Notify JS about bgfx restart (#1370)

Added an API no notify JS that the graphics context (bgfx) has been
re-created. This API call will allow JS to re-create all GPU resources
accordingly.

Core/Graphics/InternalInclude/Babylon/Graphics/DeviceContext.h

@@ -96,6 +96,7 @@ namespace Babylon::Graphics
         Update GetUpdate(const char* updateName);
 
         void RequestScreenShot(std::function<void(std::vector<uint8_t>)> callback);
+        void SetRenderResetCallback(std::function<void()> callback);
 
         arcana::task<void, std::exception_ptr> ReadTextureAsync(bgfx::TextureHandle handle, gsl::span<uint8_t> data, uint8_t mipLevel = 0);
 

Core/Graphics/Source/DeviceContext.cpp

@@ -61,6 +61,11 @@ namespace Babylon::Graphics
         return m_graphicsImpl.RequestScreenShot(std::move(callback));
     }
 
+    void DeviceContext::SetRenderResetCallback(std::function<void()> callback)
+    {
+        return m_graphicsImpl.SetRenderResetCallback(std::move(callback));
+    }
+
     arcana::task<void, std::exception_ptr> DeviceContext::ReadTextureAsync(bgfx::TextureHandle handle, gsl::span<uint8_t> data, uint8_t mipLevel)
     {
         return m_graphicsImpl.ReadTextureAsync(handle, data, mipLevel);

Core/Graphics/Source/DeviceImpl.cpp

@@ -124,6 +124,11 @@ namespace Babylon::Graphics
         m_state.Resolution.DevicePixelRatio = value;
     }
 
+    void DeviceImpl::SetRenderResetCallback(std::function<void()> callback)
+    {
+        m_renderResetCallback = std::move(callback);
+    }
+
     void DeviceImpl::AddToJavaScript(Napi::Env env)
     {
         JsRuntime::NativeObject::GetFromJavaScript(env)
@@ -164,6 +169,14 @@ namespace Babylon::Graphics
             m_state.Bgfx.Dirty = false;
 
             m_cancellationSource.emplace();
+
+            if (m_bgfxId != 0)
+            {
+                if (m_renderResetCallback)
+                {
+                    m_renderResetCallback();
+                }
+            }
         }
     }
 

Core/Graphics/Source/DeviceImpl.h

@@ -46,6 +46,7 @@ namespace Babylon::Graphics
         void UpdateMSAA(uint8_t value);
         void UpdateAlphaPremultiplied(bool enabled);
         void UpdateDevicePixelRatio(float value);
+        void SetRenderResetCallback(std::function<void()> callback);
 
         void AddToJavaScript(Napi::Env);
         static DeviceImpl& GetFromJavaScript(Napi::Env);
@@ -163,5 +164,6 @@ namespace Babylon::Graphics
 
         DeviceContext m_context;
         uintptr_t m_bgfxId = 0;
+        std::function<void()> m_renderResetCallback;
     };
 }

Plugins/NativeEngine/Source/NativeEngine.cpp

@@ -693,6 +693,7 @@ namespace Babylon
 
                 // REVIEW: Should this be here if only used by ValidationTest?
                 InstanceMethod("getFrameBufferData", &NativeEngine::GetFrameBufferData),
+                InstanceMethod("setDeviceLostCallback", &NativeEngine::SetRenderResetCallback),
             });
 
         JsRuntime::NativeObject::GetFromJavaScript(env).Set(JS_CONSTRUCTOR_NAME, func);
@@ -2070,6 +2071,18 @@ namespace Babylon
         return Napi::Value::From(env, outputData);
     }
 
+    void NativeEngine::SetRenderResetCallback(const Napi::CallbackInfo& info)
+    {
+        const auto callback{info[0].As<Napi::Function>()};
+        auto callbackPtr{std::make_shared<Napi::FunctionReference>(Napi::Persistent(callback))};
+
+        m_deviceContext.SetRenderResetCallback([this, renderResetCallback = std::move(callbackPtr)]() {
+            m_runtime.Dispatch([renderResetCallback = std::move(renderResetCallback)](auto) {
+                renderResetCallback->Call({});
+            });
+        });
+    }
+
     void NativeEngine::GetFrameBufferData(const Napi::CallbackInfo& info)
     {
         const auto callback{info[0].As<Napi::Function>()};

Plugins/NativeEngine/Source/NativeEngine.h

@@ -213,6 +213,7 @@ namespace Babylon
         Napi::Value CreateImageBitmap(const Napi::CallbackInfo& info);
         Napi::Value ResizeImageBitmap(const Napi::CallbackInfo& info);
         void GetFrameBufferData(const Napi::CallbackInfo& info);
+        void SetRenderResetCallback(const Napi::CallbackInfo& info);
         void SetStencil(NativeDataStream::Reader& data);
         void SetViewPort(NativeDataStream::Reader& data);
         void SetScissor(NativeDataStream::Reader& data);