[macOS] Both Metal and OpenGL crash on track load - Intel Iris Plus Graphics (MacBookPro16,2, Intel, Tahoe 26.3.1)

[mkoterski]

Summary

SpaghettiKart crashes on track load with both Metal and OpenGL backends on an
Intel Mac. Metal renders a black screen and crashes with EXC_ARITHMETIC (SIGFPE).
OpenGL renders menus correctly but crashes on track load with the same exception.

Tested on both a source build (commit `f7aab65da (1.0.0-13-gf7aab65da)

crash-20260314-2337.zip

`) and the
official nightly CI build (macOS-intel-x64, downloaded 2026-03-14).
Both exhibit identical behavior.

Hardware & OS

• Model: MacBookPro16,2 (13-inch, 2020, Four Thunderbolt 3 ports)
• CPU: Quad-Core Intel Core i7, 2.3 GHz
• GPU: Intel Iris Plus Graphics (built-in, no discrete GPU)
• RAM: 32 GB LPDDR4X
• macOS: Tahoe 26.3.1 (25D2128)
• Xcode CLT: 17.0.0.17000604 (AppleClang)

Steps to Reproduce

1. Download the macOS-intel nightly build from the README, or build from source:

   git clone --recursive https://github.com/HarbourMasters/SpaghettiKart.git
   cd SpaghettiKart
   cmake -H. -Bbuild-cmake -GNinja \
     -DCMAKE_BUILD_TYPE=Release \
     -DCMAKE_OSX_ARCHITECTURES=x86_64 \
     -DCMAKE_PREFIX_PATH=/usr/local \
     -DCMAKE_FIND_FRAMEWORK=LAST \
     -DNON_PORTABLE=OFF
   cmake --build build-cmake --target ExtractAssets
   cmake --build build-cmake --config Release

2. Place US ROM as baserom.us.z64 in repo root (SHA-1: 579C48E211AE952530FFC8738709F078D5DD215E).
3. Launch ./build-cmake/Spaghettify
4. Select any track from the menu (e.g. Luigi Raceway, Mario Raceway)

Expected Behavior

Track loads and race begins.

Actual Behavior

Metal (Id 2, default on macOS)

• Window title shows "Spaghetti Kart (Metal)"
• Screen is completely black from launch — no menus visible
• Audio plays correctly (title screen music, menu sounds)
• Crashes with EXC_ARITHMETIC (SIGFPE) when a track auto-loads or is selected
• Settings menu is greyed out (cannot switch backend from within the game)

OpenGL (Id 1, set via ~/spaghettify.cfg.json patch)

• Window title shows "Spaghetti Kart (OpenGL)"
• Menus render correctly (title screen, character select, track select all visible)
• Audio plays correctly
• Crashes with EXC_ARITHMETIC (SIGFPE) at the moment a track begins loading
• Last log lines before crash:

  Loading Track 8
  [Game.cpp] Clean World
  [Track] Loading... mk:luigi_raceway
  [code_800029B0.c:192] [debug] Setup Race!
  [code_800029B0.c:193] [debug] Game Speed: 2

Crash Report

Exception Type:    EXC_ARITHMETIC (SIGFPE)
Exception Codes:   0x0000000000000001, 0x0000000000000000
Termination Reason: Namespace SIGNAL, Code 8, Floating point exception: 8
Faulting Thread:   0

Full .ips crash report attached below.

Nightly Build Test

Tested the official nightly CI build (macOS-intel-x64, downloaded 2026-03-14)
with the same ROM and o2r files. Results are identical to the source build:

Build	Backend	Menus	Track Load	Crash
Nightly CI	Metal (Id 2, default)	Black screen	Crashes	EXC_ARITHMETIC (SIGFPE)
Nightly CI	OpenGL (Id 1, local config)	Render correctly	Crashes	EXC_ARITHMETIC (SIGFPE)
Source (commit [HASH])	Metal (Id 2)	Black screen	Crashes	EXC_ARITHMETIC (SIGFPE)
Source (commit [HASH])	OpenGL (Id 1)	Render correctly	Crashes	EXC_ARITHMETIC (SIGFPE)

All four combinations crash with EXC_ARITHMETIC (SIGFPE) on track load.
OpenGL renders menus correctly on both builds; Metal shows a black screen on both.
This confirms the issue is upstream and affects both CI and source builds equally.

Nightly config note: The nightly build is portable (NON_PORTABLE=ON) and
reads config from its own directory, not ~/spaghettify.cfg.json. To test
OpenGL on the nightly, the config file must be placed next to the binary:

{"Window": {"Backend": {"Id": 1, "Name": "OpenGL"}}}

Config File Notes

Findings during debugging that may be useful to other Intel Mac users:

1. Config location: With NON_PORTABLE=OFF, the config is written to ~/spaghettify.cfg.json, not the build directory. Patching the wrong file has no effect.

2. Backend enum values: The upstream README states backend ids as {OpenGL=3, Metal=4} but the actual enum in libultraship/include/ship/window/Window.h is:

   enum class WindowBackend { FAST3D_DXGI_DX11, FAST3D_SDL_OPENGL, FAST3D_SDL_METAL, WINDOW_BACKEND_COUNT };
   // DX11=0, OpenGL=1, Metal=2

3. Config key capitalization: The key is "Id" (capital I). Lowercase "id" is silently ignored by Config::GetInt("Window.Backend.Id").

4. Switching to OpenGL requires patching ~/spaghettify.cfg.json before launch:

   "Window": {
       "Backend": {
           "Id": 1,
           "Name": "OpenGL"
       }
   }

This cannot be done from in-game Settings because the Settings menu is greyed out when Metal fails to render.

Build Environment

cmake 4.2.3, ninja 1.13.2, sdl2 2.32.10, glew 2.3.1
nlohmann-json 3.12.0, spdlog 1.17.0, boost 1.90.0_1
libpng 1.6.55, libzip 1.11.4_1, tinyxml2 11.0.0
AppleClang 17.0.0.17000604

Attachments

• crash-report-intel-mac.zip — crash reports (.ips) + system info + run logs
• Full crash report from Metal SIGFPE
• Full crash report from OpenGL SIGFPE (if separate .ips available)

[mkoterski]

Update: Tested WIP Discord build (spaghetti-mac-intel-x64.zip)

Tested the WIP macOS Intel build shared on Discord (spaghetti-mac-intel-x64.zip) — version 1.0.0-15-g7dba3c3c8.

SIGFPE crash: still present in WIP build

After ad-hoc signing and configuring the OpenGL backend ("Id": 1), the WIP build crashes identically to the original report — floating point exception on track load:

[14:07:14.966] [code_800029B0.c:192] [debug] Setup Race!
[14:07:14.966] [code_800029B0.c:193] [debug] Game Speed: 2
Loading Track 8
[Game.cpp] Clean World
[Track] Loading... mk:luigi_raceway
[RaceManager] Selected human item probability table mk:human_grand_prix
[RaceManager] Selected cpu item probability table mk:cpu_grand_prix
[1]    84840 floating point exception  ./Spaghettify baserom.us.z64

Menus render correctly under OpenGL. Metal still shows a black screen.

Comparison across all tested builds

Build	Version	Backend	Menus	Track Load
Source (original report)	1.0.0-13-gf7aab65da	Metal (Id 2)	Black screen	SIGFPE
Source (original report)	1.0.0-13-gf7aab65da	OpenGL (Id 1)	OK	SIGFPE
Nightly CI (original report)	—	Metal (Id 2)	Black screen	SIGFPE
Nightly CI (original report)	—	OpenGL (Id 1)	OK	SIGFPE
WIP Discord	1.0.0-15-g7dba3c3c8	Metal (Id 2)	Black screen	SIGFPE
WIP Discord	1.0.0-15-g7dba3c3c8	OpenGL (Id 1)	OK	SIGFPE

All six combinations crash with floating point exception at the same point: after [Track] Loading... mk:luigi_raceway and the item probability table setup.

Notes

• The crash path (code_800029B0.c:192 → Setup Race! → track load → SIGFPE) is unchanged between commits f7aab65da and 7dba3c3c8
• OpenGL config for the portable WIP build must be placed next to the binary, not in ~/spaghettify.cfg.json:

  {"Window": {"Backend": {"Id": 1, "Name": "OpenGL"}}}
  

Same hardware/OS as the original report (MacBookPro16,2, Intel Iris Plus Graphics, macOS Tahoe 26.3).

[coco875]

And the version distribute as release ?

[mkoterski]

And the version distribute as release ?

Same results as above. Crashes immediately once an actually racetrack loads. Doesn't matter whether the intro demo or if you start an actual race.
The libultra Intra, SpaghettiKart Options, in-game Menus and Player Select screen work fine.

[coco875]

thanks for the report will see that once I have time

[coco875]

can you try (once build have finish) artifact on #685 ? I think it has fix the crash

[mkoterski]

First of all THANKS. Rebuilt from main at f93dce2be (post-#685 merge). Version: 1.0.0-16-gf93dce2be.

SIGFPE: appears to be fixed

The build gets past the point where all previous builds crashed (code_800029B0.c:192 → Setup Race! → SIGFPE). That crash no longer occurs.

New crash: unordered_map::at: key not found

The game now terminates immediately after initialization with a different exception:

[18:38:50.493] [os.cpp:23] [error] Failed add SDL game controller mappings from "./gamecontrollerdb.txt" (Invalid RWops)
libc++abi: terminating due to uncaught exception of type std::out_of_range: unordered_map::at: key not found

This crash happens before the Editor loads and before any Registry invocations — much earlier in the startup sequence than the original SIGFPE.

Note: The gamecontrollerdb.txt error is not new — it appeared in all previous builds (pre-#685) and the game continued past it without issue. Comparing logs:

Build	gamecontrollerdb.txt error	Next step	Crash point
Pre-#685 (1.0.0-13-gf7aab65da)	Yes — Invalid RWops	Editor loads, Registry invocations proceed	SIGFPE on track load
Post-#685 (1.0.0-16-gf93dce2be)	Yes — Invalid RWops	Immediate termination	unordered_map::at: key not found

So the unordered_map crash appears to be a regression introduced by the libultraship update, not related to the controller mappings file.

I'll leave it up to you whether the SIGFPE fix is enough to close this issue and track the unordered_map crash separately, or if you'd prefer to keep everything here. Happy to open a new issue if that's cleaner.

Built with NON_PORTABLE=OFF, OpenGL backend ("Id": 1). Same hardware/OS: MacBookPro16,2, Intel Iris Plus, macOS Tahoe 26.3.

[coco875]

the sdl error are "normal", for unordered_map it's weird did you regerate file just in case ? Can you give the stacktrace of the crash ?

[mkoterski]

Yes, regenerated .o2r files (clean ExtractAssets + full rebuild) - same crash. Also confirmed gamecontrollerdb.txt loads fine now (314 mappings) - unrelated.

Here's the lldb backtrace:

* thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGABRT
    frame #0:  libsystem_kernel.dylib`__pthread_kill + 10
    frame #1:  libsystem_pthread.dylib`pthread_kill + 259
    frame #2:  libsystem_c.dylib`abort + 126
    frame #3:  libc++abi.dylib`__abort_message + 235
    frame #4:  libc++abi.dylib`demangling_terminate_handler() + 222
    frame #5:  libobjc.A.dylib`_objc_terminate() + 104
    frame #6:  libc++abi.dylib`std::__terminate(void (*)()) + 6
    frame #7:  libc++abi.dylib`__cxxabiv1::failed_throw(__cxxabiv1::__cxa_exception*) + 27
    frame #8:  libc++abi.dylib`__cxa_throw + 69
    frame #9:  Spaghettify`std::__1::__throw_out_of_range + 53
    frame #10: Spaghettify`Ship::Menu::MenuDrawItem(WidgetInfo&, unsigned int, UIWidgets::Colors) + 15792
    frame #11: Spaghettify`Ship::Menu::DrawElement() + 18988
    frame #12: Spaghettify`GameUI::PortMenu::Draw() + 16
    frame #13: Spaghettify`Ship::SpaghettiGui::DrawMenu() + 5691
    frame #14: Spaghettify`Ship::Gui::StartDraw() + 9089
    frame #15: Spaghettify`Graphics_PushFrame + 3958
    frame #16: Spaghettify`main + 5908
    frame #17: dyld`start + 3240

Looks like it's hitting a missing key in Ship::Menu::MenuDrawItem during the very first frame draw - possibly the updated libultraship menu system expecting something SpaghettiKart's menu definitions don't provide?

[coco875]

hmm the weird thing is when I test in debug I didn't get that kind of crash on my mac, will investigate later if there is something wrong it

[mkoterski]

Could be GPU-specific. I'm on Intel Iris Plus without discrete GPU, so the OpenGL codepath might be hitting something your Mac doesn't.

Happy to run a debug build on my end if that helps. Just let me know if you want me to:

• Rebuild with -DCMAKE_BUILD_TYPE=Debug and grab a more detailed backtrace (source files + line numbers)
• Inspect the failing unordered_map::at in lldb to find the exact key it's looking for

Or anything else I could/should try?

[mkoterski]

Ran a debug build and I think found the issue. It's a missing entry in the Audio API combobox map.

The active audio backend on macOS is COREAUDIO, but the comboMap in UIWidgets::Combobox<Ship::AudioBackend> only contains SDL and WASAPI:

(lldb) p *value
(Ship::AudioBackend) COREAUDIO

(lldb) p *this
(std::unordered_map<Ship::AudioBackend, const char *>) size=2 {
  [0] = (first = SDL, second = "SDL")
  [1] = (first = WASAPI, second = "Windows Audio Session API")
}

The crash happens at UIWidgets.h:475 when the menu tries to render the "Audio API" dropdown:

if (ImGui::BeginCombo(invisibleLabel, comboMap.at(*value), options.flags))
//                                    ^^^^^^^^^^^^^^^^^ COREAUDIO not in map

Full call chain: main.c:1146 (thread5_game_loop) -> rendering_init -> end_master_display_list -> create_gfx_task_structure -> Graphics_PushFrame -> Gui::StartDraw -> SpaghettiGui::DrawMenu -> PortMenu::Draw -> Menu::DrawElement (Menu.cpp:781) -> Menu::MenuDrawItem (Menu.cpp:278) -> UIWidgets::Combobox (UIWidgets.h:475) -> unordered_map::at -> throw out_of_range

Looks like the COREAUDIO backend was added to the AudioBackend enum in the libultraship update but wasn't added to the combobox display map. Probably just needs a {COREAUDIO, "CoreAudio"} entry alongside SDL and WASAPI?

[mkoterski]

Tested a local patch - added { Ship::AudioBackend::COREAUDIO, "CoreAudio" } to src/port/ui/MenuTypes.h:258 alongside SDL and WASAPI. That fixes the combobox crash, game gets past init.

Next blocker after patching: OpenGL renderer aborts on shader load:

[gfx_opengl.cpp:319] [error] Failed to load default fragment shader, missing f3d.o2r?

f3d.o2r doesn't exist anywhere in the repo or build output, and there's no cmake target that generates it. The updated libultraship references it across all three backends (OpenGL, Metal, DX11) - looks like a new shader archive dependency that the SpaghettiKart build pipeline doesn't produce yet.

So current status on my end after #685 + CoreAudio patch:

1. SIGFPE on track load - fixed by Update libultraship #685
2. unordered_map::at crash - fixed by adding COREAUDIO to MenuTypes.h
3. f3d.o2r missing - blocks renderer init on all backends (local source builds don't generate it?)