render: do basic yes/no damage tracking

river/LayerSurface.zig

@@ -26,6 +26,7 @@ const util = @import("util.zig");
 
 const Box = @import("Box.zig");
 const Output = @import("Output.zig");
+const Subsurface = @import("Subsurface.zig");
 const XdgPopup = @import("XdgPopup.zig");
 
 const log = std.log.scoped(.layer_shell);
@@ -40,10 +41,11 @@ state: wlr.LayerSurfaceV1.State,
 destroy: wl.Listener(*wlr.LayerSurfaceV1) = wl.Listener(*wlr.LayerSurfaceV1).init(handleDestroy),
 map: wl.Listener(*wlr.LayerSurfaceV1) = wl.Listener(*wlr.LayerSurfaceV1).init(handleMap),
 unmap: wl.Listener(*wlr.LayerSurfaceV1) = wl.Listener(*wlr.LayerSurfaceV1).init(handleUnmap),
+new_popup: wl.Listener(*wlr.XdgPopup) = wl.Listener(*wlr.XdgPopup).init(handleNewPopup),
+new_subsurface: wl.Listener(*wlr.Subsurface) = wl.Listener(*wlr.Subsurface).init(handleNewSubsurface),
 
 // Listeners only active while the layer surface is mapped
 commit: wl.Listener(*wlr.Surface) = wl.Listener(*wlr.Surface).init(handleCommit),
-new_popup: wl.Listener(*wlr.XdgPopup) = wl.Listener(*wlr.XdgPopup).init(handleNewPopup),
 
 pub fn init(self: *Self, output: *Output, wlr_layer_surface: *wlr.LayerSurfaceV1) void {
     self.* = .{
@@ -62,9 +64,11 @@ pub fn init(self: *Self, output: *Output, wlr_layer_surface: *wlr.LayerSurfaceV1
     list.remove(node);
 
     // Set up listeners that are active for the entire lifetime of the layer surface
-    self.wlr_layer_surface.events.destroy.add(&self.destroy);
-    self.wlr_layer_surface.events.map.add(&self.map);
-    self.wlr_layer_surface.events.unmap.add(&self.unmap);
+    wlr_layer_surface.events.destroy.add(&self.destroy);
+    wlr_layer_surface.events.map.add(&self.map);
+    wlr_layer_surface.events.unmap.add(&self.unmap);
+    wlr_layer_surface.events.new_popup.add(&self.new_popup);
+    wlr_layer_surface.surface.events.new_subsurface.add(&self.new_subsurface);
 }
 
 fn handleDestroy(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_surface: *wlr.LayerSurfaceV1) void {
@@ -76,6 +80,8 @@ fn handleDestroy(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_surface:
     self.destroy.link.remove();
     self.map.link.remove();
     self.unmap.link.remove();
+    self.new_popup.link.remove();
+    self.new_subsurface.link.remove();
 
     const node = @fieldParentPtr(std.TailQueue(Self).Node, "data", self);
     util.gpa.destroy(node);
@@ -88,7 +94,6 @@ fn handleMap(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_surface: *wl
 
     // Add listeners that are only active while mapped
     wlr_layer_surface.surface.events.commit.add(&self.commit);
-    wlr_layer_surface.events.new_popup.add(&self.new_popup);
 
     wlr_layer_surface.surface.sendEnter(wlr_layer_surface.output.?);
 
@@ -103,7 +108,6 @@ fn handleUnmap(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_surface: *
 
     // remove listeners only active while the layer surface is mapped
     self.commit.link.remove();
-    self.new_popup.link.remove();
 
     // Remove from the output's list of layer surfaces
     const self_node = @fieldParentPtr(std.TailQueue(Self).Node, "data", self);
@@ -154,15 +158,16 @@ fn handleCommit(listener: *wl.Listener(*wlr.Surface), wlr_surface: *wlr.Surface)
         self.output.arrangeLayers();
         server.root.startTransaction();
     }
+
+    self.output.damage.addWhole();
 }
 
 fn handleNewPopup(listener: *wl.Listener(*wlr.XdgPopup), wlr_xdg_popup: *wlr.XdgPopup) void {
     const self = @fieldParentPtr(Self, "new_popup", listener);
-
-    // This will free itself on destroy
-    const xdg_popup = util.gpa.create(XdgPopup) catch {
-        wlr_xdg_popup.resource.postNoMemory();
-        return;
-    };
-    xdg_popup.init(self.output, &self.box, wlr_xdg_popup);
+    XdgPopup.create(wlr_xdg_popup, .{ .layer_surface = self });
+}
+
+fn handleNewSubsurface(listener: *wl.Listener(*wlr.Subsurface), new_wlr_subsurface: *wlr.Subsurface) void {
+    const self = @fieldParentPtr(Self, "new_subsurface", listener);
+    Subsurface.create(new_wlr_subsurface, .{ .layer_surface = self });
 }

river/Output.zig

@@ -55,6 +55,7 @@ const State = struct {
 };
 
 wlr_output: *wlr.Output,
+damage: *wlr.OutputDamage,
 
 /// All layer surfaces on the output, indexed by the layer enum.
 layers: [4]std.TailQueue(LayerSurface) = [1]std.TailQueue(LayerSurface){.{}} ** 4,
@@ -93,8 +94,8 @@ status_trackers: std.SinglyLinkedList(OutputStatus) = .{},
 
 destroy: wl.Listener(*wlr.Output) = wl.Listener(*wlr.Output).init(handleDestroy),
 enable: wl.Listener(*wlr.Output) = wl.Listener(*wlr.Output).init(handleEnable),
-frame: wl.Listener(*wlr.Output) = wl.Listener(*wlr.Output).init(handleFrame),
 mode: wl.Listener(*wlr.Output) = wl.Listener(*wlr.Output).init(handleMode),
+frame: wl.Listener(*wlr.OutputDamage) = wl.Listener(*wlr.OutputDamage).init(handleFrame),
 
 pub fn init(self: *Self, wlr_output: *wlr.Output) !void {
     // Some backends don't have modes. DRM+KMS does, and we need to set a mode
@@ -110,15 +111,17 @@ pub fn init(self: *Self, wlr_output: *wlr.Output) !void {
 
     self.* = .{
         .wlr_output = wlr_output,
+        .damage = try wlr.OutputDamage.create(wlr_output),
         .usable_box = undefined,
     };
     wlr_output.data = @ptrToInt(self);
 
     wlr_output.events.destroy.add(&self.destroy);
     wlr_output.events.enable.add(&self.enable);
-    wlr_output.events.frame.add(&self.frame);
     wlr_output.events.mode.add(&self.mode);
 
+    self.damage.events.frame.add(&self.frame);
+
     if (wlr_output.isNoop()) {
         // A noop output is always 0 x 0
         self.usable_box = .{
@@ -453,7 +456,7 @@ fn handleEnable(listener: *wl.Listener(*wlr.Output), wlr_output: *wlr.Output) vo
     if (wlr_output.enabled) server.root.addOutput(self);
 }
 
-fn handleFrame(listener: *wl.Listener(*wlr.Output), wlr_output: *wlr.Output) void {
+fn handleFrame(listener: *wl.Listener(*wlr.OutputDamage), wlr_output: *wlr.OutputDamage) void {
     // This function is called every time an output is ready to display a frame,
     // generally at the output's refresh rate (e.g. 60Hz).
     const self = @fieldParentPtr(Self, "frame", listener);

river/Root.zig

@@ -404,6 +404,8 @@ fn commitTransaction(self: *Self) void {
         }
 
         if (view_tags_changed) output.sendViewTags();
+
+        output.damage.addWhole();
     }
 }
 

river/Subsurface.zig

@@ -0,0 +1,103 @@
+// This file is part of river, a dynamic tiling wayland compositor.
+//
+// Copyright 2021 The River Developers
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+const Subsurface = @This();
+
+const std = @import("std");
+const wlr = @import("wlroots");
+const wl = @import("wayland").server.wl;
+
+const util = @import("util.zig");
+
+const LayerSurface = @import("LayerSurface.zig");
+const View = @import("View.zig");
+
+pub const Parent = union(enum) {
+    view: *View,
+    layer_surface: *LayerSurface,
+
+    pub fn damageWholeOutput(parent: Parent) void {
+        switch (parent) {
+            .view => |view| view.output.damage.addWhole(),
+            .layer_surface => |layer_surface| layer_surface.output.damage.addWhole(),
+        }
+    }
+};
+
+/// The parent at the root of this surface tree
+parent: Parent,
+wlr_subsurface: *wlr.Subsurface,
+
+// Always active
+destroy: wl.Listener(*wlr.Subsurface) = wl.Listener(*wlr.Subsurface).init(handleDestroy),
+map: wl.Listener(*wlr.Subsurface) = wl.Listener(*wlr.Subsurface).init(handleMap),
+unmap: wl.Listener(*wlr.Subsurface) = wl.Listener(*wlr.Subsurface).init(handleUnmap),
+new_subsurface: wl.Listener(*wlr.Subsurface) = wl.Listener(*wlr.Subsurface).init(handleNewSubsurface),
+
+// Only active while mapped
+commit: wl.Listener(*wlr.Surface) = wl.Listener(*wlr.Surface).init(handleCommit),
+
+pub fn create(wlr_subsurface: *wlr.Subsurface, parent: Parent) void {
+    const subsurface = util.gpa.create(Subsurface) catch {
+        std.log.crit("out of memory", .{});
+        wlr_subsurface.resource.getClient().postNoMemory();
+        return;
+    };
+    subsurface.* = .{ .wlr_subsurface = wlr_subsurface, .parent = parent };
+
+    wlr_subsurface.events.destroy.add(&subsurface.destroy);
+    wlr_subsurface.events.map.add(&subsurface.map);
+    wlr_subsurface.events.unmap.add(&subsurface.unmap);
+    wlr_subsurface.surface.events.new_subsurface.add(&subsurface.new_subsurface);
+}
+
+fn handleDestroy(listener: *wl.Listener(*wlr.Subsurface), wlr_subsurface: *wlr.Subsurface) void {
+    const subsurface = @fieldParentPtr(Subsurface, "destroy", listener);
+
+    subsurface.destroy.link.remove();
+    subsurface.map.link.remove();
+    subsurface.unmap.link.remove();
+    subsurface.new_subsurface.link.remove();
+
+    util.gpa.destroy(subsurface);
+}
+
+fn handleMap(listener: *wl.Listener(*wlr.Subsurface), wlr_subsurface: *wlr.Subsurface) void {
+    const subsurface = @fieldParentPtr(Subsurface, "map", listener);
+
+    wlr_subsurface.surface.events.commit.add(&subsurface.commit);
+    subsurface.parent.damageWholeOutput();
+}
+
+fn handleUnmap(listener: *wl.Listener(*wlr.Subsurface), wlr_subsurface: *wlr.Subsurface) void {
+    const subsurface = @fieldParentPtr(Subsurface, "unmap", listener);
+
+    subsurface.commit.link.remove();
+    subsurface.parent.damageWholeOutput();
+}
+
+fn handleCommit(listener: *wl.Listener(*wlr.Surface), surface: *wlr.Surface) void {
+    const subsurface = @fieldParentPtr(Subsurface, "commit", listener);
+
+    subsurface.parent.damageWholeOutput();
+}
+
+fn handleNewSubsurface(listener: *wl.Listener(*wlr.Subsurface), new_wlr_subsurface: *wlr.Subsurface) void {
+    const subsurface = @fieldParentPtr(Subsurface, "new_subsurface", listener);
+
+    Subsurface.create(new_wlr_subsurface, subsurface.parent);
+}

river/View.zig

@@ -278,13 +278,14 @@ pub fn saveBuffers(self: *Self) void {
 /// Otherwise, apply the pending state immediately.
 pub fn notifyConfiguredOrApplyPending(self: *Self) void {
     self.pending_serial = null;
-    if (self.shouldTrackConfigure())
-        server.root.notifyConfigured()
-    else {
+    if (self.shouldTrackConfigure()) {
+        server.root.notifyConfigured();
+    } else {
         const self_tags_changed = self.pending.tags != self.current.tags;
         self.current = self.pending;
         self.commitOpacityTransition();
         if (self_tags_changed) self.output.sendViewTags();
+        self.output.damage.addWhole();
     }
 }
 

river/XdgPopup.zig

@@ -23,32 +23,44 @@ const wl = @import("wayland").server.wl;
 
 const util = @import("util.zig");
 
-const Box = @import("Box.zig");
-const Output = @import("Output.zig");
+const Subsurface = @import("Subsurface.zig");
+const Parent = Subsurface.Parent;
 
-const log = std.log.scoped(.server);
-
-/// The output this popup is displayed on.
-output: *Output,
-
-/// Box of the parent of this popup tree. Needed to unconstrain child popups.
-parent_box: *const Box,
-
-/// The corresponding wlroots object
+/// The parent at the root of this surface tree
+parent: Parent,
 wlr_xdg_popup: *wlr.XdgPopup,
 
+// Always active
 destroy: wl.Listener(*wlr.XdgSurface) = wl.Listener(*wlr.XdgSurface).init(handleDestroy),
+map: wl.Listener(*wlr.XdgSurface) = wl.Listener(*wlr.XdgSurface).init(handleMap),
+unmap: wl.Listener(*wlr.XdgSurface) = wl.Listener(*wlr.XdgSurface).init(handleUnmap),
 new_popup: wl.Listener(*wlr.XdgPopup) = wl.Listener(*wlr.XdgPopup).init(handleNewPopup),
+new_subsurface: wl.Listener(*wlr.Subsurface) = wl.Listener(*wlr.Subsurface).init(handleNewSubsurface),
 
-pub fn init(self: *Self, output: *Output, parent_box: *const Box, wlr_xdg_popup: *wlr.XdgPopup) void {
+// Only active while mapped
+commit: wl.Listener(*wlr.Surface) = wl.Listener(*wlr.Surface).init(handleCommit),
+
+pub fn create(wlr_xdg_popup: *wlr.XdgPopup, parent: Parent) void {
+    const self = util.gpa.create(Self) catch {
+        std.log.crit("out of memory", .{});
+        wlr_xdg_popup.resource.postNoMemory();
+        return;
+    };
     self.* = .{
-        .output = output,
-        .parent_box = parent_box,
+        .parent = parent,
         .wlr_xdg_popup = wlr_xdg_popup,
     };
 
+    const parent_box = switch (parent) {
+        .view => |view| &view.pending.box,
+        .layer_surface => |layer_surface| &layer_surface.box,
+    };
+    const output_dimensions = switch (parent) {
+        .view => |view| view.output.getEffectiveResolution(),
+        .layer_surface => |layer_surface| layer_surface.output.getEffectiveResolution(),
+    };
+
     // The output box relative to the parent of the popup
-    const output_dimensions = output.getEffectiveResolution();
     var box = wlr.Box{
         .x = -parent_box.x,
         .y = -parent_box.y,
@@ -58,27 +70,52 @@ pub fn init(self: *Self, output: *Output, parent_box: *const Box, wlr_xdg_popup:
     wlr_xdg_popup.unconstrainFromBox(&box);
 
     wlr_xdg_popup.base.events.destroy.add(&self.destroy);
+    wlr_xdg_popup.base.events.map.add(&self.map);
+    wlr_xdg_popup.base.events.unmap.add(&self.unmap);
     wlr_xdg_popup.base.events.new_popup.add(&self.new_popup);
+    wlr_xdg_popup.base.surface.events.new_subsurface.add(&self.new_subsurface);
 }
 
 fn handleDestroy(listener: *wl.Listener(*wlr.XdgSurface), wlr_xdg_surface: *wlr.XdgSurface) void {
     const self = @fieldParentPtr(Self, "destroy", listener);
 
     self.destroy.link.remove();
+    self.map.link.remove();
+    self.unmap.link.remove();
     self.new_popup.link.remove();
+    self.new_subsurface.link.remove();
 
     util.gpa.destroy(self);
 }
 
-/// Called when a new xdg popup is requested by the client
+fn handleMap(listener: *wl.Listener(*wlr.XdgSurface), xdg_surface: *wlr.XdgSurface) void {
+    const self = @fieldParentPtr(Self, "map", listener);
+
+    self.wlr_xdg_popup.base.surface.events.commit.add(&self.commit);
+    self.parent.damageWholeOutput();
+}
+
+fn handleUnmap(listener: *wl.Listener(*wlr.XdgSurface), xdg_surface: *wlr.XdgSurface) void {
+    const self = @fieldParentPtr(Self, "unmap", listener);
+
+    self.commit.link.remove();
+    self.parent.damageWholeOutput();
+}
+
+fn handleCommit(listener: *wl.Listener(*wlr.Surface), surface: *wlr.Surface) void {
+    const self = @fieldParentPtr(Self, "commit", listener);
+
+    self.parent.damageWholeOutput();
+}
+
 fn handleNewPopup(listener: *wl.Listener(*wlr.XdgPopup), wlr_xdg_popup: *wlr.XdgPopup) void {
     const self = @fieldParentPtr(Self, "new_popup", listener);
 
-    // This will free itself on destroy
-    const xdg_popup = util.gpa.create(Self) catch {
-        wlr_xdg_popup.resource.postNoMemory();
-        log.crit("out of memory", .{});
-        return;
-    };
-    xdg_popup.init(self.output, self.parent_box, wlr_xdg_popup);
+    Self.create(wlr_xdg_popup, self.parent);
+}
+
+fn handleNewSubsurface(listener: *wl.Listener(*wlr.Subsurface), new_wlr_subsurface: *wlr.Subsurface) void {
+    const self = @fieldParentPtr(Self, "new_subsurface", listener);
+
+    Subsurface.create(new_wlr_subsurface, self.parent);
 }

river/XdgToplevel.zig

@@ -26,6 +26,7 @@ const util = @import("util.zig");
 
 const Box = @import("Box.zig");
 const Seat = @import("Seat.zig");
+const Subsurface = @import("Subsurface.zig");
 const View = @import("View.zig");
 const ViewStack = @import("view_stack.zig").ViewStack;
 const XdgPopup = @import("XdgPopup.zig");
@@ -42,10 +43,11 @@ xdg_surface: *wlr.XdgSurface,
 destroy: wl.Listener(*wlr.XdgSurface) = wl.Listener(*wlr.XdgSurface).init(handleDestroy),
 map: wl.Listener(*wlr.XdgSurface) = wl.Listener(*wlr.XdgSurface).init(handleMap),
 unmap: wl.Listener(*wlr.XdgSurface) = wl.Listener(*wlr.XdgSurface).init(handleUnmap),
+new_popup: wl.Listener(*wlr.XdgPopup) = wl.Listener(*wlr.XdgPopup).init(handleNewPopup),
+new_subsurface: wl.Listener(*wlr.Subsurface) = wl.Listener(*wlr.Subsurface).init(handleNewSubsurface),
 
 // Listeners that are only active while the view is mapped
 commit: wl.Listener(*wlr.Surface) = wl.Listener(*wlr.Surface).init(handleCommit),
-new_popup: wl.Listener(*wlr.XdgPopup) = wl.Listener(*wlr.XdgPopup).init(handleNewPopup),
 // zig fmt: off
 request_fullscreen: wl.Listener(*wlr.XdgToplevel.event.SetFullscreen) =
     wl.Listener(*wlr.XdgToplevel.event.SetFullscreen).init(handleRequestFullscreen),
@@ -65,6 +67,8 @@ pub fn init(self: *Self, view: *View, xdg_surface: *wlr.XdgSurface) void {
     self.xdg_surface.events.destroy.add(&self.destroy);
     self.xdg_surface.events.map.add(&self.map);
     self.xdg_surface.events.unmap.add(&self.unmap);
+    self.xdg_surface.events.new_popup.add(&self.new_popup);
+    self.xdg_surface.surface.events.new_subsurface.add(&self.new_subsurface);
 }
 
 pub fn deinit(self: *Self) void {
@@ -73,6 +77,8 @@ pub fn deinit(self: *Self) void {
         self.destroy.link.remove();
         self.map.link.remove();
         self.unmap.link.remove();
+        self.new_popup.link.remove();
+        self.new_subsurface.link.remove();
     }
 }
 
@@ -161,7 +167,6 @@ fn handleMap(listener: *wl.Listener(*wlr.XdgSurface), xdg_surface: *wlr.XdgSurfa
 
     // Add listeners that are only active while mapped
     self.xdg_surface.surface.events.commit.add(&self.commit);
-    self.xdg_surface.events.new_popup.add(&self.new_popup);
     toplevel.events.request_fullscreen.add(&self.request_fullscreen);
     toplevel.events.request_move.add(&self.request_move);
     toplevel.events.request_resize.add(&self.request_resize);
@@ -229,7 +234,6 @@ fn handleUnmap(listener: *wl.Listener(*wlr.XdgSurface), xdg_surface: *wlr.XdgSur
 
     // Remove listeners that are only active while mapped
     self.commit.link.remove();
-    self.new_popup.link.remove();
     self.request_fullscreen.link.remove();
     self.request_move.link.remove();
     self.request_resize.link.remove();
@@ -260,6 +264,7 @@ fn handleCommit(listener: *wl.Listener(*wlr.Surface), surface: *wlr.Surface) voi
             view.sendFrameDone();
         }
     } else {
+        view.output.damage.addWhole();
         // TODO: handle unexpected change in dimensions
         if (!std.meta.eql(view.surface_box, new_box))
             log.err("view changed size unexpectedly", .{});
@@ -267,16 +272,14 @@ fn handleCommit(listener: *wl.Listener(*wlr.Surface), surface: *wlr.Surface) voi
     }
 }
 
-/// Called when a new xdg popup is requested by the client
 fn handleNewPopup(listener: *wl.Listener(*wlr.XdgPopup), wlr_xdg_popup: *wlr.XdgPopup) void {
     const self = @fieldParentPtr(Self, "new_popup", listener);
+    XdgPopup.create(wlr_xdg_popup, .{ .view = self.view });
+}
 
-    // This will free itself on destroy
-    const xdg_popup = util.gpa.create(XdgPopup) catch {
-        wlr_xdg_popup.resource.postNoMemory();
-        return;
-    };
-    xdg_popup.init(self.view.output, &self.view.current.box, wlr_xdg_popup);
+fn handleNewSubsurface(listener: *wl.Listener(*wlr.Subsurface), new_wlr_subsurface: *wlr.Subsurface) void {
+    const self = @fieldParentPtr(Self, "new_subsurface", listener);
+    Subsurface.create(new_wlr_subsurface, .{ .view = self.view });
 }
 
 /// Called when the client asks to be fullscreened. We always honor the request

river/XwaylandUnmanaged.zig

@@ -37,6 +37,7 @@ request_configure: wl.Listener(*wlr.XwaylandSurface.event.Configure) =
 destroy: wl.Listener(*wlr.XwaylandSurface) = wl.Listener(*wlr.XwaylandSurface).init(handleDestroy),
 map: wl.Listener(*wlr.XwaylandSurface) = wl.Listener(*wlr.XwaylandSurface).init(handleMap),
 unmap: wl.Listener(*wlr.XwaylandSurface) = wl.Listener(*wlr.XwaylandSurface).init(handleUnmap),
+commit: wl.Listener(*wlr.Surface) = wl.Listener(*wlr.Surface).init(handleCommit),
 
 pub fn init(self: *Self, xwayland_surface: *wlr.XwaylandSurface) void {
     self.* = .{ .xwayland_surface = xwayland_surface };
@@ -78,6 +79,8 @@ fn handleMap(listener: *wl.Listener(*wlr.XwaylandSurface), xwayland_surface: *wl
     const node = @fieldParentPtr(std.TailQueue(Self).Node, "data", self);
     server.root.xwayland_unmanaged_views.prepend(node);
 
+    xwayland_surface.surface.?.events.commit.add(&self.commit);
+
     // TODO: handle keyboard focus
     // if (wlr_xwayland_or_surface_wants_focus(self.xwayland_surface)) { ...
 }
@@ -89,4 +92,11 @@ fn handleUnmap(listener: *wl.Listener(*wlr.XwaylandSurface), xwayland_surface: *
     // Remove self from the list of unmanged views in the root
     const node = @fieldParentPtr(std.TailQueue(Self).Node, "data", self);
     server.root.xwayland_unmanaged_views.remove(node);
+
+    self.commit.link.remove();
+}
+
+fn handleCommit(listener: *wl.Listener(*wlr.Surface), surface: *wlr.Surface) void {
+    var it = server.root.outputs.first;
+    while (it) |node| : (it = node.next) node.data.damage.addWhole();
 }

river/XwaylandView.zig

@@ -232,6 +232,9 @@ fn handleRequestConfigure(
 /// TODO: check for unexpected change in size and react as needed
 fn handleCommit(listener: *wl.Listener(*wlr.Surface), surface: *wlr.Surface) void {
     const self = @fieldParentPtr(Self, "commit", listener);
+
+    self.view.output.damage.addWhole();
+
     self.view.surface_box = Box{
         .x = 0,
         .y = 0,

river/render.zig

@@ -53,7 +53,19 @@ pub fn renderOutput(output: *Output) void {
     var now: os.timespec = undefined;
     os.clock_gettime(os.CLOCK_MONOTONIC, &now) catch unreachable;
 
-    output.wlr_output.attachRender(null) catch return;
+    var needs_frame: bool = undefined;
+    var damage_region: pixman.Region32 = undefined;
+    damage_region.init();
+    defer damage_region.deinit();
+    output.damage.attachRender(&needs_frame, &damage_region) catch {
+        log.err("failed to attach renderer", .{});
+        return;
+    };
+
+    if (!needs_frame) {
+        output.wlr_output.rollback();
+        return;
+    }
 
     renderer.begin(@intCast(u32, output.wlr_output.width), @intCast(u32, output.wlr_output.height));