Stop Using Nodes for Everything in Godot — Transcript

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1. 0:00See this screen? It used to take 115
2. 0:03milliseconds to render. That's nearly
3. 0:05seven dropped frames. Now, it takes
4. 0:07under 10 milliseconds. Why did this
5. 0:10screen take 115 milliseconds to render
6. 0:12and how did I fix it? This is for my
7. 0:14game Alchemortis, a dark fantasy
8. 0:17roguelite auto battler where you can
9. 0:18create your own builds using alchemy.
10. 0:20You can wishlist the game now and
11. 0:22there's a playtest available now. So,
12. 0:24head on over to the Steam page, give the
13. 0:26game a wishlist, download the playtest,
14. 0:28try it, and let me [music] know what you
15. 0:29think in the Discord server. The link to
16. 0:32the Steam page is in the description
17. 0:33below. In my game, I have cards. Each
18. 0:36card has a shape, unique art, abilities,
19. 0:39and several visual effects. Previously,
20. 0:42I was handling all of my cards' visual
21. 0:44needs the straightforward way. I had a
22. 0:46card scene which contained all of the
23. 0:47relevant nodes and materials to render
24. 0:50everything from the card background to
25. 0:51the art to the visual effects for
26. 0:53various statuses. As you can see here,
27. 0:56this scene tree ended up having a lot of
28. 0:58nodes. This wasn't a problem though
29. 1:00until I wanted to display all of the
30. 1:02cards in this unlock screen. It turns
31. 1:05out trying to instantiate roughly 100
32. 1:07card scenes like this in a single frame
33. 1:09wasn't doable without a massive process
34. 1:12time spike. I tried a number of things
35. 1:14to address this. Object pooling, [music]
36. 1:16instantiating the cards over several
37. 1:18frames instead of in one frame, and
38. 1:20others, but all of these things
39. 1:21presented their own challenges and
40. 1:23ultimately felt more like hacks or
41. 1:25workarounds that were liable to break. I
42. 1:27narrowed the problem down to this. It is
43. 1:29simply not feasible to do what I was
44. 1:31doing with the card scene and expect the
45. 1:33kind of performance that I needed. The
46. 1:35instantiation of each card scene and the
47. 1:37addition of all those nodes to the tree
48. 1:39was simply taking too long and the only
49. 1:41way to truly fix the problem was to
50. 1:43reduce the number of nodes being added
51. 1:45to the tree. I've heard a lot in Godot
52. 1:47circles about how using the rendering
53. 1:49server directly can improve performance,
54. 1:52but if you're like me, that sounds kind
55. 1:53of intimidating. But after trying and
56. 1:55failing to get these cards rendering
57. 1:57within the time of a single frame with
58. 1:58the other approaches, I decided to try
59. 2:00using the rendering server. And you know
60. 2:02what? It ended up being way more
61. 2:04straightforward than I anticipated. The
62. 2:06core idea is simple. Instead of creating
63. 2:08nodes and letting them work with the
64. 2:10rendering server for you, you work with
65. 2:12the rendering server directly. The
66. 2:13rendering server is responsible
67. 2:15ultimately for drawing textures,
68. 2:16assigning materials, and basically
69. 2:18anything else related to drawing to the
70. 2:19screen. When you add a Sprite2D to your
71. 2:22scene, for example, what's happening
72. 2:23under the hood is that the Sprite2D is
73. 2:25leveraging the rendering server to draw
74. 2:27the sprite you configure. The Sprite2D
75. 2:29isn't responsible for doing the drawing.
76. 2:31It's basically just a configuration
77. 2:33object that passes its data along to the
78. 2:35rendering server. Now, that's a
79. 2:36simplified explanation, but it's helpful
80. 2:38to think about it in that way. What this
81. 2:40means is that any node which leverages
82. 2:42the rendering server under the hood can
83. 2:43be bypassed entirely by using the
84. 2:45rendering server directly yourself.
85. 2:48Here's a quick breakdown to set up
86. 2:49something to use the rendering server.
87. 2:51First, you need to create a canvas item.
88. 2:53This registers a new canvas item which
89. 2:55can have a transform, a texture, a
90. 2:57material, among other things. This
91. 2:59create canvas item call will return an
92. 3:02RID. This is a resource ID that
93. 3:04represents the canvas item. The trick
94. 3:06here is that with the rendering server,
95. 3:08you need to manage RIDs yourself,
96. 3:10meaning that when you no longer are
97. 3:11using RIDs, you need to free them
98. 3:13explicitly. Once you have the canvas
99. 3:15item, you can assign a texture or a
100. 3:17material, among other things. To assign
101. 3:19a texture, you use canvas item add
102. 3:21texture rect, [music] for example. You
103. 3:23can also change the transform of a
104. 3:25canvas item using canvas item set
105. 3:27transform. A transform includes not just
106. 3:29the position, but rotation and scale as
107. 3:31well. I won't list out all the
108. 3:33functionality of the rendering server,
109. 3:34but hopefully you can see how the
110. 3:35pattern works. But, [music]
111. 3:37here's where it gets interesting. You
112. 3:38can also set canvas items created
113. 3:41through the rendering server as children
114. 3:43of other canvas items so that they can
115. 3:45inherit the transforms of their parents,
116. 3:47just like you'd expect from Node2Ds you
117. 3:50configure in the Godot editor. So, with
118. 3:52all that in place, I think you can start
119. 3:53to see how easy it was for me to replace
120. 3:55my card scene node structure with an
121. 3:58almost pure rendering server
122. 4:00implementation. Here's my new card
123. 4:02class. We can see that this still
124. 4:04inherits control so that I can detect
125. 4:05mouse events and retain the possibility
126. 4:07of reparenting cards to other nodes.
127. 4:09However, there are no other nodes
128. 4:11created during instantiation of a card.
129. 4:14In the card's [music] setup method, I'm
130. 4:16just establishing a tree of canvas
131. 4:18items, each one designed to replace a
132. 4:20node from the previous card scene. I've
133. 4:22got my background canvas item, my art
134. 4:24canvas item, as well as canvas items
135. 4:27that are assigned materials to render
136. 4:29some of my special card visual effects.
137. 4:31By leveraging the canvas item parenting
138. 4:33that I mentioned before, I can also
139. 4:35apply transformations to any canvas item
140. 4:37I want to in order to create a scaling
141. 4:40or positional animation, for example.
142. 4:42So, after that refactor, here is the end
143. 4:45result. That card screen that I
144. 4:47mentioned before now renders
145. 4:48approximately 100 cards in about 8
146. 4:50milliseconds, and that's on a debug
147. 4:52build. That is a huge improvement
148. 4:54compared to the 115 milliseconds to
149. 4:56render the same number of cards prior.
150. 4:58So, basically, the rendering server has
151. 5:00functionality that serves as a
152. 5:01one-to-one replacement of whatever my
153. 5:03card nodes were doing previously. By
154. 5:05using the rendering server directly, I
155. 5:07get to bypass the overhead of
156. 5:09instantiating a scene and adding many
157. 5:11nodes to the scene tree in a single
158. 5:12frame, and this isn't just a slight
159. 5:14improvement either. It's a massively
160. 5:16noticeable difference. Now, all of these
161. 5:18cards render within the time of a single
162. 5:20frame with plenty of headroom to spare.
163. 5:22[music]
164. 5:23115 milliseconds down to 8 on a debug
165. 5:26build. If your game has a similar
166. 5:28bottleneck, the rendering server is
167. 5:30worth your time. This video wasn't
168. 5:32designed to be a comprehensive rendering
169. 5:33server tutorial, but hopefully I've
170. 5:35given you a place to start. Again, my
171. 5:37game is Alchemortis. Give it a wishlist
172. 5:39if the game sounds interesting to you,
173. 5:41and again, the playtest is available
174. 5:43right now for 1 week, which you can join
175. 5:45from the Steam page. If you try it, let
176. 5:47me know what you think in the Discord
177. 5:49server. The Steam page and Discord are
178. 5:51linked below.
179. 5:53Thanks for watching this video. If you
180. 5:55want to support my work, please consider
181. 5:56wishlisting Alchemortis on Steam,
182. 5:58subscribing to my Patreon, joining the
183. 5:59Discord server, or purchasing one of my
184. 6:01courses. You can also sign up for my
185. 6:03email list at firebelly.com. The links
186. 6:05for everything are in the description
187. 6:07below.