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- /*
- * Copyright (C) 2021 Christopher J. Howard
- *
- * This file is part of Antkeeper source code.
- *
- * Antkeeper source code is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * Antkeeper source code is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
- */
-
- #ifndef ANTKEEPER_ANIMATION_HPP
- #define ANTKEEPER_ANIMATION_HPP
-
- #include <algorithm>
- #include <functional>
- #include <set>
- #include <tuple>
- #include <type_traits>
- #include <unordered_map>
-
- /**
- * Abstract base class for animations.
- */
- class animation_base
- {
- public:
- animation_base();
-
- /**
- * Advances the animation position (t) by @p dt.
- *
- * @param dt Delta time by which the animation position will be advanced.
- */
- virtual void advance(double dt) = 0;
-
- /**
- * Sets the animation position to @p t.
- *
- * @param t Position in time to which the animation position will be set.
- */
- void seek(double t);
-
- /// Sets the animation position to `0.0`.
- void rewind();
-
- /// Enables or disables looping of the animation.
- void loop(bool enabled);
-
- /// Pauses the animation.
- void pause();
-
- /// Plays the animation.
- void play();
-
- /// Stops the animation, rewinds it, and resets the loop count.
- void stop();
-
- /**
- * Sets the speed of the animation.
- *
- * @param speed Speed multiplier.
- */
- void set_speed(double speed);
-
- /// Returns `true` if looping of the animation is enabled, `false` otherwise.
- bool is_looped() const;
-
- /// Returns `true` if the animation is paused, `false` otherwise.
- bool is_paused() const;
-
- /// Returns `true` if the animation is stopped, `false` otherwise.
- bool is_stopped() const;
-
- /// Returns the current position in time of the animation.
- double get_position() const;
-
- /// Returns the current loop count of the animation.
- int get_loop_count() const;
-
- /// Returns the duration of the animation.
- virtual double get_duration() const = 0;
-
- /// Sets the callback that's executed when the animation is started from a stopped state.
- void set_start_callback(std::function<void()> callback);
-
- /// Sets the callback that's executed when a non-looped animation has finished.
- void set_end_callback(std::function<void()> callback);
-
- /**
- * Sets the callback that's executed when the animation loops.
- *
- * @param callback Loop callback function which is passed the current loop count.
- */
- void set_loop_callback(std::function<void(int)> callback);
-
- protected:
- bool looped;
- int loop_count;
- bool paused;
- bool stopped;
- double position;
- double speed;
-
- std::function<void()> start_callback;
- std::function<void()> end_callback;
- std::function<void(int)> loop_callback;
- };
-
- inline bool animation_base::is_looped() const
- {
- return looped;
- }
-
- inline bool animation_base::is_paused() const
- {
- return paused;
- }
-
- inline bool animation_base::is_stopped() const
- {
- return stopped;
- }
-
- inline double animation_base::get_position() const
- {
- return position;
- }
-
- inline int animation_base::get_loop_count() const
- {
- return loop_count;
- }
-
- template <typename T>
- class animation_channel
- {
- public:
- /// Keyframe consisting of a time and a value.
- typedef std::tuple<double, T> keyframe;
-
- /**
- * Creates an animation channel.
- *
- * @param id ID of the channel.
- */
- animation_channel(int id);
-
- /// Creates an animation channel.
- animation_channel();
-
- /// Creates an animation channel.
- animation_channel(const animation_channel& other);
-
- /// Assigns the contents of another channel to this channel.
- animation_channel& operator=(const animation_channel& other);
-
- /**
- * Adds a keyframe to the animation.
- *
- * @param k Keyframe to add.
- */
- void insert_keyframe(const keyframe& k);
-
- /**
- * Removes all keyframes on `[start, end)`.
- *
- * @param start Starting position in time (inclusive).
- * @param end Ending position in time (non-inclusive).
- */
- void remove_keyframes(double start, double end);
-
- /// Removes all keyframes from the animation.
- void remove_keyframes();
-
- /**
- * Finds the keyframes to the left and right of @p position.
- *
- * @param position Position in time.
- * @return Array containing the the keyframes on the left and right of @p position.
- */
- std::array<const keyframe*, 2> find_keyframes(double position) const;
-
- /**
- * Finds all the keyframes on `[start, end)`.
- *
- * @param start Starting position in time (inclusive).
- * @param end Ending position in time (non-inclusive).
- * @return All keyframes on `[start, end)`.
- */
- std::list<keyframe> find_keyframes(double start, double end) const;
-
- /// Returns the ID of the animation channel.
- int get_id() const;
-
- /// Returns the duration of the animation channel.
- double get_duration() const;
-
- private:
- struct keyframe_compare
- {
- inline bool operator()(const keyframe& lhs, const keyframe& rhs) const
- {
- return std::get<0>(lhs) < std::get<0>(rhs);
- }
- };
-
- int id;
- std::set<keyframe, keyframe_compare> keyframes;
- };
-
- template <typename T>
- animation_channel<T>::animation_channel(int id):
- id(id),
- keyframes(keyframe_compare())
- {}
-
- template <typename T>
- animation_channel<T>::animation_channel():
- animation_channel(-1)
- {}
-
- template <typename T>
- animation_channel<T>::animation_channel(const animation_channel& other):
- id(other.id),
- keyframes(other.keyframes)
- {}
-
- template <typename T>
- animation_channel<T>& animation_channel<T>::operator=(const animation_channel& other)
- {
- id = other.id;
- keyframes = other.keyframes;
- }
-
- template <typename T>
- void animation_channel<T>::insert_keyframe(const keyframe& k)
- {
- keyframes.emplace(k);
- }
-
- template <typename T>
- void animation_channel<T>::remove_keyframes(double start, double end)
- {
- auto lower_bound = keyframes.lower_bound({start, T()});
- auto upper_bound = keyframes.upper_bound({end, T()});
- keyframes.erase(lower_bound, upper_bound);
- }
-
- template <typename T>
- void animation_channel<T>::remove_keyframes()
- {
- keyframes.clear();
- }
-
- template <typename T>
- std::array<const typename animation_channel<T>::keyframe*, 2> animation_channel<T>::find_keyframes(double position) const
- {
- // Find the following keyframe
- auto upper_bound = keyframes.upper_bound({position, T()});
-
- // Find the preceding keyframe
- auto lower_bound = upper_bound;
- --lower_bound;
-
- std::array<const keyframe*, 2> frames;
- frames[0] = (lower_bound != keyframes.end()) ? &(*lower_bound) : nullptr;
- frames[1] = (upper_bound != keyframes.end()) ? &(*upper_bound) : nullptr;
-
- return frames;
- }
-
- template <typename T>
- std::list<typename animation_channel<T>::keyframe> animation_channel<T>::find_keyframes(double start, double end) const
- {
- std::list<keyframe> keyframe_list;
-
- auto lower_bound = keyframes.lower_bound({start, T()});
- auto upper_bound = keyframes.upper_bound({end, T()});
- for (auto iterator = lower_bound; iterator != upper_bound; ++iterator)
- {
- keyframe_list.push_back(*iterator);
- }
-
- return keyframe_list;
- }
-
- template <typename T>
- inline int animation_channel<T>::get_id() const
- {
- return id;
- }
-
- template <typename T>
- double animation_channel<T>::get_duration() const
- {
- if (keyframes.empty())
- {
- return 0.0;
- }
-
- return std::get<0>(*keyframes.rbegin());
- }
-
- /**
- * Templated keyframe animation class.
- */
- template <typename T>
- class animation: public animation_base
- {
- public:
- /// Channel for this animation type.
- typedef animation_channel<T> channel;
-
- // Keyframe type for this animation.
- typedef typename channel::keyframe keyframe;
-
- /// Interpolator function type.
- typedef typename std::decay<std::function<T(const T&, const T&, double)>>::type interpolator_type;
-
- /// Creates an animation.
- animation();
-
- /// @copydoc animation_base::advance()
- virtual void advance(double dt);
-
- /**
- * Adds a channel to the animation.
- *
- * @param id ID of the channel.
- * @return Added or pre-existing channel.
- */
- channel* add_channel(int id);
-
- /**
- * Removes a channel from the animation.
- *
- * @param id ID of the channel to remove.
- */
- void remove_channel(int id);
-
- /// Removes all channels from the animation.
- void remove_channels();
-
- /**
- * Sets the frame interpolator function object.
- *
- * @param interpolator Frame interpolator function object.
- */
- void set_interpolator(interpolator_type interpolator);
-
- /**
- * Sets the callback that's executed on each frame of animation.
- *
- * @param callback Frame callback which receives the index of an animation channel and value of an interpolated frame.
- */
- void set_frame_callback(std::function<void(int, const T&)> callback);
-
- /**
- * Returns the channel with the specified ID.
- *
- * @param id ID of the channel to get.
- */
- const channel* get_channel(int id) const;
-
- /// @copydoc animation::get_channel(int) const
- channel* get_channel(int id);
-
- /// @copydoc animation_base::get_duration() const
- virtual double get_duration() const;
-
- private:
- std::unordered_map<int, channel> channels;
- interpolator_type interpolator;
- std::function<void(int, const T&)> frame_callback;
- };
-
- template <typename T>
- animation<T>::animation():
- interpolator(nullptr),
- frame_callback(nullptr)
- {}
-
- template <typename T>
- void animation<T>::advance(double dt)
- {
- if (paused || stopped)
- {
- return;
- }
-
- // Advance position by dt
- position += dt * speed;
-
- // Determine duration of the animation
- double duration = get_duration();
-
- if (position < duration)
- {
- if (frame_callback != nullptr && interpolator != nullptr)
- {
- for (std::size_t i = 0; i < channels.size(); ++i)
- {
- auto frames = channels[i].find_keyframes(position);
-
- if (frames[0] != nullptr && frames[1] != nullptr)
- {
- // Calculate interpolated frame
- double t0 = std::get<0>(*frames[0]);
- double t1 = std::get<0>(*frames[1]);
- double alpha = (position - t0) / (t1 - t0);
- T frame = interpolator(std::get<1>(*frames[0]), std::get<1>(*frames[1]), alpha);
-
- // Pass frame to frame callback
- frame_callback(static_cast<int>(i), frame);
- }
- else if (frames[0] != nullptr)
- {
- // Pass frame to frame callback
- frame_callback(static_cast<int>(i), std::get<1>(*frames[0]));
- }
- else if (frames[1] != nullptr)
- {
- // Pass frame to frame callback
- frame_callback(static_cast<int>(i), std::get<1>(*frames[1]));
- }
- }
- }
- }
- else
- {
- if (looped)
- {
- ++loop_count;
-
- // Subtract duration of animation from position
- position -= duration;
-
- // Execute loop callback
- if (loop_callback)
- {
- loop_callback(loop_count);
- }
-
- // Call frame callback on looped frame
- if (frame_callback)
- {
- advance(0.0);
- }
- }
- else
- {
- // Call frame callback for end frame
- if (frame_callback != nullptr)
- {
- for (std::size_t i = 0; i < channels.size(); ++i)
- {
- auto frames = channels[i].find_keyframes(channels[i].get_duration());
- if (frames[0] != nullptr)
- {
- frame_callback(static_cast<int>(i), std::get<1>(*frames[0]));
- }
- }
- }
-
- stopped = true;
-
- // Call end callback
- if (end_callback)
- {
- end_callback();
- }
- }
- }
- }
-
- template <typename T>
- typename animation<T>::channel* animation<T>::add_channel(int id)
- {
- return &(*channels.emplace(id, id).first).second;
- }
-
- template <typename T>
- void animation<T>::remove_channel(int id)
- {
- auto it = channels.find(id);
- if (it != channels.end())
- {
- channels.erase(it);
- }
- }
-
- template <typename T>
- void animation<T>::remove_channels()
- {
- channels.clear();
- }
-
- template <typename T>
- void animation<T>::set_interpolator(interpolator_type interpolator)
- {
- this->interpolator = interpolator;
- }
-
- template <typename T>
- void animation<T>::set_frame_callback(std::function<void(int, const T&)> callback)
- {
- this->frame_callback = callback;
- }
-
- template <typename T>
- const typename animation<T>::channel* animation<T>::get_channel(int id) const
- {
- auto it = channels.find(id);
- if (it != channels.end())
- {
- return &it->second;
- }
-
- return nullptr;
- }
-
- template <typename T>
- typename animation<T>::channel* animation<T>::get_channel(int id)
- {
- auto it = channels.find(id);
- if (it != channels.end())
- {
- return &it->second;
- }
-
- return nullptr;
- }
-
- template <typename T>
- double animation<T>::get_duration() const
- {
- double duration = 0.0;
-
- for (auto it = channels.begin(); it != channels.end(); ++it)
- {
- duration = std::max<double>(duration, it->second.get_duration());
- }
-
- return duration;
- }
-
- #endif // ANTKEEPER_ANIMATION_HPP
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