config: custom-shader-animation

src/config/Config.zig

@@ -609,22 +609,30 @@ keybind: Keybinds = .{},
 /// On Linux, this requires OpenGL 4.2. Ghostty typically only requires
 /// OpenGL 3.3, but custom shaders push that requirement up to 4.2.
 ///
-/// The shader API is identical to the ShaderToy API: you specify a `mainImage`
+/// The shader API is identical to the Shadertoy API: you specify a `mainImage`
-/// function and the available uniforms match ShaderToy. The iChannel0 uniform
+/// function and the available uniforms match Shadertoy. The iChannel0 uniform
 /// is a texture containing the rendered terminal screen.
 ///
 /// If the shader fails to compile, the shader will be ignored. Any errors
 /// related to shader compilation will not show up as configuration errors
 /// and only show up in the log, since shader compilation happens after
-/// configuration loading on the dedicated render thread. If your shader is
+/// configuration loading on the dedicated render thread.  For interactive
-/// not working, another way to debug is to run the `ghostty
+/// development, use Shadertoy.com.
-/// +custom-shader-compile` command which will compile the shader and show any
-/// errors. For interactive development, use ShaderToy.com.
 ///
 /// This can be repeated multiple times to load multiple shaders. The shaders
 /// will be run in the order they are specified.
 @"custom-shader": RepeatablePath = .{},
 
+/// 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.
+///
+/// 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.
+@"custom-shader-animation": bool = true,
+
 /// If anything other than false, fullscreen mode on macOS will not use the
 /// native fullscreen, but make the window fullscreen without animations and
 /// using a new space. It's faster than the native fullscreen mode since it

src/renderer/Metal.zig

@@ -152,6 +152,7 @@ pub const DerivedConfig = struct {
     selection_foreground: ?terminal.color.RGB,
     invert_selection_fg_bg: bool,
     custom_shaders: std.ArrayListUnmanaged([]const u8),
+    custom_shader_animation: bool,
 
     pub fn init(
         alloc_gpa: Allocator,
@@ -206,6 +207,7 @@ pub const DerivedConfig = struct {
                 null,
 
             .custom_shaders = custom_shaders,
+            .custom_shader_animation = config.@"custom-shader-animation",
 
             .arena = arena,
         };
@@ -471,7 +473,8 @@ 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;
+    return self.custom_shader_state != null and
+        self.config.custom_shader_animation;
 }
 
 /// Returns the grid size for a given screen size. This is safe to call

src/renderer/OpenGL.zig

@@ -200,6 +200,7 @@ pub const DerivedConfig = struct {
     selection_foreground: ?terminal.color.RGB,
     invert_selection_fg_bg: bool,
     custom_shaders: std.ArrayListUnmanaged([]const u8),
+    custom_shader_animation: bool,
 
     pub fn init(
         alloc_gpa: Allocator,
@@ -254,6 +255,7 @@ pub const DerivedConfig = struct {
                 null,
 
             .custom_shaders = custom_shaders,
+            .custom_shader_animation = config.@"custom-shader-animation",
 
             .arena = arena,
         };
@@ -479,7 +481,7 @@ 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;
+    return state.custom != null and self.config.custom_shader_animation;
 }
 
 /// Callback when the focus changes for the terminal this is rendering.