1#!/usr/bin/python
2# Copyright 2015 Google Inc. All rights reserved.
3#
4# Licensed under the Apache License, Version 2.0 (the "License");
5# you may not use this file except in compliance with the License.
6# You may obtain a copy of the License at
7#
8#     http://www.apache.org/licenses/LICENSE-2.0
9#
10# Unless required by applicable law or agreed to in writing, software
11# distributed under the License is distributed on an "AS IS" BASIS,
12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13# See the License for the specific language governing permissions and
14# limitations under the License.
15
16# To run this file, use `python_sample.sh`.
17
18# Append paths to the `flatbuffers` and `MyGame` modules. This is necessary
19# to facilitate executing this script in the `samples` folder, and to root
20# folder (where it gets placed when using `cmake`).
21import os
22import sys
23sys.path.append(os.path.join(os.path.dirname(__file__), '../python'))
24
25import flatbuffers
26import MyGame.Sample.Color
27import MyGame.Sample.Equipment
28import MyGame.Sample.Monster
29import MyGame.Sample.Vec3
30import MyGame.Sample.Weapon
31
32# Example of how to use FlatBuffers to create and read binary buffers.
33
34def main():
35  builder = flatbuffers.Builder(0)
36
37  # Create some weapons for our Monster ('Sword' and 'Axe').
38  weapon_one = builder.CreateString('Sword')
39  weapon_two = builder.CreateString('Axe')
40
41  MyGame.Sample.Weapon.WeaponStart(builder)
42  MyGame.Sample.Weapon.WeaponAddName(builder, weapon_one)
43  MyGame.Sample.Weapon.WeaponAddDamage(builder, 3)
44  sword = MyGame.Sample.Weapon.WeaponEnd(builder)
45
46  MyGame.Sample.Weapon.WeaponStart(builder)
47  MyGame.Sample.Weapon.WeaponAddName(builder, weapon_two)
48  MyGame.Sample.Weapon.WeaponAddDamage(builder, 5)
49  axe = MyGame.Sample.Weapon.WeaponEnd(builder)
50
51  # Serialize the FlatBuffer data.
52  name = builder.CreateString('Orc')
53
54  MyGame.Sample.Monster.MonsterStartInventoryVector(builder, 10)
55  # Note: Since we prepend the bytes, this loop iterates in reverse order.
56  for i in reversed(range(0, 10)):
57    builder.PrependByte(i)
58  inv = builder.EndVector(10)
59
60  MyGame.Sample.Monster.MonsterStartWeaponsVector(builder, 2)
61  # Note: Since we prepend the data, prepend the weapons in reverse order.
62  builder.PrependUOffsetTRelative(axe)
63  builder.PrependUOffsetTRelative(sword)
64  weapons = builder.EndVector(2)
65
66  pos = MyGame.Sample.Vec3.CreateVec3(builder, 1.0, 2.0, 3.0)
67
68  MyGame.Sample.Monster.MonsterStart(builder)
69  MyGame.Sample.Monster.MonsterAddPos(builder, pos)
70  MyGame.Sample.Monster.MonsterAddHp(builder, 300)
71  MyGame.Sample.Monster.MonsterAddName(builder, name)
72  MyGame.Sample.Monster.MonsterAddInventory(builder, inv)
73  MyGame.Sample.Monster.MonsterAddColor(builder,
74                                        MyGame.Sample.Color.Color().Red)
75  MyGame.Sample.Monster.MonsterAddWeapons(builder, weapons)
76  MyGame.Sample.Monster.MonsterAddEquippedType(
77      builder, MyGame.Sample.Equipment.Equipment().Weapon)
78  MyGame.Sample.Monster.MonsterAddEquipped(builder, axe)
79  orc = MyGame.Sample.Monster.MonsterEnd(builder)
80
81  builder.Finish(orc)
82
83  # We now have a FlatBuffer that we could store on disk or send over a network.
84
85  # ...Saving to file or sending over a network code goes here...
86
87  # Instead, we are going to access this buffer right away (as if we just
88  # received it).
89
90  buf = builder.Output()
91
92  # Note: We use `0` for the offset here, since we got the data using the
93  # `builder.Output()` method. This simulates the data you would store/receive
94  # in your FlatBuffer. If you wanted to read from the `builder.Bytes` directly,
95  # you would need to pass in the offset of `builder.Head()`, as the builder
96  # actually constructs the buffer backwards.
97  monster = MyGame.Sample.Monster.Monster.GetRootAsMonster(buf, 0)
98
99  # Note: We did not set the `Mana` field explicitly, so we get a default value.
100  assert monster.Mana() == 150
101  assert monster.Hp() == 300
102  assert monster.Name() == 'Orc'
103  assert monster.Color() == MyGame.Sample.Color.Color().Red
104  assert monster.Pos().X() == 1.0
105  assert monster.Pos().Y() == 2.0
106  assert monster.Pos().Z() == 3.0
107
108  # Get and test the `inventory` FlatBuffer `vector`.
109  for i in xrange(monster.InventoryLength()):
110    assert monster.Inventory(i) == i
111
112  # Get and test the `weapons` FlatBuffer `vector` of `table`s.
113  expected_weapon_names = ['Sword', 'Axe']
114  expected_weapon_damages = [3, 5]
115  for i in xrange(monster.WeaponsLength()):
116    assert monster.Weapons(i).Name() == expected_weapon_names[i]
117    assert monster.Weapons(i).Damage() == expected_weapon_damages[i]
118
119  # Get and test the `equipped` FlatBuffer `union`.
120  assert monster.EquippedType() == MyGame.Sample.Equipment.Equipment().Weapon
121
122  # An example of how you can appropriately convert the table depending on the
123  # FlatBuffer `union` type. You could add `elif` and `else` clauses to handle
124  # the other FlatBuffer `union` types for this field.
125  if monster.EquippedType() == MyGame.Sample.Equipment.Equipment().Weapon:
126    # `monster.Equipped()` returns a `flatbuffers.Table`, which can be used
127    # to initialize a `MyGame.Sample.Weapon.Weapon()`, in this case.
128    union_weapon = MyGame.Sample.Weapon.Weapon()
129    union_weapon.Init(monster.Equipped().Bytes, monster.Equipped().Pos)
130
131    assert union_weapon.Name() == "Axe"
132    assert union_weapon.Damage() == 5
133
134  print 'The FlatBuffer was successfully created and verified!'
135
136if __name__ == '__main__':
137  main()
138