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- /*
- * Copyright (C) 2020 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 <functional>
- #include <set>
- #include <tuple>
- #include <type_traits>
-
- /**
- * 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);
-
- void reset();
-
- /// Returns the current position in time of the animation.
- double get_position() const;
-
- /// Sets the callback that's executed when the animation is started.
- void set_start_callback(std::function<void()> callback);
-
- /// Sets the callback that's executed when the animation ends.
- void set_end_callback(std::function<void()> callback);
-
- /// Sets the callback that's executed when the animation loops.
- void set_loop_callback(std::function<void()> callback);
-
- protected:
- double position;
- std::function<void()> start_callback;
- std::function<void()> end_callback;
- std::function<void()> loop_callback;
- };
-
- /**
- * Templated keyframe animation class.
- */
- template <typename T>
- class animation: public animation_base
- {
- public:
- /// Scheduled function consisting of a time and function object.
- typedef std::tuple<double, T> 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 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);
-
- /**
- * Returns 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> get_keyframes(double start, double end) const;
-
- /// Removes all keyframes from the animation.
- void clear();
-
- /**
- * 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 value of the interpolated frames.
- */
- void set_frame_callback(std::function<void(const T&)> callback);
-
- private:
- //static bool keyframe_compare(const keyframe& a, const keyframe & b);
-
- struct keyframe_compare
- {
- inline bool operator()(const keyframe& lhs, const keyframe& rhs) const
- {
- return std::get<0>(lhs) < std::get<0>(rhs);
- }
- };
-
- interpolator_type interpolator;
- std::function<void(const T&)> frame_callback;
- std::set<keyframe, keyframe_compare> keyframes;
- };
-
- /*
- template <typename T>
- bool animation<T>::keyframe_compare(const keyframe& a, const keyframe & b)
- {
- return std::get<0>(a) < std::get<0>(b);
- }
- */
-
- template <typename T>
- animation<T>::animation():
- interpolator(nullptr),
- frame_callback(nullptr),
- keyframes(keyframe_compare())
- {}
-
- template <typename T>
- void animation<T>::advance(double dt)
- {
- position += dt;
-
- if (frame_callback != nullptr && interpolator != nullptr)
- {
-
- auto upper_bound = keyframes.upper_bound({position, T()});
- auto lower_bound = upper_bound;
- --lower_bound;
-
- if (lower_bound != keyframes.end() && upper_bound != keyframes.end())
- {
- // Calculate interpolated frame
- double t0 = std::get<0>(*lower_bound);
- double t1 = std::get<0>(*upper_bound);
- double alpha = (position - t0) / (t1 - t0);
- T frame = interpolator(std::get<1>(*lower_bound), std::get<1>(*upper_bound), alpha);
-
- // Pass frame to frame callback
- frame_callback(frame);
- }
- }
- }
-
- template <typename T>
- void animation<T>::insert_keyframe(const keyframe& k)
- {
- keyframes.emplace(k);
- }
-
- template <typename T>
- void animation<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>
- std::list<typename animation<T>::keyframe> animation<T>::get_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>
- void animation<T>::clear()
- {
- keyframes.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(const T&)> callback)
- {
- this->frame_callback = callback;
- }
-
- #endif // ANTKEEPER_ANIMATION_HPP
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