P3D File Format - ODOLV7

Legend

see Generic FileFormat Data Types

Intro

CompressedStruct

ODOL7 uses (potentially) compressed arrays.

This obviously slows the engine down during loading. At the time of CWC development, game file sizes were important.

(potentially) compressed arrays are contained in a CompressedStruct

CompressedStructs are endemic to most blocks contained in the p3d.

CompressedStruct
{
  ulong  Count;
  <type> Array[Count];
};

if Count * sizeof(<type>) exceeds 1023 bytes the array is compressed. The resulting array will be expanded using lzh compression exactly as found in pbo's (for instance)

After de-compression, the Count remains the same because it is a count of the arraytype.

For uncompressed arrays (byte count < 1024) the Count and data are treated 'as is'.

Thus for various Array <types>

*ulong Array:    > 255  // 1024 /   sizeof(ulong)
*float thing[2]: > 127  // 1024 / 2*sizeof(float)
*SomeStructure:  >      // count * sizeof (SomeStructure) > 1023

Note that potentially compressed arrays in these structures only have an known output length. the decompressor therefore must work on infinite input length. see example decompression at end of document

Odol7Stuct

ODOLV7
{
  StandardP3DHeader Header;
  LodStruct Lods[Header.LodCount];
  struct    ModelInfo;
};

StandardP3DHeader

StandardP3DHeader
{
  char      Signature[4];      //"ODOL"
  ulong     Version;           // 7
  ulong     LodCount;          // at least one
}

LodStruct

LodStruct
{
 struct         VerticesStruct;
 struct         UnknownStruct; // contains some max/min vertices positions
 struct         TexturesStruct;
 struct         VertexIndices; 
 ulong          NoOfFaces;
 ulong          OffsetToSectionStruct;
 Face           Faces[NoOfFaces];
 ulong          nSections;
 LODSection     LODSections[nSections];
 ulong          nNamedSelections;
 NamedSelection NamedSelections[nNamedSelections];
 ulong          nNamedProperties;
 NamedProperty  NamedProperties[nNamedProperties];
 ulong          nFrames;
 Frame          Frames[nFrames];
 ulong          IconColor;
 ulong          SelectedColor;
 ulong          Unknown;
 ulong          nProxies;
 ProxyStruct    ProxyStructs[nProxies];   
};

VerticesStruct

 VerticesStruct
 { 
   CompressedStruct PointFlags //(vertices)
   {
    ulong Count;              // see P3D Point(Vertex) Flags
    ulong PointFlag[Count];     
   }
   CompressedStruct UVset
   {
    ulong  Count;              // if > 127 then array is compressed 
    UVPair UVsets[Count];       
   }
   struct Points // (Vertices)
   {
    ulong      Count;              
    XYZTriplet Point[Count]; 
   }
   struct Normals
   {
    ulong Count;             
    float Normals[Count][3];  // XZY
   }
 }

• Count is the same value for all four tables.
• The Position and Normals tables appear to be always uncompressed raw data.

UVPair

UVSet
{
 float U,V;
}

UnKnownStruct

UnKnownStruct
{
 UVPair       UnknownUV; // just a guess           
 XYZTriplet   MinPos;
 XYZTriplet   MaxPos;
 XYZTriplet   AutoCenterPos;
 float        UnknownFloat;
}

TexturesStruct

 struct Textures
 {
  ulong  Count;
  asciiz Textures[...];          // "data/1.paa\0data/2.paa\0"...
 }

Count corresponds to the number of concatenated strings. It is required, since, architecturally at least, one of more of the asciiz strings could be null.

VertexIndices

VertexIndices
{
 CompressedStruct 
 {
  ulong  Count;            // if > 511 etc  
  ushort MlodIndex[Count];
 }
 CompressedStruct
 {
  ulong  nVerticesStructs;           // same value as any of the VerticesStruct.Counts
  ushort VerticesStructNum[nVerticesStructs];
 }
}

For each of the VerticesStructs (0..Count-1) there is a lookup into the MlodIndex

MLODvertexindex = MlodIndex[ VerticesStructNum[Count] ];

Tables are used to join vertices. Each face has got 3 or 4 vertices that are unique for each face Eg. Every vertex is owned only by 1 face.

Face

Face
{
  ulong  FaceFlags;
  short  TextureIndex; 
  byte   nVertices;  // 3==Triangle or 4==Box
  ushort VerticesIndex[nVertices];
}

LODSection

 LODSection
 {
   ulong   FaceLowerIndex;
   ulong   FaceUpperIndex;
   ulong   UserValue;
   short   TextureIndex;       // as per Face struct
   ulong   (ODOL)FaceFlags;    // as per Face struct
 }

The TextureIndex is a zero based array. If set to -1, there are no textures for this face or section

NamedSelection

NamedSelection
{
 asciiz name;
 CompressedStruct VerticesIndexes
 {
  ulong  Count;                  // if > 511 then array is compressed
  ushort Vertices[Count];
 }
 CompressedStruct UnknownUshort
 {
  ulong   Count;                 // if > 511 then array is compressed
  ushort  Unknown[Count];
 }
 CompressedStruct UnknownUlong
 {
  ulong Count;                    // if > 255 then array is compressed
  ulong Unknown[Count];
 }
 byte IsSectional; 
 CompressedStruct UnknownUlong2
 {
  ulong Count;                    // if etc
  ulong Unknown[Count];
 }
 CompressedStruct Faces
 {
  ulong Count;                    // if etc
  ushort Faces[Count];
 }
 CompressedStruct TextureWeights      // probably
 {
  ulong Count;                    // if etc
  byte TextureWeights[Count];
 }
};

see NamedSelection in P3D File Format - MLOD P3DM for description of TextureWeights

NamedProperty

 NamedProperty
 {
   asciiz Name;  // "noshadow\0"
   asciiz Value; //"1\0"'
 };

Frame

   Frame
   {
     float      FrameTime;
     ulong      nBones;      //same as any  VerticesStruct.Count
     XYZTriplet BonePos[nBones];
   };

ProxyStruct

ProxyStruct
{
  asciiz          Name;
  TransformMatrix Transform;//see Generic FileFormat Data Types
  ulong           Indices[2];
}

ModelInfo

see P3D Model Info

LZ in ODOL

see Compressed LZSS File Format

Related Page(s)

Model File Formats