Apple Multitouch MacBook trackpad in Lua using LuaJIT FFI

multitouch.lua

-- Apple Multitouch MacBook trackpad in Lua using LuaJIT FFI, 2011 Michal Kottman
-- definitions from http://www.steike.com/code/multitouch/

local ffi = require 'ffi'

ffi.cdef [[
typedef struct { float x,y; } mtPoint;
typedef struct { mtPoint pos,vel; } mtReadout;

typedef struct {
  int frame;
  double timestamp;
  int identifier, state, foo3, foo4;
  mtReadout normalized;
  float size;
  int zero1;
  float angle, majorAxis, minorAxis; // ellipsoid
  mtReadout mm;
  int zero2[2];
  float unk2;
} Finger;

typedef void *MTDeviceRef;
typedef int (*MTContactCallbackFunction)(int,Finger*,int,double,int);

MTDeviceRef MTDeviceCreateDefault();
void        MTRegisterContactFrameCallback(MTDeviceRef, MTContactCallbackFunction);
void        MTDeviceStart(MTDeviceRef, int);

typedef int (*MTCallback)(int device, Finger *data, int nFingers, double timestamp, int frame);

unsigned int sleep(unsigned int seconds);
]]

local mt = ffi.load('/System/Library/PrivateFrameworks/MultitouchSupport.framework/Versions/Current/MultitouchSupport')

local callback = ffi.cast('MTCallback', function(device, data, nFingers, timestamp, frame)
	print('=== '..frame..', '..nFingers..' fingers ===')
	for i=0,nFingers-1 do
		local finger = data[i]
		local pos = finger.normalized.pos
		print(i, finger.identifier, pos.x, pos.y, finger.size)
	end
	return 0
end)

local dev = mt.MTDeviceCreateDefault()
mt.MTRegisterContactFrameCallback(dev, callback)
mt.MTDeviceStart(dev, 0);
ffi.C.sleep(0xFFFFFFFF)