Flat meshes lead to runtime error and crash

[rLaister]

The ComputeFloat Function in GenerateConvexMeshes crashes our application when a mesh that is very flat (0.1 mm) but still has a good amount of triangles (e.g. > 7000 vertices, > 45000 triangles) with the following message:

To reproduce call GenerateConvexMeshes with a flat (0.1 mm z-height) mesh that has the described amount of triangles, then the Player Application crashes.

Expected behaviour is for the Application not to crash, and the ComputeFloat function to return an error message if it cannot compute the convex meshes.

• Unity Version: 2021.3.9
• Unity machine OS + version: Windows 10
• libvhacd.dll has no version in properties. license copyright is 2011

[eliphatfs]

Found similar behavior here.

[eliphatfs]

Stacktrace:

  at <unknown> <0xffffffff>
  at (wrapper managed-to-native) MeshProcess.VHACD.ComputeFloat (void*,single*,uint,uint*,uint,MeshProcess.VHACD/Parameters*) [0x00010] in <0cfc73e9a17d4c99a663b89f7ff6b29e>:0
  at MeshProcess.VHACD.GenerateConvexMeshes (UnityEngine.Mesh) [0x0006b] in D:\SketchPad\unity\Library\PackageCache\com.unity.robotics.vhacd@854b3d8209\Runtime\VHACD.cs:148
  at ObjaverseMenu/<<Enter>g__co|13_0>d.MoveNext () [0x00857] in D:\SketchPad\unity\Assets\ProjectConcept\ObjaverseMenu.cs:228
  at UnityEngine.SetupCoroutine.InvokeMoveNext (System.Collections.IEnumerator,intptr) [0x00027] in <a78ba17154144f538987598c967cc088>:0
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void_object_intptr (object,intptr,intptr,intptr) [0x00027] in <a78ba17154144f538987598c967cc088>:0

=================================================================
Got a SIGSEGV while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries 
used by your application.
=================================================================

Received signal SIGSEGV
Stack trace:
0x00007ff96e0a31ee (libvhacd) GetNConvexHulls
0x00007ff96e0a4536 (libvhacd) GetNConvexHulls
0x00007ff96e0a8339 (libvhacd) GetNConvexHulls
0x0000024db01b868e (Mono JIT Code) (wrapper managed-to-native) MeshProcess.VHACD:ComputeFloat (void*,single*,uint,uint*,uint,MeshProcess.VHACD/Parameters*)
0x0000024db01b76d3 (Mono JIT Code) [VHACD.cs:148] MeshProcess.VHACD:GenerateConvexMeshes (UnityEngine.Mesh) 
0x0000024be04af203 (Mono JIT Code) [ObjaverseMenu.cs:228] ObjaverseMenu/<<Enter>g__co|13_0>d:MoveNext () 
0x0000024c2d02859c (Mono JIT Code) UnityEngine.SetupCoroutine:InvokeMoveNext (System.Collections.IEnumerator,intptr)
0x0000024c2d0286c7 (Mono JIT Code) (wrapper runtime-invoke) <Module>:runtime_invoke_void_object_intptr (object,intptr,intptr,intptr)
0x00007ff94a2c00e0 (mono-2.0-bdwgc) [mini-runtime.c:2849] mono_jit_runtime_invoke 
0x00007ff94a242ac2 (mono-2.0-bdwgc) [object.c:2921] do_runtime_invoke 
0x00007ff94a24bb1f (mono-2.0-bdwgc) [object.c:2968] mono_runtime_invoke 
0x00007ff67a08f064 (Unity) scripting_method_invoke
0x00007ff67a08a161 (Unity) ScriptingInvocation::Invoke
0x00007ff67a041d5c (Unity) Coroutine::Run
0x00007ff67a03efac (Unity) Coroutine::ContinueCoroutine
0x00007ff679bb8a54 (Unity) DelayedCallManager::Update
0x00007ff679db7f79 (Unity) `InitPlayerLoopCallbacks'::`2'::UpdateScriptRunDelayedDynamicFrameRateRegistrator::Forward
0x00007ff679d9f06a (Unity) ExecutePlayerLoop
0x00007ff679d9f1d9 (Unity) ExecutePlayerLoop
0x00007ff679da6239 (Unity) PlayerLoop
0x00007ff67aa83bf1 (Unity) PlayerLoopController::UpdateScene
0x00007ff67aa81e19 (Unity) Application::TickTimer
0x00007ff67af00981 (Unity) MainMessageLoop
0x00007ff67af04b21 (Unity) WinMain
0x00007ff67c600f6e (Unity) __scrt_common_main_seh
0x00007ff9abc926bd (KERNEL32) BaseThreadInitThunk
0x00007ff9acc8dfb8 (ntdll) RtlUserThreadStart