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/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkottieAnimator_DEFINED
#define SkottieAnimator_DEFINED
#include "SkCubicMap.h"
#include "SkMakeUnique.h"
#include "SkottiePriv.h"
#include "SkottieProperties.h"
#include "SkSGScene.h"
#include "SkTypes.h"
#include <memory>
#include <vector>
namespace skottie {
class KeyframeIntervalBase : public SkNoncopyable {
public:
KeyframeIntervalBase() = default;
KeyframeIntervalBase(KeyframeIntervalBase&&) = default;
KeyframeIntervalBase& operator=(KeyframeIntervalBase&&) = default;
float t0() const { return fT0; }
float t1() const { return fT1; }
bool isValid() const { return fT0 < fT1 || fHold; }
bool contains(float t) const { return t >= fT0 && t <= fT1; }
protected:
// Parse the current interval AND back-fill prev interval t1.
bool parse(const Json::Value&, KeyframeIntervalBase* prev);
// Computes a "local" t (relative to [fT0..fT1]), and mapped
// through the cubic (if applicable).
float localT(float t) const;
bool isHold() const { return fHold; }
private:
// Initialized for non-linear interpolation.
std::unique_ptr<SkCubicMap> fCubicMap;
// Start/end times.
float fT0 = 0,
fT1 = 0;
bool fHold = false;
};
// Describes a keyframe interpolation interval (v0@t0) -> (v1@t1).
template <typename T>
class KeyframeInterval final : public KeyframeIntervalBase {
public:
bool parse(const Json::Value& k, KeyframeInterval* prev) {
SkASSERT(k.isObject());
if (!this->INHERITED::parse(k, prev) ||
!ValueTraits<T>::Parse(k["s"], &fV0)) {
return false;
}
if (this->isHold()) {
// Hold v1 == v0.
fV1 = fV0;
} else if (!ValueTraits<T>::Parse(k["e"], &fV1)) {
return false;
}
return ValueTraits<T>::Cardinality(fV0) == ValueTraits<T>::Cardinality(fV1) &&
(!prev || ValueTraits<T>::Cardinality(fV0) == ValueTraits<T>::Cardinality(prev->fV0));
}
void lerp(float t, T*) const;
private:
// Start/end values.
T fV0,
fV1;
using INHERITED = KeyframeIntervalBase;
};
template <typename T>
std::vector<KeyframeInterval<T>> ParseFrames(const Json::Value& jframes) {
std::vector<KeyframeInterval<T>> frames;
if (jframes.isArray()) {
frames.reserve(jframes.size());
KeyframeInterval<T>* prev_frame = nullptr;
for (const auto& jframe : jframes) {
if (!jframe.isObject())
continue;
KeyframeInterval<T> frame;
if (frame.parse(jframe, prev_frame)) {
frames.push_back(std::move(frame));
prev_frame = &frames.back();
}
}
}
// If we couldn't determine a t1 for the last frame, discard it.
if (!frames.empty() && !frames.back().isValid()) {
frames.pop_back();
}
return frames;
}
// Binds an animated/keyframed property to a node attribute setter.
template <typename ValT, typename NodeT>
class Animator final : public sksg::Animator {
public:
using ApplyFuncT = void(*)(NodeT*, const ValT&);
static std::unique_ptr<Animator> Make(std::vector<KeyframeInterval<ValT>>&& frames,
sk_sp<NodeT> node,
ApplyFuncT&& applyFunc) {
return (node && !frames.empty())
? std::unique_ptr<Animator>(new Animator(std::move(frames),
std::move(node),
std::move(applyFunc)))
: nullptr;
}
void onTick(float t) override {
const auto& frame = this->findFrame(t);
ValT val;
frame.lerp(t, &val);
fFunc(fTarget.get(), val);
}
private:
Animator(std::vector<KeyframeInterval<ValT>>&& frames, sk_sp<NodeT> node,
ApplyFuncT&& applyFunc)
: fFrames(std::move(frames))
, fTarget(std::move(node))
, fFunc(std::move(applyFunc)) {}
const KeyframeInterval<ValT>& findFrame(float t) const;
const std::vector<KeyframeInterval<ValT>> fFrames;
sk_sp<NodeT> fTarget;
ApplyFuncT fFunc;
};
template <typename ValT, typename NodeT>
const KeyframeInterval<ValT>& Animator<ValT, NodeT>::findFrame(float t) const {
SkASSERT(!fFrames.empty());
// TODO: cache last/current frame?
auto f0 = fFrames.begin(),
f1 = fFrames.end() - 1;
SkASSERT(f0->isValid());
SkASSERT(f1->isValid());
if (t < f0->t0()) {
return *f0;
}
if (t > f1->t1()) {
return *f1;
}
while (f0 != f1) {
SkASSERT(f0 < f1);
SkASSERT(t >= f0->t0() && t <= f1->t1());
const auto f = f0 + (f1 - f0) / 2;
SkASSERT(f->isValid());
if (t > f->t1()) {
f0 = f + 1;
} else {
f1 = f;
}
}
SkASSERT(f0 == f1);
SkASSERT(f0->contains(t));
return *f0;
}
} // namespace skottie
#endif // SkottieAnimator_DEFINED
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