Subnautica

Update 1.23.83358 (v458752) over the base game, SDK 13.3.5. Unity 2019.4.36f1 IL2CPP with FMOD on NVN, the engine of Subnautica: Below Zero: its sdk and subsdk0 (the movie module) are Below Zero's builds, which AI: THE SOMNIUM FILES - nirvanA Initiative (0100713016CCC000) and Pokémon Scarlet 1.0.0 (0100A3D008C5C000) ship too; only main differs. Plays on the Mac. Tested there (a short test): the title, the main menu, a new Survival game, the lifepod opening with control, picking up and using the fire extinguisher, at 30 fps with music, in a 15-minute run. Leaving the lifepod was not reached. iOS is untested.

What it needs

Memory

• As on Below Zero, nninitStartup hands application pool − used memory to StandardAllocator as one address region (0.94 GB, returning to main+0x34de00) and never sets a heap, and every other region comes from Unity's virtual allocator (AllocateAddressRegion called at main+0x717924).
• The ALLOC_BUCKET cut. nso_fnmap.py from Below Zero's main finds the BucketAllocator constructor (main+0x60af48) and AddMoreBuckets (main+0x60b45c) as exact matches; the memory manager setup's call (main+0x60e7c8 in the function at main+0x60e720) passes the same arguments (granularity 16, 32 buckets, 4 MB blocks, mov w5, #0xff at main+0x60ea64) with the ALLOC_BUCKET name. With the cut its reservation is 0.25 GB at +1.04 GB. This is a workaround for the iPhone's address space (the alias region is 64 GB on a Switch), as on Below Zero.
• Measured with DM_REGIONS on the Mac: in the lifepod after 8 minutes, 330 live regions holding 2.50 GB (1.87 GB mapped), 0.84 GB of gaps, the end at +3.40 GB of the 4.375 GB alias region; at the end of a 15-minute run 321 regions, 2.47 GB, the end at +3.33 GB. The high-water mark reached +3.26 GB while the Survival game loaded.
• Resident about 3.0 GB on the Mac in the lifepod, 0.87 GB of Metal allocations, flat from frame 21,000 to 27,000.

Files and shaders

• Resolved: offline depth metadata. Update 1.23.83358 selects near-zero NVN depth in run/b3.log (through frame 27,900), with no later GL switch. A short isolated boot reproduced the call with matching registered module IDs; evidence is in 0100429011144000-work/depth-mode-audit/boot-20261031/ beside the NSPs. The profile now declares depth_mode zero for the shared archive mechanism. This confirms the input; rebuilt archive acceptance and performance were not retested.
• RomFS: 15,570 files, 3.9 GB: 5,467 UnityFS bundles (Addressables, Data/StreamingAssets/aa/Switch), 20 FMOD banks, 5,416 .optoctrees and 4,582 .bin world-streaming files (SNUnmanagedData/Build18).
• 17,956 shaders: 8,972 vertex, 8,957 pixel, 2 geometry and 25 compute, read with Unity 2019.4's layouts; 11 are the player's GLSLC outputs in main. All of them build for the Mac (8 minutes with an empty cache); the first boot prebuilds 16,548 pipeline pairs in about 45 s, and no run met a shader missing from the map.
• Current, cause unknown: [RED] texture type mismatch: shader … declares slot 135 (or 136) as Metal type 2, texture ID 800 is type 7 (NVN target 2, format 0x38, Metal format 71); bound as is, 5 to 8 times a run in two pixel shaders: a 3D RGBA8 texture in a slot the translated shader declares 2D, the reverse of A 2D texture in a 3D slot binds the zero 3D texture. Every Below Zero run logs the same lines. Nothing wrong was seen on screen; which pass and texture these are is not found.

Frame rate

• 30 fps, as on the Switch: the game sets present interval 1 at its window and 2 once it runs. On the Mac (M-series) frame time p50 33.33 ms, p95 33.5–33.7 ms in the lifepod; GPU p50 3–6 ms, p95 under 9 ms; CPU energy 0.9 W.
• The game crops its window textures to the size it renders (WindowCrop 0,0 1440x810 of 1920x1080 at the menu): a DM_CTL screenshot without DM_NVN_SHOT_OUT shows the whole window texture, the screen and DM_NVN_SHOT_OUT=1920x1080 the crop.
• Not tried: present_interval display for 60 fps.

Audio

• FMOD on one AudioOut; music and effects play.
• Current, cause unknown: [RED] audio #0: the device has not called back for 216–219 ms while playing once in each of three runs: twice right after AudioOut Start (3–5 s from boot), once at frame 3,300 (about 110 s, in the menu). In two of them the log shows the Mac's output device changing at that moment (audio device buffer: … after output changed), so a device change on the Mac is one candidate; for the stall right after the start, the device's start-up latency is another, as the watchdog in hle_audio.c counts its 200 ms from AudioOutputUnitStart. The restart a second later plays on. Below Zero's line comes at the landing instead (its note).

Mac routes

• From a fresh save, with DM_CTL (run/ctl.sh in the work folder) 35 s after the first frame (after the first boot's pipeline prebuild): Plus, A (Play), A (New Game), A (Survival), 40 s later A (Press any button), about 60 s later the player has control in the lifepod. The fire extinguisher lies on the floor beside the ladder; standing in the fire kills the player ("You died.").

Open

• iOS untested.
• Leaving the lifepod and swimming: the world outside, its streaming and the address space it takes (watch the [mem] alias region mapped up to lines) are not measured.
• The audio stall at start (Audio) and the texture type mismatch (Files and shaders).

Found on this game

• The sdk cuts and the ALLOC_BUCKET cut are Below Zero's.
• Offline depth metadata: Offline pipeline archive and profile depth disagree.