KinematicBody3D with move_and_slide() does unreliable is_on_floor() detection when nearly on platform's edge

[archerallstars]

Godot version:

• Godot 3.2.4 beta 5

OS/device including version:

• Windows 10 Home 64-bit, Version 20H2, OS build 19042.746
• Intel® UHD Graphics 620, Version 27.20.100.9126

Issue description:

Since GodotPhysics has an issue #45060 that causes the KinematicBody3D to move bumpy/jittering on a flat surface, as a solution, I put the is_on_floor() condition to only apply the gravity when the body is not on the floor.

However, when the body is nearly on the edge of the platform, the is_on_floor() flickeringly returns true and false even though the body is always on the floor, as shown in the screen recording below (from 0:17 onward):

2021-01-15.16-44-38.mp4

Steps to reproduce:

1. Open the reproduction project.
2. Run the scene.
3. See the print results in the output window.

Minimal reproduction project:

test.zip

[archerallstars]

For anyone who's still finding a way to work around this bug, you can use the RayCast node instead. My working setup as shown below:

[pouleyKetchoupp]

Confirmed in 3.2.4 beta 6.
Godot Physics: is_on_floor becomes inconsistent near the end of the platform.
Bullet: is_on_floor is inconsistent all along and the body jitters.

[Sv1nnet]

Btw I noticed that C# script handles IsOnFloor more correctly than GDScript.
Here are 2 project in C# and GDScript that demonstrate the different result of the same movement logic.

Godot version:

• v3.2.4.beta6.mono.official

1. Just move any player along the whole ground - in C# IsOnFloor detects the floor correctly, but GDScript doesn't;
2. But then move a player between blocks;
3. Let him just stand there;
4. Have the second player standing on another one and you see that IsOnFloor doesn't work correctly in both C# and GDScript;

C# - IsOnFloor_bug_cs.zip
GDScript - IsOnFloor_bug_gdscript.zip

[pouleyKetchoupp]

In 3.3.2, I can't reproduce this issue with Godot Physics (tested with the original MRP and in 2D with the test from #45219 (comment)).

Please confirm so this issue can be marked as Bullet-only.

[archerallstars]

In 3.3.2, I can't reproduce this issue with Godot Physics (tested with the original MRP and in 2D with the test from #45219 (comment)).

Please confirm so this issue can be marked as Bullet-only.

I also can't reproduce this issue in 3.3.2 as shown in the screen recording below:

2.mp4

[akien-mga]

So it seems the GodotPhysics bug was fixed in 3.3.2 or earlier (maybe 3.3).

The Bullet specific issue is a duplicate of #45058.