tga_encoder = {} local LUA_ARGS_LIMIT = 1000 local image = setmetatable({}, { __call = function(self, ...) local t = setmetatable({}, {__index = self}) t:constructor(...) return t end, }) function image:constructor(pixels) self.bytes = {} self.chunks = {self.bytes} self.pixels = pixels self.width = #pixels[1] self.height = #pixels self:encode() end function image:insert(byte) table.insert(self.bytes, byte) if #self.bytes == LUA_ARGS_LIMIT then self.bytes = {} table.insert(self.chunks, self.bytes) end end function image:littleendian(size, value) for i = 1, size do local byte = value % 256 value = value - byte value = value / 256 self:insert(byte) end end function image:encode_colormap_spec() -- first entry index self:littleendian(2, 0) -- number of entries self:littleendian(2, 0) -- number of bits per pixel self:insert(0) end function image:encode_image_spec() -- X- and Y- origin self:littleendian(2, 0) self:littleendian(2, 0) -- width and height self:littleendian(2, self.width) self:littleendian(2, self.height) -- pixel depth self:insert(24) -- image descriptor self:insert(0) end function image:encode_header() -- id length self:insert(0) -- no image id info -- color map type self:insert(0) -- no color map -- image type self:insert(2) -- uncompressed true-color image -- color map specification self:encode_colormap_spec() -- image specification self:encode_image_spec() end function image:encode_data() for _, row in ipairs(self.pixels) do for _, pixel in ipairs(row) do self:insert(pixel[3]) self:insert(pixel[2]) self:insert(pixel[1]) end end end function image:encode() -- encode header self:encode_header() -- no color map and image id data -- encode data self:encode_data() -- no extension area end function image:get_data() local data = "" for _, bytes in ipairs(self.chunks) do data = data .. string.char(unpack(bytes)) end return data .. string.char(0, 0, 0, 0) .. string.char(0, 0, 0, 0) .. "TRUEVISION-XFILE." .. string.char(0) end function image:save(filename) self.data = self.data or self:get_data() local f = assert(io.open(filename, "w")) f:write(self.data) f:close() end tga_encoder.image = image