From ed3a827b5f2865cd06a13bbc1cda42f1ebb9a095 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Mon, 16 Mar 2026 16:41:39 +0100
Subject: [PATCH] Implement `GPUDeviceWebGPU::WaitForGPU`

---
 .../WebGPU/GPUContextWebGPU.cpp               |  2 ++
 .../GraphicsDevice/WebGPU/GPUDeviceWebGPU.cpp | 22 ++++++++++++++++++-
 .../GraphicsDevice/WebGPU/GPUDeviceWebGPU.h   |  1 +
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/Source/Engine/GraphicsDevice/WebGPU/GPUContextWebGPU.cpp b/Source/Engine/GraphicsDevice/WebGPU/GPUContextWebGPU.cpp
index 0962eb98e..dae0d98ba 100644
--- a/Source/Engine/GraphicsDevice/WebGPU/GPUContextWebGPU.cpp
+++ b/Source/Engine/GraphicsDevice/WebGPU/GPUContextWebGPU.cpp
@@ -561,6 +561,7 @@ void GPUContextWebGPU::Flush()
     {
         wgpuQueueSubmit(_device->Queue, 1, &commandBuffer);
         wgpuCommandBufferRelease(commandBuffer);
+        _device->QueueSubmits++;
     }
 }
 
@@ -1075,6 +1076,7 @@ void GPUContextWebGPU::FlushRenderPass()
         _blendFactorDirty = true;
     _scissorRectDirty |= _scissorRect != Rectangle(0, 0, attachmentSize.Width, attachmentSize.Height);
     _viewportDirty |= _viewport != Viewport(Float2(attachmentSize.Width, attachmentSize.Height));
+    ASSERT_LOW_LAYER(_scissorRect.GetWidth() <= attachmentSize.Width && _scissorRect.GetHeight() <= attachmentSize.Height);
 }
 
 void GPUContextWebGPU::FlushBindGroup()
diff --git a/Source/Engine/GraphicsDevice/WebGPU/GPUDeviceWebGPU.cpp b/Source/Engine/GraphicsDevice/WebGPU/GPUDeviceWebGPU.cpp
index 7935b5a07..1abf8a386 100644
--- a/Source/Engine/GraphicsDevice/WebGPU/GPUDeviceWebGPU.cpp
+++ b/Source/Engine/GraphicsDevice/WebGPU/GPUDeviceWebGPU.cpp
@@ -796,7 +796,27 @@ void GPUDeviceWebGPU::Dispose()
 
 void GPUDeviceWebGPU::WaitForGPU()
 {
-    // TODO: this could use onSubmittedWorkDone (assuming any submit has been already done)
+    if (QueueSubmits == 0)
+        return;
+    QueueSubmits = 0;
+    AsyncCallbackWebGPU<WGPUQueueWorkDoneCallbackInfo> workDone(WGPU_QUEUE_WORK_DONE_CALLBACK_INFO_INIT);
+    workDone.Info.callback = [](WGPUQueueWorkDoneStatus status, WGPUStringView message, WGPU_NULLABLE void* userdata1, WGPU_NULLABLE void* userdata2)
+    {
+        AsyncCallbackDataWebGPU& userData = *reinterpret_cast<AsyncCallbackDataWebGPU*>(userdata1);
+        userData.Call(status == WGPUQueueWorkDoneStatus_Success, status, message);
+    };
+    wgpuQueueOnSubmittedWorkDone(Queue, workDone.Info);
+    auto workDoneResult = workDone.Wait();
+    if (workDoneResult == WGPUWaitStatus_TimedOut)
+    {
+        LOG(Error, "WebGPU queue wait has timed out after {}s", workDone.Data.WaitTime);
+        return;
+    }
+    if (workDoneResult == WGPUWaitStatus_Error)
+    {
+        LOG(Error, "Failed to wait for WebGPU queue. Error: {}, 0x{:x}", workDone.Data.Message, workDone.Data.Status);
+        return;
+    }
 }
 
 GPUQueryWebGPU GPUDeviceWebGPU::AllocateQuery(GPUQueryType type)
diff --git a/Source/Engine/GraphicsDevice/WebGPU/GPUDeviceWebGPU.h b/Source/Engine/GraphicsDevice/WebGPU/GPUDeviceWebGPU.h
index 5b56126ac..4527cb0a7 100644
--- a/Source/Engine/GraphicsDevice/WebGPU/GPUDeviceWebGPU.h
+++ b/Source/Engine/GraphicsDevice/WebGPU/GPUDeviceWebGPU.h
@@ -141,6 +141,7 @@ public:
     WGPUBuffer DefaultBuffer = nullptr;
     GPUDataUploaderWebGPU DataUploader;
     uint32 MinUniformBufferOffsetAlignment = 1;
+    uint32 QueueSubmits = 0;
     bool TimestampQuery = false;
     uint32 QuerySetsCount = 0;
     GPUQuerySetWebGPU* QuerySets[WEBGPU_MAX_QUERY_SETS] = {};