tearing-control: minor cleanups/style improvements

This commit also tweaks the riverctl interface to make the global
allow-tearing option apply only to tearing-control-v1 hints from
clients. The global option no longer affects tearing/no-tearing rules
explicitly created by the user.

doc/riverctl.1.scd

@@ -307,11 +307,10 @@ matches everything while _\*\*_ and the empty string are invalid.
 	- *fullscreen*: Make the view fullscreen. Applies only to new views.
 	- *no-fullscreen*: Don't make the view fullscreen. Applies only to
 	  new views.
-	- *tearing*: Enable tearing for view when fullscreen regardless of the
-	  supplied tearing hint. Note that tearing additionally requires setting the
-	  *allow-tearing* server option. Applies to new and existing views.
-	- *no-tearing*: Disable tearing for view regardless of the supplied
-	  tearing hint. Applies to new and existing views.
+	- *tearing*: Allow the view to tear when fullscreen regardless of the
+	  view's preference. Applies to new and existing views.
+	- *no-tearing*: Disable tearing for the view regardless of the view's
+	  preference. Applies to new and existing views.
 
 	Both *float* and *no-float* rules are added to the same list,
 	which means that adding a *no-float* rule with the same arguments
@@ -371,7 +370,8 @@ matches everything while _\*\*_ and the empty string are invalid.
 	default-attach-mode if any.
 
 *allow-tearing* *enabled*|*disabled*
-	Allow windows to tear if requested by either the program or the user.
+	Allow fullscreen views to tear if requested by the view. See also the
+	*tearing* rule to force enable tearing for specific views.
 
 *background-color* _0xRRGGBB_|_0xRRGGBBAA_
 	Set the background color.

river/Config.zig

@@ -31,11 +31,6 @@ const Mode = @import("Mode.zig");
 const RuleList = @import("rule_list.zig").RuleList;
 const View = @import("View.zig");
 
-pub const AllowTearing = enum {
-    disabled,
-    enabled,
-};
-
 pub const AttachMode = union(enum) {
     top,
     bottom,
@@ -73,8 +68,8 @@ pub const Dimensions = struct {
     height: u31,
 };
 
-/// Whether to allow tearing page flips if a view requests it.
-allow_tearing: AllowTearing = .disabled,
+/// Whether to allow tearing page flips when fullscreen if a view requests it.
+allow_tearing: bool = false,
 
 /// Color of background in RGBA with premultiplied alpha (alpha should only affect nested sessions)
 background_color: [4]f32 = [_]f32{ 0.0, 0.16862745, 0.21176471, 1.0 }, // Solarized base03

river/Output.zig

@@ -557,18 +557,21 @@ fn renderAndCommit(output: *Output, scene_output: *wlr.SceneOutput) !void {
         }
     }
 
-    if (output.allowTearing() and server.config.allow_tearing == .enabled) {
-        state.tearing_page_flip = true;
-
-        if (!output.wlr_output.testState(&state)) {
-            log.debug("tearing page flip test failed for {s}, retrying without tearing", .{output.wlr_output.name});
-            state.tearing_page_flip = false;
+    if (output.current.fullscreen) |fullscreen| {
+        if (fullscreen.allowTearing()) {
+            state.tearing_page_flip = true;
+            if (!output.wlr_output.testState(&state)) {
+                log.debug("tearing page flip test failed for {s}, retrying without tearing", .{
+                    output.wlr_output.name,
+                });
+                state.tearing_page_flip = false;
+            }
         }
     }
 
     if (!output.wlr_output.commitState(&state)) return error.CommitFailed;
 
-    if (output.gamma_dirty) output.gamma_dirty = false;
+    output.gamma_dirty = false;
 
     if (server.lock_manager.state == .locked or
         (server.lock_manager.state == .waiting_for_lock_surfaces and output.locked_content.node.enabled) or
@@ -642,14 +645,6 @@ fn setTitle(output: Output) void {
     }
 }
 
-fn allowTearing(output: *Output) bool {
-    if (output.current.fullscreen) |fullscreen_view| {
-        return fullscreen_view.allowTearing();
-    }
-
-    return false;
-}
-
 pub fn handleLayoutNamespaceChange(output: *Output) void {
     // The user changed the layout namespace of this output. Try to find a
     // matching layout.

river/View.zig

@@ -61,8 +61,8 @@ const AttachRelativeMode = enum {
 };
 
 const TearingMode = enum {
-    override_false,
-    override_true,
+    no_tearing,
+    tearing,
     window_hint,
 };
 
@@ -184,7 +184,6 @@ foreign_toplevel_handle: ForeignToplevelHandle = .{},
 /// Connector name of the output this view occupied before an evacuation.
 output_before_evac: ?[]const u8 = null,
 
-// Current tearing mode of the view. Defaults to using the window tearing hint.
 tearing_mode: TearingMode = .window_hint,
 
 pub fn create(impl: Impl) error{OutOfMemory}!*View {
@@ -582,14 +581,19 @@ pub fn getAppId(view: View) ?[*:0]const u8 {
     };
 }
 
-/// Return true if the view can currently tear.
+/// Return true if tearing should be allowed for the view.
 pub fn allowTearing(view: *View) bool {
     switch (view.tearing_mode) {
-        TearingMode.override_false => return false,
-        TearingMode.override_true => return true,
-        TearingMode.window_hint => if (view.rootSurface()) |root_surface| {
-            return server.tearing_control_manager.hintFromSurface(root_surface) == .@"async";
-        } else return false,
+        .no_tearing => return false,
+        .tearing => return true,
+        .window_hint => {
+            if (server.config.allow_tearing) {
+                if (view.rootSurface()) |root_surface| {
+                    return server.tearing_control_manager.hintFromSurface(root_surface) == .@"async";
+                }
+            }
+            return false;
+        },
     }
 }
 
@@ -662,7 +666,7 @@ pub fn map(view: *View) !void {
     }
 
     if (server.config.rules.tearing.match(view)) |tearing| {
-        view.tearing_mode = if (tearing) .override_true else .override_false;
+        view.tearing_mode = if (tearing) .tearing else .no_tearing;
     }
 
     if (server.config.rules.dimensions.match(view)) |dimensions| {

river/command/config.zig

@@ -31,8 +31,11 @@ pub fn allowTearing(
 ) Error!void {
     if (args.len < 2) return Error.NotEnoughArguments;
     if (args.len > 2) return Error.TooManyArguments;
-    server.config.allow_tearing = std.meta.stringToEnum(Config.AllowTearing, args[1]) orelse
+
+    const arg = std.meta.stringToEnum(enum { enabled, disabled }, args[1]) orelse
         return Error.UnknownOption;
+
+    server.config.allow_tearing = arg == .enabled;
 }
 
 pub fn borderWidth(

river/command/rule.zig

@@ -211,7 +211,7 @@ fn apply_tearing_rules() void {
         if (view.destroying) continue;
 
         if (server.config.rules.tearing.match(view)) |tearing| {
-            view.tearing_mode = if (tearing) .override_true else .override_false;
+            view.tearing_mode = if (tearing) .tearing else .no_tearing;
         }
     }
 }