112 lines
3.0 KiB
C++
112 lines
3.0 KiB
C++
/*
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SPDX-FileCopyrightText: 2020 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
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SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#pragma once
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#include "kwinglobals.h"
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#include <QObject>
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namespace KWin
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{
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class RenderLoopPrivate;
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/**
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* The RenderLoop class represents the compositing scheduler on a particular output.
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*
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* The RenderLoop class drives the compositing. The frameRequested() signal is emitted
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* when the loop wants a new frame to be rendered. The frameCompleted() signal is
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* emitted when a previously rendered frame has been presented on the screen. In case
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* you want the compositor to repaint the scene, call the scheduleRepaint() function.
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*/
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class KWIN_EXPORT RenderLoop : public QObject
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{
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Q_OBJECT
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public:
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explicit RenderLoop(QObject *parent = nullptr);
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~RenderLoop() override;
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/**
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* Pauses the render loop. While the render loop is inhibited, scheduleRepaint()
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* requests are queued.
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*
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* Once the render loop is uninhibited, the pending schedule requests are going to
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* be re-applied.
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*/
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void inhibit();
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/**
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* Uninhibits the render loop.
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*/
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void uninhibit();
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/**
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* This function must be called before the Compositor starts rendering the next
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* frame.
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*/
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void beginFrame();
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/**
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* This function must be called after the Compositor has finished rendering the
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* next frame.
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*/
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void endFrame();
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/**
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* Returns the refresh rate at which the output is being updated, in millihertz.
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*/
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int refreshRate() const;
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/**
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* Sets the refresh rate of this RenderLoop to @a refreshRate, in millihertz.
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*/
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void setRefreshRate(int refreshRate);
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/**
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* Schedules a compositing cycle at the next available moment.
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*/
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void scheduleRepaint();
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/**
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* Returns the timestamp of the last frame that has been presented on the screen.
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* The returned timestamp is sourced from the monotonic clock.
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*/
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std::chrono::nanoseconds lastPresentationTimestamp() const;
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/**
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* If a repaint has been scheduled, this function returns the expected time when
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* the next frame will be presented on the screen. The returned timestamp is sourced
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* from the monotonic clock.
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*/
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std::chrono::nanoseconds nextPresentationTimestamp() const;
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Q_SIGNALS:
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/**
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* This signal is emitted when the refresh rate of this RenderLoop has changed.
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*/
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void refreshRateChanged();
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/**
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* This signal is emitted when a frame has been actually presented on the screen.
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* @a timestamp indicates the time when it took place.
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*/
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void framePresented(RenderLoop *loop, std::chrono::nanoseconds timestamp);
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/**
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* This signal is emitted when the render loop wants a new frame to be composited.
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*
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* The Compositor should make a connection to this signal using Qt::DirectConnection.
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*/
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void frameRequested(RenderLoop *loop);
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private:
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QScopedPointer<RenderLoopPrivate> d;
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friend class RenderLoopPrivate;
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};
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} // namespace KWin
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