NavigationMeshInstance crash baking static colliders with PlaneShape and ConvexPolygon

[dweremeichik]

Godot version

v3.5.stable.official [991bb6a]

System information

Debian 11 (bullseye), OpenGL ES 3.0 Renderer: Mesa DRI Intel(R) HD Graphics 4400 (HSW GT2) Async. shader compilation: OFF

Issue description

Editor crash when attempting to bake a NavigationMeshInstance with Parsed Geometry (geometry_parsed_geometry_type) set to Static Colliders with a PlaneShape and ConvexPolygon as descendants.

================================================================
handle_crash: Program crashed with signal 11
Engine version: Godot Engine v3.5.stable.official (991bb6ac74ac8c09d7683041b50a8ced3a2defb1)
Dumping the backtrace. Please include this when reporting the bug to the project developer.
[1] /lib/x86_64-linux-gnu/libc.so.6(+0x38d60) [0x7f25190f1d60] (??:0)
[2] godot() [0x11205ab] (??:0)
[3] godot() [0xfda0cb] (??:0)
[4] godot() [0xfdc752] (??:0)
[5] godot() [0xabffd9] (??:0)
[6] godot() [0x2e6fd89] (??:0)
[7] godot() [0x2e7b14a] (??:0)
[8] godot() [0x20012ea] (??:0)
[9] godot() [0x20025a0] (??:0)
[10] godot() [0x20028ee] (??:0)
[11] godot() [0x179c895] (??:0)
[12] godot() [0x2e6f937] (??:0)
[13] godot() [0x2015381] (??:0)
[14] godot() [0x201ba21] (??:0)
[15] godot() [0x201dd25] (??:0)
[16] godot() [0x201dffb] (??:0)
[17] godot() [0xd08ad5] (??:0)
[18] godot() [0x2e6fd89] (??:0)
[19] godot() [0x2e61cbe] (??:0)
[20] godot() [0x1fb1a5b] (??:0)
[21] godot() [0x1fca810] (??:0)
[22] godot() [0xa40c0b] (??:0)
[23] godot() [0xa41e59] (??:0)
[24] godot() [0xa46f74] (??:0)
[25] godot() [0xa015dc] (??:0)
[26] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xea) [0x7f25190dcd0a] (??:0)
[27] godot() [0xa13fde] (??:0)
-- END OF BACKTRACE --
================================================================

Steps to reproduce

Your best bet is to simply use the attached MRP, that being said:

Create this structure:

The first collision shape should be a PlaneShape.
MeshInstance2 is translated 1 unit in the Y direction.
The second collision shape is a ConvexPolygon and was generated from MeshInstance2; its settings look like:

(If you change the z value for any of the four points, the crash no longer occurs.)

Under NavigationMeshInstance create a NavMesh. Change Geoemtry -> Parsed Geometry to Static Colliders. Click Bake NavMesh. The crash should occur.

Minimal reproduction project

nav_bake_crash_mrp.zip

[timothyqiu]

Probably related to recastnavigation/recastnavigation#514

[smix8]

PlaneShape or even ConvexPolygon is not the problem here. The first is ignored by the parsing anyway as it is deprecated.

Rotating your shape even by 0.001 prevents the crash. It crashes because source geometry aligned 100% with the y-axis with no depth is invalid and it fails the ReCast span calculation. This is not specific to ConvexPolygon, it will happen with any other node type in Godot that allows to set the geometry depth to zero. Since Godot has no checks for this situation it adds the corrupted source geometry regardless which crashes ReCast that also has no check for it. What @timothyqiu linked prevents the crash on the ReCast side but it does not change the fact that this source geometry is illogical and should never be used in the first place.

[grahamboree]

This can happen when the extent of the input geometry bounding box is less than half the CellSize. This generates a heightfield size of 0 on either the x or z axis, and causes Recast to crash.

Here's another sample project that causes a crash in the Recast code.
GodotRecastTest.zip

This has been fixed upstream in Recast as part of recastnavigation/recastnavigation@3901c58. I've submitted a PR (#69189) to update the Recast integration in Godot to fix this issue.