P3D File Format - ODOLV7
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Overall
byte: 8 bits unsigned char: 8 bit ascii character char[]: fixed length string asciiz: null terminated char string asciiz[]: fixed length null terminated ulong: unsigned integer 32bit. 4 bytes ushort: unsigned short integer 16bit 2 bytes float: 4 bytes
Note that potentically 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
struct ODOL
{
char Signature[4]; //"ODOL"
ulong Version; // 7
ulong LodCount; // at least one
LodStruct Lod[LodCount];
ulong ResolutionCount; // same as LodCount
float Resolution[ResolutionCount];
byte unknownBytes[24];
float offset[3]; // model offset (unknown functionality)
ulong mapIconColor; // RGBA 32 color
ulong mapSelectedColor; // RGBA 32 color
ulong unknownValue;
float bboxMinPosition[3]; // minimum coordinates of bounding box
float bboxMaxPosition[3]; // maximum coordinates of bounding box
float wrpModelOffset[3]; // offset value to apply when object is placed on a WRP
float offset2[3]; // another offset value (unknown functionality)
};
LodStruct
LodStruct
{
VerticesStruct[...];
float fvalue[12]; // unknown: contains some max/min vertices positions
ulong TexturesCount;
Asciiz Textures[TexturesCount]; // "data/1.paa\0data/2.paa\0"...
TableStruct[...];
ulong FacesCount;
ulong uvalue; // unknown
struct Face[FacesCount];
ulong uvalue2; // unknown
byte uchar[18*uvalue2]; // unknown valuea
NamedStruct[...];
ulong uvalue7; // unknown value ???
struct ustruct[uvalue7]; // unknown value
ulong ProxiCount;
struct Proxi[ProxiCount];
}; // end of lod
VerticesStruct
VerticesStruct
{
CompressedStruct Attribs
{
ulong Count;
ulong Attribs[Count]; // if > 255 then array is compressed
}
CompressedStruct UVset
{
ulong Count; // again same value
float UVset[Count]; // if > 127 then array is compressed
}
CompressedStruct Position
{
ulong Count; // again same value
float Position[Count][3]; // XZY. If > etc
}
CompressedStruct Normals
{
ulong Count; // again same value
float Normals[Count][3]; // XZY. If > etc
}
}
TableStruct
struct TableStruct
{
CompressedStruct Table1
{
ulong Count;
ushort Table1[Count];// if > 511 array compressed
}
CompressedStruct Table2
{
ulong Count; // this Count is same value as any Vertices.Count
ushort Table2[Count];// > 511 then array is compressed
}
}
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.
MLODvertexindex = Table1[ Table2[ODOLvertexindex] ];
NamedStruct
NamedStruct
{
CompressedStruct Selection
{
ulong Count;
struct NamedSelection[Count];
}
CompressedStruct Properties
{
ulong Count;
struct NamedPropeties[Count]
}
}
NamedSelection
struct NamedSelection
{
asciiz name;
CompressedStruct Vertices
{
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 Unknown;
CompressedStruct UnknownUlong2
{
ulong Count; // if etc
ulong Unknown[Count];
}
CompressedStruct Faces
{
ulong Count; // if etc
ushort Faces[Count];
}
CompressedStruct UnknownByte
{
ulong Count; // if etc
byte Unknown[Count];
}
};
Faces
struct Face
{
ulong Attribs;
ushort TextureIndex; //if ((int)TextureIndex==-1) no texture;
byte Count; // 3 or 4
ushort VerticesIndex[Count]; //! size of array is not constant.
};
CompressedStruct
a compressed struct is such that if the Count * sizeof data type is > 1023 then lzh compression is used
Thus,
- ulong arrays = > 255
- float[2] = > 127
- etc
Proxi
struct Proxi
{
char Name[...] // zero ended string
float rotationMatrix[9];
float translation[3];
};
ustruct
struct ustruct // unknown value
{
uint uvalue8;// unknown value
uint uvalue9;// unknown value
char uarray[12*uvalue9];// unknown value :-( i know nothing about it
};
NamedPropeties
struct NamedPropeties
{
char Name[...];
char Value[...]; // 'n','o','s','h','a','d','o','w','\0','1','\0'...
};
LZ in ODOL
Lempel-Ziv compression
Note1.
Regardless of method, 4 extra bytes representing the checksum exist at end of the data count.
Note2. The compression code is identical to that employed by pbo packed structures. However, unlike pbo's, the size of the compressed data is unknown, only it's ultimate length. The code below fudges it.
pascal code
function LZBlockRead(var F:file; var outdata:array of byte;szout:integer):byte;
var
k, r, pr, pi,po,i,j:integer;
flags:word;
buf:array[0..$100e] of byte;
c:byte;
crc:integer;
begin
po:=0;
pi:=0;
flags:=0;
r:=0;
for k := 0 to $100F-1 do buf[k] := $20;
while (po < szout) do
begin
flags:= flags shr 1;
if ((flags and $100)= 0) then
begin
BlockRead(F,c,1); // direct reading from file
inc(pi);
flags := c or $ff00;
end;
if (flags and 1)=1 then
begin
if (po >= szout)then break;
BlockRead(F,c,1); // direct reading from file
inc(pi);
outdata[po] := c;
inc(po);
buf[r] := c;
inc(r);
r :=r and $fff;
end
else
begin
i:=0;
BlockRead(F,i,1); // direct reading from file
inc(pi);
j:=0;
BlockRead(F,j,1); // direct reading from file
inc(pi);
i :=i or ((j and $f0) shl 4);
j := (j and $0f) + 2;
pr := r;
for k := 0 to j do
begin
c := buf[(pr - i + k) and $fff];
if (po >= szout) then break;
outdata[po]:= c;
inc(po);
buf[r]:= c;
inc(r);
r :=r and $fff;
end;
end;
end;
BlockRead(F,crc,4); // 4 byte checksum.
result:= pi;
end;
C code
int Decode(unsigned char *in,unsigned char *out,int szin,int szout)
{
szin = szin > 0? szin: 0x7fffffff;
int i, j, k, r = 0, pr, pi = 0,po = 0;
unsigned int flags = 0;
unsigned char buf[0x100F], c;
for (i = 0; i < 0x100F; buf[i] = 0x20, i++);
while (pi < szin && po < szout)
{
if (((flags >>= 1) & 256) == 0)
{
if(pi >= szin)break;
c = in[pi++];
flags = c | 0xff00;
}
if (flags & 1)
{
if(pi >= szin || po >= szout)break;
c = in[pi++];
out[po++] = c;
buf[r++] = c;
r &= 0xfff;
} else
{
if(pi + 1 >= szin)break;
i = in[pi++];
j = in[pi++];
i |= (j & 0xf0) << 4;
j = (j & 0x0f) + 2;
pr = r;
for (k = 0; k <= j; k++)
{
c = buf[(pr - i + k) & 0xfff];
if(po >= szout)break;
out[po++] = c;
buf[r++] = c;
r &= 0xfff;
}
}
}
return pi;// next 4 bytes = checksum
}