Support wl_surface.damage_buffer

Add compositor support for wl_surface.damage_buffer requests.
This also required updating wl_compositor to version 4.

Fixes: QTBUG-74927
Change-Id: I887ed04e60fe14ecce7df6a517950b0091e2ad54
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

7 files changed, 81 insertions, 20 deletions

diff --git a/src/compositor/compositor_api/qwaylandcompositor.cpp b/src/compositor/compositor_api/qwaylandcompositor.cpp
index 8878ce121..fb99f9413 100644
--- a/src/compositor/compositor_api/qwaylandcompositor.cpp
+++ b/src/compositor/compositor_api/qwaylandcompositor.cpp
@@ -190,7 +190,7 @@ void QWaylandCompositorPrivate::init()
         if (socketArg != -1 && socketArg + 1 < arguments.size())
             socket_name = arguments.at(socketArg + 1).toLocal8Bit();
     }
-    wl_compositor::init(display, 3);
+    wl_compositor::init(display, 4);
     wl_subcompositor::init(display, 1);
 
 #if QT_CONFIG(wayland_datadevice)
diff --git a/src/compositor/compositor_api/qwaylandsurface.cpp b/src/compositor/compositor_api/qwaylandsurface.cpp
index 2ebb04a35..efd186fc5 100644
--- a/src/compositor/compositor_api/qwaylandsurface.cpp
+++ b/src/compositor/compositor_api/qwaylandsurface.cpp
@@ -195,9 +195,26 @@ void QWaylandSurfacePrivate::surface_attach(Resource *, struct wl_resource *buff
     pending.newlyAttached = true;
 }
 
+/*
+    Note: The Wayland protocol specifies that buffer scale and damage can be interleaved, so
+    we cannot scale the damage region until commit. We assume that clients will either use
+    surface_damage or surface_damage_buffer within one frame for one surface.
+*/
+
 void QWaylandSurfacePrivate::surface_damage(Resource *, int32_t x, int32_t y, int32_t width, int32_t height)
 {
+    if (Q_UNLIKELY(pending.damageInBufferCoordinates && !pending.damage.isNull()))
+        qCWarning(qLcWaylandCompositor) << "Unsupported: Client is using both wl_surface.damage_buffer and wl_surface.damage.";
+    pending.damage = pending.damage.united(QRect(x, y, width, height));
+    pending.damageInBufferCoordinates = false;
+}
+
+void QWaylandSurfacePrivate::surface_damage_buffer(Resource *, int32_t x, int32_t y, int32_t width, int32_t height)
+{
+    if (Q_UNLIKELY(!pending.damageInBufferCoordinates && !pending.damage.isNull()))
+        qCWarning(qLcWaylandCompositor) << "Unsupported: Client is using both wl_surface.damage_buffer and wl_surface.damage.";
     pending.damage = pending.damage.united(QRect(x, y, width, height));
+    pending.damageInBufferCoordinates = true;
 }
 
 void QWaylandSurfacePrivate::surface_frame(Resource *resource, uint32_t callback)
@@ -240,7 +257,24 @@ void QWaylandSurfacePrivate::surface_commit(Resource *)
     QSize surfaceSize = bufferSize / bufferScale;
     sourceGeometry = !pending.sourceGeometry.isValid() ? QRect(QPoint(), surfaceSize) : pending.sourceGeometry;
     destinationSize = pending.destinationSize.isEmpty() ? sourceGeometry.size().toSize() : pending.destinationSize;
-    damage = pending.damage.intersected(QRect(QPoint(), destinationSize));
+    if (!pending.damageInBufferCoordinates || pending.bufferScale == 1) {
+        // pending.damage is already in surface coordinates
+        damage = pending.damage.intersected(QRect(QPoint(), destinationSize));
+    } else {
+        // We must transform pending.damage from buffer coordinate system to surface coordinates
+        // TODO(QTBUG-85461): Also support wp_viewport setting more complex transformations
+        auto xform = [](const QRect &r, int scale) -> QRect {
+            QRect res{
+                QPoint{ r.x() / scale, r.y() / scale },
+                QPoint{ (r.right() + scale - 1) / scale, (r.bottom() + scale - 1) / scale }
+            };
+            return res;
+        };
+        damage = {};
+        for (const QRect &r : pending.damage) {
+            damage |= xform(r, bufferScale).intersected(QRect{{}, destinationSize});
+        }
+    }
     hasContent = bufferRef.hasContent();
     frameCallbacks << pendingFrameCallbacks;
     inputRegion = pending.inputRegion.intersected(QRect(QPoint(), destinationSize));
@@ -255,6 +289,7 @@ void QWaylandSurfacePrivate::surface_commit(Resource *)
     pending.offset = QPoint();
     pending.newlyAttached = false;
     pending.damage = QRegion();
+    pending.damageInBufferCoordinates = false;
     pendingFrameCallbacks.clear();
 
     // Notify buffers and views
diff --git a/src/compositor/compositor_api/qwaylandsurface_p.h b/src/compositor/compositor_api/qwaylandsurface_p.h
index 3f657c9d0..1150ccf91 100644
--- a/src/compositor/compositor_api/qwaylandsurface_p.h
+++ b/src/compositor/compositor_api/qwaylandsurface_p.h
@@ -116,6 +116,7 @@ protected:
                         struct wl_resource *buffer, int x, int y) override;
     void surface_damage(Resource *resource,
                         int32_t x, int32_t y, int32_t width, int32_t height) override;
+    void surface_damage_buffer(Resource *resource, int32_t x, int32_t y, int32_t width, int32_t height) override;
     void surface_frame(Resource *resource,
                        uint32_t callback) override;
     void surface_set_opaque_region(Resource *resource,
@@ -141,6 +142,7 @@ public: //member variables
     struct {
         QWaylandBufferRef buffer;
         QRegion damage;
+        bool damageInBufferCoordinates = false;
         QPoint offset;
         bool newlyAttached = false;
         QRegion inputRegion;
diff --git a/tests/auto/compositor/compositor/mockclient.cpp b/tests/auto/compositor/compositor/mockclient.cpp
index 76ccd0c58..53e10d687 100644
--- a/tests/auto/compositor/compositor/mockclient.cpp
+++ b/tests/auto/compositor/compositor/mockclient.cpp
@@ -166,7 +166,7 @@ void MockClient::handleGlobalRemove(void *data, wl_registry *wl_registry, uint32
 void MockClient::handleGlobal(uint32_t id, const QByteArray &interface)
 {
     if (interface == "wl_compositor") {
-        compositor = static_cast<wl_compositor *>(wl_registry_bind(registry, id, &wl_compositor_interface, 3));
+        compositor = static_cast<wl_compositor *>(wl_registry_bind(registry, id, &wl_compositor_interface, 4));
     } else if (interface == "wl_output") {
         auto output = static_cast<wl_output *>(wl_registry_bind(registry, id, &wl_output_interface, 2));
         m_outputs.insert(id, output);
diff --git a/tests/auto/compositor/compositor/tst_compositor.cpp b/tests/auto/compositor/compositor/tst_compositor.cpp
index a44aef2f3..902f420de 100644
--- a/tests/auto/compositor/compositor/tst_compositor.cpp
+++ b/tests/auto/compositor/compositor/tst_compositor.cpp
@@ -531,8 +531,6 @@ void tst_WaylandCompositor::mapSurfaceHiDpi()
     };
 
     QObject::connect(waylandSurface, &QWaylandSurface::damaged, [=] (const QRegion &damage) {
-        // Currently, QWaylandSurface::size returns the size in pixels.
-        // Should be fixed or removed for Qt 6.
         QCOMPARE(damage, QRect(QPoint(), surfaceSize));
         verifyComittedState();
     });
@@ -570,6 +568,12 @@ void tst_WaylandCompositor::mapSurfaceHiDpi()
     QTRY_COMPARE(destinationSizeSpy.count(), 1);
     QTRY_COMPARE(bufferScaleSpy.count(), 1);
     QTRY_COMPARE(offsetSpy.count(), 1);
+    QTRY_COMPARE(damagedSpy.count(), 1);
+
+    // Now verify that wl_surface_damage_buffer gets mapped properly
+    wl_surface_damage_buffer(surface, 0, 0, bufferSize.width(), bufferSize.height());
+    wl_surface_commit(surface);
+    QTRY_COMPARE(damagedSpy.count(), 2);
 
     wl_surface_destroy(surface);
 }
diff --git a/tests/manual/scaling-compositor/main.qml b/tests/manual/scaling-compositor/main.qml
index 056af4e5b..655bae1c2 100644
--- a/tests/manual/scaling-compositor/main.qml
+++ b/tests/manual/scaling-compositor/main.qml
@@ -48,10 +48,9 @@
 **
 ****************************************************************************/
 
-import QtQuick 2.2
+import QtQuick 2.15
 import QtQuick.Window 2.2
-import QtQuick.Controls 2.0
-import QtWayland.Compositor 1.0
+import QtWayland.Compositor 1.3
 
 WaylandCompositor {
     id: comp
@@ -66,16 +65,7 @@ WaylandCompositor {
             height: 500
             visible: true
             title: "Scaling compositor x" + output.scaleFactor
-            Button {
-                id: incrementButton
-                text: "+"
-                onClicked: ++output.scaleFactor
-            }
-            Button {
-                text: "-"
-                onClicked: output.scaleFactor = Math.max(1, output.scaleFactor - 1)
-                anchors.left: incrementButton.right
-            }
+
             Repeater {
                 model: shellSurfaces
                 ShellSurfaceItem {
@@ -83,6 +73,33 @@ WaylandCompositor {
                     onSurfaceDestroyed: shellSurfaces.remove(index);
                 }
             }
+
+            Rectangle {
+                id: incrementButton
+                color: "#c0f0d0"
+                Text {
+                    text: "+"
+                }
+                width: 100
+                height: 30
+                TapHandler {
+                    onTapped: ++output.scaleFactor
+                }
+            }
+
+            Rectangle {
+                id: decrementButton
+                color: "#f0d0c0"
+                Text {
+                    text: "-"
+                }
+                width: 100
+                height: 30
+                TapHandler {
+                    onTapped: output.scaleFactor = Math.max(1, output.scaleFactor - 1)
+                }
+                anchors.left: incrementButton.right
+            }
         }
     }
 
@@ -91,4 +108,8 @@ WaylandCompositor {
     WlShell {
         onWlShellSurfaceCreated: shellSurfaces.append({shellSurface: shellSurface});
     }
+    XdgShell {
+        onToplevelCreated:
+            shellSurfaces.append({shellSurface: xdgSurface});
+    }
 }
diff --git a/tests/manual/scaling-compositor/scaling-compositor.pro b/tests/manual/scaling-compositor/scaling-compositor.pro
index 847e07ea7..200dc8c40 100644
--- a/tests/manual/scaling-compositor/scaling-compositor.pro
+++ b/tests/manual/scaling-compositor/scaling-compositor.pro
@@ -1,7 +1,6 @@
 TEMPLATE = app
 
-QT += gui qml quickcontrols2
-
+QT += gui qml
 SOURCES += main.cpp
 
 RESOURCES += qml.qrc