From 63a47d0ba573fea37a6d96630aba1a7e466f9e93 Mon Sep 17 00:00:00 2001
From: yonihemi <2340723+yonihemi@users.noreply.github.com>
Date: Mon, 6 Jan 2025 22:01:41 +0800
Subject: [PATCH] iOS: Fix crash on device

---
 src/renderer/Metal.zig     | 35 +++++++++++++++++++++++------------
 src/renderer/metal/api.zig |  4 ++++
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/src/renderer/Metal.zig b/src/renderer/Metal.zig
index 75e61ebc0..5ad45da8e 100644
--- a/src/renderer/Metal.zig
+++ b/src/renderer/Metal.zig
@@ -209,20 +209,31 @@ pub const GPUState = struct {
     }
 
     fn chooseDevice() error{NoMetalDevice}!objc.Object {
-        const devices = objc.Object.fromId(mtl.MTLCopyAllDevices());
-        defer devices.release();
         var chosen_device: ?objc.Object = null;
-        var iter = devices.iterate();
-        while (iter.next()) |device| {
-            // We want a GPU that’s connected to a display.
-            if (device.getProperty(bool, "isHeadless")) continue;
-            chosen_device = device;
-            // If the user has an eGPU plugged in, they probably want
-            // to use it. Otherwise, integrated GPUs are better for
-            // battery life and thermals.
-            if (device.getProperty(bool, "isRemovable") or
-                device.getProperty(bool, "isLowPower")) break;
+
+        switch (comptime builtin.os.tag) {
+            .macos => {
+                const devices = objc.Object.fromId(mtl.MTLCopyAllDevices());
+                defer devices.release();
+
+                var iter = devices.iterate();
+                while (iter.next()) |device| {
+                    // We want a GPU that’s connected to a display.
+                    if (device.getProperty(bool, "isHeadless")) continue;
+                    chosen_device = device;
+                    // If the user has an eGPU plugged in, they probably want
+                    // to use it. Otherwise, integrated GPUs are better for
+                    // battery life and thermals.
+                    if (device.getProperty(bool, "isRemovable") or
+                        device.getProperty(bool, "isLowPower")) break;
+                }
+            },
+            .ios => {
+                chosen_device = objc.Object.fromId(mtl.MTLCreateSystemDefaultDevice());
+            },
+            else => @compileError("unsupported target for Metal"),
         }
+
         const device = chosen_device orelse return error.NoMetalDevice;
         return device.retain();
     }
diff --git a/src/renderer/metal/api.zig b/src/renderer/metal/api.zig
index bd4f407cd..48056ae5e 100644
--- a/src/renderer/metal/api.zig
+++ b/src/renderer/metal/api.zig
@@ -175,4 +175,8 @@ pub const MTLSize = extern struct {
     depth: c_ulong,
 };
 
+/// https://developer.apple.com/documentation/metal/1433367-mtlcopyalldevices
 pub extern "c" fn MTLCopyAllDevices() ?*anyopaque;
+
+/// https://developer.apple.com/documentation/metal/1433401-mtlcreatesystemdefaultdevice
+pub extern "c" fn MTLCreateSystemDefaultDevice() ?*anyopaque;