backends/wayland: Introduce cursor layers

It's a necessary step to let kwin repaint the cursor from Compositor.

Unfortunately, it also means that we need to add more (temporary) code
to paint the cursor in backends.

src/backends/wayland/wayland_egl_backend.cpp

@@ -26,6 +26,7 @@
 #include <kwinglutils.h>
 
 // KDE
+#include <KWayland/Client/shm_pool.h>
 #include <KWayland/Client/surface.h>
 
 // Qt
@@ -61,13 +62,13 @@ static QVector<EGLint> regionToRects(const QRegion &region, Output *output)
     return rects;
 }
 
-WaylandEglOutput::WaylandEglOutput(WaylandOutput *output, WaylandEglBackend *backend)
+WaylandEglPrimaryLayer::WaylandEglPrimaryLayer(WaylandOutput *output, WaylandEglBackend *backend)
     : m_waylandOutput(output)
     , m_backend(backend)
 {
 }
 
-bool WaylandEglOutput::init()
+bool WaylandEglPrimaryLayer::init()
 {
     auto surface = m_waylandOutput->surface();
     const QSize nativeSize = m_waylandOutput->geometry().size() * m_waylandOutput->scale();
@@ -94,35 +95,23 @@ bool WaylandEglOutput::init()
     return true;
 }
 
-WaylandEglOutput::~WaylandEglOutput()
+WaylandEglPrimaryLayer::~WaylandEglPrimaryLayer()
 {
     wl_egl_window_destroy(m_overlay);
 }
 
-GLFramebuffer *WaylandEglOutput::fbo() const
+GLFramebuffer *WaylandEglPrimaryLayer::fbo() const
 {
     return m_fbo.get();
 }
 
-bool WaylandEglOutput::makeContextCurrent() const
+std::optional<OutputLayerBeginFrameInfo> WaylandEglPrimaryLayer::beginFrame()
 {
-    if (m_eglSurface == EGL_NO_SURFACE) {
-        return false;
-    }
     if (eglMakeCurrent(m_backend->eglDisplay(), m_eglSurface, m_eglSurface, m_backend->context()) == EGL_FALSE) {
         qCCritical(KWIN_WAYLAND_BACKEND) << "Make Context Current failed";
-        return false;
+        return std::nullopt;
     }
-    EGLint error = eglGetError();
-    if (error != EGL_SUCCESS) {
-        qCWarning(KWIN_WAYLAND_BACKEND) << "Error occurred while creating context " << error;
-        return false;
-    }
-    return true;
-}
 
-std::optional<OutputLayerBeginFrameInfo> WaylandEglOutput::beginFrame()
-{
     const QSize nativeSize = m_waylandOutput->pixelSize();
     if (!m_fbo || m_fbo->size() != nativeSize) {
         m_fbo = std::make_unique<GLFramebuffer>(0, nativeSize);
@@ -130,9 +119,6 @@ std::optional<OutputLayerBeginFrameInfo> WaylandEglOutput::beginFrame()
         wl_egl_window_resize(m_overlay, nativeSize.width(), nativeSize.height(), 0, 0);
     }
 
-    eglWaitNative(EGL_CORE_NATIVE_ENGINE);
-    makeContextCurrent();
-
     QRegion repair;
     if (m_backend->supportsBufferAge()) {
         repair = m_damageJournal.accumulate(m_bufferAge, infiniteRegion());
@@ -145,14 +131,14 @@ std::optional<OutputLayerBeginFrameInfo> WaylandEglOutput::beginFrame()
     };
 }
 
-bool WaylandEglOutput::endFrame(const QRegion &renderedRegion, const QRegion &damagedRegion)
+bool WaylandEglPrimaryLayer::endFrame(const QRegion &renderedRegion, const QRegion &damagedRegion)
 {
     m_damageJournal.add(damagedRegion);
     GLFramebuffer::popFramebuffer();
     return true;
 }
 
-void WaylandEglOutput::aboutToStartPainting(const QRegion &damage)
+void WaylandEglPrimaryLayer::aboutToStartPainting(const QRegion &damage)
 {
     if (m_bufferAge > 0 && !damage.isEmpty() && m_backend->supportsPartialUpdate()) {
         QVector<EGLint> rects = regionToRects(damage, m_waylandOutput);
@@ -164,7 +150,7 @@ void WaylandEglOutput::aboutToStartPainting(const QRegion &damage)
     }
 }
 
-void WaylandEglOutput::present()
+void WaylandEglPrimaryLayer::present()
 {
     m_waylandOutput->surface()->setupFrameCallback();
     m_waylandOutput->surface()->setScale(std::ceil(m_waylandOutput->scale()));
@@ -187,6 +173,81 @@ void WaylandEglOutput::present()
     }
 }
 
+WaylandEglCursorLayer::WaylandEglCursorLayer(WaylandOutput *output, WaylandEglBackend *backend)
+    : m_output(output)
+    , m_backend(backend)
+{
+}
+
+WaylandEglCursorLayer::~WaylandEglCursorLayer()
+{
+    eglMakeCurrent(m_backend->eglDisplay(), EGL_NO_SURFACE, EGL_NO_SURFACE, m_backend->context());
+    m_framebuffer.reset();
+    m_texture.reset();
+}
+
+qreal WaylandEglCursorLayer::scale() const
+{
+    return m_scale;
+}
+
+void WaylandEglCursorLayer::setScale(qreal scale)
+{
+    m_scale = scale;
+}
+
+QPoint WaylandEglCursorLayer::hotspot() const
+{
+    return m_hotspot;
+}
+
+void WaylandEglCursorLayer::setHotspot(const QPoint &hotspot)
+{
+    m_hotspot = hotspot;
+}
+
+QSize WaylandEglCursorLayer::size() const
+{
+    return m_size;
+}
+
+void WaylandEglCursorLayer::setSize(const QSize &size)
+{
+    m_size = size;
+}
+
+std::optional<OutputLayerBeginFrameInfo> WaylandEglCursorLayer::beginFrame()
+{
+    if (eglMakeCurrent(m_backend->eglDisplay(), EGL_NO_SURFACE, EGL_NO_SURFACE, m_backend->context()) == EGL_FALSE) {
+        qCCritical(KWIN_WAYLAND_BACKEND) << "Make Context Current failed";
+        return std::nullopt;
+    }
+
+    const QSize bufferSize = m_size.expandedTo(QSize(64, 64));
+    if (!m_texture || m_texture->size() != bufferSize) {
+        m_texture = std::make_unique<GLTexture>(GL_RGBA8, bufferSize);
+        m_framebuffer = std::make_unique<GLFramebuffer>(m_texture.get());
+    }
+
+    GLFramebuffer::pushFramebuffer(m_framebuffer.get());
+    return OutputLayerBeginFrameInfo{
+        .renderTarget = RenderTarget(m_framebuffer.get()),
+        .repaint = infiniteRegion(),
+    };
+}
+
+bool WaylandEglCursorLayer::endFrame(const QRegion &renderedRegion, const QRegion &damagedRegion)
+{
+    GLFramebuffer::popFramebuffer();
+
+    // Technically, we could pass a linux-dmabuf buffer, but host kwin does not support that atm.
+    const QImage image = m_texture->toImage().mirrored(false, true);
+    KWayland::Client::Buffer::Ptr buffer = m_output->backend()->display()->shmPool()->createBuffer(image);
+    m_output->cursor()->update(buffer, m_scale, m_hotspot);
+
+    return true;
+}
+
 WaylandEglBackend::WaylandEglBackend(WaylandBackend *b)
     : AbstractEglBackend()
     , m_backend(b)
@@ -196,13 +257,7 @@ WaylandEglBackend::WaylandEglBackend(WaylandBackend *b)
 
     connect(m_backend, &WaylandBackend::outputAdded, this, &WaylandEglBackend::createEglWaylandOutput);
     connect(m_backend, &WaylandBackend::outputRemoved, this, [this](Output *output) {
-        auto it = std::find_if(m_outputs.begin(), m_outputs.end(), [output](const auto &o) {
+        m_outputs.erase(output);
-            return o->m_waylandOutput == output;
-        });
-        if (it == m_outputs.end()) {
-            return;
-        }
-        m_outputs.erase(it);
     });
 
     b->setEglBackend(this);
@@ -220,11 +275,15 @@ void WaylandEglBackend::cleanupSurfaces()
 
 bool WaylandEglBackend::createEglWaylandOutput(Output *waylandOutput)
 {
-    const auto output = std::make_shared<WaylandEglOutput>(static_cast<WaylandOutput *>(waylandOutput), this);
+    auto cursorLayer = std::make_unique<WaylandEglCursorLayer>(static_cast<WaylandOutput *>(waylandOutput), this);
-    if (!output->init()) {
+    auto primaryLayer = std::make_unique<WaylandEglPrimaryLayer>(static_cast<WaylandOutput *>(waylandOutput), this);
+    if (!primaryLayer->init()) {
         return false;
     }
-    m_outputs.insert(waylandOutput, output);
+    m_outputs[waylandOutput] = Layers{
+        .primaryLayer = std::move(primaryLayer),
+        .cursorLayer = std::move(cursorLayer),
+    };
     return true;
 }
 
@@ -293,13 +352,12 @@ bool WaylandEglBackend::initRenderingContext()
         }
     }
 
-    if (m_outputs.isEmpty()) {
+    if (m_outputs.empty()) {
         qCCritical(KWIN_WAYLAND_BACKEND) << "Create Window Surfaces failed";
         return false;
     }
 
-    const auto &firstOutput = m_outputs.first();
+    return makeCurrent();
-    return firstOutput->makeContextCurrent();
 }
 
 bool WaylandEglBackend::initBufferConfigs()
@@ -340,7 +398,7 @@ bool WaylandEglBackend::initBufferConfigs()
 std::shared_ptr<KWin::GLTexture> WaylandEglBackend::textureForOutput(KWin::Output *output) const
 {
     auto texture = std::make_unique<GLTexture>(GL_RGBA8, output->pixelSize());
-    GLFramebuffer::pushFramebuffer(m_outputs[output]->fbo());
+    GLFramebuffer::pushFramebuffer(m_outputs.at(output).primaryLayer->fbo());
     GLFramebuffer renderTarget(texture.get());
     renderTarget.blitFromFramebuffer(QRect(0, texture->height(), texture->width(), -texture->height()));
     GLFramebuffer::popFramebuffer();
@@ -359,12 +417,17 @@ std::unique_ptr<SurfaceTexture> WaylandEglBackend::createSurfaceTextureWayland(S
 
 void WaylandEglBackend::present(Output *output)
 {
-    m_outputs[output]->present();
+    m_outputs[output].primaryLayer->present();
 }
 
 OutputLayer *WaylandEglBackend::primaryLayer(Output *output)
 {
-    return m_outputs[output].get();
+    return m_outputs[output].primaryLayer.get();
+}
+
+WaylandEglCursorLayer *WaylandEglBackend::cursorLayer(Output *output)
+{
+    return m_outputs[output].cursorLayer.get();
 }
 
 }

src/backends/wayland/wayland_egl_backend.h

@@ -17,6 +17,8 @@
 #include <optional>
 #include <wayland-egl.h>
 
+#include <KWayland/Client/buffer.h>
+
 #include <memory>
 
 class QTemporaryFile;
@@ -34,16 +36,15 @@ class WaylandBackend;
 class WaylandOutput;
 class WaylandEglBackend;
 
-class WaylandEglOutput : public OutputLayer
+class WaylandEglPrimaryLayer : public OutputLayer
 {
 public:
-    WaylandEglOutput(WaylandOutput *output, WaylandEglBackend *backend);
+    WaylandEglPrimaryLayer(WaylandOutput *output, WaylandEglBackend *backend);
-    ~WaylandEglOutput() override;
+    ~WaylandEglPrimaryLayer() override;
 
     bool init();
 
     GLFramebuffer *fbo() const;
-    bool makeContextCurrent() const;
     void present();
 
     std::optional<OutputLayerBeginFrameInfo> beginFrame() override;
@@ -62,6 +63,36 @@ private:
     friend class WaylandEglBackend;
 };
 
+class WaylandEglCursorLayer : public OutputLayer
+{
+    Q_OBJECT
+
+public:
+    WaylandEglCursorLayer(WaylandOutput *output, WaylandEglBackend *backend);
+    ~WaylandEglCursorLayer() override;
+
+    qreal scale() const;
+    void setScale(qreal scale);
+
+    QPoint hotspot() const;
+    void setHotspot(const QPoint &hotspot);
+
+    QSize size() const;
+    void setSize(const QSize &size);
+
+    std::optional<OutputLayerBeginFrameInfo> beginFrame() override;
+    bool endFrame(const QRegion &renderedRegion, const QRegion &damagedRegion) override;
+
+private:
+    WaylandOutput *m_output;
+    WaylandEglBackend *m_backend;
+    std::unique_ptr<GLFramebuffer> m_framebuffer;
+    std::unique_ptr<GLTexture> m_texture;
+    QPoint m_hotspot;
+    QSize m_size;
+    qreal m_scale = 1.0;
+};
+
 /**
  * @brief OpenGL Backend using Egl on a Wayland surface.
  *
@@ -87,6 +118,7 @@ public:
     void init() override;
     void present(Output *output) override;
     OutputLayer *primaryLayer(Output *output) override;
+    WaylandEglCursorLayer *cursorLayer(Output *output);
 
     bool havePlatformBase() const
     {
@@ -105,10 +137,16 @@ private:
 
     void cleanupSurfaces() override;
 
-    void presentOnSurface(WaylandEglOutput *output, const QRegion &damagedRegion);
+    void presentOnSurface(WaylandEglPrimaryLayer *output, const QRegion &damagedRegion);
+
+    struct Layers
+    {
+        std::unique_ptr<WaylandEglPrimaryLayer> primaryLayer;
+        std::unique_ptr<WaylandEglCursorLayer> cursorLayer;
+    };
 
     WaylandBackend *m_backend;
-    QMap<Output *, std::shared_ptr<WaylandEglOutput>> m_outputs;
+    std::map<Output *, Layers> m_outputs;
     bool m_havePlatformBase;
     friend class EglWaylandTexture;
 };

src/backends/wayland/wayland_output.cpp

@@ -8,10 +8,16 @@
 */
 #include "wayland_output.h"
 #include "core/renderloop_p.h"
+#include "composite.h"
 #include "wayland_backend.h"
 #include "wayland_display.h"
+#include "wayland_egl_backend.h"
+#include "wayland_qpainter_backend.h"
 #include "wayland_server.h"
 
+#include "kwingltexture.h"
+#include "kwinglutils.h"
+
 #include <KWayland/Client/compositor.h>
 #include <KWayland/Client/pointer.h>
 #include <KWayland/Client/pointerconstraints.h>
@@ -21,6 +27,8 @@
 
 #include <KLocalizedString>
 
+#include <QPainter>
+
 #include <cmath>
 
 namespace KWin
@@ -73,11 +81,13 @@ void WaylandCursor::disable()
 
 void WaylandCursor::update(KWayland::Client::Buffer::Ptr buffer, qreal scale, const QPoint &hotspot)
 {
-    m_buffer = buffer;
+    if (m_buffer != buffer || m_scale != scale || m_hotspot != hotspot) {
-    m_scale = scale;
+        m_buffer = buffer;
-    m_hotspot = hotspot;
+        m_scale = scale;
+        m_hotspot = hotspot;
 
-    sync();
+        sync();
+    }
 }
 
 void WaylandCursor::sync()
@@ -157,6 +167,11 @@ WaylandCursor *WaylandOutput::cursor() const
     return m_cursor.get();
 }
 
+WaylandBackend *WaylandOutput::backend() const
+{
+    return m_backend;
+}
+
 RenderLoop *WaylandOutput::renderLoop() const
 {
     return m_renderLoop.get();
@@ -164,12 +179,17 @@ RenderLoop *WaylandOutput::renderLoop() const
 
 bool WaylandOutput::setCursor(const QImage &image, const QPoint &hotspot)
 {
-    KWayland::Client::Buffer::Ptr buffer;
+    if (m_hasPointerLock) {
-    if (!image.isNull()) {
+        return false;
-        buffer = m_backend->display()->shmPool()->createBuffer(image);
     }
-    m_cursor->update(buffer, image.devicePixelRatio(), hotspot);
+
-    return !m_hasPointerLock;
+    if (WaylandEglBackend *backend = qobject_cast<WaylandEglBackend *>(Compositor::self()->backend())) {
+        renderCursorOpengl(backend, image, hotspot);
+    } else if (WaylandQPainterBackend *backend = qobject_cast<WaylandQPainterBackend *>(Compositor::self()->backend())) {
+        renderCursorQPainter(backend, image, hotspot);
+    }
+
+    return true;
 }
 
 bool WaylandOutput::moveCursor(const QPoint &position)
@@ -178,6 +198,68 @@ bool WaylandOutput::moveCursor(const QPoint &position)
     return !m_hasPointerLock;
 }
 
+void WaylandOutput::renderCursorOpengl(WaylandEglBackend *backend, const QImage &image, const QPoint &hotspot)
+{
+    WaylandEglCursorLayer *cursorLayer = backend->cursorLayer(this);
+    cursorLayer->setSize(image.size());
+    cursorLayer->setScale(image.devicePixelRatio());
+    cursorLayer->setHotspot(hotspot);
+
+    std::optional<OutputLayerBeginFrameInfo> beginInfo = cursorLayer->beginFrame();
+    if (!beginInfo) {
+        return;
+    }
+
+    const QRect cursorRect(QPoint(0, 0), image.size() / image.devicePixelRatio());
+
+    QMatrix4x4 mvp;
+    mvp.ortho(QRect(QPoint(), beginInfo->renderTarget.size()));
+
+    glClearColor(0, 0, 0, 0);
+    glClear(GL_COLOR_BUFFER_BIT);
+
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+    GLTexture texture(image);
+    texture.bind();
+    ShaderBinder binder(ShaderTrait::MapTexture);
+    binder.shader()->setUniform(GLShader::ModelViewProjectionMatrix, mvp);
+    texture.render(cursorRect, beginInfo->renderTarget.devicePixelRatio());
+    texture.unbind();
+    glDisable(GL_BLEND);
+
+    cursorLayer->endFrame(infiniteRegion(), infiniteRegion());
+}
+
+void WaylandOutput::renderCursorQPainter(WaylandQPainterBackend *backend, const QImage &image, const QPoint &hotspot)
+{
+    WaylandQPainterCursorLayer *cursorLayer = backend->cursorLayer(this);
+    cursorLayer->setSize(image.size());
+    cursorLayer->setScale(image.devicePixelRatio());
+    cursorLayer->setHotspot(hotspot);
+
+    std::optional<OutputLayerBeginFrameInfo> beginInfo = cursorLayer->beginFrame();
+    if (!beginInfo) {
+        return;
+    }
+
+    const QRect cursorRect(QPoint(0, 0), image.size() / image.devicePixelRatio());
+
+    QImage *c = std::get<QImage *>(beginInfo->renderTarget.nativeHandle());
+    c->setDevicePixelRatio(scale());
+    c->fill(Qt::transparent);
+
+    QPainter p;
+    p.begin(c);
+    p.setWorldTransform(logicalToNativeMatrix(cursorRect, 1, transform()).toTransform());
+    p.setRenderHint(QPainter::SmoothPixmapTransform);
+    p.drawImage(QPoint(0, 0), image);
+    p.end();
+
+    cursorLayer->endFrame(infiniteRegion(), infiniteRegion());
+}
+
 void WaylandOutput::init(const QSize &pixelSize, qreal scale)
 {
     m_renderLoop->setRefreshRate(s_refreshRate);

src/backends/wayland/wayland_output.h

@@ -32,6 +32,8 @@ namespace KWin
 namespace Wayland
 {
 class WaylandBackend;
+class WaylandEglBackend;
+class WaylandQPainterBackend;
 
 class WaylandCursor
 {
@@ -74,6 +76,7 @@ public:
     bool isReady() const;
     KWayland::Client::Surface *surface() const;
     WaylandCursor *cursor() const;
+    WaylandBackend *backend() const;
 
     void lockPointer(KWayland::Client::Pointer *pointer, bool lock);
     void resize(const QSize &pixelSize);
@@ -84,6 +87,8 @@ public:
 private:
     void handleConfigure(const QSize &size, KWayland::Client::XdgShellSurface::States states, quint32 serial);
     void updateWindowTitle();
+    void renderCursorOpengl(WaylandEglBackend *backend, const QImage &image, const QPoint &hotspot);
+    void renderCursorQPainter(WaylandQPainterBackend *backend, const QImage &image, const QPoint &hotspot);
 
     std::unique_ptr<RenderLoop> m_renderLoop;
     std::unique_ptr<KWayland::Client::Surface> m_surface;

src/backends/wayland/wayland_qpainter_backend.cpp

@@ -36,26 +36,19 @@ WaylandQPainterBufferSlot::~WaylandQPainterBufferSlot()
     buffer->setUsed(false);
 }
 
-WaylandQPainterOutput::WaylandQPainterOutput(WaylandOutput *output)
+WaylandQPainterPrimaryLayer::WaylandQPainterPrimaryLayer(WaylandOutput *output)
     : m_waylandOutput(output)
+    , m_pool(output->backend()->display()->shmPool())
 {
+    connect(m_pool, &KWayland::Client::ShmPool::poolResized, this, &WaylandQPainterPrimaryLayer::remapBuffer);
 }
 
-WaylandQPainterOutput::~WaylandQPainterOutput()
+WaylandQPainterPrimaryLayer::~WaylandQPainterPrimaryLayer()
 {
     m_slots.clear();
 }
 
-bool WaylandQPainterOutput::init(KWayland::Client::ShmPool *pool)
+void WaylandQPainterPrimaryLayer::remapBuffer()
-{
-    m_pool = pool;
-
-    connect(pool, &KWayland::Client::ShmPool::poolResized, this, &WaylandQPainterOutput::remapBuffer);
-
-    return true;
-}
-
-void WaylandQPainterOutput::remapBuffer()
 {
     qCDebug(KWIN_WAYLAND_BACKEND) << "Remapped back buffer of surface" << m_waylandOutput->surface();
 
@@ -65,7 +58,7 @@ void WaylandQPainterOutput::remapBuffer()
     }
 }
 
-void WaylandQPainterOutput::present()
+void WaylandQPainterPrimaryLayer::present()
 {
     for (const auto &slot : m_slots) {
         if (slot.get() == m_back) {
@@ -82,12 +75,12 @@ void WaylandQPainterOutput::present()
     s->commit();
 }
 
-WaylandQPainterBufferSlot *WaylandQPainterOutput::back() const
+WaylandQPainterBufferSlot *WaylandQPainterPrimaryLayer::back() const
 {
     return m_back;
 }
 
-WaylandQPainterBufferSlot *WaylandQPainterOutput::acquire()
+WaylandQPainterBufferSlot *WaylandQPainterPrimaryLayer::acquire()
 {
     const QSize nativeSize(m_waylandOutput->pixelSize());
     if (m_swapchainSize != nativeSize) {
@@ -116,12 +109,12 @@ WaylandQPainterBufferSlot *WaylandQPainterOutput::acquire()
     return m_back;
 }
 
-QRegion WaylandQPainterOutput::accumulateDamage(int bufferAge) const
+QRegion WaylandQPainterPrimaryLayer::accumulateDamage(int bufferAge) const
 {
     return m_damageJournal.accumulate(bufferAge, infiniteRegion());
 }
 
-std::optional<OutputLayerBeginFrameInfo> WaylandQPainterOutput::beginFrame()
+std::optional<OutputLayerBeginFrameInfo> WaylandQPainterPrimaryLayer::beginFrame()
 {
     WaylandQPainterBufferSlot *slot = acquire();
     return OutputLayerBeginFrameInfo{
@@ -130,12 +123,71 @@ std::optional<OutputLayerBeginFrameInfo> WaylandQPainterOutput::beginFrame()
     };
 }
 
-bool WaylandQPainterOutput::endFrame(const QRegion &renderedRegion, const QRegion &damagedRegion)
+bool WaylandQPainterPrimaryLayer::endFrame(const QRegion &renderedRegion, const QRegion &damagedRegion)
 {
     m_damageJournal.add(damagedRegion);
     return true;
 }
 
+WaylandQPainterCursorLayer::WaylandQPainterCursorLayer(WaylandOutput *output)
+    : m_output(output)
+{
+}
+
+WaylandQPainterCursorLayer::~WaylandQPainterCursorLayer()
+{
+}
+
+qreal WaylandQPainterCursorLayer::scale() const
+{
+    return m_scale;
+}
+
+void WaylandQPainterCursorLayer::setScale(qreal scale)
+{
+    m_scale = scale;
+}
+
+QPoint WaylandQPainterCursorLayer::hotspot() const
+{
+    return m_hotspot;
+}
+
+void WaylandQPainterCursorLayer::setHotspot(const QPoint &hotspot)
+{
+    m_hotspot = hotspot;
+}
+
+QSize WaylandQPainterCursorLayer::size() const
+{
+    return m_size;
+}
+
+void WaylandQPainterCursorLayer::setSize(const QSize &size)
+{
+    m_size = size;
+}
+
+std::optional<OutputLayerBeginFrameInfo> WaylandQPainterCursorLayer::beginFrame()
+{
+    const QSize bufferSize = m_size.expandedTo(QSize(64, 64));
+    if (m_backingStore.size() != bufferSize) {
+        m_backingStore = QImage(bufferSize, QImage::Format_ARGB32_Premultiplied);
+    }
+
+    return OutputLayerBeginFrameInfo{
+        .renderTarget = RenderTarget(&m_backingStore),
+        .repaint = infiniteRegion(),
+    };
+}
+
+bool WaylandQPainterCursorLayer::endFrame(const QRegion &renderedRegion, const QRegion &damagedRegion)
+{
+    KWayland::Client::Buffer::Ptr buffer = m_output->backend()->display()->shmPool()->createBuffer(m_backingStore);
+    m_output->cursor()->update(buffer, m_scale, m_hotspot);
+    return true;
+}
+
 WaylandQPainterBackend::WaylandQPainterBackend(Wayland::WaylandBackend *b)
     : QPainterBackend()
     , m_backend(b)
@@ -147,13 +199,7 @@ WaylandQPainterBackend::WaylandQPainterBackend(Wayland::WaylandBackend *b)
     }
     connect(m_backend, &WaylandBackend::outputAdded, this, &WaylandQPainterBackend::createOutput);
     connect(m_backend, &WaylandBackend::outputRemoved, this, [this](Output *waylandOutput) {
-        auto it = std::find_if(m_outputs.begin(), m_outputs.end(), [waylandOutput](const auto &output) {
+        m_outputs.erase(waylandOutput);
-            return output->m_waylandOutput == waylandOutput;
-        });
-        if (it == m_outputs.end()) {
-            return;
-        }
-        m_outputs.erase(it);
     });
 }
 
@@ -163,19 +209,26 @@ WaylandQPainterBackend::~WaylandQPainterBackend()
 
 void WaylandQPainterBackend::createOutput(Output *waylandOutput)
 {
-    const auto output = std::make_shared<WaylandQPainterOutput>(static_cast<WaylandOutput *>(waylandOutput));
+    m_outputs[waylandOutput] = Layers{
-    output->init(m_backend->display()->shmPool());
+        .primaryLayer = std::make_unique<WaylandQPainterPrimaryLayer>(static_cast<WaylandOutput *>(waylandOutput)),
-    m_outputs.insert(waylandOutput, output);
+        .cursorLayer = std::make_unique<WaylandQPainterCursorLayer>(static_cast<WaylandOutput *>(waylandOutput)),
+    };
 }
 
 void WaylandQPainterBackend::present(Output *output)
 {
-    m_outputs[output]->present();
+    m_outputs[output].primaryLayer->present();
 }
 
 OutputLayer *WaylandQPainterBackend::primaryLayer(Output *output)
 {
-    return m_outputs[output].get();
+    return m_outputs[output].primaryLayer.get();
-}
+}
+
+WaylandQPainterCursorLayer *WaylandQPainterBackend::cursorLayer(Output *output)
+{
+    return m_outputs[output].cursorLayer.get();
+}
+
 }
 }

src/backends/wayland/wayland_qpainter_backend.h

@@ -13,6 +13,8 @@
 #include "qpainterbackend.h"
 #include "utils/damagejournal.h"
 
+#include <KWayland/Client/buffer.h>
+
 #include <QImage>
 #include <QObject>
 #include <QWeakPointer>
@@ -46,16 +48,15 @@ public:
     int age = 0;
 };
 
-class WaylandQPainterOutput : public OutputLayer
+class WaylandQPainterPrimaryLayer : public OutputLayer
 {
 public:
-    WaylandQPainterOutput(WaylandOutput *output);
+    WaylandQPainterPrimaryLayer(WaylandOutput *output);
-    ~WaylandQPainterOutput() override;
+    ~WaylandQPainterPrimaryLayer() override;
 
     std::optional<OutputLayerBeginFrameInfo> beginFrame() override;
     bool endFrame(const QRegion &renderedRegion, const QRegion &damagedRegion) override;
 
-    bool init(KWayland::Client::ShmPool *pool);
     void remapBuffer();
 
     WaylandQPainterBufferSlot *back() const;
@@ -77,6 +78,34 @@ private:
     friend class WaylandQPainterBackend;
 };
 
+class WaylandQPainterCursorLayer : public OutputLayer
+{
+    Q_OBJECT
+
+public:
+    explicit WaylandQPainterCursorLayer(WaylandOutput *output);
+    ~WaylandQPainterCursorLayer() override;
+
+    qreal scale() const;
+    void setScale(qreal scale);
+
+    QPoint hotspot() const;
+    void setHotspot(const QPoint &hotspot);
+
+    QSize size() const;
+    void setSize(const QSize &size);
+
+    std::optional<OutputLayerBeginFrameInfo> beginFrame() override;
+    bool endFrame(const QRegion &renderedRegion, const QRegion &damagedRegion) override;
+
+private:
+    WaylandOutput *m_output;
+    QImage m_backingStore;
+    QPoint m_hotspot;
+    QSize m_size;
+    qreal m_scale = 1.0;
+};
+
 class WaylandQPainterBackend : public QPainterBackend
 {
     Q_OBJECT
@@ -86,13 +115,20 @@ public:
 
     void present(Output *output) override;
     OutputLayer *primaryLayer(Output *output) override;
+    WaylandQPainterCursorLayer *cursorLayer(Output *output);
 
 private:
     void createOutput(Output *waylandOutput);
     void frameRendered();
 
+    struct Layers
+    {
+        std::unique_ptr<WaylandQPainterPrimaryLayer> primaryLayer;
+        std::unique_ptr<WaylandQPainterCursorLayer> cursorLayer;
+    };
+
     WaylandBackend *m_backend;
-    QMap<Output *, std::shared_ptr<WaylandQPainterOutput>> m_outputs;
+    std::map<Output *, Layers> m_outputs;
 };
 
 } // namespace Wayland