Draft out snap builder

Author: ChillerDragon

lib/packer.rb

@@ -8,6 +8,7 @@
 
 class Packer
   # Format: ESDDDDDD EDDDDDDD EDD... Extended, Data, Sign
+  # @return [Array<int>]
   def self.pack_int(num)
     # the first byte can fit 6 bits
     # because the first two bits are extended and sign

lib/snapshot/builder.rb

@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require_relative 'snapshot'
+
+# should be merged with SnapItemBase
+class SnapItem
+  # @param type [Integer] type of the item for example 5 is obj_flag
+  # @param id [Integer] id of said item for characters thats the ClientID
+  # @param fields [Array] array of uncompressed integers
+  #                       for example [0, 0, 1] for obj_flag
+  #                       would set
+  #                       m_X = 0
+  #                       m_Y = 0
+  #                       m_Team = 1
+  def initialize(type, id, size, fields)
+    @type = type
+    @id = id
+    @size = size
+    @fields = fields
+  end
+
+  # basically to_network
+  # tee int array that will be sent over
+  # the wire
+  def to_a
+    Packer.pack_int(@type) +
+      Packer.pack_int(@id) +
+      fields.map { |field| Packer.pack_int(field) }
+  end
+end
+
+class SnapshotBuilder
+  def initialize
+    @data_size = 0
+    @num_items = 0
+    @items = []
+  end
+
+  ##
+  # insert new snap item into the snap
+  #
+  # https://chillerdragon.github.io/teeworlds-protocol/07/snap_items.html
+  #
+  # @param type [Integer] type of the item for example 5 is obj_flag
+  # @param id [Integer] id of said item for characters thats the ClientID
+  # @param fields [Array] array of uncompressed integers
+  #                       for example [0, 0, 1] for obj_flag
+  #                       would set
+  #                       m_X = 0
+  #                       m_Y = 0
+  #                       m_Team = 1
+  def new_item(type, id, size, fields)
+    item = SnapItem.new(type, id, size, fields)
+    @items.push(item)
+  end
+
+  # @return [Snapshot]
+  def finish
+    Snapshot.new
+  end
+end

lib/snapshot/snapshot.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+# shared by client and server
+class Snapshot
+  attr_accessor :game_tick, :items
+
+  def initialize(items)
+    # @type game_tick [Integer]
+    @game_tick = 0
+    # @type items [Array<SnapItemBase>]
+    @items = items
+  end
+
+  # @return crc [Integer] cyclic redundancy check a checksum of all snap items
+  def crc
+    sum = 0
+    @items.each do |item|
+      sum += item.to_a.sum
+    end
+    sum
+  end
+end

lib/snapshot/unpacker.rb

@@ -19,15 +19,7 @@
 require_relative 'events/death'
 require_relative 'events/hammer_hit'
 require_relative '../packer'
-
-class Snapshot
-  attr_accessor :game_tick, :items
-
-  def initialize(items)
-    @game_tick = 0
-    @items = items
-  end
-end
+require_relative 'snapshot'
 
 class DDNetSnapItem
   attr_accessor :notes, :name
@@ -76,6 +68,7 @@ def self.valid_type?(type)
 class SnapshotUnpacker
   def initialize(client)
     @client = client
+    # @type verbose [Boolean]
     @verbose = client.verbose_snap
   end
 
@@ -181,6 +174,7 @@ def snap_single(chunk)
     invalid = false
     item_type = u.get_int
     id_parsed = u.parsed.last
+    # @type snap_items [Array<SnapItemBase>]
     snap_items = []
     while item_type
       obj = nil

lib/teeworlds_server.rb

@@ -65,7 +65,7 @@ def seq
 
 class TeeworldsServer
   attr_accessor :clients
-  attr_reader :hooks, :shutdown_reason
+  attr_reader :hooks, :shutdown_reason, :current_game_tick
 
   def initialize(options = {})
     @verbose = options[:verbose] || false
@@ -448,7 +448,7 @@ def tick_start_time(tick)
     #       m_GameStartTime + (time_freq()*Tick)/SERVER_TICK_SPEED;
   end
 
-  def do_snapshot
+  def do_snap_empty
     delta_tick = -1
     # DeltaTick = m_aClients[i].m_LastAckedSnapshot;
     data = []
@@ -470,6 +470,30 @@ def do_snapshot
     end
   end
 
+  def do_snap_single
+    builder = SnapshotBuilder.new
+    snap = builder.finish
+    items = snap.to_a
+
+    data = []
+    # Game tick   Int
+    data += Packer.pack_int(@current_game_tick)
+    # Delta tick  Int
+    data += Packer.pack_int(@current_game_tick - delta_tick)
+    # Crc   Int
+    data += Packer.pack_int(snap.crc)
+    # Part size   Int   The size of this part. Meaning the size in bytes of the next raw data field.
+    data += Packer.pack_int(items.size)
+    # Data
+    data += items
+
+    p data
+  end
+
+  def do_snapshot
+    do_snap_empty
+  end
+
   def get_player_by_id(id)
     @clients[id]&.player
   end

spec/09_snap_builder_spec.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+# require_relative '../lib/snapshot/builder.rb'
+#
+# describe 'SnapshotBuilder', :snapshot do
+#   context 'finish' do
+#     it 'Should create correct snap' do
+#       builder = SnapshotBuilder.new
+#       snap = builder.finish
+#       expected_payload = [
+#         0x00, 0x01, 0x00, 0x0a, # removed_items=0 num_item_deltas=1 _zero=0 type=10 NetObj::Character
+#         0x00, 0x29, 0x00, 0x0d, # id=0 tick=41 x=0 y=13
+#         0x00, 0xb3, 0x36, 0x00, # vel_x=0 vel_y=3507 angle=0
+#         0x00, 0x40, 0x00, 0x00, # direction=0 jumped=-1 hooked_player=0 hook_state=0
+#         0x00, 0x00, 0x00, 0x00, # hook_tick=0 hook_x=0 hook_y=0 hook_dx=0
+#         0x00, 0x00, 0x00, 0x00, # hook_dy=0 health=0 armor=0 ammo_count=0
+#         0x00, 0x00, 0x00, 0x00, # weapon=0 emote=0 attack_tick=0 triggered_events=0
+#       ]
+#       expect(snap.to_a).to eq(expected_payload)
+#     end
+#   end
+# end
+
+# >>> snap NETMSG_SNAPSINGLE (8)
+# id=8 game_tick=1908 delta_tick=38
+# num_parts=1 part=0 crc=16846 part_size=28
+#
+# header:
+# 11 b4 1d 26      ...& int 17 >> 1 = 8 int 1908 int 38
+# 8e 87 02 1c      .... int 16846 int 28
+#
+# payload:
+# 00 01 00 0a      .... removed_items=0 num_item_deltas=1 _zero=0 type=10 NetObj::Character
+# 00 29 00 0d      .).. id=0 tick=41 x=0 y=13
+# 00 b3 36 00      ..6. vel_x=0 vel_y=3507 angle=0
+# 00 40 00 00      .@.. direction=0 jumped=-1 hooked_player=0 hook_state=0
+# 00 00 00 00      .... hook_tick=0 hook_x=0 hook_y=0 hook_dx=0
+# 00 00 00 00      .... hook_dy=0 health=0 armor=0 ammo_count=0
+# 00 00 00 00      .... weapon=0 emote=0 attack_tick=0 triggered_events=0