Not public? They are
local function trilaterate( A, B, C )
local a2b = B.position - A.position
local a2c = C.position - A.position
if math.abs( a2b:normalize():dot( a2c:normalize() ) ) > 0.999 then
return nil
end
local d = a2b:length()
local ex = a2b:normalize( )
local i = ex:dot( a2c )
local ey = (a2c - (ex * i)):normalize()
local j = ey:dot( a2c )
local ez = ex:cross( ey )
local r1 = A.distance
local r2 = B.distance
local r3 = C.distance
local x = (r1*r1 - r2*r2 + d*d) / (2*d)
local y = (r1*r1 - r3*r3 - x*x + (x-i)*(x-i) + j*j) / (2*j)
local result = A.position + (ex * x) + (ey * y)
local zSquared = r1*r1 - x*x - y*y
if zSquared > 0 then
local z = math.sqrt( zSquared )
local result1 = result + (ez * z)
local result2 = result - (ez * z)
local rounded1, rounded2 = result1:round(), result2:round()
if rounded1.x ~= rounded2.x or rounded1.y ~= rounded2.y or rounded1.z ~= rounded2.z then
return result1, result2
else
return rounded1
end
end
return result:round()
end
local function narrow( p1, p2, fix )
local dist1 = math.abs( (p1 - fix.position):length() - fix.distance )
local dist2 = math.abs( (p2 - fix.position):length() - fix.distance )
if math.abs(dist1 - dist2) < 0.05 then
return p1, p2
elseif dist1 < dist2 then
return p1:round()
else
return p2:round()
end
end
function locate( _nTimeout, _bDebug )
if _bDebug then
print( "Finding position..." )
end
rednet.broadcast( "PING" )
local startTime = os.clock()
local timeOut = _nTimeout
local timeElapsed = 0
local tFixes = {}
local p1, p2 = nil
while timeElapsed < timeOut and (p1 == nil or p2 ~= nil) do
local sender, message, distance = rednet.receive( timeOut - timeElapsed )
if sender and distance then
local result = textutils.unserialize( message )
if type(result) == "table" and #result == 3 then
local tFix = { id = sender, position = vector.new( result[1], result[2], result[3] ), distance = distance }
if _bDebug then
print( tFix.distance.." metres from "..tostring( tFix.position ) )
end
table.insert( tFixes, tFix )
if #tFixes >= 3 then
if not p1 then
p1, p2 = trilaterate( tFixes[1], tFixes[2], tFixes[#tFixes] )
else
p1, p2 = narrow( p1, p2, tFixes[#tFixes] )
end
end
end
end
timeElapsed = os.clock() - startTime
end
if p1 and p2 then
if _bDebug then
print( "Ambiguous position" )
print( "Could be "..p1.x..","..p1.y..","..p1.z.." or "..p2.x..","..p2.y..","..p2.z )
end
return nil
elseif p1 then
if _bDebug then
print( "Position is "..p1.x..","..p1.y..","..p1.z )
end
return p1.x, p1.y, p1.z
else
if _bDebug then
print( "Could not determine position" )
end
return nil
end
end
Copied from mods/ComputerCraft1.48/lua/rom/apis/gps
