src/animation/state_machine.cpp

#include "rive/animation/state_machine.hpp"
#include "rive/animation/layer_state.hpp"
#include "rive/animation/state_transition.hpp"
#include "rive/artboard.hpp"
#include "rive/importers/artboard_importer.hpp"
#include "rive/animation/state_machine_layer.hpp"
#include "rive/animation/state_machine_input.hpp"
#include "rive/animation/state_machine_listener.hpp"
#include "rive/scripted/scripted_object.hpp"
#include "rive/scripted/scripted_interpolator.hpp"
#include "rive/data_bind/data_bind.hpp"
#include "rive/animation/layer_state.hpp"
#include "rive/animation/state_transition.hpp"
#include "rive/animation/layer_state_flags.hpp"
#ifndef WITH_RIVE_EDITOR
#include "rive/animation/transition_condition.hpp"
#include "rive/animation/transition_property_viewmodel_comparator.hpp"
#include "rive/animation/transition_self_comparator.hpp"
#include "rive/animation/transition_value_artboard_comparator.hpp"
#include "rive/animation/transition_value_asset_comparator.hpp"
#include "rive/animation/transition_value_boolean_comparator.hpp"
#include "rive/animation/transition_value_color_comparator.hpp"
#include "rive/animation/transition_value_enum_comparator.hpp"
#include "rive/animation/transition_value_number_comparator.hpp"
#include "rive/animation/transition_value_string_comparator.hpp"
#include "rive/animation/transition_value_trigger_comparator.hpp"
#include "rive/animation/transition_viewmodel_condition.hpp"
#include "rive/data_bind/bindable_property_boolean.hpp"
#include "rive/data_bind/bindable_property_color.hpp"
#include "rive/data_bind/bindable_property_enum.hpp"
#include "rive/data_bind/bindable_property_integer.hpp"
#include "rive/data_bind/bindable_property_number.hpp"
#include "rive/data_bind/bindable_property_string.hpp"
#include "rive/data_bind/bindable_property_trigger.hpp"
#include "rive/data_bind_flags.hpp"
#include <unordered_set>
#endif

#include <algorithm>

using namespace rive;

#ifndef WITH_RIVE_EDITOR
// Settle-safety, see LayerState::transitionsSettleSafe. A comparator is tracked
// when every value it reads can only change through a dirty event on one of the
// instance's own data binds, or a change of its data context: both unsettle the
// instance's layers. Exact type keys on purpose, so a new condition or
// comparator type starts out untracked (always searched) rather than
// inheriting its parent's answer. `untracked` holds the objects that state
// machine binds write without going through that path.
static bool isTrackedComparator(
    TransitionComparator* comparator,
    const std::unordered_set<const Core*>& untracked)
{
  if (comparator == nullptr)
  {
    // A missing side compares as ConditionComparisonNone: always false.
    return true;
  }
  if (untracked.count(comparator) != 0)
  {
    return false;
  }
  switch (comparator->coreType())
  {
    case TransitionPropertyViewModelComparatorBase::typeKey:
    {
      auto bindable = comparator->as<TransitionPropertyViewModelComparator>()
                          ->bindableProperty();
      if (bindable == nullptr || untracked.count(bindable) != 0)
      {
        return false;
      }
      switch (bindable->coreType())
      {
        case BindablePropertyNumberBase::typeKey:
        case BindablePropertyIntegerBase::typeKey:
        case BindablePropertyBooleanBase::typeKey:
        case BindablePropertyStringBase::typeKey:
        case BindablePropertyColorBase::typeKey:
        case BindablePropertyEnumBase::typeKey:
        case BindablePropertyTriggerBase::typeKey:
          return true;
        default:
          // Asset, artboard and view model bindables are also written
          // outside their binds' dirty path.
          return false;
      }
    }
    case TransitionValueNumberComparatorBase::typeKey:
    case TransitionValueBooleanComparatorBase::typeKey:
    case TransitionValueStringComparatorBase::typeKey:
    case TransitionValueColorComparatorBase::typeKey:
    case TransitionValueEnumComparatorBase::typeKey:
    case TransitionValueTriggerComparatorBase::typeKey:
    case TransitionValueAssetComparatorBase::typeKey:
    case TransitionValueArtboardComparatorBase::typeKey:
    case TransitionSelfComparatorBase::typeKey:
      return true;
    default:
      // Component and artboard property comparators read live values
      // that nothing reports to the state machine.
      return false;
  }
}

static bool isTrackedCondition(
    TransitionCondition* condition,
    const std::unordered_set<const Core*>& untracked)
{
  // Only view model conditions are tracked. State machine inputs, focus,
  // artboard and scripted conditions keep the full search.
  if (condition == nullptr ||
      condition->coreType() != TransitionViewModelConditionBase::typeKey)
  {
    return false;
  }
  auto viewModelCondition = condition->as<TransitionViewModelCondition>();
  return isTrackedComparator(viewModelCondition->leftComparator(), untracked) &&
         isTrackedComparator(viewModelCondition->rightComparator(), untracked);
}

static bool isSettleSafe(
    const LayerState* state,
    const std::unordered_set<const Core*>& untracked)
{
  // A random state can allow transitions and still take none (a draw of
  // exactly 1.0 falls through the weights), and must be searched again.
  if ((static_cast<LayerStateFlags>(state->flags()) &
       LayerStateFlags::Random) == LayerStateFlags::Random)
  {
    return false;
  }
  for (size_t i = 0, count = state->transitionCount(); i < count; i++)
  {
    auto transition = state->transition(i);
    if (transition == nullptr || transition->isDisabled())
    {
      continue;
    }
    for (size_t j = 0, conditions = transition->conditionCount();
         j < conditions;
         j++)
    {
      if (!isTrackedCondition(transition->condition(j), untracked))
      {
        return false;
      }
    }
  }
  return true;
}

// Whether a view model condition on one of `state`'s transitions answers yes
// to `reads`.
static bool anyViewModelCondition(
    const LayerState* state,
    bool (TransitionViewModelCondition::*reads)() const)
{
  for (size_t i = 0, count = state->transitionCount(); i < count; i++)
  {
    auto transition = state->transition(i);
    if (transition == nullptr)
    {
      continue;
    }
    for (size_t j = 0, conditions = transition->conditionCount();
         j < conditions;
         j++)
    {
      auto condition = transition->condition(j);
      if (condition != nullptr &&
          condition->coreType() == TransitionViewModelConditionBase::typeKey &&
          (condition->as<TransitionViewModelCondition>()->*reads)())
      {
        return true;
      }
    }
  }
  return false;
}

// Only the flags are read here, since a layer's animations and target states
// may not be resolved yet when this runs (see onAddedClean).
static bool transitionsIgnoreTime(const LayerState* state)
{
  for (size_t i = 0, count = state->transitionCount(); i < count; i++)
  {
    auto transition = state->transition(i);
    if (transition != nullptr && !transition->isDisabled() &&
        transition->enableExitTime())
    {
      return false;
    }
  }
  return true;
}
#endif

StateMachine::StateMachine() {}

StateMachine::~StateMachine() {}

StatusCode StateMachine::onAddedDirty(CoreContext* context)
{
  StatusCode code;
  for (auto& object : m_Inputs)
  {
    if ((code = object->onAddedDirty(context)) != StatusCode::Ok)
    {
      return code;
    }
  }
  for (auto& object : m_Layers)
  {
    if ((code = object->onAddedDirty(context)) != StatusCode::Ok)
    {
      return code;
    }
  }
  for (auto& object : m_Listeners)
  {
    if ((code = object->onAddedDirty(context)) != StatusCode::Ok)
    {
      return code;
    }
  }
  return StatusCode::Ok;
}

StatusCode StateMachine::onAddedClean(CoreContext* context)
{
  StatusCode code;
  for (auto& object : m_Inputs)
  {
    if ((code = object->onAddedClean(context)) != StatusCode::Ok)
    {
      return code;
    }
  }
  for (auto& object : m_Layers)
  {
    if ((code = object->onAddedClean(context)) != StatusCode::Ok)
    {
      return code;
    }
  }
  for (auto& object : m_Listeners)
  {
    if ((code = object->onAddedClean(context)) != StatusCode::Ok)
    {
      return code;
    }
  }
#ifndef WITH_RIVE_EDITOR
  // Classified here, once the whole artboard has been read, from what
  // reading attaches: conditions, comparators, bindables and flags. Importers
  // resolve later still (a layer's only when the next layer arrives, which
  // can be in the next artboard), so nothing they fill in, like a state's
  // animation, is read here. Bindables fed once never report later source
  // changes, and binds aimed at anything but a bindable write the shared
  // definition (a comparator's constant, say) directly.
  std::unordered_set<const Core*> untracked;
  for (auto& dataBind : m_dataBinds)
  {
    auto target = dataBind->target();
    bool bindsOnce = enums::is_flag_set(
        static_cast<DataBindFlags>(dataBind->flags()),
        DataBindFlags::Once);
    if (target != nullptr && (bindsOnce || !target->is<BindableProperty>()))
    {
      untracked.insert(target);
    }
  }
  for (auto& layer : m_Layers)
  {
    for (size_t i = 0, count = layer->stateCount(); i < count; i++)
    {
      auto state = layer->state(i);
      if (state != nullptr)
      {
        state->transitionsSettleSafe(isSettleSafe(state, untracked));
        state->transitionsIgnoreTime(transitionsIgnoreTime(state));
        m_readsComponentTriggers = m_readsComponentTriggers ||
                                   anyViewModelCondition(
                                       state,
                                       &TransitionViewModelCondition::
                                           readsComponentTrigger);
        m_readsPendingChanges = m_readsPendingChanges ||
                                anyViewModelCondition(
                                    state,
                                    &TransitionViewModelCondition::
                                        readsPendingChange);
        addScriptedInterpolators(state);
      }
    }
  }
#endif
  return StatusCode::Ok;
}

// A scripted interpolator on a transition runs per StateMachineInstance, like
// the machine's other scripted objects: registering it here makes every
// instance clone it (inputs bound against that instance) and initialize it.
// Transitions resolved their interpolator in onAddedDirty. Several
// transitions can share one, so each is registered once.
void StateMachine::addScriptedInterpolators(const LayerState* state)
{
  for (size_t i = 0, count = state->transitionCount(); i < count; i++)
  {
    auto transition = state->transition(i);
    if (transition == nullptr)
    {
      continue;
    }
    auto interpolator = transition->interpolator();
    if (interpolator == nullptr || !interpolator->is<ScriptedInterpolator>())
    {
      continue;
    }
    ScriptedObject* scripted = interpolator->as<ScriptedInterpolator>();
    if (std::find(
            m_scriptedObjects.begin(),
            m_scriptedObjects.end(),
            scripted) == m_scriptedObjects.end())
    {
      addScriptedObject(scripted);
    }
  }
}

StatusCode StateMachine::import(ImportStack& importStack)
{
  auto artboardImporter = importStack.latest<ArtboardImporter>(
      ArtboardBase::typeKey);
  if (artboardImporter == nullptr)
  {
    return StatusCode::MissingObject;
  }
  artboardImporter->addStateMachine(this);
  return Super::import(importStack);
}

void StateMachine::addLayer(std::unique_ptr<StateMachineLayer> layer)
{
  m_Layers.push_back(std::move(layer));
}

void StateMachine::addInput(std::unique_ptr<StateMachineInput> input)
{
  m_Inputs.push_back(std::move(input));
}

void StateMachine::addListener(std::unique_ptr<StateMachineListener> listener)
{
  m_Listeners.push_back(std::move(listener));
}

void StateMachine::addDataBind(std::unique_ptr<DataBind> dataBind)
{
  m_dataBinds.push_back(std::move(dataBind));
}

const StateMachineInput* StateMachine::input(std::string name) const
{
  for (auto& input : m_Inputs)
  {
    if (input->name() == name)
    {
      return input.get();
    }
  }
#ifdef WITH_RIVE_EDITOR
  for (auto* input : m_editorInputs)
  {
    if (input != nullptr && input->name() == name)
    {
      return input;
    }
  }
#endif
  return nullptr;
}

const StateMachineInput* StateMachine::input(size_t index) const
{
  if (index < m_Inputs.size())
  {
    return m_Inputs[index].get();
  }
#ifdef WITH_RIVE_EDITOR
  if (m_Inputs.empty() && index < m_editorInputs.size())
  {
    return m_editorInputs[index];
  }
#endif
  return nullptr;
}

const StateMachineLayer* StateMachine::layer(std::string name) const
{
  for (auto& layer : m_Layers)
  {
    if (layer->name() == name)
    {
      return layer.get();
    }
  }
#ifdef WITH_RIVE_EDITOR
  for (auto* layer : m_editorLayers)
  {
    if (layer != nullptr && layer->name() == name)
    {
      return layer;
    }
  }
#endif
  return nullptr;
}

const StateMachineLayer* StateMachine::layer(size_t index) const
{
  if (index < m_Layers.size())
  {
    return m_Layers[index].get();
  }
#ifdef WITH_RIVE_EDITOR
  if (m_Layers.empty() && index < m_editorLayers.size())
  {
    return m_editorLayers[index];
  }
#endif
  return nullptr;
}

const StateMachineListener* StateMachine::listener(size_t index) const
{
  if (index < m_Listeners.size())
  {
    return m_Listeners[index].get();
  }
#ifdef WITH_RIVE_EDITOR
  if (m_Listeners.empty() && index < m_editorListeners.size())
  {
    return m_editorListeners[index];
  }
#endif
  return nullptr;
}

const DataBind* StateMachine::dataBind(size_t index) const
{
  if (index < m_dataBinds.size())
  {
    return m_dataBinds[index].get();
  }
#ifdef WITH_RIVE_EDITOR
  if (m_dataBinds.empty() && index < m_editorDataBinds.size())
  {
    return m_editorDataBinds[index];
  }
#endif
  return nullptr;
}

void StateMachine::addScriptedObject(ScriptedObject* object)
{
  m_scriptedObjects.push_back(object);
}