Action System (Input Handling)

[mario-deluna]

We require a simple abstraction system in VISU to handle inputs context dependent. My plan is to have 2 layers:

Action Map

• Binds an action identifier to a button or axis. For example

  $actionMap->bind('place_item', MouseButton::PRIMARY)

• Tracks all incoming input events to update internal states:
  • $actionMap->isButtonUp('place_item') -> is the button currently up (released)
  • $actionMap->isButtonDown('place_item') -> is the button currently pressed down
  • $actionMap->didButtonPress('place_item') -> has the button been pressed down since the last update
  • $actionMap->didButtonRelease('place_item') -> has the button been released since the last update

Action Contexts

• An action context holds an action map and can be switched dynamically. Allowing you to have multiple contexts for different input requirements:

  $contextMap->register('pause_menu', $menuActionMap);
  $contextMap->register('level_editor_main', $levelEditorMain);
  $contextMap->register('level_editor_selected', $levelEditorSelected);
  $contextMap->switchTo('level_editor_main');
  
  if ($contextMap->actions->didClick($clickSignal)) {
    if ($entity = $this->hitsEntity($clickSignal->pos)) {
        $this->selectedEntity = $entity;
        $contextMap->switchTo('level_editor_selected');
    }
  }
  
  if ($contextMap->actions->isButtonDown('rotate_left')) {
    // rotate...
  }
  
  if ($contextMap->actions->didButtonPress('copy')) {
    // copy...
  }
  // etc..

Action Queue

Finally for more complex actions, especially actions that require parameters I suggest an action queue:

$actionQueue = new ActionQueue();

// ... 
$this->dispatcher->register('input.click', function(ClickSignal $signal) 
{
     if ($entity = $this->matchesSomeConditions($signal)) {
         $actionQueue->push(new SelectEntityAction($entity));
     }
});

// in the update loop
function update(Entities $entities)
{
    while($action = $actionQueue->pop()) {
        if ($actionQueue instanceof SelectEntityAction) {
            // .. do whatever is needed
        }
    }
}

[mario-deluna]

@borisstock First version:

https://github.com/phpgl/visu/commit/1c11d25363e8070c3c74357493c5b85ff53ce6a2

und

https://github.com/phpgl/php-towerdefense/commit/b120f30600cddc38110eecf8e0c8543cbb0b4103

A key map can be defined over the container:

input.actions.level_editor.selected: VISU\OS\InputActionMap()
     - importArrayMap({
         place: '#click',
         rotate_left: '@Key::COMMA',
         rotate_right: '@Key::PERIOD',
         scale_up: '@Key::K',
         scale_down: '@Key::L',
         delete: '@Key::BACKSPACE',
         copy: '@Key::C',

System can then use the input context like so:

if ($inputContext->actions->isButtonDown('rotate_left')) {
    $transform->orientation->rotate(0.01, new Vec3(0, 1, 0));
} else if ($inputContext->actions->isButtonDown('rotate_right')) {
    $transform->orientation->rotate(-0.01, new Vec3(0, 1, 0));
}

if ($inputContext->actions->isButtonDown('scale_up')) {
    $transform->scale += 0.1;
} else if ($inputContext->actions->isButtonDown('scale_down')) {
    $transform->scale -= 0.1;
}

if ($inputContext->actions->didButtonRelease('copy')) {
    // ...
}

[mario-deluna]

Combination of:

• Input Action Maps
• Input Context Claiming
• And Signal Queues

Should cover most cases for input handling for now.