Merge pull request #2056 from ghostty-org/metal

metal: precompile shaders as part of the build

build.zig

@@ -16,6 +16,7 @@ const BuildConfig = build_config.BuildConfig;
 const WasmTarget = @import("src/os/wasm/target.zig").Target;
 const LibtoolStep = @import("src/build/LibtoolStep.zig");
 const LipoStep = @import("src/build/LipoStep.zig");
+const MetallibStep = @import("src/build/MetallibStep.zig");
 const XCFrameworkStep = @import("src/build/XCFrameworkStep.zig");
 const Version = @import("src/build/Version.zig");
 const Command = @import("src/Command.zig");
@@ -1076,6 +1077,7 @@ fn addDeps(
     // This makes things like `os/log.h` available for cross-compiling.
     if (step.rootModuleTarget().isDarwin()) {
         try @import("apple_sdk").addPaths(b, &step.root_module);
+        try addMetallib(b, step);
     }
 
     // We always need the Zig packages
@@ -1262,6 +1264,34 @@ fn addDeps(
     return static_libs;
 }
 
+/// Generate Metal shader library
+fn addMetallib(
+    b: *std.Build,
+    step_: ?*std.Build.Step.Compile,
+) !void {
+    // Our static state between runs. We memoize so we only compile
+    // the Metal shaders once.
+    const MetalState = struct {
+        var generated: ?std.Build.LazyPath = null;
+    };
+
+    const output = MetalState.generated orelse metal: {
+        const step = MetallibStep.create(b, .{
+            .name = "Ghostty",
+            .sources = &.{b.path("src/renderer/shaders/cell.metal")},
+        });
+
+        break :metal step.output;
+    };
+
+    if (step_) |step| {
+        output.addStepDependencies(&step.step);
+        step.root_module.addAnonymousImport("ghostty_metallib", .{
+            .root_source_file = output,
+        });
+    }
+}
+
 /// Generate help files
 fn addHelp(
     b: *std.Build,

pkg/macos/dispatch.zig

@@ -0,0 +1,8 @@
+pub const c = @import("dispatch/c.zig");
+pub const data = @import("dispatch/data.zig");
+pub const queue = @import("dispatch/queue.zig");
+pub const Data = data.Data;
+
+test {
+    @import("std").testing.refAllDecls(@This());
+}

pkg/macos/dispatch/c.zig

@@ -0,0 +1,3 @@
+pub usingnamespace @cImport({
+    @cInclude("dispatch/dispatch.h");
+});

pkg/macos/dispatch/data.zig

@@ -0,0 +1,31 @@
+const std = @import("std");
+const foundation = @import("../foundation.zig");
+const c = @import("c.zig");
+
+pub const Data = opaque {
+    pub const DESTRUCTOR_DEFAULT = c.DISPATCH_DATA_DESTRUCTOR_DEFAULT;
+
+    pub fn create(
+        data: []const u8,
+        queue: ?*anyopaque,
+        destructor: ?*anyopaque,
+    ) !*Data {
+        return dispatch_data_create(
+            data.ptr,
+            data.len,
+            queue,
+            destructor,
+        ) orelse return error.OutOfMemory;
+    }
+
+    pub fn release(data: *Data) void {
+        foundation.c.CFRelease(data);
+    }
+};
+
+extern "c" fn dispatch_data_create(
+    data: [*]const u8,
+    len: usize,
+    queue: ?*anyopaque,
+    destructor: ?*anyopaque,
+) ?*Data;

pkg/macos/dispatch/queue.zig

@@ -0,0 +1,8 @@
+const std = @import("std");
+const c = @import("c.zig");
+
+pub const Queue = *anyopaque; // dispatch_queue_t
+
+pub fn getMain() Queue {
+    return c.dispatch_get_main_queue().?;
+}

pkg/macos/main.zig

@@ -1,5 +1,6 @@
 pub const foundation = @import("foundation.zig");
 pub const animation = @import("animation.zig");
+pub const dispatch = @import("dispatch.zig");
 pub const graphics = @import("graphics.zig");
 pub const os = @import("os.zig");
 pub const text = @import("text.zig");

src/build/MetallibStep.zig

@@ -0,0 +1,48 @@
+/// A zig build step that compiles a set of ".metal" files into a
+/// ".metallib" file.
+const MetallibStep = @This();
+
+const std = @import("std");
+const Step = std.Build.Step;
+const RunStep = std.Build.Step.Run;
+const LazyPath = std.Build.LazyPath;
+
+pub const Options = struct {
+    /// The name of the xcframework to create.
+    name: []const u8,
+
+    /// The Metal source files.
+    sources: []const LazyPath,
+};
+
+step: *Step,
+output: LazyPath,
+
+pub fn create(b: *std.Build, opts: Options) *MetallibStep {
+    const self = b.allocator.create(MetallibStep) catch @panic("OOM");
+
+    const run_ir = RunStep.create(
+        b,
+        b.fmt("metal {s}", .{opts.name}),
+    );
+    run_ir.addArgs(&.{ "xcrun", "-sdk", "macosx", "metal", "-o" });
+    const output_ir = run_ir.addOutputFileArg(b.fmt("{s}.ir", .{opts.name}));
+    run_ir.addArgs(&.{"-c"});
+    for (opts.sources) |source| run_ir.addFileArg(source);
+
+    const run_lib = RunStep.create(
+        b,
+        b.fmt("metallib {s}", .{opts.name}),
+    );
+    run_lib.addArgs(&.{ "xcrun", "-sdk", "macosx", "metallib", "-o" });
+    const output_lib = run_lib.addOutputFileArg(b.fmt("{s}.metallib", .{opts.name}));
+    run_lib.addFileArg(output_ir);
+    run_lib.step.dependOn(&run_ir.step);
+
+    self.* = .{
+        .step = &run_lib.step,
+        .output = output_lib,
+    };
+
+    return self;
+}

src/renderer/metal/shaders.zig

@@ -156,27 +156,29 @@ pub const PostUniforms = extern struct {
 
 /// Initialize the MTLLibrary. A MTLLibrary is a collection of shaders.
 fn initLibrary(device: objc.Object) !objc.Object {
-    // Hardcoded since this file isn't meant to be reusable.
-    const data = @embedFile("../shaders/cell.metal");
-    const source = try macos.foundation.String.createWithBytes(
-        data,
-        .utf8,
-        false,
+    const start = try std.time.Instant.now();
+
+    const data = try macos.dispatch.Data.create(
+        @embedFile("ghostty_metallib"),
+        macos.dispatch.queue.getMain(),
+        macos.dispatch.Data.DESTRUCTOR_DEFAULT,
     );
-    defer source.release();
+    defer data.release();
 
     var err: ?*anyopaque = null;
     const library = device.msgSend(
         objc.Object,
-        objc.sel("newLibraryWithSource:options:error:"),
+        objc.sel("newLibraryWithData:error:"),
         .{
-            source,
-            @as(?*anyopaque, null),
+            data,
             &err,
         },
     );
     try checkError(err);
 
+    const end = try std.time.Instant.now();
+    log.debug("shader library loaded time={}us", .{end.since(start) / std.time.ns_per_us});
+
     return library;
 }
 

src/renderer/shaders/cell.metal

@@ -1,3 +1,5 @@
+#include <metal_stdlib>
+
 using namespace metal;
 
 struct Uniforms {
@@ -291,6 +293,7 @@ fragment float4 cell_text_fragment(CellTextVertexOut in [[stage_in]],
   constexpr sampler textureSampler(address::clamp_to_edge, filter::linear);
 
   switch (in.mode) {
+    default:
     case MODE_TEXT_CURSOR:
     case MODE_TEXT_CONSTRAINED:
     case MODE_TEXT_POWERLINE: