From 3df692f29ad447581ed0b20e1bde57515c259900 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Fri, 3 Aug 2018 01:17:00 +0200
Subject: [PATCH] Animation: added Player::addRawCallback().

Provides some further optimization opportunities.
---
 doc/snippets/MagnumAnimation.cpp         | 24 +++++++++
 src/Magnum/Animation/Player.h            | 63 ++++++++++++++++++++++--
 src/Magnum/Animation/Test/Benchmark.cpp  | 34 ++++++++++++-
 src/Magnum/Animation/Test/PlayerTest.cpp | 32 +++++++++++-
 4 files changed, 146 insertions(+), 7 deletions(-)

diff --git a/doc/snippets/MagnumAnimation.cpp b/doc/snippets/MagnumAnimation.cpp
index b778a22df..7169d1687 100644
--- a/doc/snippets/MagnumAnimation.cpp
+++ b/doc/snippets/MagnumAnimation.cpp
@@ -161,6 +161,30 @@ timer.advance(timeline.previousFrameTime());
 /* [Player-higher-order-animated-time] */
 }
 
+{
+/* [Player-addRawCallback] */
+Animation::Track<Float, Int> track;
+
+Int result;
+std::vector<Int> data;
+auto callback = [](std::vector<Int>& data, Int value) {
+    data.push_back(value);
+};
+
+Animation::Player<Float> player;
+player.addRawCallback(track,
+    [](const Animation::TrackViewStorage<Float>& track, Float key,
+    std::size_t& hint, void* destination, void(*callback)(), void* userData) {
+        Int value = static_cast<const Animation::TrackView<Float, Int>&>(track)
+            .atStrict(key, hint);
+        if(value == *static_cast<Int*>(destination)) return;
+        *static_cast<Int*>(destination) = value;
+        reinterpret_cast<void(*)(std::vector<Int>&, Int)>(callback)
+            (*static_cast<std::vector<Int>*>(userData), value);
+    }, &result, reinterpret_cast<void(*)()>(+callback), &data);
+/* [Player-addRawCallback] */
+}
+
 {
 /* [Track-usage] */
 const Animation::Track<Float, Vector2> jump{{
diff --git a/src/Magnum/Animation/Player.h b/src/Magnum/Animation/Player.h
index 64165c5b6..3462eac04 100644
--- a/src/Magnum/Animation/Player.h
+++ b/src/Magnum/Animation/Player.h
@@ -108,7 +108,9 @@ implementation:
 
 The @ref addWithCallbackOnChange() variant will fire the callback only if the
 interpolated value changes, which is useful for triggering other events. See
-@ref Animation-Player-higher-order "below" for an example.
+@ref Animation-Player-higher-order "below" for an example. Lastly, there is
+@ref addRawCallback() that allows for greater control and further performance
+optimizations. See its documentation for a usage example code snippet.
 
 By default, the @ref duration() of an animation is calculated implicitly from
 all added tracks. You can use @ref setDuration() to specify a custom duration
@@ -323,7 +325,7 @@ template<class T, class K
          * @brief Whether the player is empty
          *
          * @see @ref size(), @ref add(), @ref addWithCallback(),
-         *      @ref addWithCallbackOnChange()
+         *      @ref addWithCallbackOnChange(), @ref addRawCallback()
          */
         bool isEmpty() const;
 
@@ -331,7 +333,7 @@ template<class T, class K
          * @brief Count of tracks managed by this player
          *
          * @see @ref isEmpty(), @ref add(), @ref addWithCallback(),
-         *      @ref addWithCallbackOnChange()
+         *      @ref addWithCallbackOnChange(), @ref addRawCallback()
          */
         std::size_t size() const;
 
@@ -372,6 +374,7 @@ template<class T, class K
          *
          * See the overload below for a more convenient type-safe way to pass
          * user data.
+         * @see @ref addRawCallback()
          */
         #ifdef DOXYGEN_GENERATING_OUTPUT
         template<class V, class R> Player<T, K>& addWithCallback(const TrackView<K, V, R>& track, void(*callback)(const K&, const R&, void*), void* userData = nullptr);
@@ -404,7 +407,8 @@ template<class T, class K
          * Equivalent to calling the above with a lambda wrapper that casts
          * @cpp void* @ce back to @cpp T* @ce and dereferences it in order to
          * pass it to @p callback. There is no additional overhead compared to
-         * the overload taking the @cpp void* @ce pointer.
+         * the overload taking the @cpp void* @ce pointer, however see
+         * @ref addRawCallback() for optimization possibilities.
          */
         #ifdef DOXYGEN_GENERATING_OUTPUT
         template<class V, class R, class U> Player<T, K>& addWithCallback(const TrackView<K, V, R>& track, void(*callback)(const K&, const R&, U&), U& userData);
@@ -439,6 +443,7 @@ template<class T, class K
          *
          * See the overload below for a more convenient type-safe way to pass
          * user data.
+         * @see @ref addRawCallback()
          */
         #ifdef DOXYGEN_GENERATING_OUTPUT
         template<class V, class R> Player<T, K>& addWithCallbackOnChange(const TrackView<K, V, R>& track, void(*callback)(const K&, const R&, void*), R& destination, void* userData = nullptr);
@@ -466,7 +471,8 @@ template<class T, class K
          * Equivalent to calling the above with a lambda wrapper that casts
          * @cpp void* @ce back to @cpp T* @ce and dereferences it in order to
          * pass it to @p callback. There is no additional overhead compared to
-         * the overload taking the @cpp void* @ce pointer.
+         * the overload taking the @cpp void* @ce pointer, however see
+         * @ref addRawCallback() for optimization possibilities.
          */
         #ifdef DOXYGEN_GENERATING_OUTPUT
         template<class V, class R, class U> Player<T, K>& addWithCallbackOnChange(const TrackView<K, V, R>& track, void(*callback)(const K&, const R&, void*), R& destination, U& userData);
@@ -488,6 +494,48 @@ template<class T, class K
         }
         #endif
 
+        /**
+         * @brief Add a track with a raw callback
+         *
+         * This is a low-level function meant to be used if you want to avoid
+         * the extra overhead of an additional callback in @ref addWithCallback()
+         * or @ref addWithCallbackOnChange(), want more flexibility in the user
+         * callback or want to control the track interpolation directly --- for
+         * example taking advantage of @ref TrackView::atStrict() or passing an
+         * inlineable interpolator function instead of using the saved
+         * interpolator function pointer.
+         *
+         * The callback takes the raw @ref TrackViewStorage reference (which
+         * you need to cast to a correct type), the interpolated key and hint
+         * that's meant to be passed to @ref TrackView::at(), the destination
+         * pointer (equivalent to the one passed to @ref add()), user callback
+         * pointer (which again needs to be cast to a correct type) and user
+         * data pointer. The following code snippet shows implementation of the
+         * @ref addWithCallbackOnChange() API using this function, using a
+         * custom callback to add a value to a vector if it changes:
+         *
+         * @snippet MagnumAnimation.cpp Player-addRawCallback
+         */
+        #ifdef DOXYGEN_GENERATING_OUTPUT
+        template<class V, class R, class Callback> Player<T, K>& addRawCallback(const TrackView<K, V, R>& track, void(*callback)(const TrackViewStorage<K>&, K, std::size_t&, void*, void(*)(), void*), void* destination, void(*userCallback)(), void* userData);
+        #else
+        template<class V, class R, class Callback> Player<T, K>& addRawCallback(const TrackView<K, V, R>& track, Callback callback, void* destination, void(*userCallback)(), void* userData);
+        #endif
+
+        /** @overload
+         *
+         * Note that the track ownership is *not* transferred to the
+         * @ref Player and you have to ensure that it's kept in scope for the
+         * whole lifetime of the @ref Player instance.
+         */
+        #ifdef DOXYGEN_GENERATING_OUTPUT
+        template<class V, class R> Player<T, K>& addRawCallback(const Track<K, V, R>& track, void(*callback)(const TrackViewStorage<K>&, K, std::size_t&, void*, void(*)(), void*), void* destination, void(*userCallback)(), void* userData);
+        #else
+        template<class V, class R, class Callback> Player<T, K>& addRawCallback(const Track<K, V, R>& track, Callback callback, void* destination, void(*userCallback)(), void* userData) {
+            return addRawCallback(TrackView<K, V, R>{track}, callback, destination, userCallback, userData);
+        }
+        #endif
+
         /**
          * @brief State
          *
@@ -641,6 +689,11 @@ template<class T, class K> template<class V, class R, class U, class Callback> P
             *static_cast<R*>(destination) = result;
         }, &destination, reinterpret_cast<void(*)()>(callbackPtr), &userData);
 }
+
+template<class T, class K> template<class V, class R, class Callback> Player<T, K>& Player<T, K>::addRawCallback(const TrackView<K, V, R>& track, Callback callback, void* destination, void(*userCallback)(), void* userData) {
+    auto callbackPtr = static_cast<void(*)(const TrackViewStorage<K>&, K, std::size_t&, void*, void(*)(), void*)>(callback);
+    return addInternal(track, callbackPtr, destination, userCallback, userData);
+}
 #endif
 
 #if defined(CORRADE_TARGET_WINDOWS) && !defined(__MINGW32__)
diff --git a/src/Magnum/Animation/Test/Benchmark.cpp b/src/Magnum/Animation/Test/Benchmark.cpp
index 6ef9180ed..07dde5ab5 100644
--- a/src/Magnum/Animation/Test/Benchmark.cpp
+++ b/src/Magnum/Animation/Test/Benchmark.cpp
@@ -47,6 +47,8 @@ struct Benchmark: TestSuite::Tester {
     void playerAdvanceEmptyTrack();
     void playerAdvance();
     void playerAdvanceCallback();
+    void playerAdvanceRawCallback();
+    void playerAdvanceRawCallbackDirectInterpolator();
 
     Containers::Array<Float> _keys;
     Containers::Array<Int> _values;
@@ -76,7 +78,9 @@ Benchmark::Benchmark() {
                    &Benchmark::playerAdvanceEmpty,
                    &Benchmark::playerAdvanceEmptyTrack,
                    &Benchmark::playerAdvance,
-                   &Benchmark::playerAdvanceCallback}, 10);
+                   &Benchmark::playerAdvanceCallback,
+                   &Benchmark::playerAdvanceRawCallback,
+                   &Benchmark::playerAdvanceRawCallbackDirectInterpolator}, 10);
 
     _keys = Containers::Array<Float>{DataSize};
     _values = Containers::Array<Int>{Containers::DirectInit, DataSize, 1};
@@ -228,6 +232,34 @@ void Benchmark::playerAdvanceCallback() {
     CORRADE_COMPARE(result, 125000);
 }
 
+void Benchmark::playerAdvanceRawCallback() {
+    Int result{};
+    Player<Float> player;
+    player.addRawCallback(_track, [](const TrackViewStorage<Float>& track, Float key, std::size_t& hint, void* destination, void(*)(), void*) {
+            *static_cast<Int*>(destination) += static_cast<const TrackView<Float, Int>&>(track).atStrict(key, hint);
+        }, &result, nullptr, nullptr)
+        .play({});
+    CORRADE_BENCHMARK(250) {
+        for(Float i = 0.0f; i < 500.0f; i += 1.0f)
+            player.advance(i);
+    }
+    CORRADE_COMPARE(result, 125000);
+}
+
+void Benchmark::playerAdvanceRawCallbackDirectInterpolator() {
+    Int result{};
+    Player<Float> player;
+    player.addRawCallback(_track, [](const TrackViewStorage<Float>& track, Float key, std::size_t& hint, void* destination, void(*)(), void*) {
+            *static_cast<Int*>(destination) += static_cast<const TrackView<Float, Int>&>(track).atStrict(Math::select, key, hint);
+        }, &result, nullptr, nullptr)
+        .play({});
+    CORRADE_BENCHMARK(250) {
+        for(Float i = 0.0f; i < 500.0f; i += 1.0f)
+            player.advance(i);
+    }
+    CORRADE_COMPARE(result, 125000);
+}
+
 }}}
 
 CORRADE_TEST_MAIN(Magnum::Animation::Test::Benchmark)
diff --git a/src/Magnum/Animation/Test/PlayerTest.cpp b/src/Magnum/Animation/Test/PlayerTest.cpp
index e90b16f5f..e61bf49d5 100644
--- a/src/Magnum/Animation/Test/PlayerTest.cpp
+++ b/src/Magnum/Animation/Test/PlayerTest.cpp
@@ -62,6 +62,7 @@ struct PlayerTest: TestSuite::Tester {
     void addWithCallbackTemplate();
     void addWithCallbackOnChange();
     void addWithCallbackOnChangeTemplate();
+    void addRawCallback();
 
     void runFor100YearsFloat();
     void runFor100YearsChrono();
@@ -114,7 +115,8 @@ PlayerTest::PlayerTest() {
               &PlayerTest::addWithCallback,
               &PlayerTest::addWithCallbackTemplate,
               &PlayerTest::addWithCallbackOnChange,
-              &PlayerTest::addWithCallbackOnChangeTemplate});
+              &PlayerTest::addWithCallbackOnChangeTemplate,
+              &PlayerTest::addRawCallback});
 
     addInstancedTests({
         &PlayerTest::runFor100YearsFloat,
@@ -704,6 +706,34 @@ void PlayerTest::addWithCallbackOnChangeTemplate() {
     CORRADE_COMPARE(data.called, 2);
 }
 
+void PlayerTest::addRawCallback() {
+    Animation::Track<Float, Int> track;
+
+    Int result = -1;
+    std::vector<Int> data;
+    auto callback = [](std::vector<Int>& data, Int value) {
+        data.push_back(value);
+    };
+
+    Animation::Player<Float> player;
+    player.addRawCallback(track,
+        [](const Animation::TrackViewStorage<Float>& track, Float key,
+        std::size_t& hint, void* destination, void(*callback)(), void* userData) {
+            Int value = static_cast<const Animation::TrackView<Float, Int>&>(track).at(key, hint);
+            if(value == *static_cast<Int*>(destination)) return;
+            *static_cast<Int*>(destination) = value;
+            reinterpret_cast<void(*)(std::vector<Int>&, Int)>(callback)(*static_cast<std::vector<Int>*>(userData), value);
+        }, &result, reinterpret_cast<void(*)()>(+callback), &data)
+        .play({});
+
+    /* Should add the default-constructed value into the vector, but only once */
+    CORRADE_COMPARE(data, std::vector<Int>{});
+    player.advance({});
+    CORRADE_COMPARE(data, std::vector<Int>{0});
+    player.advance(1.0f);
+    CORRADE_COMPARE(data, std::vector<Int>{0});
+}
+
 void PlayerTest::runFor100YearsFloat() {
     auto&& data = RunFor100YearsData[testCaseInstanceId()];
     setTestCaseDescription(data.name);