _root;
private GltfBinary.Chunk _parent;
public byte[] data() { return data; }
public GltfBinary _root() { return _root; }
public GltfBinary.Chunk _parent() { return _parent; }
}
private Header header;
private ArrayList<Chunk> chunks;
private GltfBinary _root;
private KaitaiStruct _parent;
public Header header() { return header; }
public ArrayList<Chunk> chunks() { return chunks; }
public GltfBinary _root() { return _root; }
public KaitaiStruct _parent() { return _parent; }
}