Wrp File Format - OPRWv17 to 24
Introduction
For a general description of wrp files see 8WVR
Legend
see Generic FileFormat Data Types
File Format
- Texture and Terrain Grid Sizes are derived from the header.
This document is based on analysis of arma1 wrps (OPRW18). The following are known differences between them, and later versions
- OPRW17 (Elite) does not have the clutter
- OPRW20 (sara and desert pbo's) :So far, this is the SAME format as 18 except PackedBytes1
- OPRW23 (vbs2lite us) :So far, this is the SAME format as 20
- OPRW24 (arma2)uses lzo compresion, not, lzss
OPRWv17://elite
OPRWv18://arma1
OPRWv20://arma1 sara
OPRWv23://vbs2_lite
OPRWv24://arma2
{
WrpHeader Header;
ushort GridBlock_CellEnv[TerrainGridSizeXY]; // a gridblock containing cellenv bits (16 bits per terrain cell).
// Bits 0-2 are ground (0x0), coast (0x1), beach (0x2) and sea (0x3). Bit 4 indicates road/airstrip.
byte GridBlock_CfgEnvSounds[TerrainGridSizeXY]; // a gridblock. mostly the value 0x03 and probably related to Config.cpp CfgEnvSounds class
ulong nPeaks;
XYZTriplet PeakPositions[nPeaks];
ushort GridBlock_TextureIndex[TextureGridSizeXY]; // rvmat file index
if !Elite
if ArmaOne
ushort RandomClutter[TextureGridSizeXY];//compressed. probably random values needed for calculating clutter models position
//seems to be related to clutters or sat mask distance as it is
//responsible for the clutterbug
else
byte GridBlock_ClutterMask[TerrainGridSizeXY];
endif
endif
float Elevation[TerrainGridSizeXY]; //compressed
ulong nTextures;
Texture Textures[nTextures]; //"PrefixRoot\data\layers\some.rvmat\0\0"
ulong nModels;
asciiz modelPaths[nModels]; //"ca\buildings\kostelik.p3d\0"
ulong nClassedModels;
ClassedModel Models[nClassedModels]; //"Land_Hangar\0" : "ca\buildings\Hangar.p3d\0"
ushort GridBlock_UnknownGrid3[TerrainGridSizeXY]; // a gridblock
ulong SizeOfObjects; //in bytes
ushort GridBlock_UnknownGrid4[TerrainGridSizeXY]; // a gridblock
ulong SizeOfMapInfo; //in bytes
byte Bytes2[TextureGridSizeXY]; //compressed. seems to be connected to roads, runways and special grounds
byte Bytes3[TerrainGridSizeXY]; //compressed. unknown but 0x00 for forests and roads and sea, mostly 0x03 and rarely 0x02
ulong maxObjectID;
ulong SizeOfRoadNets; //in bytes
RoadNet RoadNets[SizeOfRoadNets];
Object Objects[SizeOfObjects/SizeOfObject]; // SizeOfObject ==60
MapInfo MapInfos[...];
}
- Because of the variable length of the asciiz strings in RoadParts, the actual position of the following #Objects block cannot be pre-calculated. Therefore the SizeOfRoadNets can be used, as it is the size (in bytes) of this RoadNet block.
- Similarly, SizeOfObjects can be used to skip to the MapInfo
ClutterMask
Each byte represents the intensity or, number of clutter objects for that area of terrain
- Sea and road texture areas have zilch.
- desert areas have very low values
WrpHeader
WrpHeader
{
char Filetype; // "OPWR"
ulong version; // 0x12 = 18
XYPair TextureGridSize; // 256 x 256 (SaraLite), 128 x 128 (Intro)
XYPair TerrainGridSize; // 1024 x 1024 (SaraLite), 512 x 512 (Intro)
float CellSize; // Texture grid cell size in meters (40m)
}
This is a traditional wrp header endemic to most wrp formats. The CellSize was introduced during Elite. The terrain grid cell size can be derived as follows: CellSize * TextureGridSizeX / TerrainGridSizeX, and is 10m for SaraLite and Intro.
GridBlock
The result of decompressing any GridBlock is to produce an array the size of the Header's TextureGridSizeXY, at the TypeSize specified. Eg be it byte, or ushort.
There are five gridblocks in the file, two ushort arrays, and 3 byte arrays(if present)
- when the grid is present, the leading flag = 0x01
- when a default fill GridBlock exists
{
byte flag; // =0
ulong FillBits; // = almost always zero
}
GridBlock is currently in the 'discussion tab'.
Texture
Texture
{
Concatenated Asciiz TextureFilenames; //"PrefixRoot\data\layers\some.rvmat\0\0" (Arma)
//"PrefixRoot\desert\data\pt.bimpas\0\0" (ELite)
//"PboRoot\more_anim.01.pac\0" (OFP)(by way of example)
}
- The ofp entry is solely here by way of example. No such entry exists in arma/Elite format.
This entry, and it's TextureIndices, are erroneously referred to as "Materials". This because of the rvMat(erial) extension to the filename. However, the original file name was bimpas (for elite) and in both cases they comprise, ultimately of (a series of) pac/paa files. Thus, this documentation refers to texturing intent and retains that concept from previous versions of wrp files.
- see PrefixRoot\ description. Essentially, it is a reference to a pbo.
Each cell in the grid references a (series of) texture(s) for it's surface. The TextureIndex is an index into these texture filenames.
Thus, each entry of this materials list consists of concatenated asciiz strings in the form
"AnRvmatFile\0AnotherOne\0EvenMore\0\0"
Ie, the end of this entry = \0\0
It so happens that only one, single 'texture', a single rvmat file, is used per cell, but, the construct is there to have any amount.
therefore, this list is of the form
"AnRvmatFile\0\0"
There is always, at least one materials entry. The 1st entry. The first entry (effectively index 0) is a dummy, with an empty path, because it will never be accessed. Indexes start at 1.
Similar to it's 8WVR cousin (from which it is derived)the rvmat filenames *should* be unique (redundant, duplicate entries, defeat the purpose of the index). However, there is quite often some duplication.
The ushort Textureindices (once decomposed from a GridBlock) contain references to a 'texture'. no index value of zero can exist. (The first texture of the list is always a dummy entry)
ClassedModel
ClassedModel
{
asciiz class_name; //"Land_Hangar\0"
asciiz model_path; //"ca\buildings\Hangar.p3d"
XYZTriplet Position;
ulong unknown;
}
This is a fairly repetitious list of often identically named class and model, used as an index from an as yet unknown grid table.
RoadNet
RoadNet
{
ulong nRoadParts; // Zero or More...
RoadPart RoadParts[nRoadParts];
} [TextureSize];
Every cell on the map has a RoadNet entry. If there are no road(s) for that cell, there are no RoadParts (nRoadParts=0)
RoadParts, while, ultimately being no more (or less) than just another P3D model, are contained separately to models generally, to better realize terrain streaming and for AI driving ability.
RoadPart
RoadPart
{
ushort nRoadPositions;// at least 1
XYZTriplet RoadPositions[nRoadPositions];
byte Flags[4];
if WrpType==24
byte MoreFlags[nRoadPositions];
Asciiz P3DModel;
XYZTransform Transform[12]; // same as that found for this object in the ObjectsList
}
Object Optional
Object
{
ulong ObjectID;
ulong modelIndex; // into the [[#Models|models path name list]] (1 based)
float TransformMatrix[3][4]; // standard directX transform matrix
ulong 0x02;
}
- maxObjectID is somewhat irrelevant. It is indeed the id of the highest value ObjectID, but, these 'ID's, while unique are highly arbitrary in nature and alter on any change to the 'world' when editing in oxygen/visitor. This ID can occur anywhere in the object list, and the id values before it are non-sequential. maxObjectID cannot be used as a nObject ID's eg.
- If SizeOfObjects above == 0 then there are no objects.
Note that unlike it's 4/8WVR cousin, where each Object entry contains (an often) repetitious list of p3d files. The same construct is (now) used as per Textures and Indexes. Namely, a common list of models is indexed into, by each Object entry.
MapInfo Optional
MapInfo
{
ulong infoType;
MapData[...];
}
Mapinfo, when it exists, extends to end of file. The sizeof each entry, is determined by it's info type thus:
MapData
MapData
{
if(infoType in [0,1,2,10,11,13,14,15,16,17,22,23,26,27,30]) MapType1;
if(infoType in [24,31,32]) MapType2;
if(infoType in [25,33]) MapType3;
if(infoType in [3,4,8,9,18,19,20,21,28,29]) MapType4;
if(infoType in [34]) MapType5;
if(infoType in [35]) MapType35;
}
MapType1
MapType1
{
ulong ObjectId
float x, z
}
MapType2
MapType2
{
ulong ObjectId
float Bounds[4][2];
}
MapType3
MapType3
{
ulong unknown[2];
float line[2][2];?
}
MapType4
MapType4
{
ulong ObjectId
float Bounds[4][2];
byte Color[4] //rgba
}
MapType5
MapType5
{
ulong ObjectId
float line[2][2];?
}
MapType35
MapType35 // found in chernarus
{
ulong ObjectId
float line[3][2];?
byte unknown;
}
Type 35 is also found in oprw23 formats but is currently indecipherable and may, in fact, be an error
Packed Data
All variables starting with "Packed" are compressed with the common BIS algorithm that is also used in paa and OFP pbo files.