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-rw-r--r--gfx/thebes/SoftwareVsyncSource.cpp143
1 files changed, 143 insertions, 0 deletions
diff --git a/gfx/thebes/SoftwareVsyncSource.cpp b/gfx/thebes/SoftwareVsyncSource.cpp
new file mode 100644
index 0000000000..b8e12390e7
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+++ b/gfx/thebes/SoftwareVsyncSource.cpp
@@ -0,0 +1,143 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include "SoftwareVsyncSource.h"
+#include "base/task.h"
+#include "gfxPlatform.h"
+#include "nsThreadUtils.h"
+
+namespace mozilla::gfx {
+
+SoftwareVsyncSource::SoftwareVsyncSource(const TimeDuration& aInitialVsyncRate)
+ : mVsyncEnabled(false),
+ mVsyncRate(TimeDuration{aInitialVsyncRate},
+ "SoftwareVsyncSource::mVsyncRate") {
+ MOZ_ASSERT(NS_IsMainThread());
+ mVsyncThread = new base::Thread("SoftwareVsyncThread");
+ MOZ_RELEASE_ASSERT(mVsyncThread->Start(),
+ "GFX: Could not start software vsync thread");
+}
+
+SoftwareVsyncSource::~SoftwareVsyncSource() {
+ MOZ_ASSERT(NS_IsMainThread());
+ if (mVsyncThread) {
+ mVsyncThread->Stop();
+ delete mVsyncThread;
+ }
+};
+
+void SoftwareVsyncSource::EnableVsync() {
+ MOZ_ASSERT(mVsyncThread->IsRunning());
+ if (NS_IsMainThread()) {
+ if (mVsyncEnabled) {
+ return;
+ }
+ mVsyncEnabled = true;
+
+ mVsyncThread->message_loop()->PostTask(
+ NewRunnableMethod("SoftwareVsyncSource::EnableVsync", this,
+ &SoftwareVsyncSource::EnableVsync));
+ return;
+ }
+
+ MOZ_ASSERT(IsInSoftwareVsyncThread());
+ TimeStamp vsyncTime = TimeStamp::Now();
+ TimeStamp outputTime = vsyncTime + GetVsyncRate();
+ NotifyVsync(vsyncTime, outputTime);
+}
+
+void SoftwareVsyncSource::DisableVsync() {
+ MOZ_ASSERT(mVsyncThread->IsRunning());
+ if (NS_IsMainThread()) {
+ if (!mVsyncEnabled) {
+ return;
+ }
+ mVsyncEnabled = false;
+
+ mVsyncThread->message_loop()->PostTask(
+ NewRunnableMethod("SoftwareVsyncSource::DisableVsync", this,
+ &SoftwareVsyncSource::DisableVsync));
+ return;
+ }
+
+ MOZ_ASSERT(IsInSoftwareVsyncThread());
+ if (mCurrentVsyncTask) {
+ mCurrentVsyncTask->Cancel();
+ mCurrentVsyncTask = nullptr;
+ }
+}
+
+bool SoftwareVsyncSource::IsVsyncEnabled() {
+ MOZ_ASSERT(NS_IsMainThread());
+ return mVsyncEnabled;
+}
+
+bool SoftwareVsyncSource::IsInSoftwareVsyncThread() {
+ return mVsyncThread->thread_id() == PlatformThread::CurrentId();
+}
+
+void SoftwareVsyncSource::NotifyVsync(const TimeStamp& aVsyncTimestamp,
+ const TimeStamp& aOutputTimestamp) {
+ MOZ_ASSERT(IsInSoftwareVsyncThread());
+
+ TimeStamp displayVsyncTime = aVsyncTimestamp;
+ TimeStamp now = TimeStamp::Now();
+ // Posted tasks can only have integer millisecond delays
+ // whereas TimeDurations can have floating point delays.
+ // Thus the vsync timestamp can be in the future, which large parts
+ // of the system can't handle, including animations. Force the timestamp to be
+ // now.
+ if (aVsyncTimestamp > now) {
+ displayVsyncTime = now;
+ }
+
+ VsyncSource::NotifyVsync(displayVsyncTime, aOutputTimestamp);
+
+ // Prevent skew by still scheduling based on the original
+ // vsync timestamp
+ ScheduleNextVsync(aVsyncTimestamp);
+}
+
+TimeDuration SoftwareVsyncSource::GetVsyncRate() {
+ auto rate = mVsyncRate.Lock();
+ return *rate;
+}
+
+void SoftwareVsyncSource::SetVsyncRate(const TimeDuration& aNewRate) {
+ auto rate = mVsyncRate.Lock();
+ *rate = aNewRate;
+}
+
+void SoftwareVsyncSource::ScheduleNextVsync(TimeStamp aVsyncTimestamp) {
+ MOZ_ASSERT(IsInSoftwareVsyncThread());
+ TimeDuration vsyncRate = GetVsyncRate();
+ TimeStamp nextVsync = aVsyncTimestamp + vsyncRate;
+ TimeDuration delay = nextVsync - TimeStamp::Now();
+ if (delay.ToMilliseconds() < 0) {
+ delay = TimeDuration::FromMilliseconds(0);
+ nextVsync = TimeStamp::Now();
+ }
+
+ TimeStamp outputTime = nextVsync + vsyncRate;
+
+ mCurrentVsyncTask = NewCancelableRunnableMethod<TimeStamp, TimeStamp>(
+ "SoftwareVsyncSource::NotifyVsync", this,
+ &SoftwareVsyncSource::NotifyVsync, nextVsync, outputTime);
+
+ RefPtr<Runnable> addrefedTask = mCurrentVsyncTask;
+ mVsyncThread->message_loop()->PostDelayedTask(addrefedTask.forget(),
+ delay.ToMilliseconds());
+}
+
+void SoftwareVsyncSource::Shutdown() {
+ MOZ_ASSERT(NS_IsMainThread());
+ DisableVsync();
+ mVsyncThread->Stop();
+ delete mVsyncThread;
+ mVsyncThread = nullptr;
+}
+
+} // namespace mozilla::gfx