Resample touch events on frame boundaries.

Bug: 6375101
Change-Id: I8774e366306bb2b6b4e42b913525bf25b0380ec3

Author: Jeff Brown

core/java/android/view/InputEventReceiver.java

@@ -46,7 +46,8 @@ private static native int nativeInit(InputEventReceiver receiver,
             InputChannel inputChannel, MessageQueue messageQueue);
     private static native void nativeDispose(int receiverPtr);
     private static native void nativeFinishInputEvent(int receiverPtr, int seq, boolean handled);
-    private static native void nativeConsumeBatchedInputEvents(int receiverPtr);
+    private static native void nativeConsumeBatchedInputEvents(int receiverPtr,
+            long frameTimeNanos);
 
     /**
      * Creates an input event receiver bound to the specified input channel.
@@ -114,7 +115,7 @@ public void onInputEvent(InputEvent event) {
      * immediately (such as a pointer up event).
      */
     public void onBatchedInputEventPending() {
-        consumeBatchedInputEvents();
+        consumeBatchedInputEvents(-1);
     }
 
     /**
@@ -150,13 +151,16 @@ public final void finishInputEvent(InputEvent event, boolean handled) {
      *
      * This method forces all batched input events to be delivered immediately.
      * Should be called just before animating or drawing a new frame in the UI.
+     *
+     * @param frameTimeNanos The time in the {@link System#nanoTime()} time base
+     * when the current display frame started rendering, or -1 if unknown.
      */
-    public final void consumeBatchedInputEvents() {
+    public final void consumeBatchedInputEvents(long frameTimeNanos) {
         if (mReceiverPtr == 0) {
             Log.w(TAG, "Attempted to consume batched input events but the input event "
                     + "receiver has already been disposed.");
         } else {
-            nativeConsumeBatchedInputEvents(mReceiverPtr);
+            nativeConsumeBatchedInputEvents(mReceiverPtr, frameTimeNanos);
         }
     }
 

core/java/android/view/ViewRootImpl.java

@@ -4204,11 +4204,11 @@ void unscheduleConsumeBatchedInput() {
         }
     }
 
-    void doConsumeBatchedInput() {
+    void doConsumeBatchedInput(long frameTimeNanos) {
         if (mConsumeBatchedInputScheduled) {
             mConsumeBatchedInputScheduled = false;
             if (mInputEventReceiver != null) {
-                mInputEventReceiver.consumeBatchedInputEvents();
+                mInputEventReceiver.consumeBatchedInputEvents(frameTimeNanos);
             }
             doProcessInputEvents();
         }
@@ -4248,7 +4248,7 @@ public void dispose() {
     final class ConsumeBatchedInputRunnable implements Runnable {
         @Override
         public void run() {
-            doConsumeBatchedInput();
+            doConsumeBatchedInput(mChoreographer.getFrameTimeNanos());
         }
     }
     final ConsumeBatchedInputRunnable mConsumedBatchedInputRunnable =

core/jni/android_app_NativeActivity.cpp

@@ -207,7 +207,7 @@ int32_t AInputQueue::getEvent(AInputEvent** outEvent) {
 
     uint32_t consumerSeq;
     InputEvent* myEvent = NULL;
-    status_t res = mConsumer.consume(&mPooledInputEventFactory, true /*consumeBatches*/,
+    status_t res = mConsumer.consume(&mPooledInputEventFactory, true /*consumeBatches*/, -1,
             &consumerSeq, &myEvent);
     if (res != android::OK) {
         if (res != android::WOULD_BLOCK) {

core/jni/android_view_InputEventReceiver.cpp

@@ -52,7 +52,7 @@ class NativeInputEventReceiver : public RefBase {
 
     status_t initialize();
     status_t finishInputEvent(uint32_t seq, bool handled);
-    status_t consumeEvents(JNIEnv* env, bool consumeBatches);
+    status_t consumeEvents(JNIEnv* env, bool consumeBatches, nsecs_t frameTime);
 
 protected:
     virtual ~NativeInputEventReceiver();
@@ -130,15 +130,16 @@ int NativeInputEventReceiver::handleReceiveCallback(int receiveFd, int events, v
     }
 
     JNIEnv* env = AndroidRuntime::getJNIEnv();
-    status_t status = r->consumeEvents(env, false /*consumeBatches*/);
+    status_t status = r->consumeEvents(env, false /*consumeBatches*/, -1);
     r->mMessageQueue->raiseAndClearException(env, "handleReceiveCallback");
     return status == OK || status == NO_MEMORY ? 1 : 0;
 }
 
-status_t NativeInputEventReceiver::consumeEvents(JNIEnv* env, bool consumeBatches) {
+status_t NativeInputEventReceiver::consumeEvents(JNIEnv* env,
+        bool consumeBatches, nsecs_t frameTime) {
 #if DEBUG_DISPATCH_CYCLE
-    ALOGD("channel '%s' ~ Consuming input events, consumeBatches=%s.", getInputChannelName(),
-            consumeBatches ? "true" : "false");
+    ALOGD("channel '%s' ~ Consuming input events, consumeBatches=%s, frameTime=%lld.",
+            getInputChannelName(), consumeBatches ? "true" : "false", frameTime);
 #endif
 
     if (consumeBatches) {
@@ -150,7 +151,7 @@ status_t NativeInputEventReceiver::consumeEvents(JNIEnv* env, bool consumeBatche
         uint32_t seq;
         InputEvent* inputEvent;
         status_t status = mInputConsumer.consume(&mInputEventFactory,
-                consumeBatches, &seq, &inputEvent);
+                consumeBatches, frameTime, &seq, &inputEvent);
         if (status) {
             if (status == WOULD_BLOCK) {
                 if (!skipCallbacks && !mBatchedInputEventPending
@@ -270,10 +271,11 @@ static void nativeFinishInputEvent(JNIEnv* env, jclass clazz, jint receiverPtr,
     }
 }
 
-static void nativeConsumeBatchedInputEvents(JNIEnv* env, jclass clazz, jint receiverPtr) {
+static void nativeConsumeBatchedInputEvents(JNIEnv* env, jclass clazz, jint receiverPtr,
+        jlong frameTimeNanos) {
     sp<NativeInputEventReceiver> receiver =
             reinterpret_cast<NativeInputEventReceiver*>(receiverPtr);
-    status_t status = receiver->consumeEvents(env, true /*consumeBatches*/);
+    status_t status = receiver->consumeEvents(env, true /*consumeBatches*/, frameTimeNanos);
     if (status && status != DEAD_OBJECT && !env->ExceptionCheck()) {
         String8 message;
         message.appendFormat("Failed to consume batched input event.  status=%d", status);
@@ -291,7 +293,7 @@ static JNINativeMethod gMethods[] = {
             (void*)nativeDispose },
     { "nativeFinishInputEvent", "(IIZ)V",
             (void*)nativeFinishInputEvent },
-    { "nativeConsumeBatchedInputEvents", "(I)V",
+    { "nativeConsumeBatchedInputEvents", "(IJ)V",
             (void*)nativeConsumeBatchedInputEvents },
 };
 

include/androidfw/Input.h

@@ -208,6 +208,7 @@ struct PointerCoords {
     status_t setAxisValue(int32_t axis, float value);
 
     void scale(float scale);
+    void lerp(const PointerCoords& a, const PointerCoords& b, float alpha);
 
     inline float getX() const {
         return getAxisValue(AMOTION_EVENT_AXIS_X);

include/androidfw/InputTransport.h

@@ -33,6 +33,7 @@
 #include <utils/RefBase.h>
 #include <utils/String8.h>
 #include <utils/Vector.h>
+#include <utils/BitSet.h>
 
 namespace android {
 
@@ -271,6 +272,9 @@ class InputConsumer {
      * If consumeBatches is true, then events are still batched but they are consumed
      * immediately as soon as the input channel is exhausted.
      *
+     * The frameTime parameter specifies the time when the current display frame started
+     * rendering in the CLOCK_MONOTONIC time base, or -1 if unknown.
+     *
      * The returned sequence number is never 0 unless the operation failed.
      *
      * Returns OK on success.
@@ -280,7 +284,7 @@ class InputConsumer {
      * Other errors probably indicate that the channel is broken.
      */
     status_t consume(InputEventFactoryInterface* factory, bool consumeBatches,
-            uint32_t* outSeq, InputEvent** outEvent);
+            nsecs_t frameTime, uint32_t* outSeq, InputEvent** outEvent);
 
     /* Sends a finished signal to the publisher to inform it that the message
      * with the specified sequence number has finished being process and whether
@@ -298,7 +302,7 @@ class InputConsumer {
      * has a deferred event to be processed.  Deferred events are somewhat special in
      * that they have already been removed from the input channel.  If the input channel
      * becomes empty, the client may need to do extra work to ensure that it processes
-     * the deferred event despite the fact that the inptu channel's file descriptor
+     * the deferred event despite the fact that the input channel's file descriptor
      * is not readable.
      *
      * One option is simply to call consume() in a loop until it returns WOULD_BLOCK.
@@ -329,11 +333,55 @@ class InputConsumer {
 
     // Batched motion events per device and source.
     struct Batch {
-        uint32_t seq; // sequence number of last input message batched in the event
-        MotionEvent event;
+        Vector<InputMessage> samples;
     };
     Vector<Batch> mBatches;
 
+    // Touch state per device and source, only for sources of class pointer.
+    struct History {
+        nsecs_t eventTime;
+        BitSet32 idBits;
+        PointerCoords pointers[MAX_POINTERS];
+
+        void initializeFrom(const InputMessage* msg) {
+            eventTime = msg->body.motion.eventTime;
+            idBits.clear();
+            for (size_t i = 0; i < msg->body.motion.pointerCount; i++) {
+                uint32_t id = msg->body.motion.pointers[i].properties.id;
+                idBits.markBit(id);
+                size_t index = idBits.getIndexOfBit(id);
+                pointers[index].copyFrom(msg->body.motion.pointers[i].coords);
+            }
+        }
+    };
+    struct TouchState {
+        int32_t deviceId;
+        int32_t source;
+        size_t historyCurrent;
+        size_t historySize;
+        History history[2];
+
+        void initialize(int32_t deviceId, int32_t source) {
+            this->deviceId = deviceId;
+            this->source = source;
+            historyCurrent = 0;
+            historySize = 0;
+        }
+
+        void addHistory(const InputMessage* msg) {
+            historyCurrent ^= 1;
+            if (historySize < 2) {
+                historySize += 1;
+            }
+            history[historyCurrent].initializeFrom(msg);
+        }
+
+        const History* getHistory(size_t index) const {
+            return &history[(historyCurrent + index) & 1];
+        }
+    };
+    Vector<TouchState> mTouchStates;
+
     // Chain of batched sequence numbers.  When multiple input messages are combined into
     // a batch, we append a record here that associates the last sequence number in the
     // batch with the previous one.  When the finished signal is sent, we traverse the
@@ -344,13 +392,26 @@ class InputConsumer {
     };
     Vector<SeqChain> mSeqChains;
 
+    status_t consumeBatch(InputEventFactoryInterface* factory,
+            nsecs_t frameTime, uint32_t* outSeq, InputEvent** outEvent);
+    status_t consumeSamples(InputEventFactoryInterface* factory,
+            Batch& batch, size_t count, uint32_t* outSeq, InputEvent** outEvent);
+
+    void updateTouchState(InputMessage* msg);
+    void resampleTouchState(nsecs_t frameTime, MotionEvent* event,
+            const InputMessage *next);
+
     ssize_t findBatch(int32_t deviceId, int32_t source) const;
+    ssize_t findTouchState(int32_t deviceId, int32_t source) const;
+
     status_t sendUnchainedFinishedSignal(uint32_t seq, bool handled);
 
     static void initializeKeyEvent(KeyEvent* event, const InputMessage* msg);
     static void initializeMotionEvent(MotionEvent* event, const InputMessage* msg);
-    static bool canAppendSamples(const MotionEvent* event, const InputMessage* msg);
-    static void appendSamples(MotionEvent* event, const InputMessage* msg);
+    static void addSample(MotionEvent* event, const InputMessage* msg);
+    static bool canAddSample(const Batch& batch, const InputMessage* msg);
+    static ssize_t findSampleNoLaterThan(const Batch& batch, nsecs_t time);
+    static bool shouldResampleTool(int32_t toolType);
 };
 
 } // namespace android

libs/androidfw/Input.cpp

@@ -229,6 +229,26 @@ void PointerCoords::scale(float scaleFactor) {
     scaleAxisValue(*this, AMOTION_EVENT_AXIS_TOOL_MINOR, scaleFactor);
 }
 
+void PointerCoords::lerp(const PointerCoords& a, const PointerCoords& b, float alpha) {
+    bits = 0;
+    for (uint64_t bitsRemaining = a.bits | b.bits; bitsRemaining; ) {
+        int32_t axis = __builtin_ctz(bitsRemaining);
+        uint64_t axisBit = 1LL << axis;
+        bitsRemaining &= ~axisBit;
+        if (a.bits & axisBit) {
+            if (b.bits & axisBit) {
+                float aval = a.getAxisValue(axis);
+                float bval = b.getAxisValue(axis);
+                setAxisValue(axis, aval + alpha * (bval - aval));
+            } else {
+                setAxisValue(axis, a.getAxisValue(axis));
+            }
+        } else {
+            setAxisValue(axis, b.getAxisValue(axis));
+        }
+    }
+}
+
 #ifdef HAVE_ANDROID_OS
 status_t PointerCoords::readFromParcel(Parcel* parcel) {
     bits = parcel->readInt64();