From 56cffe5b6a0c4bca1b926d9d80c9298122e4a573 Mon Sep 17 00:00:00 2001
From: John Reck <jreck@google.com>
Date: Mon, 3 Feb 2020 16:47:12 -0800
Subject: [PATCH] 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
---
 libs/hwui/renderthread/CanvasContext.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libs/hwui/renderthread/CanvasContext.cpp b/libs/hwui/renderthread/CanvasContext.cpp
index 699b96a685c9f..2b48c35819338 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);
 }