BlockLua/src/util/vector.lua

-- Vector math class with operators
local vector_meta
local vector_new
local function vector_check(v, n, name, argn)
  if not v.__is_vector then
    error('vector ' .. name .. ': argument #' .. (argn or 1)
      .. ': expected vector, got ' .. type(v), n + 1)
  end
end
local function vector_checksamelen(v1, v2, name)
  vector_check(v1, 3, name, 1)
  vector_check(v2, 3, name, 2)
  if #v1 ~= #v2 then
    error('vector ' .. name .. ': vector lengths do not match (lengths are '
      .. #v1 .. ' and ' .. #v2 .. ')', 3)
  end
  return #v1
end
local function vector_checklen(v1, v2, name, len)
  vector_check(v1, 3, name, 1)
  vector_check(v2, 3, name, 2)
  if #v1 ~= len or #v2 ~= len then
    error('vector ' .. name .. ': vector lengths are not ' .. len .. ' (lengths are '
      .. #v1 .. ' and ' .. #v2 .. ')', 3)
  end
end
local function vector_opnnn(name, op)
  return function(v1, v2)
    local len = vector_checksamelen(v1, v2, name)
    local v3 = {}
    for i = 1, len do
      v3[i] = op(v1[i], v2[i])
    end
    return vector_new(v3)
  end
end
local function vector_opnxn(name, op)
  return function(v1, v2)
    local v1v = type(v1) == 'table' and v1.__is_vector
    local v2v = type(v2) == 'table' and v2.__is_vector
    if v1v and v2v then
      local len = vector_checksamelen(v1, v2, name)
      local v3 = {}
      for i = 1, len do
        v3[i] = op(v1[i], v2[i])
      end
      return vector_new(v3)
    else
      if v2v then v1, v2 = v2, v1 end
      local len = #v1
      local v3 = {}
      for i = 1, len do
        v3[i] = op(v1[i], v2)
      end
      return vector_new(v3)
    end
  end
end
local function vector_opn0n(name, op)
  return function(v1)
    --vector_check(v1, 1, name)
    local len = #v1
    local v2 = {}
    for i = 1, len do
      v2[i] = op(v1[i])
    end
    return vector_new(v2)
  end
end
local vector_indices = { x = 1, y = 2, z = 3, w = 4, r = 1, g = 2, b = 3, a = 4 }
local vector_meta = {
  __is_vector     = true,
  __index         = function(t, k)
    if tonumber(k) then
      return rawget(t, k)
    elseif vector_indices[k] then
      return rawget(t, vector_indices[k])
    else
      return getmetatable(t)[k]
    end
  end,
  __newindex      = function(t, k, v)
    if tonumber(k) then
      rawset(t, k, v)
    elseif vector_indices[k] then
      rawset(t, vector_indices[k], v)
    else
      return
    end
  end,
  __add           = vector_opnnn('add', function(x1, x2) return x1 + x2 end),
  __sub           = vector_opnnn('sub', function(x1, x2) return x1 - x2 end),
  __mul           = vector_opnxn('mul', function(x1, x2) return x1 * x2 end),
  __div           = vector_opnxn('div', function(x1, x2) return x1 / x2 end),
  __pow           = vector_opnxn('pow', function(x1, x2) return x1 ^ x2 end),
  __unm           = vector_opn0n('inv', function(x1) return -x1 end),
  __concat        = nil,
  --__len = function(v1) return #v1 end,
  __len           = nil,
  __eq            = function(v1, v2)
    local len = vector_checksamelen(v1, v2, 'equals')
    for i = 1, len do
      if v1[i] ~= v2[i] then return false end
    end
    return true
  end,
  __lt            = nil,
  __le            = nil,
  __call          = nil,
  abs             = vector_opn0n('abs', math.abs),
  length          = function(v1)
    --vector_check(v1, 2, 'length')
    local len = #v1
    local l = 0
    for i = 1, len do
      l = l + v1[i] ^ 2
    end
    return math.sqrt(l)
  end,
  normalize       = function(v1)
    --vector_check(v1, 2, 'normal')
    local length = v1:length()
    local len = #v1
    local v3 = {}
    for i = 1, len do
      if length == 0 then
        v3[i] = 0
      else
        v3[i] = v1[i] / length
      end
    end
    return vector_new(v3)
  end,
  __tostring      = function(v1)
    --vector_check(v1, 2, 'tostring')
    local st = {}
    local len = #v1
    for i = 1, len do
      table.insert(st, tostring(v1[i]))
    end
    return 'vector{ ' .. table.concat(st, ', ') .. ' }'
  end,
  unpack          = function(v1) return unpack(v1) end,
  floor           = vector_opn0n('floor', function(x1) return math.floor(x1) end),
  ceil            = vector_opn0n('ceil', function(x1) return math.ceil(x1) end),
  round           = vector_opn0n('round', function(x1) return math.floor(x1 + 0.5) end),
  dot             = function(v1, v2)
    local len = vector_checksamelen(v1, v2, 'dot')
    local x = 0
    for i = 1, len do
      x = x + v1[i] * v2[i]
    end
    return x
  end,
  cross           = function(v1, v2)
    vector_checklen(v1, v2, 'cross', 3)
    return vector_new {
      v1[2] * v2[3] - v1[3] * v2[2],
      v1[3] * v2[1] - v1[1] * v2[3],
      v1[1] * v2[2] - v1[2] * v2[1],
    }
  end,
  rotateByAngleId = function(v1, r)
    --vector_check(v1, 2, 'rotate')
    if type(r) ~= 'number' or r % 1 ~= 0 then
      error('vector rotateByAngleId: invalid rotation ' .. tostring(r), 2)
    end
    r = r % 4
    local v2
    if r == 0 then
      v2 = vector_new { v1[1], v1[2], v1[3] }
    elseif r == 1 then
      v2 = vector_new { v1[2], -v1[1], v1[3] }
    elseif r == 2 then
      v2 = vector_new { -v1[1], -v1[2], v1[3] }
    elseif r == 3 then
      v2 = vector_new { -v1[2], v1[1], v1[3] }
    else
      error('vector rotateByAngleId: invalid rotation ' .. r, 2)
    end
    return v2
  end,
  rotateZ         = function(v, r)
    --vector_check(v, 2, 'rotate2d')
    if type(r) ~= 'number' then
      error('vector rotateZ: invalid rotation ' .. tostring(r), 2)
    end
    local len = math.sqrt(v[1] ^ 2 + v[2] ^ 2)
    local ang = math.atan2(v[2], v[1]) + r
    local v2 = vector_new { math.cos(ang) * len, math.sin(ang) * len }
    return v2
  end,
  tsString        = function(v)
    --vector_check(v, 2, 'tsString')
    return table.concat(v, ' ')
  end,
  distance        = function(v1, v2)
    local len = vector_checksamelen(v1, v2, 'distance')
    local sum = 0
    for i = 1, len do
      sum = sum + (v1[i] - v2[i]) ^ 2
    end
    return math.sqrt(sum)
  end,
  copy            = function(v)
    --vector_check(v, 2, 'copy')
    return vector_new(v)
  end,
}
vector_new = function(vi)
  if vi then
    if type(vi) == 'string' then
      local vi2 = {}
      for val in vi:gmatch('[0-9%.%-e]+') do
        table.insert(vi2, tonumber(val))
      end
      vi = vi2
    elseif type(vi) ~= 'table' then
      error('vector: argument #1: expected input table, got ' .. type(vi), 2)
    end
    local v = {}
    if #vi > 0 then
      for i = 1, #vi do v[i] = vi[i] end
    else
      for n, i in pairs(vector_indices) do v[i] = vi[n] end
      if #v == 0 then
        error('vector: argument #1: table contains no values', 2)
      end
    end
    setmetatable(v, vector_meta)
    return v
  else
    error('vector: argument #1: expected input table, got nil', 2)
  end
end

vector = vector_new

print('  Executed vector.lua')

return vector_new