GTA III's RenderWare Engine Kevin Wijsenbach RenderWare is a graphics engine by Criterion Software that was used by Rockstar for their titles Manhunt, Bully, GTA III, Vice City and San Andreas. GTA's portable successors Liberty City Stories and Vice City Stories use a clone of the original RenderWare engine (called Rockstar Leeds), which was already influenced by Rockstar's next-gen RAGE engine. The biggest challenge was finding out what to load, and how. I used the website GTAModding as a reference. Second was to figure out how GTA III's data translates to Unity. Loading the game world goes as follows: 1. Load the models/gta3.img archive file Process the model files Process the texture archives 2. Load the data/default.dat map listing 3. Load the data/gta3.dat map listing 4. Iterate the item placement instances Tools I've Used Name Description Website RW Analyze Viewer for RenderWare binary stream files Steve's GTA Page IMG Tool IMG archive editor GTAForums Hex Fiend Hex editor ridiculous_fish Archive File To improve I/O speed, archive files reflect sectors of CD-ROM's. The directory and the raw binary files are stored in separate files, the directory entries are stored in a .dir and the content pointed by the directory in the .img itself. The directory archive ( .dir ) must have the same name as the .img archive. The directory archive contains no header, just the following structure repeated until the end of the file. Directory Entry Format Description uint Offset (in sectors 1) uint Size (in sectors) char[24] Name of the file The .img file itself has no special structure or header, just all the raw binary files pointed by the directory archive. RenderWare binary stream RenderWare binary stream files are hierarchically structured binary data files. GTA III's model files use the file extension .dff and texture archives use .txd . The streams are split up into chunks. Each section has a 12 byte header and can either be empty, contain data or more child chunks. The content depends on the type and parent chunks. Chunk Format Description uint Section type uint Size uint Version Model File ( .dff ) Clump Chunk Frame List Chunk Frame Chunk Extension Chunk Geometry List Chunk Geometry Chunk Material List Chunk Material Chunk Texture (optional) Chunk String (texture name) Chunk String (alpha name) Chunk Extension Chunk Atomic Chunk Clump Format Description uint Atomic count Frame List Format Description uint Frame count Frame Format Description Matrix3x3 Rotation matrix Vector3 Position 2 uint Parent frame index uint Unknown Frame List Extension A frame list may have an extension section. For this section the extension can appear multiple times. The amount of extensions may not match the number of frames, but usually does since the extensions are holding the names of the single frames. Geometry List Format Description uint Geometry count Geometry Format Description uint Flags uint Triangle count uint Vertex count uint Morph target count (always 1 ) float Ambient float Specular float Diffuse Color[vertexCount] Vertex colors (only exists if HasColors flag is set) Texture coordinates (only exists if HasTexCoords flag is Vector2[vertexCount] set) ushort[triangleCount * 3] Indices 3 Vector4 Bounding sphere bool Geometry has vertices bool Geometry has normals Vector3[vertexCount] Vertices Vector3[vertexCount] Normals (only if HasNormals flag is set) Material List Format Description uint Material count uint[materialCount] Instance indices 4 Material Format Description uint Flags Color Color uint Unknown bool Material is textured float Ambient float Specular float Diffuse Texture Format Description byte Texture filtering byte Texture wrap ushort Padding Geometry Extension The extension of an geometry can hold a Bin Mesh plugin chunk. A Bin Mesh is an optimized representation of the model topology. Triangles are grouped together into Meshes by their Material. Format Description uint Type uint Mesh count uint Index count (total) Bin Mesh Format Description uint Index count uint Material index uint[indexCount] Indices (in reverse order) Atomic An atomic section can associate a Frame with a Geometry. They are transformed from object-space based on the transformation rules that are set for the Frame. Format Description uint Frame index uint Geometry index uint Unknown uint Unknown Texture Archive ( .txd ) Texture Dictionary Texture Native Texture Dictionary Format Description ushort Texture count ushort Platform ID 5 Texture Native Format Description uint Platform ID byte Texture filtering byte Texture wrap ushort Padding char[32] Texture name char[32] Alpha name uint Raster format bool Texture has alpha ushort Width ushort Height byte Bits per pixel byte Mip map count byte Raster type byte Compression Color[256] Color palette (only exists if the PAL8 raster format flag is set) uint Amount of bytes to read next One of two things can happen next: 1. If the PAL8 flag is set, read using the color palette. Each pixel is a byte, which is the palette index. 2. Just read the amount of bytes, and repeat for each mip map. Map Listing ( .dat ) A .dat file lists which files define the game map. Each line links to a map file, unless it's empty or starts with # (comment). There are different types of files, so a identifier specifies the filetype. Identifier Filetype IDE Item definition TEXDICTION Texture archive MODELFILE Model file COLFILE Collision file IPL Item placement Item Definition ( .ide ) Item definition files are stored in plain text, and split up into sections. Each section starts with a four-character identifier. The identifier is followed by the definition entries. Each entry takes one line and every line follows certain rules. Lines can also be empty or commented. The end of a section is terminated by end . Lines itself are always formatted in the same way differing only in the number of parameters. Parameters are usually separated by , . Sections Identifier Description objs Objects Timed objects (similar to objs , but also defines the time range the object can be tobj rendered) hier Cutscene objects cars Vehicles peds Pedestrians path Waypoints for NPC spawns Object Format Description int Object ID string Model name string Texture name int Mesh count int[3] Draw distances int Object flags int Time on (if timed object) int Time off (if timed object) Vehicle Format Description int Object ID string Model name string Texture name string Vehicle type string Handling ID string Vehicle class int Spawn frequency int Unknown string Component rules Pedestrian Format Description int Object ID string Model name string Texture name string Pedestrian type string Behaviour string Animation group string Cars pedestrian will drive Collision File ( .col ) Unlike the graphical models, collision models are not only comprised of triangles, but also spheres and boxes. Collision files are stored binary. Format Description uint Magic ( COLL ) uint Size char[22] Name float Bounding sphere radius Vector3 Bounding sphere center Vector3 Bounds min Vector3 Bounds max uint Collision sphere count Sphere[sphereCount] Collision spheres uint Unknown uint Collision box count Box[boxCount] Collision boxes uint Vertex count Vector3[vertexCount] Vertices uint Face count Face[faceCount] Faces Collision Surface Format Description byte Material byte Flag byte Brightness byte Light Collision Sphere Format Description float Radius Vector3 Center Surface Collision surface Collision Box Format Description Vector3 Min Vector3 Max Surface Collision surface Face Format Description uint[3] Triangle indices Surface Collision surface Item Placement ( .ipl ) Item placement files are used to create and place different objects, zones of special behaviour or paths in the world. The files are stored in plain text. The structure and format is similar item definition files. Sections Identifier Description inst Instances zone Ingame zones cull Zones with special behaviour pick Weapon pickups Instance Format Description int Model ID string Model name Vector3 Position Vector3 Scale 6 Quaternion Rotation 7 Zone Format Description string Name int Type Vector3 Area min Vector3 Area max int Island string .gtx text file Screenshots Types Section Type public enum SectionType { None = 0, Struct = 1, String = 2, Extension = 3, Texture = 6, Material = 7, MaterialList = 8, FrameList = 14, Geometry = 15, Clump = 16, Atomic = 20, TextureNative = 21, TextureDictionary = 22, GeometryList = 26, MorphPlugin = 261, SkinPlugin = 278, ParticlesPlugin = 280, UVAnimationPlugin = 309, BinMeshPlugin = 1294, Frame = 39056126 } Geometry Flags [System.Flags] public enum GeometryFlags { IsTriangleStrip = 1 << 0, HasTranslation = 1 << 1, HasTexCoords = 1 << 2, HasColors = 1 << 3, HasNormals = 1 << 4, IsLit = 1 << 5, ModulateMaterialColor = 1 << 6, HasMultipleTexCoords = 1 << 7, Native = 1 << 24 } Bin Mesh Type public enum BinMeshType { TriangleList = 0, TriangleStrip = 1 } Texture Filtering public enum TextureFiltering { None = 0, Nearest = 1, Linear = 2, MipNearest = 3, MipLinear = 4, LinearMipNearest = 5, LinearMipLinear = 6 } Raster Format [System.Flags] public enum RasterFormat { ARGB1555 = 0x0100, RGB565 = 0x0200, RGBA4444 = 0x0300, LUM8 = 0x0400, RGBA32 = 0x0500, RGB24 = 0x0600, RGB555 = 0x0a00, AutoMipMap = 0x1000, PAL8 = 0x2000, PAL4 = 0x4000, MipMap = 0x8000 } Object Flags [System.Flags] public enum ObjectFlags { Wet = 1 << 0, TimeObjectNight = 1 << 1, AlphaTransparency1 = 1 << 2, AlphaTransparency2 = 1 << 3, TimeObjectDay = 1 << 4, InteriorObject = 1 << 5, Shadows = 1 << 6 } Vehicle Type switch (type) { case "car": return Vehicle.Type.Car; case "boat": return Vehicle.Type.Boat;