void
GeckoTouchDispatcher::ResampleTouchMoves(MultiTouchInput& aOutTouch, TimeStamp aVsyncTime)
{
MOZ_RELEASE_ASSERT(mTouchMoveEvents.size() >= 2);
mTouchQueueLock.AssertCurrentThreadOwns();
MultiTouchInput currentTouch = mTouchMoveEvents.back();
mTouchMoveEvents.pop_back();
MultiTouchInput baseTouch = mTouchMoveEvents.back();
mTouchMoveEvents.clear();
mTouchMoveEvents.push_back(currentTouch);
TimeStamp sampleTime = aVsyncTime - mVsyncAdjust;
TimeDuration touchDiff = currentTouch.mTimeStamp - baseTouch.mTimeStamp;
if (touchDiff < mMinDelta) {
aOutTouch = currentTouch;
#ifdef LOG_RESAMPLE_DATA
LOG("The touches are too close, skip resampling\n");
#endif
return;
}
if (currentTouch.mTimeStamp < sampleTime) {
TimeDuration maxResampleTime = std::min(touchDiff / int64_t(2), mMaxPredict);
TimeStamp maxTimestamp = currentTouch.mTimeStamp + maxResampleTime;
if (sampleTime > maxTimestamp) {
sampleTime = maxTimestamp;
#ifdef LOG_RESAMPLE_DATA
LOG("Overshot extrapolation time, adjusting sample time\n");
#endif
}
}
ResampleTouch(aOutTouch, baseTouch, currentTouch, sampleTime - baseTouch.mTimeStamp, touchDiff);
// Both mTimeStamp and mTime are being updated to sampleTime here.
// mTime needs to be updated using a delta since TimeStamp doesn't
// provide a way to obtain a raw value.
aOutTouch.mTime += (sampleTime - aOutTouch.mTimeStamp).ToMilliseconds();
aOutTouch.mTimeStamp = sampleTime;
}
// Interpolates with the touch event prior to SampleTime
// and with the future touch event past sample time
int32_t
GeckoTouchDispatcher::InterpolateTouch(MultiTouchInput& aOutTouch, uint64_t aSampleTime)
{
MOZ_RELEASE_ASSERT(mTouchMoveEvents.size() >= 2);
mTouchQueueLock.AssertCurrentThreadOwns();
// currentTouch < SampleTime < futureTouch
MultiTouchInput futureTouch = mTouchMoveEvents.back();
mTouchMoveEvents.pop_back();
MultiTouchInput currentTouch = mTouchMoveEvents.back();
mTouchMoveEvents.clear();
mTouchMoveEvents.push_back(futureTouch);
uint64_t currentTouchTime = mLastTouchTime - mTouchTimeDiff;
int64_t frameDiff = aSampleTime - currentTouchTime;
ResampleTouch(aOutTouch, currentTouch, futureTouch, frameDiff, mTouchTimeDiff, true);
return nanosecToMillisec(frameDiff);
}
