cinera_handmade.network/cmuratori/hero/code/code284.hmml

[video output=day284 member=cmuratori stream_platform=twitch stream_username=handmade_hero project=code title="Reorganizing the Head and Body Code" vod_platform=youtube id=sEHDoJnZSKY annotator=Miblo]
[1:40][Run the game and recap our current situation]
[2:56][Stand on the FloatyThingForNow and note a bug]
[3:44][handmade_world_mode.cpp: Set Found = false for the HeroBody]
[5:18][Run the game, note that the body cannot find a traversable and consider making the head operate more specifically]
[7:46][handmade_world_mode.cpp: Decouple of the hopping from the head and make it happen more predictably]
[12:27][Run the game, move the head and find that the body does not hop]
[12:57][4coder: Indentation request]
[13:12][handmade_world_mode.cpp: Make the controller also control the body, if one exists]
[21:37][Run the game and hop around]
[21:48][handmade_world_mode.cpp: Make the Head test to see if the Body can move to a traversable]
[26:08][handmade_entity.h: Introduce IsEqual]
[28:21][Run the game and find that nothing has changed]
[30:51][handmade_world_mode.cpp: Investigate this behaviour with the FloatyThingForNow like a bug, starting with DEBUG_VALUE]
[35:27][Record a loop in order to investigate it]
[46:00][Blackboard: Figuring out the tile delta]
[59:36][win32_handmade.cpp: Copy a loop and provide the ability to play one back independently of recording]
[1:01:52][Run the game and try playing back a loop]
[1:23:14][Moment of realisation: This isn't even a bug]
[1:24:44][Owl of Shame Moment: FloatyThingForNow is hard-setting the P.z][quote 484]
[1:25:05][Blackboard: How the FloatyThingForNow messes with the relative coordinate system]
[1:27:20][handmade_world_mode.cpp: Set the P.z as a delta for now and then hop onto the FloatyThingForNow and find that the bug has gone]
[1:28:39][Blackboard: sine and cosine as derivatives of each other]
[1:35:06][Q&A][:speech]
[1:36:06][@klemensbaum][Is there a geometric explanation for the quaternion sandwich product? Where does the formula q * p * conj(q) come from?]
[1:37:00][@mr4thdimention][I am a bit unclear on why the relative positioning of Z worked. Is Z rebased somewhere in the code?]
[1:38:33][@zakssi][I'm still quite newbie on programming, but wouldn't commenting your code a bit more help in situations like today?]
[1:40:40][@cubercaleb][Only three swears? I have counted a lot more than that]
[1:41:04][@longboolean][So, not only did that bug effect the floating thing going to high / low, but it also was the cause of the head picking the wrong point and the body jumping to it?]
[1:41:23][Blackboard: What was causing the guy to jump]
[1:43:15][@themindoverall][What if you really wanted to set an absolute position for an entity? How would you handle that?]
[1:44:00][Blackboard: Quaternion Sandwich Product or Similarity Transform]
[1:45:56][@klemensbaum][Yes, that's the question]
[1:46:34][Blackboard: The algebraic reason]
[1:48:56][Blackboard: Things that represent a frame of reference]
[1:54:38][Blackboard: Knowing what B is in the space of A]
[1:57:27][Blackboard: The Similarity Transform]
[2:03:16][Blackboard: Diagram of the transform]
[2:07:17][Blackboard: Why do we care about this?]
[2:10:35][Blackboard: Thinking about this algebraically]
[2:12:05][Blackboard: Doing this transform, with P encoded in a different space]
[2:16:08][Blackboard: Transforming a bone chain]
[2:21:02][Blackboard: Inserting and expanding the identity]
[2:25:43][@klemensbaum][Thank you, very insightful explanation. Can you recommend a book where I can learn more about these kinds of things? How did you learn it all in such an intuitive way?]
[2:29:21][@jameswidman][Would any of this have been mentioned in the comments in the Granny source code, or is it considered "obvious" to people working in that context?]
[2:30:51][Wrap it up][:speech]
[2:31:32][Relaunch the awesome ~Milton and find that everything is saved and undoable]
[/video]