Class: RGame::Engine::ActionMapper

Inherits:
Object
  • Object
show all
Defined in:
lib/rgame/engine/input/action_mapper.rb

Overview

Polls an InputBackend through a binding map and produces an Actions snapshot. The map is { action_name => { axis: %i[neg pos] } | { button: %i[ids] } }; physical ids are decoupled from any backend's constants (the backend resolves them), so remapping is just swapping this data.

Pure logic: the backend is duck-typed — the whole interface is down?(physical_id) — so a test passes a fake and a game passes RGame::Core::Input.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(map) ⇒ ActionMapper

Returns a new instance of ActionMapper.



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# File 'lib/rgame/engine/input/action_mapper.rb', line 16

def initialize(map)
  @map = map
  # One reusable snapshot: there's exactly one input state per tick, so we
  # mutate these in place each poll instead of allocating (after the first
  # poll warms the hash keys, steady-state polling allocates nothing).
  # `@prev_held` carries last frame's button state so Actions can answer edge
  # queries (pressed?/released?).
  @held = {}
  @prev_held = {}
  @axes = {}
  @actions = Actions.new(held: @held, axes: @axes, prev_held: @prev_held)
end

Instance Attribute Details

#map ⇒ Object

Returns the value of attribute map.



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# File 'lib/rgame/engine/input/action_mapper.rb', line 14

def map
  @map
end

Instance Method Details

#poll(backend) ⇒ Object 



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# File 'lib/rgame/engine/input/action_mapper.rb', line 29

def poll(backend)
  # Snapshot this frame's held state as "previous" before recomputing it
  # (in-place copy: no allocation once the keys exist).
  @held.each { |name, down| @prev_held[name] = down }

  @map.each do |name, binding|
    if (axis = binding[:axis])
      neg, pos = axis
      @axes[name] = (backend.down?(pos) ? 1.0 : 0.0) - (backend.down?(neg) ? 1.0 : 0.0)
    end
    @held[name] = binding[:button].any? { |b| backend.down?(b) } if binding[:button]
  end

  @actions
end