Add dummy OutputLayer type

It's needed to make repaint scheduling in render layers simple.

src/CMakeLists.txt

@@ -83,6 +83,7 @@ target_sources(kwin PRIVATE
     options.cpp
     osd.cpp
     outline.cpp
+    outputlayer.cpp
     overlaywindow.cpp
     placement.cpp
     platform.cpp

src/abstract_output.cpp

@@ -8,6 +8,7 @@
 */
 
 #include "abstract_output.h"
+#include "outputlayer.h"
 #include <KSharedConfig>
 #include <KConfigGroup>
 
@@ -78,6 +79,7 @@ QDebug operator<<(QDebug debug, const AbstractOutput *output)
 
 AbstractOutput::AbstractOutput(QObject *parent)
     : QObject(parent)
+    , m_layer(new OutputLayer(this))
 {
 }
 
@@ -85,6 +87,11 @@ AbstractOutput::~AbstractOutput()
 {
 }
 
+OutputLayer *AbstractOutput::layer() const
+{
+    return m_layer;
+}
+
 QUuid AbstractOutput::uuid() const
 {
     return QUuid();

src/abstract_output.h

@@ -26,6 +26,7 @@ class OutputChangeSetV2;
 namespace KWin
 {
 class EffectScreenImpl;
+class OutputLayer;
 class RenderLoop;
 
 class KWIN_EXPORT GammaRamp
@@ -93,6 +94,11 @@ public:
     explicit AbstractOutput(QObject *parent = nullptr);
     ~AbstractOutput() override;
 
+    /**
+     * Returns the primary layer. TODO: remove it
+     */
+    OutputLayer *layer() const;
+
     /**
      * Returns a short identifiable name of this output.
      */
@@ -262,6 +268,7 @@ Q_SIGNALS:
 private:
     Q_DISABLE_COPY(AbstractOutput)
     EffectScreenImpl *m_effectScreen = nullptr;
+    OutputLayer *m_layer;
     int m_directScanoutCount = 0;
     friend class EffectScreenImpl; // to access m_effectScreen
 };

src/outputlayer.cpp

@@ -0,0 +1,32 @@
+/*
+    SPDX-FileCopyrightText: 2022 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#include "outputlayer.h"
+
+namespace KWin
+{
+
+OutputLayer::OutputLayer(QObject *parent)
+    : QObject(parent)
+{
+}
+
+QRegion OutputLayer::repaints() const
+{
+    return m_repaints;
+}
+
+void OutputLayer::addRepaint(const QRegion &region)
+{
+    m_repaints += region;
+}
+
+void OutputLayer::resetRepaints()
+{
+    m_repaints = QRegion();
+}
+
+} // namespace KWin

src/outputlayer.h

@@ -0,0 +1,32 @@
+/*
+    SPDX-FileCopyrightText: 2022 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#pragma once
+
+#include "kwin_export.h"
+
+#include <QObject>
+#include <QRegion>
+
+namespace KWin
+{
+
+class KWIN_EXPORT OutputLayer : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit OutputLayer(QObject *parent = nullptr);
+
+    QRegion repaints() const;
+    void resetRepaints();
+    void addRepaint(const QRegion &region);
+
+private:
+    QRegion m_repaints;
+};
+
+} // namespace KWin