From 0c2d23e55cd487986336fa33c6d005dbfd789c18 Mon Sep 17 00:00:00 2001
From: Ben Doherty <bendoherty@google.com>
Date: Fri, 1 Nov 2024 14:16:54 -0700
Subject: [PATCH] Metal: unbind SwapChain upon destruction (#8244)

---
 filament/backend/src/metal/MetalDriver.mm | 29 ++++++++++++++---------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/filament/backend/src/metal/MetalDriver.mm b/filament/backend/src/metal/MetalDriver.mm
index c65922fa78..29a0f6fed9 100644
--- a/filament/backend/src/metal/MetalDriver.mm
+++ b/filament/backend/src/metal/MetalDriver.mm
@@ -821,17 +821,24 @@ void MetalDriver::destroyRenderTarget(Handle<HwRenderTarget> rth) {
 }
 
 void MetalDriver::destroySwapChain(Handle<HwSwapChain> sch) {
-    if (sch) {
-        auto* swapChain = handle_cast<MetalSwapChain>(sch);
-        // If the SwapChain is a pixel buffer, we need to wait for the current command buffer to
-        // complete before destroying it. This is because pixel buffer SwapChains hold a
-        // MetalExternalImage that could still being rendered into.
-        if (UTILS_UNLIKELY(swapChain->isPixelBuffer())) {
-            executeAfterCurrentCommandBufferCompletes(
-                    [this, sch]() mutable { destruct_handle<MetalSwapChain>(sch); });
-        } else {
-            destruct_handle<MetalSwapChain>(sch);
-        }
+    if (UTILS_UNLIKELY(!sch)) {
+        return;
+    }
+    auto* swapChain = handle_cast<MetalSwapChain>(sch);
+    if (mContext->currentDrawSwapChain == swapChain) {
+        mContext->currentDrawSwapChain = nullptr;
+    }
+    if (mContext->currentReadSwapChain == swapChain) {
+        mContext->currentReadSwapChain = nullptr;
+    }
+    // If the SwapChain is a pixel buffer, we need to wait for the current command buffer to
+    // complete before destroying it. This is because pixel buffer SwapChains hold a
+    // MetalExternalImage that could still being rendered into.
+    if (UTILS_UNLIKELY(swapChain->isPixelBuffer())) {
+        executeAfterCurrentCommandBufferCompletes(
+                [this, sch]() mutable { destruct_handle<MetalSwapChain>(sch); });
+    } else {
+        destruct_handle<MetalSwapChain>(sch);
     }
 }