Expose a way to set the color of Shape3D debug mesh

[Zylann]

This allows scripts and extensions that don't use nodes to still obtain a colored mesh using get_debug_mesh, so they can keep drawing them when the debug option is enabled.

Since #90644, debug shapes of my voxel terrain plugin stopped showing. I found out it's because now Shape3D has customizable colors, but they default to transparent black, which is invisible (I assume it is exploited to mean "null" in some places).
Shape3D.get_debug_mesh is where that color is used. So the only way to make it generate with the right color is to expose set_debug_color. This is also the way CollisionShape3D nodes are working.

An alternative would be to pass these options directly to get_debug_mesh, but that would break compatibility.

[dsnopek]

This seems to have the same goal as PR #100317?

[Zylann]

It looks similar, however #100317 does not expose methods of Shape3D, which is necessary when nodes are not used.

[Bromeon]

Is there already consensus on moving forward with either this or #100317? The absence of Shape3D::set_debug_color() breaks some GDExtension codegen in Release mode 🙂

[Zylann]

Actually there is no "either", both PRs can be done. They each do different things but they are not conflicting (even though there might need to be some code merging).

[dalexeev]

If you are interested, could you also update the following methods?

godot/scene/2d/physics/collision_shape_2d.cpp

Lines 232 to 235 in 89001f9

	Color CollisionShape2D::_get_default_debug_color() const {
	const SceneTree *st = SceneTree::get_singleton();
	return st ? st->get_debug_collisions_color() : Color(0.0, 0.0, 0.0, 0.0);
	}

godot/scene/3d/physics/collision_shape_3d.cpp

Lines 252 to 255 in 89001f9

	Color CollisionShape3D::_get_default_debug_color() const {
	const SceneTree *st = SceneTree::get_singleton();
	return st ? st->get_debug_collisions_color() : Color(0.0, 0.0, 0.0, 0.0);
	}

const SceneTree *st = SceneTree::get_singleton();
return st ? st->get_debug_collisions_color() : GLOBAL_GET("debug/shapes/collision/shape_color");

[Zylann]

@dalexeev added.