SA Model Viewer base

public/js/rw/stream.js

@@ -0,0 +1,154 @@
+// RenderWare binary stream: every chunk is a 12 byte header followed by its
+// body, and container chunks simply hold more chunks. That one rule covers
+// both DFF and TXD.
+
+export const RW = {
+  STRUCT: 0x01,
+  STRING: 0x02,
+  EXTENSION: 0x03,
+  TEXTURE: 0x06,
+  MATERIAL: 0x07,
+  MATLIST: 0x08,
+  FRAMELIST: 0x0e,
+  GEOMETRY: 0x0f,
+  CLUMP: 0x10,
+  ATOMIC: 0x14,
+  TEXNATIVE: 0x15,
+  TEXDICT: 0x16,
+  GEOMETRYLIST: 0x1a,
+  BINMESH: 0x50e,
+  SKIN: 0x116,
+  HANIM: 0x11e,
+  FRAME_NAME: 0x253f2fe,
+};
+
+// GTA:SA ships RenderWare 3.6.0.3, which packs to 0x1803FFFF.
+export const SA_VERSION = 0x36003;
+
+export function unpackVersion(libraryId) {
+  if (libraryId & 0xffff0000) {
+    return (((libraryId >> 14) & 0x3ff00) + 0x30000) | ((libraryId >> 16) & 0x3f);
+  }
+  return libraryId << 8;
+}
+
+export function versionString(version) {
+  // major.minor.revision.build - the build number lives in the low 6 bits.
+  return [(version >> 16) & 0xf, (version >> 12) & 0xf, (version >> 8) & 0xf, version & 0x3f].join('.');
+}
+
+export class Reader {
+  constructor(view, start, end) {
+    this.view = view;
+    this.pos = start;
+    this.end = end;
+  }
+  get remaining() {
+    return this.end - this.pos;
+  }
+  u8() {
+    return this.view.getUint8(this.pos++);
+  }
+  u16() {
+    const v = this.view.getUint16(this.pos, true);
+    this.pos += 2;
+    return v;
+  }
+  u32() {
+    const v = this.view.getUint32(this.pos, true);
+    this.pos += 4;
+    return v;
+  }
+  i32() {
+    const v = this.view.getInt32(this.pos, true);
+    this.pos += 4;
+    return v;
+  }
+  f32() {
+    const v = this.view.getFloat32(this.pos, true);
+    this.pos += 4;
+    return v;
+  }
+  skip(n) {
+    this.pos += n;
+  }
+  bytes(n) {
+    const v = new Uint8Array(this.view.buffer, this.view.byteOffset + this.pos, n);
+    this.pos += n;
+    return v;
+  }
+  // Fixed width, null padded name field.
+  fixedString(n) {
+    const raw = this.bytes(n);
+    let len = raw.indexOf(0);
+    if (len < 0) len = n;
+    return String.fromCharCode(...raw.subarray(0, len));
+  }
+  f32Array(n) {
+    const out = new Float32Array(n);
+    for (let i = 0; i < n; i++) out[i] = this.f32();
+    return out;
+  }
+}
+
+export class Chunk {
+  constructor(view, offset, limit) {
+    this.view = view;
+    this.type = view.getUint32(offset, true);
+    this.size = view.getUint32(offset + 4, true);
+    this.version = unpackVersion(view.getUint32(offset + 8, true));
+    this.start = offset + 12;
+    this.end = Math.min(this.start + this.size, limit === undefined ? view.byteLength : limit);
+  }
+
+  reader() {
+    return new Reader(this.view, this.start, this.end);
+  }
+
+  *children() {
+    let offset = this.start;
+    // A 12 byte header has to fit before anything can be read.
+    while (offset + 12 <= this.end) {
+      const child = new Chunk(this.view, offset, this.end);
+      yield child;
+      const step = 12 + child.size;
+      if (step <= 0) break; // corrupt size, don't spin
+      offset += step;
+    }
+  }
+
+  find(type) {
+    for (const child of this.children()) {
+      if (child.type === type) return child;
+    }
+    return null;
+  }
+
+  findAll(type) {
+    const out = [];
+    for (const child of this.children()) {
+      if (child.type === type) out.push(child);
+    }
+    return out;
+  }
+
+  // Convenience for the STRUCT chunk that nearly every container starts with.
+  structReader() {
+    const struct = this.find(RW.STRUCT);
+    if (!struct) throw new Error(`chunk 0x${this.type.toString(16)} has no struct`);
+    return struct.reader();
+  }
+}
+
+export function readRoot(buffer, expectedType) {
+  if (buffer.byteLength < 12) throw new Error('file is too small to be a RenderWare stream');
+  const view = new DataView(buffer);
+  const root = new Chunk(view, 0);
+  if (expectedType !== undefined && root.type !== expectedType) {
+    throw new Error(
+      `expected chunk 0x${expectedType.toString(16)}, got 0x${root.type.toString(16)} ` +
+        '(wrong file type, or the file is compressed/encrypted)'
+    );
+  }
+  return root;
+}