Archive 19/01/2023.

Weird Update() execution after node being removed

CE184

I found the component Update() function is still executed one time after the component/node is removed. And the override base class function is not executed at that place.

I have a base component class for character control:

class CharacterControllerBase : public LogicComponent {
 URHO3D_OBJECT(CharacterControllerBase, LogicComponent)
 ...

And another derived class

class CharacterControllerPlayer : public CharacterControllerBase {
 URHO3D_OBJECT(CharacterControllerPlayer, CharacterControllerBase)
 ...

In the base class, Update() function is:

void CharacterControllerBase::Update(float timestep) {
  LogicComponent::Update(timestep);
  // ...
  spdlog::debug("base charcter_control_input_ type: {}",
                magic_enum::enum_name(character_control_input_->GetInputType()));
  if (character_control_input_->GetInputType() == kPlayer) {
    spdlog::debug("base charcter_control_input_: {}", character_control_input_);
    // ...
  }
}

And in the derived class, Update() function is:

void CharacterControllerPlayer::Update(float timestep) {
  CharacterControllerBase::Update(timestep);  // not called?
  spdlog::debug("charcter_control_input_: {}", character_control_input_);
  // ...
}

During the program, I created this derived component CharacterControllerPlayer to attached to the character node, and then remove the whole node when character dies:

  spdlog::debug("{}: Character died.", node_->GetName().CString());
  node->Remove();

I am confused by the log dump

// Before node is removed, Update() execution seems normal.
[2021-01-06 10:26:42.531] [debug] base charcter_control_input_ type: kPlayer
[2021-01-06 10:26:42.531] [debug] base charcter_control_input_: 0x7fc0dd9a7c60
[2021-01-06 10:26:42.531] [debug] charcter_control_input_: 0x7fc0dd9a7c60
...
[2021-01-06 10:26:42.584] [debug] Player: Character died.
[2021-01-06 10:26:42.586] [debug] charcter_control_input_: 0x0
// Notice character_control_input_ is another component attached to the node and is nullptr after node is removed.

After player dies and the node is removed. The CharacterControllerPlayer::Update() is still called! However, the base class function CharacterControllerBase::Update(timestep); is in the override function but is not called?!

SirNate0

In the // ... in the base class do you return early at some point? Maybe on some null pointer check or something?

CE184

You are right! the check death logic is there and node->Remove() is called during that time. Stupid me.