extract_metadata.lua

--
-- json.lua
--
-- Copyright (c) 2018 rxi
--
-- Permission is hereby granted, free of charge, to any person obtaining a copy of
-- this software and associated documentation files (the "Software"), to deal in
-- the Software without restriction, including without limitation the rights to
-- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-- of the Software, and to permit persons to whom the Software is furnished to do
-- so, subject to the following conditions:
--
-- The above copyright notice and this permission notice shall be included in all
-- copies or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-- SOFTWARE.
--

local json = { _version = "0.1.1" }

-------------------------------------------------------------------------------
-- Encode
-------------------------------------------------------------------------------

local encode

local escape_char_map = {
  [ "\\" ] = "\\\\",
  [ "\"" ] = "\\\"",
  [ "\b" ] = "\\b",
  [ "\f" ] = "\\f",
  [ "\n" ] = "\\n",
  [ "\r" ] = "\\r",
  [ "\t" ] = "\\t",
}

local escape_char_map_inv = { [ "\\/" ] = "/" }
for k, v in pairs(escape_char_map) do
  escape_char_map_inv[v] = k
end


local function escape_char(c)
  return escape_char_map[c] or string.format("\\u%04x", c:byte())
end


local function encode_nil(val)
  return "null"
end


local function encode_table(val, stack)
  local res = {}
  stack = stack or {}

  -- Circular reference?
  if stack[val] then error("circular reference") end

  stack[val] = true

  if val[1] ~= nil or next(val) == nil then
    -- Treat as array -- check keys are valid and it is not sparse
    local n = 0
    for k in pairs(val) do
      if type(k) ~= "number" then
        error("invalid table: mixed or invalid key types")
      end
      n = n + 1
    end
    if n ~= #val then
      error("invalid table: sparse array")
    end
    -- Encode
    for i, v in ipairs(val) do
      table.insert(res, encode(v, stack))
    end
    stack[val] = nil
    return "[" .. table.concat(res, ",") .. "]"

  else
    -- Treat as an object
    for k, v in pairs(val) do
      if type(k) ~= "string" then
        error("invalid table: mixed or invalid key types")
      end
      table.insert(res, encode(k, stack) .. ":" .. encode(v, stack))
    end
    stack[val] = nil
    return "{" .. table.concat(res, ",") .. "}"
  end
end


local function encode_string(val)
  return '"' .. val:gsub('[%z\1-\31\\"]', escape_char) .. '"'
end


local function encode_number(val)
  -- Check for NaN, -inf and inf
  if val ~= val or val <= -math.huge or val >= math.huge then
    error("unexpected number value '" .. tostring(val) .. "'")
  end
  return string.format("%.14g", val)
end


local type_func_map = {
  [ "nil"     ] = encode_nil,
  [ "table"   ] = encode_table,
  [ "string"  ] = encode_string,
  [ "number"  ] = encode_number,
  [ "boolean" ] = tostring,
}


encode = function(val, stack)
  local t = type(val)
  local f = type_func_map[t]
  if f then
    return f(val, stack)
  end
  error("unexpected type '" .. t .. "'")
end


function json.encode(val)
  return ( encode(val) )
end


-------------------------------------------------------------------------------
-- Decode
-------------------------------------------------------------------------------

local parse

local function create_set(...)
  local res = {}
  for i = 1, select("#", ...) do
    res[ select(i, ...) ] = true
  end
  return res
end

local space_chars   = create_set(" ", "\t", "\r", "\n")
local delim_chars   = create_set(" ", "\t", "\r", "\n", "]", "}", ",")
local escape_chars  = create_set("\\", "/", '"', "b", "f", "n", "r", "t", "u")
local literals      = create_set("true", "false", "null")

local literal_map = {
  [ "true"  ] = true,
  [ "false" ] = false,
  [ "null"  ] = nil,
}


local function next_char(str, idx, set, negate)
  for i = idx, #str do
    if set[str:sub(i, i)] ~= negate then
      return i
    end
  end
  return #str + 1
end


local function decode_error(str, idx, msg)
  local line_count = 1
  local col_count = 1
  for i = 1, idx - 1 do
    col_count = col_count + 1
    if str:sub(i, i) == "\n" then
      line_count = line_count + 1
      col_count = 1
    end
  end
  error( string.format("%s at line %d col %d", msg, line_count, col_count) )
end


local function codepoint_to_utf8(n)
  -- http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=iws-appendixa
  local f = math.floor
  if n <= 0x7f then
    return string.char(n)
  elseif n <= 0x7ff then
    return string.char(f(n / 64) + 192, n % 64 + 128)
  elseif n <= 0xffff then
    return string.char(f(n / 4096) + 224, f(n % 4096 / 64) + 128, n % 64 + 128)
  elseif n <= 0x10ffff then
    return string.char(f(n / 262144) + 240, f(n % 262144 / 4096) + 128,
                       f(n % 4096 / 64) + 128, n % 64 + 128)
  end
  error( string.format("invalid unicode codepoint '%x'", n) )
end


local function parse_unicode_escape(s)
  local n1 = tonumber( s:sub(3, 6),  16 )
  local n2 = tonumber( s:sub(9, 12), 16 )
  -- Surrogate pair?
  if n2 then
    return codepoint_to_utf8((n1 - 0xd800) * 0x400 + (n2 - 0xdc00) + 0x10000)
  else
    return codepoint_to_utf8(n1)
  end
end


local function parse_string(str, i)
  local has_unicode_escape = false
  local has_surrogate_escape = false
  local has_escape = false
  local last
  for j = i + 1, #str do
    local x = str:byte(j)

    if x < 32 then
      decode_error(str, j, "control character in string")
    end

    if last == 92 then -- "\\" (escape char)
      if x == 117 then -- "u" (unicode escape sequence)
        local hex = str:sub(j + 1, j + 5)
        if not hex:find("%x%x%x%x") then
          decode_error(str, j, "invalid unicode escape in string")
        end
        if hex:find("^[dD][89aAbB]") then
          has_surrogate_escape = true
        else
          has_unicode_escape = true
        end
      else
        local c = string.char(x)
        if not escape_chars[c] then
          decode_error(str, j, "invalid escape char '" .. c .. "' in string")
        end
        has_escape = true
      end
      last = nil

    elseif x == 34 then -- '"' (end of string)
      local s = str:sub(i + 1, j - 1)
      if has_surrogate_escape then
        s = s:gsub("\\u[dD][89aAbB]..\\u....", parse_unicode_escape)
      end
      if has_unicode_escape then
        s = s:gsub("\\u....", parse_unicode_escape)
      end
      if has_escape then
        s = s:gsub("\\.", escape_char_map_inv)
      end
      return s, j + 1

    else
      last = x
    end
  end
  decode_error(str, i, "expected closing quote for string")
end


local function parse_number(str, i)
  local x = next_char(str, i, delim_chars)
  local s = str:sub(i, x - 1)
  local n = tonumber(s)
  if not n then
    decode_error(str, i, "invalid number '" .. s .. "'")
  end
  return n, x
end


local function parse_literal(str, i)
  local x = next_char(str, i, delim_chars)
  local word = str:sub(i, x - 1)
  if not literals[word] then
    decode_error(str, i, "invalid literal '" .. word .. "'")
  end
  return literal_map[word], x
end


local function parse_array(str, i)
  local res = {}
  local n = 1
  i = i + 1
  while 1 do
    local x
    i = next_char(str, i, space_chars, true)
    -- Empty / end of array?
    if str:sub(i, i) == "]" then
      i = i + 1
      break
    end
    -- Read token
    x, i = parse(str, i)
    res[n] = x
    n = n + 1
    -- Next token
    i = next_char(str, i, space_chars, true)
    local chr = str:sub(i, i)
    i = i + 1
    if chr == "]" then break end
    if chr ~= "," then decode_error(str, i, "expected ']' or ','") end
  end
  return res, i
end


local function parse_object(str, i)
  local res = {}
  i = i + 1
  while 1 do
    local key, val
    i = next_char(str, i, space_chars, true)
    -- Empty / end of object?
    if str:sub(i, i) == "}" then
      i = i + 1
      break
    end
    -- Read key
    if str:sub(i, i) ~= '"' then
      decode_error(str, i, "expected string for key")
    end
    key, i = parse(str, i)
    -- Read ':' delimiter
    i = next_char(str, i, space_chars, true)
    if str:sub(i, i) ~= ":" then
      decode_error(str, i, "expected ':' after key")
    end
    i = next_char(str, i + 1, space_chars, true)
    -- Read value
    val, i = parse(str, i)
    -- Set
    res[key] = val
    -- Next token
    i = next_char(str, i, space_chars, true)
    local chr = str:sub(i, i)
    i = i + 1
    if chr == "}" then break end
    if chr ~= "," then decode_error(str, i, "expected '}' or ','") end
  end
  return res, i
end


local char_func_map = {
  [ '"' ] = parse_string,
  [ "0" ] = parse_number,
  [ "1" ] = parse_number,
  [ "2" ] = parse_number,
  [ "3" ] = parse_number,
  [ "4" ] = parse_number,
  [ "5" ] = parse_number,
  [ "6" ] = parse_number,
  [ "7" ] = parse_number,
  [ "8" ] = parse_number,
  [ "9" ] = parse_number,
  [ "-" ] = parse_number,
  [ "t" ] = parse_literal,
  [ "f" ] = parse_literal,
  [ "n" ] = parse_literal,
  [ "[" ] = parse_array,
  [ "{" ] = parse_object,
}


parse = function(str, idx)
  local chr = str:sub(idx, idx)
  local f = char_func_map[chr]
  if f then
    return f(str, idx)
  end
  decode_error(str, idx, "unexpected character '" .. chr .. "'")
end


function json.decode(str)
  if type(str) ~= "string" then
    error("expected argument of type string, got " .. type(str))
  end
  local res, idx = parse(str, next_char(str, 1, space_chars, true))
  idx = next_char(str, idx, space_chars, true)
  if idx <= #str then
    decode_error(str, idx, "trailing garbage")
  end
  return res
end


--------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------
local pc = app.pixelColor
function icolor(pixel)
    return "rgba(" .. pc.rgbaR(pixel) .. ", " .. pc.rgbaG(pixel) .. ", " .. pc.rgbaB(pixel) .. ", " .. pc.rgbaA(pixel) .. ")"
end

local debug = false
function log(message)
  return debug and print(message)
end

function irectangle(rectangle)
  return "rectangle(" .. rectangle.x .. ", " .. rectangle.y .. ", " .. rectangle.width .. ", " .. rectangle.height .. ")"
end

function ipoint(point)
  return "point(" .. point.x .. ", " .. point.y .. ")"
end


function get_layer(sprite, name)
    for i, layer in ipairs(sprite.layers) do
        if layer.name == name then
            return layer
        end
    end
end


-- Return the cels of the given layer indexed by frame number.
function get_layer_cels(sprite, layer_name)
  local layer = get_layer(app.activeSprite, layer_name)
  local cels  = {}
  for i, cel in ipairs(layer.cels) do
    cels[cel.frame] = cel
  end
  return cels
end


function find_origin(cel, color)
    log("Search origin in cel for frame " .. cel.frame .. " in layer " .. cel.layer.name .. " looking for color " .. icolor(color))
    local image  = cel.image
    local bounds = cel.bounds
    local width  = bounds.width

    for y = 0, bounds.height do
        for x = 0, width do
            if image:getPixel(x,y) == color then
                return {
                    x = x + bounds.x,
                    y = y + bounds.y
                }
            end
        end
    end
end


function find_boxes(cel, color, origin)
    if not cel then return end

    local boxes          = {}
    local image          = cel.image
    local bounds         = cel.bounds
    local ignored_points = {}
    log("Search box of color " .. icolor(color) .. " in the cel for frame " .. cel.frame .. " and layer " .. cel.layer.name .. ". Origin is " .. ipoint(origin))

    for y = 0, bounds.height do
        for x = 0, bounds.width do
            -- Search for pixels of the right color and which doesn't belong to a previously visited rectangle.
            local pixel = image:getPixel(x, y)
            if pixel == color and not ignored_points[x .. "_" .. y] then
                local rectangle, visited_points = get_rectangle(cel, Point(x, y), color)
                rectangle.x = x + bounds.x - origin.x
                rectangle.y = y + bounds.y - origin.y
                log("Add box " .. irectangle(rectangle))
                table.insert(boxes, rectangle)
                -- Mark the pixels of this rectangle as visited.
                for point, _ in pairs(visited_points) do
                  ignored_points[point] = true
                end
            end
        end
    end

    return boxes
end


-- Image being processes from top left corner, the first pixel encountered 
-- is always the top left of a rectangle. Just follow the horizontal line
-- to the right until you get no more pixel, then go down until no more pixel
-- down, then left, then top until you reach the starting point.
function get_rectangle(cel, start, color)
    log("Start exploring a rectangle from " .. ipoint(start))

    local rectangle      = { x = start.x, y = start.y, width = nil, height = nil }
    local visited_points = { [start.x .. "_" .. start.y] = true}
    local image          = cel.image
    local bounds         = cel.bounds
    local width          = bounds.width
    local point          = { x = start.x, y = start.y }
    local watchdog       = 1000
    
    repeat
      watchdog = watchdog - 1
        if point and image:getPixel(point.x + 1, point.y) == color then -- Go right.
          visited_points[point.x + 1 .. "_" .. point.y] = true
          point.x = point.x + 1
        elseif point and image:getPixel(point.x, point.y + 1) == color then -- Go down.
          visited_points[point.x .. "_" .. point.y + 1] = true
          point.y = point.y + 1
        else -- Found the bottom right corner!
          rectangle.width = point.x - start.x + 1
          rectangle.height = point.y - start.y + 1
        end
    until rectangle.width or watchdog == 0

    -- Add the remaining points to the visited points.
    for x = start.x, point.x do
      visited_points[x .. "_" .. point.y] = true
    end

    for y = start.y, point.y do
      visited_points[start.x .. "_" .. y] = true
    end

    return rectangle, visited_points
end


function extract_animations(sprite, colors)
    local origin_layer   = get_layer(sprite, "Origin")
    local hitboxes_cels  = get_layer_cels(sprite, "Hitboxes")
    local hurtboxes_cels = get_layer_cels(sprite, "Hurtboxes")
    local moveboxes_cels = get_layer_cels(sprite, "Moveboxes")
    local animations = {}

    for _, tag in ipairs(sprite.tags) do
        animations[tag.name] = {
            name   = tag.name,
            frames = {}
        }
    
        for i = 1, tag.frames do
            local frame_index = tag.fromFrame + i - 1
            local origin = find_origin(origin_layer.cels[frame_index], colors.origin)
            log("Process frame " .. frame_index .. " of animation " .. tag.name)
            
            animations[tag.name].frames[i] = {
                index     = i,
                origin    = origin,
                hitboxes  = find_boxes(hitboxes_cels[frame_index], colors.hitbox, origin),
                hurtboxes = find_boxes(hurtboxes_cels[frame_index], colors.hurtbox, origin),
                moveboxes = find_boxes(moveboxes_cels[frame_index], colors.movebox, origin),
                rectangle = {
                  x      = (frame_index - 1) * sprite.width,
                  y      = 0,
                  width  = sprite.width,
                  height = sprite.height
                }
            }
        end
    end

    return animations
end


local red    = pc.rgba(255, 0, 0, 255)
local green  = pc.rgba(0, 255, 0, 255)
local blue   = pc.rgba(0, 0, 255, 255)
local yellow = pc.rgba(255, 255, 0, 255)
local colors = {
  origin   = red,
  movebox  = green,
  hurtbox  = blue,
  hitbox   = yellow
}


local animations = extract_animations(app.activeSprite, colors)
local file       = io.open("hero.json", "w")
io.output(file)
io.write(json.encode(animations))
io.close()