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.

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

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.

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,

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 => {},
+        }
+    }
 };