Unity packed font binary template

UnityPackedFont.bt

//--------------------------------------
//--- 010 Editor v5.0 Binary Template
//--------------------------------------
// Unity binary font atlas format
// Documented by WRS
//--------------------------------------

struct UnityFontAtlas
{
  uint unknown_0[2];
  uint unknown_1[2];
  uint version; // ?
  uint unknown_02;
  uint len <bgcolor=0x00ff80>;
  char name[len] <bgcolor=0x80ff00>;
  if(len&3)ubyte name_pad[4-(len&3)]; // Aligned to 4 bytes
};

struct UnityGlyph
{
  wchar_t character[2] <bgcolor=0x8080ff>;
  float x,w,y,h; // mult by image dim (512,2048)
  float pool[7]; // other glyph info (kerning, etc)
};

//--------------------------------------

UnityFontAtlas hdr <bgcolor=0xc0c0c0>;

if(hdr.version>1728) { Printf("Warning: May fail to parse\n"); }

uint ascii_count <bgcolor=0xffff00>;
UnityGlyph ascii_glyphs[ascii_count];

uint unicode_count <bgcolor=0xffff00>;
UnityGlyph unicode_glyphs[unicode_count];

local uint rem_count = (FileSize()-FTell()) / sizeof(float);
float tail[rem_count];

//--------------------------------------

Printf("------ Info -------\n");
Printf("Font:    %s\n", hdr.name);
Printf("Ascii:   %d\n", ascii_count);
Printf("Unicode: %d\n", unicode_count);
Printf("Tail:    %d\n", rem_count);

//--------------------------------------
local int used_space = 0;

void Process(UnityGlyph& g, uint d)
{
  local uint x1 = g.x*d;
  local uint x2 = g.w*d;
  local uint y1 = g.y*d;
  local uint y2 = g.h*d;

  local uint space = (y2-y1)*(x2-x1);
  used_space += space;
}

local uint dim = 2048;
local uint i;

i=0;while(i<ascii_count)
{
  Process(ascii_glyphs[i],dim);
  ++i;
}

i=0;while(i<unicode_count)
{
  Process(unicode_glyphs[i],dim);
  ++i;
}

Printf("------ Metrics -------\n");
Printf("Pixels:  %d\n", (dim*dim));
Printf("In-use:  %d\n", used_space);

local float p=(float)used_space/(float)(dim*dim);
Printf("Used:    %.03f%%\n", p);

//--------------------------------------

Included a metrics calculator which shows how well packed the image is.

Also (thinking about it) the bounding boxes are guaranteed to overlap...