[video output=day315 member=cmuratori stream_platform=twitch stream_username=handmade_hero project=code title="Un-reversing Sort Key Order" vod_platform=youtube id=jr55zspbhGc annotator=Miblo]
[0:11][Recap and set the stage for the day]
[2:07][Blackboard: Layered Sorting]
[4:27][Blackboard: How we currently pull entities out of the simulation for sorting]
[7:44][Blackboard: Our choices for doing this layered sorting]
[10:50][handmade_render.cpp: Consider how the code is currently working]
[12:40][handmade_entity.cpp: Make UpdateAndRenderEntities() sort on the old position of the Entity]
[13:46][handmade_entity.h and .cpp: Add ZLayer to the entity struct and make BeginSim() set that Dest->ZLayer]
[14:26][handmade_entity.cpp: Make UpdateAndRenderEntities() keep track of and conditionally operate based on the CurrentAbsoluteZLayer]
[18:33][handmade_render_group.cpp: Introduce PushSortBarrier()]
[20:00][Run the game and hit the assertion in BuildSpriteGraph()]
[20:23][handmade_render.cpp: Read through BuildSpriteGraph() and make it break after incrementing the NodeIndexA]
[21:40][Debugger: Hit the assertion in BuildSpriteGraph() and investigate what's happening]
[23:52][handmade_render.cpp: Change LastIndex to OnePastLastIndex in SortEntries() and operate on it accordingly]
[26:37][Debugger: Run the game, hit the assertion in RecursiveFrontToBack() and investigate why]
[28:43][handmade_render.cpp: Prevent BuildSpriteGraph() from taking NodeIndexA but rather set it relative, and then simplify SortEntries()]
[31:53][Debugger: Run the game and hit the assertion in OpenGLRenderCommands()]
[32:21][handmade_render_group.cpp: Make PushSortBarrier() increment the PushBufferElementCount]
[33:53][handmade_render.cpp: Make SortEntries() change the total number of things to reflect how many there are without barriers]
[36:17]["It's like Doctors Without Barriers, you know what I'm saying?"][quote 509]
[36:48][Run the game and see that we are actually running, but that the sorting doesn't appear to be right per se]
[37:27][Debugger: Step into UpdateAndRenderEntities() and investigate what's happening with the sorting]
[40:02][handmade_render_group.cpp: Make PushSortBarrier() reverse the sense of the sort]
[41:38][handmade_platform.h: Consolidate game_render_commands and game_render_prep into something more sane]
[43:47][handmade_platform.h: Introduce GetSpriteBounds()]
[44:37][handmade_render_group.cpp: Make PushSortBarrier() call GetSpriteBounds() and operate according to what it returns]
[46:58][handmade_render_group.cpp: Make PushRenderElement_() similarly operate according to what GetSpriteBounds() returns]
[48:15][handmade_render_group.cpp: Make BeginAggregateSortKey() and EndAggregateSortKey() work a little differently]
[50:52][handmade_platform.h: Rename GetSpriteBounds() to GetSortEntries() and fix compile errors]
[54:27]["Go away, Five minute warning!"][quote 510]
[59:28][Run the game and crash and burn]
[1:00:28][handmade_render_group.cpp: Introduce push_buffer_result struct and PushBuffer() to do some of the work of PushRenderElement_()]
[1:05:28][handmade_render_group.cpp: Make PushClipRect() call PushBuffer()]
[1:07:15][handmade_render_group.cpp: Make PushBuffer() correctly set Result.SortEntry]
[1:07:31][Run the game and hit the assertion in SafeTruncateToU16()]
[1:07:53][Q&A][:speech]
[1:09:01][Debugger: Step into PushRenderElement() and GameUpdateAndRender() and inspect the values]
[1:10:52][handmade_platform.h: Make RenderCommandStruct() take the correct default values]
[1:12:02][@dj_crixl][You mentioned earlier that the compiler would optimize the code making pointer comparison unsafe. When does that happen?]
[1:12:24][Blackboard: "Memory Region" / "Allocation", and Pointer Arithmetic]
[1:16:59][Assign homework][:speech]
[1:17:56][Wrap it up][:speech]
[/video]