chore: upgrade libghostty and preserve terminal behavior (#3906)

1 files changed, 38 insertions, 0 deletions

diff --git a/vendor/libghostty-vt/src/renderer/Metal.zig b/vendor/libghostty-vt/src/renderer/Metal.zig
index 6c7432d2..9247454d 100644
--- a/vendor/libghostty-vt/src/renderer/Metal.zig
+++ b/vendor/libghostty-vt/src/renderer/Metal.zig
@@ -407,6 +407,44 @@ pub inline fn beginFrame(
     return try Frame.begin(.{ .queue = self.queue }, renderer, target);
 }
 
+/// Warm up the Metal device machinery. The first Metal device query in
+/// a process takes multiple milliseconds; once warm, subsequent queries
+/// are effectively free. Calling this early (e.g. on a background
+/// thread at app startup; Metal device queries are thread-safe) moves
+/// that one-time cost off the critical path of the first surface's
+/// renderer initialization.
+pub fn warmup() void {
+    const device = chooseDevice() catch return;
+    defer device.release();
+
+    // Create and release a command queue. The first command queue
+    // created for a device pays additional one-time driver setup
+    // costs; subsequent creations are much cheaper.
+    const queue = device.msgSend(objc.Object, objc.sel("newCommandQueue"), .{});
+    queue.release();
+
+    // Build and discard our shader pipelines for both pixel formats we
+    // may use (which one is used depends on the blending config). The
+    // first pipeline state creation compiles shaders which is slow;
+    // once warm, later creations hit driver and OS caches.
+    inline for (.{
+        mtl.MTLPixelFormat.bgra8unorm_srgb,
+        mtl.MTLPixelFormat.bgra8unorm,
+    }) |format| {
+        if (shaders.Shaders.init(
+            std.heap.c_allocator,
+            device,
+            &.{},
+            format,
+        )) |s| {
+            var s_mut = s;
+            s_mut.deinit(std.heap.c_allocator);
+        } else |err| {
+            log.warn("metal warmup shader init failed err={}", .{err});
+        }
+    }
+}
+
 fn chooseDevice() error{NoMetalDevice}!objc.Object {
     var chosen_device: ?objc.Object = null;