117 lines
9.4 KiB
Plaintext
117 lines
9.4 KiB
Plaintext
[video output=day642 member=cmuratori stream_platform=twitch stream_username=handmade_hero project=code title="Debugging Voxel Collision Bounds" vod_platform=youtube id=qDFhSyS6kes annotator=Miblo]
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[0:00][Recap and set the stage for the day][:speech]
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[1:03][Demo our incomplete :collision detector][:run]
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[3:29][Reacquaint ourselves with the :collision detector in MoveEntity()][:research]
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[5:19][Thoughts on allowing for buggy gameplay code][:collision :speech]
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[9:03][Reacquaint ourselves with the :collision detector in MoveEntity() (cont.)][:research]
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[11:44][A* and Dijkstra's algorithm][:pathfinding :speech]
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[16:49][@thesandvichmaker][@handmade_hero Dijkstra?]
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[17:02][@fda0][Dijkstra's algorithm seems like a bad name when the guy created, like, 50 algorithms]
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[18:48][Reacquaint ourselves with the :collision detector in MoveEntity() (cont.)][:research]
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[20:19][TODO([@cmuratori casey]): We should probably store corners and only test when they are untested][:collision :optimisation]
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[22:12][Reacquaint ourselves with the :collision detector in MoveEntity() (cont.)][:research]
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[23:03][@dedknd][Photolithography machines manufacturer ASML is also Dutch, supplying TSMC and Samsung]
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[23:07][@thesandvichmaker][If you tell me your name and date of birth my brain will actually process what you sound like]
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[23:30][@thesandvichmaker][Dutch national pride]
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[26:35][TODO([@cmuratori casey]): We need to think through the way we handle embedding…][:collision]
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[27:37][Reacquaint ourselves with the :collision detector in MoveEntity() (cont.)][:research]
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[29:01][Investigate why the glove did not move][:collision :research]
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[30:05][The glove's :collision search doesn't go beyond the "home" voxel][:collision :run]
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[31:22][Make MoveEntity() diagram the full voxel span][:collision :"debug visualisation"]
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[33:13][The glove's :collision search doesn't touch the full voxel span][:collision :run]
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[34:06][Make MoveEntity() diagram the line from FromP to ToP][:collision :"debug visualisation"]
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[34:23][The glove's full voxel span does not encompass the whole line from FromP to ToP][:collision :run]
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[35:10][Make MoveEntity() colour in grey the line from FromP to ToP][:collision :"debug visualisation"]
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[35:16][Clean out old code from MoveEntity() and correctly set the VoxelEndingCorner][:collision]
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[39:25][The glove's full voxel span correctly encompasses the whole line from FromP to ToP][:collision :run]
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[39:58][Start to investigate why the flood search doesn't work][:collision :research]
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[40:48][Make MoveEntity() diagram the tested voxel][:collision :"debug visualisation"]
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[41:52][The glove's :collision search tests one cell][:run]
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[42:04][Investigate why MoveEntity() never calls PushVoxelStack() in the "Flip" loop][:collision :research]
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[44:00][Step in to MoveEntity()][:collision :run]
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[44:34][Flip the Occupied tests in MoveEntity()][:collision]
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[45:20][Step in to MoveEntity() to find that it now calls PushVoxelStack()][:collision :run]
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[45:33][Our glove's :collision flood search now permits :movement][:run]
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[45:48][Our :collision erroneously permits embedding and corner roll-off doesn't happen][:run]
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[47:09][Increase the :collision search space by one voxel in MoveEntity()]
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[47:50][Our corner roll-off now works][:collision :run]
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[48:00][We must fix embedding and :performance][:collision :run]
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[48:29][Plan to fix embedding][:collision :research]
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[49:48][Plan to fix embedding: 1) Track tested voxel corners][:collision :research]
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[49:58][Plan to fix embedding: 2) Track embedding, to prevent movement to an embedded cell][:collision :research]
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[51:00][Disable the embedding recovery code in MoveEntity()][:collision]
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[51:17][Our :collision still permits embedding][:run]
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[51:25][Scrutinise MoveEntity() for code that permits embedding][:collision :research]
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[53:38][Make MoveEntity() test for embedding before considering a cell][:collision]
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[54:29][Our :collision still permits embedding][:run]
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[55:09][Scrutinise MoveEntity() for code that permits embedding][:collision :research]
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[55:39][Fix the embedding test loop in MoveEntity() to use Cell.Min][:collision]
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[56:11][Our :collision now prevents embedding][:run]
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[56:39][Our glove gets stuck on a corner][:collision :run]
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[57:31][Relieve MoveEntity() of testing for embedding before considering a cell][:collision]
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[57:47][Our :collision continues to prevent embedding, but we can get stuck in the doorway][:run]
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[59:31][Optimising the :collision routine][:optimisation :research]
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[1:00:37][Let MoveEntity() early-out of the :collision voxel pushing loop if BestDistanceSq == 0][:collision :optimisation]
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[1:01:15][Our glove can get embedded in the hero][:collision :optimisation :run]
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[1:01:42][Our :collision flood search tests all voxels in a clear straight line][:optimisation :run]
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[1:03:20][Determine to push :collision voxels closest-first][:optimisation :research]
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[1:04:31][Determine to improve our early-out condition in MoveEntity()][:collision :optimisation :research]
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[1:05:32][Change MoveEntity() to early-out if the BestCellI and TargetCellI match, introducing ClampToVoxelDim()][:collision :optimisation]
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[1:08:37][Our :collision is more efficient][:optimisation :run]
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[1:09:12][Rephrase the :collision voxel expansion in MoveEntity()]
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[1:10:00][The glove can penetrate right through the wall][:collision :run]
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[1:10:34][Scan MoveEntity() for code that permits through-embedding][:collision :research]
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[1:11:00][The glove can penetrate right through the wall when turning][:collision :run]
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[1:11:40][Scrutinise MoveEntity() for code that permits embedding][:collision :research]
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[1:12:33][Try to single-step the :collision detector][:run]
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[1:14:53][Walk into the wall, getting the glove embedded][:collision :run]
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[1:15:43][Introduce Round() for MoveEntity() to use when setting VoxelStartingCorner and VoxelEndingCorner[ref
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site=Intel
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page="Intel Intrinsics Guide"
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url=https://software.intel.com/sites/landingpage/IntrinsicsGuide/]][:collision :mathematics]
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[1:20:20][Our glove's and the expanded :collision search voxels are not aligned][:run]
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[1:21:15][Investigate our voxel misalignment in MoveEntity()][:collision :research]
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[1:22:08][Revert MoveEntity() to use Floor() when setting VoxelStartingCorner and VoxelEndingCorner][:collision]
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[1:22:48][Increase the VoxelMaxCorner by 2× the CellDim][:collision]
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[1:23:35][Our :performance has tanked][:collision :run]
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[1:24:05][Reduce VOXEL_STACK_DIM from 16 to 8][:collision]
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[1:24:26][Our :collision voxels remain misaligned][:run]
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[1:25:50][Change MoveEntity() to include the starting point, factoring in a DeltaPClamp to the VoxelEndingCorner][:collision]
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[1:31:44][Our :collision search bounds and embedding are improved][:run]
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[1:32:56][Continue to optimise the :collision routine, augmenting voxel_stack with Repulsion and introducing voxel_corners and CheckCorners() for MoveEntity() to use][:"data structure" :optimisation]
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[1:52:49][Hit an assertion on CornerI in CheckCorners()][:collision :run]
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[1:53:32][Rephrase assertions in CheckCorners()][:collision]
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[1:54:06][Add assertions in CheckCorners on the incoming CellI dimensions][:collision]
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[1:55:18][Hit an assertion on CellI in CheckCorners()][:collision :run]
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[1:55:28][Investigate our out-of-bounds :collision voxel push in MoveEntity()][:research]
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[1:56:52][Respecify MaxVoxelDim as MaxDeltaDim in MoveEntity()][:collision]
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[1:57:33][Hit an assertion on CellI in CheckCorners()][:collision :run]
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[1:57:43][Continue to investigate our out-of-bounds :collision voxel push in MoveEntity()][:research]
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[1:58:18][Change MoveEntity() to use FloorToV3S() when setting VoxelDim][:collision]
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[1:58:34][Hit an assertion on CellI in CheckCorners()][:collision :run]
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[1:58:49][Add assertions on the VoxelDim in MoveEntity()][:collision]
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[1:59:24][Hit an assertion on VoxelDim in MoveEntity()][:collision :run]
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[1:59:44][:Run in -Od, hit an assertion on VoxelDim in MoveEntity() and inspect the values][:collision]
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[2:01:53][Fix our assertions on the VoxelDim in MoveEntity()][:collision]
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[2:02:08][Hit an assertion on VoxelDim in MoveEntity() and inspect the values][:collision :run]
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[2:03:27][Decrease the MaxDeltaDim by 3 per axis in MoveEntity()][:collision]
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[2:03:39][No longer hit that assertion on VoxelDim in MoveEntity()][:collision :run]
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[2:04:02][:Run in -O2, and no longer hit that assertion on VoxelDim in MoveEntity()][:collision]
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[2:04:34][Corner roll-off now works, we no longer embed, but we can still get stuck on corners][:collision :run]
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[2:07:04][TODO([@cmuratori casey]): Do initial check to see if we're embedded...][:collision]
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[2:07:52][Q&A][:speech]
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[2:09:24][@insobot][Q: Polling raw input make it reasonable to give it a coincidence that we do not worry about the nail salon?][:"input handling"]
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[2:10:28][@thesandvichmaker][@handmade_hero, @insobot has cheered me up, but I've been real down on programming lately. Have you ever had a phase where you were just totally over computers?]
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[2:16:24][@mindmark42][Q: Do you think it is safe to assume if a CPU has AVX2 it has FMA, or should I always check the cpuflags? I'm not sure where to look if such a thing is true[ref
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site=Intel
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page="Intel Intrinsics Guide"
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url=https://software.intel.com/sites/landingpage/IntrinsicsGuide/]][:isa]
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[2:21:19][@mindmark42][Ya, I was wondering if all AVX2 CPUs on the market have the FMA extensions because all two of mine have them[ref
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site=uops.info
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url=https://uops.info/table.html][ref
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site=Intel
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page="Intel Intrinsics Guide"
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url=https://software.intel.com/sites/landingpage/IntrinsicsGuide/]][:isa]
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[2:29:22][We're done][:speech]
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[/video]
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