ANIM_evaluation.hh

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/* SPDX-FileCopyrightText: 2023 Blender Developers
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

#pragma once
 
#include "BLI_map.hh"
#include "BLI_string_ref.hh"
 
#include "ANIM_action.hh"
 
namespace blender::animrig {
 
/* Identifies the property that an evaluated animation value is for.
 *
 * This could be replaced with either `FCurveIdentifier` or `RNAPath`.  However,
 * `FCurveIdentifier` is semantically meant to represent an fcurve itself rather
 * than the property an fcurve might be for, and moreover not all animation will
 * necessarily come from fcurves in the future anyway.  `RNAPath` would be more
 * semantically appropriate, but it stores a full copy of the string component
 * of the path, and here we want to be lighter than that and use a string
 * reference.
 */
class PropIdentifier {
 public:
  StringRefNull rna_path;
  int array_index;
 
  PropIdentifier() = default;
 
  PropIdentifier(const StringRefNull rna_path, const int array_index)
      : rna_path(rna_path), array_index(array_index)
  {
  }
 
  bool operator==(const PropIdentifier &other) const
  {
    return rna_path == other.rna_path && array_index == other.array_index;
  }
  bool operator!=(const PropIdentifier &other) const
  {
    return !(*this == other);
  }
 
  uint64_t hash() const
  {
    return get_default_hash(rna_path, array_index);
  }
};

class AnimatedProperty {
 public:
  float value;
  PathResolvedRNA prop_rna;
 
  AnimatedProperty(const float value, const PathResolvedRNA &prop_rna)
      : value(value), prop_rna(prop_rna)
  {
  }
};
 
/* Result of FCurve evaluation for an action slot.
 * Mapping from property identifier to its float value.
 *
 * Can be fed to the evaluation of the next layer, mixed with another strip, or
 * used to modify actual RNA properties.
 *
 * TODO: see if this is efficient, and contains enough info, for mixing. For now
 * this just captures the FCurve evaluation result, but doesn't have any info
 * about how to do the mixing (LERP, quaternion SLERP, etc.).
 */
class EvaluationResult {
 protected:
  using EvaluationMap = Map<PropIdentifier, AnimatedProperty>;
  EvaluationMap result_;
 
 public:
  EvaluationResult() = default;
  EvaluationResult(const EvaluationResult &other) = default;
  ~EvaluationResult() = default;
 
  operator bool() const
  {
    return !this->is_empty();
  }
  bool is_empty() const
  {
    return result_.is_empty();
  }
 
  void store(const StringRefNull rna_path,
             const int array_index,
             const float value,
             const PathResolvedRNA &prop_rna)
  {
    PropIdentifier key(rna_path, array_index);
    AnimatedProperty anim_prop(value, prop_rna);
    result_.add_overwrite(key, anim_prop);
  }
 
  AnimatedProperty value(const StringRefNull rna_path, const int array_index) const
  {
    PropIdentifier key(rna_path, array_index);
    return result_.lookup(key);
  }
 
  const AnimatedProperty *lookup_ptr(const PropIdentifier &key) const
  {
    return result_.lookup_ptr(key);
  }
  AnimatedProperty *lookup_ptr(const PropIdentifier &key)
  {
    return result_.lookup_ptr(key);
  }
 
  EvaluationMap::ItemIterator items() const
  {
    return result_.items();
  }
};

EvaluationResult evaluate_action(PointerRNA &animated_id_ptr,
                                 Action &action,
                                 slot_handle_t slot_handle,
                                 const AnimationEvalContext &anim_eval_context);

void evaluate_and_apply_action(PointerRNA &animated_id_ptr,
                               Action &action,
                               slot_handle_t slot_handle,
                               const AnimationEvalContext &anim_eval_context,
                               bool flush_to_original);
 
}  // namespace blender::animrig