custom shader animation can be set to "always" to always remain active

Fixes #1225

The `custom-shader-animation` configuration can now be set to "always"
which keeps animation active even if the terminal is unfocused.

7 files changed, 88 insertions, 27 deletions

diff --git a/src/Surface.zig b/src/Surface.zig
index aa75bb0e6..a25b2fe74 100644
--- a/src/Surface.zig
+++ b/src/Surface.zig
@@ -511,6 +511,7 @@ pub fn init(
     // Create the renderer thread
     var render_thread = try renderer.Thread.init(
         alloc,
+        config,
         rt_surface,
         &self.renderer,
         &self.renderer_state,
@@ -831,23 +832,14 @@ fn changeConfig(self: *Surface, config: *const configpkg.Config) !void {
 
     // We need to store our configs in a heap-allocated pointer so that
     // our messages aren't huge.
-    var renderer_config_ptr = try self.alloc.create(Renderer.DerivedConfig);
-    errdefer self.alloc.destroy(renderer_config_ptr);
+    var renderer_message = try renderer.Message.initChangeConfig(self.alloc, config);
+    errdefer renderer_message.deinit();
     var termio_config_ptr = try self.alloc.create(termio.Impl.DerivedConfig);
     errdefer self.alloc.destroy(termio_config_ptr);
-
-    // Update our derived configurations for the renderer and termio,
-    // then send them a message to update.
-    renderer_config_ptr.* = try Renderer.DerivedConfig.init(self.alloc, config);
-    errdefer renderer_config_ptr.deinit();
     termio_config_ptr.* = try termio.Impl.DerivedConfig.init(self.alloc, config);
     errdefer termio_config_ptr.deinit();
-    _ = self.renderer_thread.mailbox.push(.{
-        .change_config = .{
-            .alloc = self.alloc,
-            .ptr = renderer_config_ptr,
-        },
-    }, .{ .forever = {} });
+
+    _ = self.renderer_thread.mailbox.push(renderer_message, .{ .forever = {} });
     _ = self.io_thread.mailbox.push(.{
         .change_config = .{
             .alloc = self.alloc,
diff --git a/src/config.zig b/src/config.zig
index 398f5fa92..78e033361 100644
--- a/src/config.zig
+++ b/src/config.zig
@@ -10,6 +10,7 @@ pub const url = @import("config/url.zig");
 pub const CopyOnSelect = Config.CopyOnSelect;
 pub const Keybinds = Config.Keybinds;
 pub const MouseShiftCapture = Config.MouseShiftCapture;
+pub const CustomShaderAnimation = Config.CustomShaderAnimation;
 pub const NonNativeFullscreen = Config.NonNativeFullscreen;
 pub const OptionAsAlt = Config.OptionAsAlt;
 pub const ShellIntegrationFeatures = Config.ShellIntegrationFeatures;
diff --git a/src/config/Config.zig b/src/config/Config.zig
index 9881580b9..3f093865f 100644
--- a/src/config/Config.zig
+++ b/src/config/Config.zig
@@ -815,15 +815,21 @@ keybind: Keybinds = .{},
 /// If true (default), the focused terminal surface will run an animation
 /// loop when custom shaders are used. This uses slightly more CPU (generally
 /// less than 10%) but allows the shader to animate. This only runs if there
-/// are custom shaders.
+/// are custom shaders and the terminal is focused.
 ///
 /// If this is set to false, the terminal and custom shader will only render
 /// when the terminal is updated. This is more efficient but the shader will
 /// not animate.
 ///
+/// This can also be set to "always", which will always run the animation
+/// loop regardless of whether the terminal is focused or not. The animation
+/// loop will still only run when custom shaders are used. Note that this
+/// will use more CPU per terminal surface and can become quite expensive
+/// depending on the shader and your terminal usage.
+///
 /// This value can be changed at runtime and will affect all currently
 /// open terminals.
-@"custom-shader-animation": bool = true,
+@"custom-shader-animation": CustomShaderAnimation = .true,
 
 /// If anything other than false, fullscreen mode on macOS will not use the
 /// native fullscreen, but make the window fullscreen without animations and
@@ -2079,6 +2085,15 @@ fn equalField(comptime T: type, old: T, new: T) bool {
     }
 }
 
+/// Valid values for custom-shader-animation
+/// c_int because it needs to be extern compatible
+/// If this is changed, you must also update ghostty.h
+pub const CustomShaderAnimation = enum(c_int) {
+    false,
+    true,
+    always,
+};
+
 /// Valid values for macos-non-native-fullscreen
 /// c_int because it needs to be extern compatible
 /// If this is changed, you must also update ghostty.h
diff --git a/src/renderer/Metal.zig b/src/renderer/Metal.zig
index 9c17702e0..9e9fbaea4 100644
--- a/src/renderer/Metal.zig
+++ b/src/renderer/Metal.zig
@@ -155,7 +155,6 @@ pub const DerivedConfig = struct {
     invert_selection_fg_bg: bool,
     min_contrast: f32,
     custom_shaders: std.ArrayListUnmanaged([:0]const u8),
-    custom_shader_animation: bool,
     links: link.Set,
 
     pub fn init(
@@ -218,7 +217,6 @@ pub const DerivedConfig = struct {
                 null,
 
             .custom_shaders = custom_shaders,
-            .custom_shader_animation = config.@"custom-shader-animation",
             .links = links,
 
             .arena = arena,
@@ -488,8 +486,7 @@ pub fn threadExit(self: *const Metal) void {
 /// True if our renderer has animations so that a higher frequency
 /// timer is used.
 pub fn hasAnimations(self: *const Metal) bool {
-    return self.custom_shader_state != null and
-        self.config.custom_shader_animation;
+    return self.custom_shader_state != null;
 }
 
 /// Returns the grid size for a given screen size. This is safe to call
diff --git a/src/renderer/OpenGL.zig b/src/renderer/OpenGL.zig
index 66fd966ee..af6910c0a 100644
--- a/src/renderer/OpenGL.zig
+++ b/src/renderer/OpenGL.zig
@@ -252,7 +252,6 @@ pub const DerivedConfig = struct {
     invert_selection_fg_bg: bool,
     min_contrast: f32,
     custom_shaders: std.ArrayListUnmanaged([:0]const u8),
-    custom_shader_animation: bool,
     links: link.Set,
 
     pub fn init(
@@ -315,7 +314,6 @@ pub const DerivedConfig = struct {
                 null,
 
             .custom_shaders = custom_shaders,
-            .custom_shader_animation = config.@"custom-shader-animation",
             .links = links,
 
             .arena = arena,
@@ -558,7 +556,7 @@ pub fn threadExit(self: *const OpenGL) void {
 /// timer is used.
 pub fn hasAnimations(self: *const OpenGL) bool {
     const state = self.gl_state orelse return false;
-    return state.custom != null and self.config.custom_shader_animation;
+    return state.custom != null;
 }
 
 /// Callback when the focus changes for the terminal this is rendering.
diff --git a/src/renderer/Thread.zig b/src/renderer/Thread.zig
index 156d6cd6d..178dca14e 100644
--- a/src/renderer/Thread.zig
+++ b/src/renderer/Thread.zig
@@ -7,6 +7,7 @@ const builtin = @import("builtin");
 const xev = @import("xev");
 const renderer = @import("../renderer.zig");
 const apprt = @import("../apprt.zig");
+const configpkg = @import("../config.zig");
 const BlockingQueue = @import("../blocking_queue.zig").BlockingQueue;
 const tracy = @import("tracy");
 const trace = tracy.trace;
@@ -72,6 +73,9 @@ mailbox: *Mailbox,
 /// Mailbox to send messages to the app thread
 app_mailbox: App.Mailbox,
 
+/// Configuration we need derived from the main config.
+config: DerivedConfig,
+
 flags: packed struct {
     /// This is true when a blinking cursor should be visible and false
     /// when it should not be visible. This is toggled on a timer by the
@@ -82,11 +86,22 @@ flags: packed struct {
     has_inspector: bool = false,
 } = .{},
 
+pub const DerivedConfig = struct {
+    custom_shader_animation: configpkg.CustomShaderAnimation,
+
+    pub fn init(config: *const configpkg.Config) DerivedConfig {
+        return .{
+            .custom_shader_animation = config.@"custom-shader-animation",
+        };
+    }
+};
+
 /// Initialize the thread. This does not START the thread. This only sets
 /// up all the internal state necessary prior to starting the thread. It
 /// is up to the caller to start the thread with the threadMain entrypoint.
 pub fn init(
     alloc: Allocator,
+    config: *const configpkg.Config,
     surface: *apprt.Surface,
     renderer_impl: *renderer.Renderer,
     state: *renderer.State,
@@ -122,6 +137,7 @@ pub fn init(
 
     return Thread{
         .alloc = alloc,
+        .config = DerivedConfig.init(config),
         .loop = loop,
         .wakeup = wakeup_h,
         .stop = stop_h,
@@ -199,6 +215,7 @@ fn startDrawTimer(self: *Thread) void {
     // If our renderer doesn't suppoort animations then we never run this.
     if (!@hasDecl(renderer.Renderer, "hasAnimations")) return;
     if (!self.renderer.hasAnimations()) return;
+    if (self.config.custom_shader_animation == .false) return;
 
     // Set our active state so it knows we're running. We set this before
     // even checking the active state in case we have a pending shutdown.
@@ -236,8 +253,10 @@ fn drainMailbox(self: *Thread) !void {
                 try self.renderer.setFocus(v);
 
                 if (!v) {
-                    // Stop the draw timer
-                    self.stopDrawTimer();
+                    if (self.config.custom_shader_animation != .always) {
+                        // Stop the draw timer
+                        self.stopDrawTimer();
+                    }
 
                     // If we're not focused, then we stop the cursor blink
                     if (self.cursor_c.state() == .active and
@@ -308,8 +327,9 @@ fn drainMailbox(self: *Thread) !void {
             },
 
             .change_config => |config| {
-                defer config.alloc.destroy(config.ptr);
-                try self.renderer.changeConfig(config.ptr);
+                defer message.deinit();
+                try self.changeConfig(config.thread);
+                try self.renderer.changeConfig(config.impl);
 
                 // Stop and start the draw timer to capture the new
                 // hasAnimations value.
@@ -322,6 +342,10 @@ fn drainMailbox(self: *Thread) !void {
     }
 }
 
+fn changeConfig(self: *Thread, config: *const DerivedConfig) !void {
+    self.config = config.*;
+}
+
 fn wakeupCallback(
     self_: ?*Thread,
     _: *xev.Loop,
diff --git a/src/renderer/message.zig b/src/renderer/message.zig
index 3278a2c1c..73faa0ad7 100644
--- a/src/renderer/message.zig
+++ b/src/renderer/message.zig
@@ -1,6 +1,7 @@
 const std = @import("std");
 const assert = std.debug.assert;
 const Allocator = std.mem.Allocator;
+const configpkg = @import("../config.zig");
 const font = @import("../font/main.zig");
 const renderer = @import("../renderer.zig");
 const terminal = @import("../terminal/main.zig");
@@ -45,9 +46,42 @@ pub const Message = union(enum) {
     /// The derived configuration to update the renderer with.
     change_config: struct {
         alloc: Allocator,
-        ptr: *renderer.Renderer.DerivedConfig,
+        thread: *renderer.Thread.DerivedConfig,
+        impl: *renderer.Renderer.DerivedConfig,
     },
 
     /// Activate or deactivate the inspector.
     inspector: bool,
+
+    /// Initialize a change_config message.
+    pub fn initChangeConfig(alloc: Allocator, config: *const configpkg.Config) !Message {
+        const thread_ptr = try alloc.create(renderer.Thread.DerivedConfig);
+        errdefer alloc.destroy(thread_ptr);
+        const config_ptr = try alloc.create(renderer.Renderer.DerivedConfig);
+        errdefer alloc.destroy(config_ptr);
+
+        thread_ptr.* = renderer.Thread.DerivedConfig.init(config);
+        config_ptr.* = try renderer.Renderer.DerivedConfig.init(alloc, config);
+        errdefer config_ptr.deinit();
+
+        return .{
+            .change_config = .{
+                .alloc = alloc,
+                .thread = thread_ptr,
+                .impl = config_ptr,
+            },
+        };
+    }
+
+    pub fn deinit(self: *const Message) void {
+        switch (self.*) {
+            .change_config => |v| {
+                v.impl.deinit();
+                v.alloc.destroy(v.impl);
+                v.alloc.destroy(v.thread);
+            },
+
+            else => {},
+        }
+    }
 };