build: build metal lib

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");
@@ -1072,6 +1073,7 @@ 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
@@ -1257,6 +1259,34 @@ 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,

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

@@ -159,7 +159,7 @@ fn initLibrary(device: objc.Object) !objc.Object {
     const start = try std.time.Instant.now();
 
     const data = try macos.dispatch.Data.create(
-        @embedFile("../shaders/Ghostty.metallib"),
+        @embedFile("ghostty_metallib"),
         macos.dispatch.queue.getMain(),
         macos.dispatch.Data.DESTRUCTOR_DEFAULT,
     );