Rollback Netcode Q&A

We had a big live Q&A about rollback netcode!

Core-A Gaming's Rollback primer video: https://www.youtube.com/watch?v=0NLe4...

NetherRealm's GDC Talk on Rollback: https://www.youtube.com/watch?v=7jb0F...

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0:00 Introduction 2:42 How do I add rollback into my indie game? 3:25 Is GGPO the only resource for rollback? 4:36 The Main Concept of Rollback 7:24 What is determinism and why is it important? 9:26 Decoupling a game's Render phase 13:04 Game update loop efficiency 15:05 How complex is it to add rollback to a game that never had it originally? 16:44 Why is rollback so difficult to add to any fighting game? 17:51 Why do companies not invest in rollback despite fan demand? 24:18 Are 3D games more difficult to develop rollback for? 28:03 Will Tekken 8 have rollback? 31:18 The community's demand for rollback 34:21 How do you implement GGPO into Unreal, Unity & other engines? 44:47 What engine should hobbyists use to get started with rollback? 52:01 Where does WiFi and Ethernet come into all this? 56:02 Can you point out what your Unity rollback demo is doing? 1:00:28 Does fast gameplay effect rollback? 1:02:50 Does frame data change during bad connections? 1:05:05 At what phase of development should you implement rollback? 1:13:40 Can you briefly explain your determinism setup in Unity? 1:16:46 How would you test rollbacks to simulate bad network conditions? 1:18:32 How do you send network data for rollback? 1:22:12 What is the difference between TCP and UDP for network communication? 1:26:21 Do you know what Harada meant by Tekken's animation being difficult for rollback? 1:27:00 Are you going to use GGPO or make your own rollback? 1:28:06 How do fighting games detect desyncs? 1:29:44 In the future could there be anything better than GGPO? 1:30:53 Character animation designed for rollback. 1:32:31 How long have you been working on Pocket Fighter EX? 1:33:01 Can you make a program to add rollback to any game? 1:33:37 Does your rollback test code change when you add multiplayer? 1:34:19 How would rollback work in games that have more than two players? 1:35:38 Do you think they could put rollback into KOFXIII like they did in older games? 1:37:46 Why does Ghost of Tsushima target performance and other games don't? 1:39:37 Could you brute force rollback into PlayStation 1 & 2 and Dreamcast era games? 1:41:49 What are some things I should optimize for rollback? 1:42:45 How can Mortal Kombat and Guilty Gear have rollback and be so graphically intensive? 1:44:35 What exactly is game source code? 1:45:37 What data does rollback send between players? 1:46:31 How do you manage sound and physics in rollback games? 1:48:48 What about syncing particles, FX, HUD, etc in rollback games? 1:57:40 How difficult would it be to add the rewind feature from Guilty Gear AC+R into recent games with rollback? 1:59:23 Do you have to sacrifice gameplay in any way to add rollback?

Thanks again to everyone for submitting questions!