Adjust present time calculation

Adjust the target present time when using
render_ahead to better fit in the gaps between
vsync pulses. This prevents small clock
drifts from causing jank.

Bug: 143540628
Test: manual, looked at systrace
Change-Id: I26ae6ebf16a3dea48dfd8e1c420d9e5e43e42bcb

1 files changed, 2 insertions, 1 deletions

diff --git a/libs/hwui/renderthread/CanvasContext.cpp b/libs/hwui/renderthread/CanvasContext.cpp
index 699b96a685c9..2b48c3581933 100644
--- a/libs/hwui/renderthread/CanvasContext.cpp
+++ b/libs/hwui/renderthread/CanvasContext.cpp
@@ -429,7 +429,8 @@ void CanvasContext::setPresentTime() {
 
     if (renderAhead) {
         presentTime = mCurrentFrameInfo->get(FrameInfoIndex::Vsync) +
-                (frameIntervalNanos * (renderAhead + 1));
+                (frameIntervalNanos * (renderAhead + 1)) - DeviceInfo::get()->getAppOffset() +
+                (frameIntervalNanos / 2);
     }
     native_window_set_buffers_timestamp(mNativeSurface->getNativeWindow(), presentTime);
 }