The GridMap freezes if meshes are changed frequently

[Valeryn4]

Godot version

3.3.2-stable

System information

Windows 10, GTX 1050ti, GLES3

Issue description

GridMap freezes and throws errors if grids change frequently

ERROR: get: Condition "!id_map.has(p_rid.get_data())" is true. Returned: __null
   At: ./core/rid.h:150
ERROR: body_add_shape: Condition "!body" is true.
   At: modules/bullet/bullet_physics_server.cpp:504

see this video: https://www.youtube.com/watch?v=ckImAKQaIuw

Maybe this is related to issue?

Steps to reproduce

Create a GridMap project and change tiles frequently, in large numbers in one frame.
Decreasing the octave will increase the errors.

Minimal reproduction project

This project. Run Test.tscn
SCP Manager.zip

LEFT_CLICK - Set block/Remove block
RIGHT_CLICK - Move Camera
WHILE_MOUSE - Zoom

GitHub: https://github.com/Valeryn4/Godot-GridMap-Err

[Valeryn4]

And maybe this problem: #33648

[Calinou]

Can you reproduce this if you change the 3D physics engine to GodotPhysics in the Project Settings?

[Valeryn4]

Can you reproduce this if you change the 3D physics engine to GodotPhysics in the Project Settings?

yes

ERROR: get: Condition "!id_map.has(p_rid.get_data())" is true. Returned: __null
   At: ./core/rid.h:150 @ get()
ERROR: body_clear_shapes: Condition "!body" is true.
   At: servers/physics/physics_server_sw.cpp:614 @ body_clear_shapes()

[Valeryn4]

may be problem in: modules/gridmap/grid_map.cpp in g.static_body ?

bool GridMap::_octant_update(const OctantKey &p_key) {
	....

	//erase body shapes
420:	PhysicsServer::get_singleton()->body_clear_shapes(g.static_body); /* <<<< IS OK! */
        ....
                                                                            /* \/\/ IS NOT OK*/
496:			PhysicsServer::get_singleton()->body_add_shape(g.static_body, shapes[i].shape->get_rid(), xform * shapes[i].local_transform); 

I don't have a GDB debugger at hand right now to trace the life cycle of STATIC_BODY

[Valeryn4]

I've done some experiments.
Remove ALL physics body in meshlib.
Disable all collision layer.

ERROR: get: Condition "!id_map.has(p_rid.get_data())" is true. Returned: __null
   At: ./core/rid.h:150
ERROR: body_clear_shapes: Condition "!body" is true.
   At: modules/bullet/bullet_physics_server.cpp:567
ERROR: getornull: Condition "!id_map.has(p_rid.get_data())" is true. Returned: __null
   At: ./core/rid.h:160
ERROR: mesh_clear: Condition "!mesh" is true.
   At: drivers/gles3/rasterizer_storage_gles3.cpp:4401
ERROR: Invalid ID.
   At: modules/bullet/bullet_physics_server.cpp:1535

I deleted and created a large number of cells - caused errors and visual glitches.

If I delete or create cells one by one per frame - no problem.

Perhaps the problem is not in physics, but in the work of the octaves of the "GridMap" itself

[Valeryn4]

HEY! may be is problems? @Calinou

void GridMap::_update_octants_callback() { 

	if (!awaiting_update)
		return;

	List<OctantKey> to_delete;
	for (Map<OctantKey, Octant *>::Element *E = octant_map.front(); E; E = E->next()) {

		if (_octant_update(E->key())) { /*free g.static_body <<<<<<<*/
			to_delete.push_back(E->key()); /*push remove queue <<<<<<<<<<*/
		}
	}

	while (to_delete.front()) {
		octant_map.erase(to_delete.front()->get()); /* erase FRONT queue <<<<<<*/
		to_delete.pop_back(); /* pop BACK! skip empty octans <<<<<<< */
	}
	...
}

fixed

while (to_delete.front()) {
		octant_map.erase(to_delete.front()->get()); //erase FRONT queue
		to_delete.pop_front(); // FIXXXXXX ?
	}

[Calinou]

HEY! may be is problems?

I don't use GridMaps extensively or have experience dealing with the physics server, so I don't know. cc @pouleyKetchoupp

[Valeryn4]

The problem is logical.
We free the element from the top, and then we pop the last element.
If you extract several octans at once in one frame, a problem arises.