Volume File Format
------------------

struct VolumeHeader
{
	char magic[4];
	int version;
	char texName[256];
	bool wrap;
	int volSize;
	int numChannels;
	int bytesPerChannel;
};

The first 4096 bytes of the .vol files contain the header and zero padding to fill the 4096 bytes up. Then follows an array of volSize*volSize*volSize*numChannels*bytesPerChannel bytes containing the actual volume data.

The header elements are:
magic: should be "VOLU"
version: should be 4
texName: the name of the texture
wrap: is the texture tileable?
volSize: side length of the teture
numChannels: e.g. 3 for RGB
bytesPerChannel: 1 for bytes, 4 for float

The header can be read in C/C++ as follows:

FILE * fin = fopen("volume.vol", "wb");
char buf[4096];
fread(buf, 4096, 1, fin);

VolumeHeader * header = (VolumeHeader *)buf;
if ((header->magic[0] != 'V') || (header->magic[1] != 'O') || (header->magic[2] != 'L') || (header->magic[3] != 'U'))
	error("bad header: invalid magic");
if (header->version != 4)
	error("bad header: version != 4");
if (header->bytesPerChannel != 1)
	error("bad header: only byte textures supported");
	
int volBytes = header->volSize*header->volSize*header->volSize*header->numChannels;
unsigned char * data = new unsigned char[volBytes];
fread(data, volBytes, 1, fin);

fclose(fin);