diff --git a/src/d3d12/d3d12_renderer.cpp b/src/d3d12/d3d12_renderer.cpp
index 2342d50e..4a6270b8 100644
--- a/src/d3d12/d3d12_renderer.cpp
+++ b/src/d3d12/d3d12_renderer.cpp
@@ -115,7 +115,7 @@ namespace wr
 		SetName(m_compute_queue, L"Default D3D12 Compute Command Queue");
 		SetName(m_copy_queue, L"Default D3D12 Copy Command Queue");
 
-		if (window.has_value())
+		if (window.has_value() && window.value()->HasPhysicalWindow())
 		{
 			m_render_window = d3d12::CreateRenderWindow(m_device, window.value()->GetWindowHandle(), m_direct_queue, d3d12::settings::num_back_buffers);
 		}
@@ -159,7 +159,7 @@ namespace wr
 		m_raytracing_offset_sb_pool = CreateStructuredBufferPool(rt_offset_align_size);
 
 		// Begin Recording
-		auto frame_idx = m_render_window.has_value() ? m_render_window.value()->m_frame_idx : 0;
+		auto frame_idx = GetFrameIdx();
 		d3d12::Begin(m_direct_cmd_list, frame_idx);
 
 		// Stage fullscreen quad
@@ -304,6 +304,8 @@ namespace wr
 		// Optional CPU-visible copy of the render target pixel data
 		const auto cpu_output_texture = frame_graph.GetOutputTexture();
 
+		++frame_counter;
+
 		// Optional CPU-visible copy of the render target pixel and/or depth data
 		return frame_graph.GetOutputTexture();
 	}
@@ -997,13 +999,6 @@ namespace wr
 	{
 		d3d12::Begin(m_direct_cmd_list, frame_idx);
 
-		if (clear_frame_buffer)
-		{
-			CD3DX12_CPU_DESCRIPTOR_HANDLE rtv_descriptor(m_render_window.value()->m_rtv_descriptor_heap->GetCPUDescriptorHandleForHeapStart());
-
-			rtv_descriptor.Offset(frame_idx, m_render_window.value()->m_rtv_descriptor_increment_size);
-		}
-
 		for (int i = 0; i < m_structured_buffer_pools.size(); ++i)
 		{
 			m_structured_buffer_pools[i]->UpdateBuffers(m_direct_cmd_list, frame_idx);
@@ -1285,8 +1280,7 @@ namespace wr
 		}
 		else
 		{
-			LOGW("Called `D3D12RenderSystem::GetFrameIdx` without a window!");
-			return 0;
+			return frame_counter % d3d12::settings::num_back_buffers;
 		}
 	}
 
diff --git a/src/d3d12/d3d12_renderer.hpp b/src/d3d12/d3d12_renderer.hpp
index aba212cc..e06f0e32 100644
--- a/src/d3d12/d3d12_renderer.hpp
+++ b/src/d3d12/d3d12_renderer.hpp
@@ -305,6 +305,7 @@ namespace wr
 		MaterialHandle m_last_material = { nullptr, 0 };
 
 		bool m_skybox_changed = false;
+		std::uint32_t frame_counter = 0;
 
 	};
 
diff --git a/src/render_tasks/d3d12_cubemap_convolution.hpp b/src/render_tasks/d3d12_cubemap_convolution.hpp
index 081f802e..f086b67c 100644
--- a/src/render_tasks/d3d12_cubemap_convolution.hpp
+++ b/src/render_tasks/d3d12_cubemap_convolution.hpp
@@ -138,11 +138,10 @@ namespace wr
 
 			if (radiance->m_is_staged)
 			{
-				if (n_render_system.m_render_window.has_value())
 				{
 					auto cmd_list = fg.GetCommandList<d3d12::CommandList>(handle);
 					const auto viewport = d3d12::CreateViewport(static_cast<int>(irradiance->m_width), static_cast<int>(irradiance->m_height));
-					const auto frame_idx = n_render_system.GetRenderWindow()->m_frame_idx;
+					const auto frame_idx = n_render_system.GetFrameIdx();
 
 					d3d12::BindViewport(cmd_list, viewport);
 					d3d12::BindPipeline(cmd_list, data.in_pipeline);
diff --git a/src/render_tasks/d3d12_deferred_composition.cpp b/src/render_tasks/d3d12_deferred_composition.cpp
index e49e5fd5..bafe5c5f 100644
--- a/src/render_tasks/d3d12_deferred_composition.cpp
+++ b/src/render_tasks/d3d12_deferred_composition.cpp
@@ -251,7 +251,6 @@ namespace wr
 				}
 			}
 
-			if (n_render_system.m_render_window.has_value())
 			{
 				const auto viewport = n_render_system.m_viewport;
 				const auto frame_idx = n_render_system.GetFrameIdx();
diff --git a/src/render_tasks/d3d12_deferred_main.hpp b/src/render_tasks/d3d12_deferred_main.hpp
index b081e0cc..7643926b 100644
--- a/src/render_tasks/d3d12_deferred_main.hpp
+++ b/src/render_tasks/d3d12_deferred_main.hpp
@@ -58,10 +58,9 @@ namespace wr
 			auto& data = fg.GetData<DeferredMainTaskData>(handle);
 			auto cmd_list = fg.GetCommandList<d3d12::CommandList>(handle);
 
-			if (n_render_system.m_render_window.has_value())
 			{
 				const auto viewport = n_render_system.m_viewport;
-				const auto frame_idx = n_render_system.GetRenderWindow()->m_frame_idx;
+				const auto frame_idx = n_render_system.GetFrameIdx();
 
 				d3d12::BindViewport(cmd_list, viewport);
 				d3d12::BindPipeline(cmd_list, data.in_pipeline);
diff --git a/src/render_tasks/d3d12_equirect_to_cubemap.hpp b/src/render_tasks/d3d12_equirect_to_cubemap.hpp
index c05b091f..a0cc1579 100644
--- a/src/render_tasks/d3d12_equirect_to_cubemap.hpp
+++ b/src/render_tasks/d3d12_equirect_to_cubemap.hpp
@@ -209,11 +209,10 @@ namespace wr
 			d3d12::TextureResource* equirect_text = static_cast<d3d12::TextureResource*>(data.in_equirect.m_pool->GetTextureResource(data.in_equirect));
 			d3d12::TextureResource* cubemap_text = static_cast<d3d12::TextureResource*>(data.out_cubemap.m_pool->GetTextureResource(data.out_cubemap));
 
-			if (n_render_system.m_render_window.has_value())
 			{
 				auto cmd_list = fg.GetCommandList<d3d12::CommandList>(handle);
 				const auto viewport = d3d12::CreateViewport(static_cast<int>(cubemap_text->m_width), static_cast<int>(cubemap_text->m_height));
-				const auto frame_idx = n_render_system.GetRenderWindow()->m_frame_idx;
+				const auto frame_idx = n_render_system.GetFrameIdx();
 
 				d3d12::BindViewport(cmd_list, viewport);
 				d3d12::BindPipeline(cmd_list, data.in_pipeline);
diff --git a/src/render_tasks/d3d12_imgui_render_task.hpp b/src/render_tasks/d3d12_imgui_render_task.hpp
index 8971d2b6..11ec6407 100644
--- a/src/render_tasks/d3d12_imgui_render_task.hpp
+++ b/src/render_tasks/d3d12_imgui_render_task.hpp
@@ -41,7 +41,7 @@ namespace wr
 		{
 			auto& n_render_system = static_cast<D3D12RenderSystem&>(rs);
 
-			if (!n_render_system.m_window.has_value())
+			if (!n_render_system.m_window.has_value() || !n_render_system.m_window.value()->HasPhysicalWindow())
 			{
 				LOGC("Tried using imgui without a window!");
 			}
@@ -91,7 +91,6 @@ namespace wr
 			auto cmd_list = fg.GetCommandList<d3d12::CommandList>(handle);
 
 			// Temp rendering
-			if (n_render_system.m_render_window.has_value())
 			{
 				auto frame_idx = n_render_system.GetFrameIdx();
 
diff --git a/src/render_tasks/d3d12_path_tracer.hpp b/src/render_tasks/d3d12_path_tracer.hpp
index f760c525..b99c855c 100644
--- a/src/render_tasks/d3d12_path_tracer.hpp
+++ b/src/render_tasks/d3d12_path_tracer.hpp
@@ -39,9 +39,9 @@ namespace wr
 		d3d12::AccelerationStructure out_tlas = {};
 
 		// Shader tables
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_raygen_shader_table = { nullptr, nullptr, nullptr };
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_miss_shader_table = { nullptr, nullptr, nullptr };
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_hitgroup_shader_table = { nullptr, nullptr, nullptr };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_raygen_shader_table = { };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_miss_shader_table = { };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_hitgroup_shader_table = { };
 
 		// Pipeline objects
 		d3d12::StateObject* out_state_object = nullptr;
@@ -195,10 +195,9 @@ namespace wr
 				auto& rt_registry = RTPipelineRegistry::Get();
 				data.out_state_object = static_cast<d3d12::StateObject*>(rt_registry.Find(state_objects::path_tracer_state_object));
 
-				// Create Shader Tables
-				CreateShaderTables(device, data, 0);
-				CreateShaderTables(device, data, 1);
-				CreateShaderTables(device, data, 2);
+				// Create Shader Tables
+				for (int i = 0; i < d3d12::settings::num_back_buffers; ++i)
+					CreateShaderTables(device, data, i);
 			}
 
 		}
@@ -246,7 +245,6 @@ namespace wr
 			// Wait for AS to be built
 			d3d12::UAVBarrierAS(cmd_list, as_build_data.out_tlas, frame_idx);
 
-			if (n_render_system.m_render_window.has_value())
 			{
 				d3d12::BindRaytracingPipeline(cmd_list, data.out_state_object, d3d12::GetRaytracingType(device) == RaytracingType::FALLBACK);
 
diff --git a/src/render_tasks/d3d12_raytracing_task.hpp b/src/render_tasks/d3d12_raytracing_task.hpp
index 0841d770..fda51381 100644
--- a/src/render_tasks/d3d12_raytracing_task.hpp
+++ b/src/render_tasks/d3d12_raytracing_task.hpp
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-#pragma once
+ #pragma once
 
 #include "../d3d12/d3d12_renderer.hpp"
 #include "../d3d12/d3d12_functions.hpp"
@@ -38,9 +38,9 @@ namespace wr
 	{
 		d3d12::AccelerationStructure out_tlas;
 
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_raygen_shader_table = { nullptr, nullptr, nullptr };
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_miss_shader_table = { nullptr, nullptr, nullptr };
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_hitgroup_shader_table = { nullptr, nullptr, nullptr };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_raygen_shader_table = { };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_miss_shader_table = { };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_hitgroup_shader_table = { };
 		d3d12::StateObject* out_state_object = nullptr;
 		d3d12::RootSignature* out_root_signature = nullptr;
 		D3D12ConstantBufferHandle* out_cb_camera_handle = nullptr;
@@ -151,15 +151,13 @@ namespace wr
 
 				data.tlas_requires_init = true;
 
-				CreateShaderTables(device, data, 0);
-				CreateShaderTables(device, data, 1);
-				CreateShaderTables(device, data, 2);
+				for(int i = 0; i < d3d12::settings::num_back_buffers; ++i)
+					CreateShaderTables(device, data, i);
 			}
 
-			for (auto frame_idx = 0; frame_idx < 1; frame_idx++)
 			{
 				d3d12::DescHeapCPUHandle desc_handle = data.out_uav_from_rtv.GetDescriptorHandle();
-				d3d12::CreateUAVFromSpecificRTV(n_render_target, desc_handle, frame_idx, n_render_target->m_create_info.m_rtv_formats[frame_idx]);
+				d3d12::CreateUAVFromSpecificRTV(n_render_target, desc_handle, 0, n_render_target->m_create_info.m_rtv_formats[0]);
 			}
 		}
 
@@ -184,7 +182,6 @@ namespace wr
 				d3d12::UAVBarrierAS(cmd_list, as_build_data.out_tlas, frame_idx);
 			}
 
-			if (n_render_system.m_render_window.has_value())
 			{
 
 				d3d12::BindRaytracingPipeline(cmd_list, data.out_state_object, d3d12::GetRaytracingType(device) == RaytracingType::FALLBACK);
@@ -334,6 +331,7 @@ namespace wr
 //#ifdef _DEBUG
 				CreateShaderTables(device, data, frame_idx);
 //#endif
+
 				d3d12::DispatchRays(cmd_list,
 					data.out_hitgroup_shader_table[frame_idx], 
 					data.out_miss_shader_table[frame_idx], 
diff --git a/src/render_tasks/d3d12_rt_hybrid_helpers.hpp b/src/render_tasks/d3d12_rt_hybrid_helpers.hpp
index be1918d2..d0865adb 100644
--- a/src/render_tasks/d3d12_rt_hybrid_helpers.hpp
+++ b/src/render_tasks/d3d12_rt_hybrid_helpers.hpp
@@ -40,9 +40,9 @@ namespace wr
 		d3d12::AccelerationStructure out_tlas = {};
 
 		// Shader tables
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_raygen_shader_table = { nullptr, nullptr, nullptr };
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_miss_shader_table = { nullptr, nullptr, nullptr };
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_hitgroup_shader_table = { nullptr, nullptr, nullptr };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_raygen_shader_table = { };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_miss_shader_table = { };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> out_hitgroup_shader_table = { };
 
 
 		// Pipeline objects
diff --git a/src/render_tasks/d3d12_rt_reflection_task.hpp b/src/render_tasks/d3d12_rt_reflection_task.hpp
index b3a473b9..a0142b44 100644
--- a/src/render_tasks/d3d12_rt_reflection_task.hpp
+++ b/src/render_tasks/d3d12_rt_reflection_task.hpp
@@ -112,7 +112,6 @@ namespace wr
 				d3d12::UAVBarrierAS(cmd_list, as_build_data.out_tlas, frame_idx);
 			}
 
-			if (n_render_system.m_render_window.has_value())
 			{
 				d3d12::BindRaytracingPipeline(cmd_list, data.base_data.out_state_object, d3d12::GetRaytracingType(device) == RaytracingType::FALLBACK);
 
diff --git a/src/render_tasks/d3d12_rt_shadow_task.hpp b/src/render_tasks/d3d12_rt_shadow_task.hpp
index 4b380e2d..09e86879 100644
--- a/src/render_tasks/d3d12_rt_shadow_task.hpp
+++ b/src/render_tasks/d3d12_rt_shadow_task.hpp
@@ -127,7 +127,6 @@ namespace wr
 				d3d12::UAVBarrierAS(cmd_list, as_build_data.out_tlas, frame_idx);
 			}
 
-			if (n_render_system.m_render_window.has_value())
 			{
 				d3d12::BindRaytracingPipeline(cmd_list, data.base_data.out_state_object, d3d12::GetRaytracingType(device) == RaytracingType::FALLBACK);
 
diff --git a/src/render_tasks/d3d12_rtao_task.hpp b/src/render_tasks/d3d12_rtao_task.hpp
index 48416a36..f3529386 100644
--- a/src/render_tasks/d3d12_rtao_task.hpp
+++ b/src/render_tasks/d3d12_rtao_task.hpp
@@ -50,9 +50,9 @@ namespace wr
 		d3d12::AccelerationStructure out_tlas = {};
 
 		// Shader tables
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> in_raygen_shader_table = { nullptr, nullptr, nullptr };
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> in_miss_shader_table = { nullptr, nullptr, nullptr };
-		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> in_hitgroup_shader_table = { nullptr, nullptr, nullptr };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> in_raygen_shader_table = { };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> in_miss_shader_table = { };
+		std::array<d3d12::ShaderTable*, d3d12::settings::num_back_buffers> in_hitgroup_shader_table = { };
 
 		// Pipeline objects
 		d3d12::StateObject* in_state_object;
@@ -66,7 +66,6 @@ namespace wr
 		DescriptorAllocation in_depthbuffer;
 
 		bool tlas_requires_init = false;
-
 	};
 	
 	namespace internal
@@ -165,9 +164,8 @@ namespace wr
 				data.in_root_signature = static_cast<d3d12::RootSignature*>(rs_registry.Find(root_signatures::rt_ao_global));
 
 				// Create Shader Tables
-				CreateShaderTables(device, data, 0);
-				CreateShaderTables(device, data, 1);
-				CreateShaderTables(device, data, 2);
+				for (int i = 0; i < d3d12::settings::num_back_buffers; ++i)
+					CreateShaderTables(device, data, i);
 			}
 		}
 
@@ -186,7 +184,6 @@ namespace wr
 			fg.WaitForPredecessorTask<CubemapConvolutionTaskData>();
 			float scalar = 1.0f;
 
-			if (n_render_system.m_render_window.has_value())
 			{
 
 				d3d12::BindRaytracingPipeline(cmd_list, data.in_state_object, false);
diff --git a/src/render_tasks/d3d12_shadow_denoiser_task.hpp b/src/render_tasks/d3d12_shadow_denoiser_task.hpp
index ca8dfd22..f76e5c1d 100644
--- a/src/render_tasks/d3d12_shadow_denoiser_task.hpp
+++ b/src/render_tasks/d3d12_shadow_denoiser_task.hpp
@@ -571,7 +571,6 @@ namespace wr
 				data.m_constant_buffer_pool->Update(data.m_denoiser_settings_buffer[i], sizeof(temp::ShadowDenoiserSettings_CBData), 0, n_render_system.GetFrameIdx(), (uint8_t*)& data.m_denoiser_settings);
 			}
 
-			if (n_render_system.m_render_window.has_value())
 			{
 				const auto viewport = n_render_system.m_viewport;
 				const auto frame_idx = n_render_system.GetFrameIdx();
diff --git a/src/window.cpp b/src/window.cpp
index 48fcdca8..63e1406f 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -26,7 +26,7 @@ namespace wr
 {
 
 
-	Window::Window(HINSTANCE instance, int show_cmd, std::string const & name, std::uint32_t width, std::uint32_t height)
+	Window::Window(HINSTANCE instance, std::string const &name, std::uint32_t width, std::uint32_t height, bool show)
 		: m_title(name), m_instance(instance)
 	{
 		WNDCLASSEX wc;
@@ -85,26 +85,53 @@ namespace wr
 
 		SetWindowLongPtr(m_handle, GWLP_USERDATA, (LONG_PTR)this);
 
-		ShowWindow(m_handle, show_cmd);
+		ShowWindow(m_handle, show ? SW_SHOWNORMAL : SW_HIDE);
 		UpdateWindow(m_handle);
-
-		m_running = true;
 	}
-
-	Window::Window(HINSTANCE instance, std::string const& name, std::uint32_t width, std::uint32_t height, bool show)
-		: Window(instance, show ? SW_SHOWNORMAL : SW_HIDE, name, width, height)
-	{
+	
+	Window::Window( std::string const &name, std::uint32_t width, std::uint32_t height)
+		: m_title(name), m_window_width(width), m_window_height(height) {
 
 	}
 
 	Window::~Window()
 	{
 		Stop();
-		UnregisterClassA(m_title.c_str(), m_instance);
+
+		if (m_instance)
+		{
+			UnregisterClassA(m_title.c_str(), m_instance);
+		}
 	}
 
 	void Window::PollEvents()
 	{
+		//Handle virtual window
+
+		if(!m_handle)
+		{
+			if (m_render_func)
+			{
+				float dt = std::chrono::duration<float>(std::chrono::high_resolution_clock::now() - m_prev_time).count();
+
+				if (!m_has_time_point) {
+					dt = 0;
+					m_has_time_point = true;
+
+					if (m_resize_callback) {
+						m_resize_callback(m_window_width, m_window_height);
+					}
+				}
+
+				m_prev_time = std::chrono::high_resolution_clock::now();
+				m_render_func(dt);
+			}
+
+			return;
+		}
+
+		//Handle physical window
+
 		MSG msg;
 		if (PeekMessage(&msg, m_handle, 0, 0, PM_REMOVE))
 		{
@@ -118,15 +145,25 @@ namespace wr
 
 	void Window::Show()
 	{
-		ShowWindow(m_handle, SW_SHOW);
+		if(m_handle)
+		{
+			ShowWindow(m_handle, SW_SHOW);
+		}
+		else
+		{
+			LOGW("Window::show called on virtual window");
+		}
 	}
 
 	void Window::Stop()
 	{
-		DestroyWindow(m_handle);
+		if (m_handle)
+		{
+			DestroyWindow(m_handle);
+		}
 	}
 
-	void Window::SetRenderLoop(std::function<void()> render_func)
+	void Window::SetRenderLoop(std::function<void (float dt)> render_func)
 	{
 		m_render_func = std::move(render_func);
 	}
@@ -138,22 +175,38 @@ namespace wr
 			PollEvents();
 		}
 
-		UnregisterClassA(m_title.c_str(), m_instance);
+		if(m_instance)
+		{
+			UnregisterClassA(m_title.c_str(), m_instance);
+		}
 	}
 
 	void Window::SetKeyCallback(KeyCallback callback)
 	{
 		m_key_callback = std::move(callback);
+
+		if(!m_handle)
+		{
+			LOGW("Window::SetKeyCallback called on virtual window");
+		}
 	}
 
 	void Window::SetMouseCallback(MouseCallback callback)
 	{
 		m_mouse_callback = std::move(callback);
+
+		if (!m_handle) {
+			LOGW("Window::SetMouseCallback called on virtual window");
+		}
 	}
 
 	void Window::SetMouseWheelCallback(MouseWheelCallback callback)
 	{
 		m_mouse_wheel_callback = std::move(callback);
+
+		if (!m_handle) {
+			LOGW("Window::SetMouseWheelCallback called on virtual window");
+		}
 	}
 
 	void Window::SetResizeCallback(ResizeCallback callback)
@@ -168,6 +221,11 @@ namespace wr
 
 	std::int32_t Window::GetWidth() const
 	{
+		if (!m_handle)
+		{
+			return m_window_width;
+		}
+
 		RECT r;
 		GetClientRect(m_handle, &r);
 		return static_cast<std::int32_t>(r.right - r.left);
@@ -175,6 +233,10 @@ namespace wr
 
 	std::int32_t Window::GetHeight() const
 	{
+		if (!m_handle) {
+			return m_window_height;
+		}
+
 		RECT r;
 		GetClientRect(m_handle, &r);
 		return static_cast<std::int32_t>(r.bottom - r.top);
@@ -190,8 +252,18 @@ namespace wr
 		return m_handle;
 	}
 
+	bool Window::HasPhysicalWindow() const
+	{
+		return m_handle;
+	}
+
 	bool Window::IsFullscreen() const
 	{
+		if(!m_handle)
+		{
+			return true;
+		}
+
 		RECT a, b;
 		GetWindowRect(m_handle, &a);
 		GetWindowRect(GetDesktopWindow(), &b);
@@ -220,7 +292,15 @@ namespace wr
 		case WM_PAINT:
 			if (m_render_func)
 			{
-				m_render_func();
+				float dt = std::chrono::duration<float>(std::chrono::high_resolution_clock::now() - m_prev_time).count();
+
+				if (!m_has_time_point) {
+					dt = 0;
+					m_has_time_point = true;
+				}
+
+				m_prev_time = std::chrono::high_resolution_clock::now();
+				m_render_func(dt);
 			}
 			return 0;
 		case WM_DESTROY:
diff --git a/src/window.hpp b/src/window.hpp
index bff54367..cbae11a5 100644
--- a/src/window.hpp
+++ b/src/window.hpp
@@ -17,6 +17,7 @@
 
 #include <Windows.h>
 #include <functional>
+#include <chrono>
 
 namespace wr
 {
@@ -28,7 +29,9 @@ namespace wr
 		using ResizeCallback = std::function<void(std::uint32_t width, std::uint32_t height)>;
 		using MouseWheelCallback = std::function<void(int key, int action, int mods)>;
 	public:
+
 		/*!
+		Creates a physical window
 		* @param instance A handle to the current instance of the application.
 		* @param name Window title.
 		* @param width Initial window width.
@@ -36,7 +39,15 @@ namespace wr
 		* @param show Controls whether the window will be shown. Default is true.
 		*/
 		Window(HINSTANCE instance, std::string const& name, std::uint32_t width, std::uint32_t height, bool show = true);
-		Window(HINSTANCE instance, int show_cmd, std::string const& name, std::uint32_t width, std::uint32_t height);
+
+		/*!
+		Creates a non-physical window
+		* @param name Window title.
+		* @param width Initial window width.
+		* @param height Initial window height.
+		*/
+		Window(std::string const &name, std::uint32_t width, std::uint32_t height);
+
 		~Window();
 
 		Window(const Window&) = delete;
@@ -52,7 +63,7 @@ namespace wr
 		void Stop();
 
 		/*! Give the window a function to call on repaint */
-		void SetRenderLoop(std::function<void()> render_func);
+		void SetRenderLoop(std::function<void (float dt)> render_func);
 		/*! Start a loop that runs until the window is closed. */
 		void StartRenderLoop();
 
@@ -77,6 +88,8 @@ namespace wr
 		HWND GetWindowHandle() const;
 		/*! Checks whether the window is fullscreen */
 		bool IsFullscreen() const;
+		/*! Checks whether the window is OS backed or not */
+		bool HasPhysicalWindow() const;
 
 	private:
 		/*! WindowProc that calls `WindowProc_Impl` */
@@ -89,16 +102,19 @@ namespace wr
 		ResizeCallback m_resize_callback;
 		MouseWheelCallback m_mouse_wheel_callback;
 
-		std::function<void()> m_render_func;
+		std::function<void (float dt)> m_render_func;
 
 		std::string m_title;
 
-		bool m_running;
-		HWND m_handle;
-		HINSTANCE m_instance;
+		bool m_running = true;
+		HWND m_handle = nullptr;
+		HINSTANCE m_instance = nullptr;
 
 		std::int32_t m_window_width = 0;
 		std::int32_t m_window_height = 0;
+
+		decltype(std::chrono::high_resolution_clock::now()) m_prev_time;
+		bool m_has_time_point = false;
 	};
 
 } /* wr */
diff --git a/tests/common/scene.hpp b/tests/common/scene.hpp
index 96bb7851..ebecc38d 100644
--- a/tests/common/scene.hpp
+++ b/tests/common/scene.hpp
@@ -30,7 +30,7 @@ class Scene
 	virtual ~Scene();
 
 	virtual void Init(wr::D3D12RenderSystem* rs, unsigned int width, unsigned int height, void* extra = nullptr);
-	virtual void Update(float delta = 0) = 0;
+	virtual void Update(float delta_time) = 0;
 	std::shared_ptr<wr::SceneGraph> GetSceneGraph();
 	template<typename T>
 	std::shared_ptr<T> GetCamera();
diff --git a/tests/demo/demo.cpp b/tests/demo/demo.cpp
index d1719c77..e8ebd03a 100644
--- a/tests/demo/demo.cpp
+++ b/tests/demo/demo.cpp
@@ -130,6 +130,7 @@ int WispEntry()
 	wr::ModelLoader* assimp_model_loader = new wr::AssimpModelLoader();
 	wr::ModelLoader* gltf_model_loader = new wr::TinyGLTFModelLoader();
 
+	TRY_M(CoInitialize(nullptr), "Couldn't CoInitialize");
 	render_system->Init(window.get());	
 
 	phys_engine.CreatePhysicsWorld();
@@ -151,12 +152,10 @@ int WispEntry()
 	auto file_watcher = new util::FileWatcher("resources/shaders", std::chrono::milliseconds(100));
 	file_watcher->StartAsync(&ShaderDirChangeDetected);
 
-	window->SetRenderLoop([&]() {
-		// Find delta
-		float delta = ImGui::GetIO().DeltaTime;
-		bool capture_frame = engine::recorder.ShouldCaptureAndIncrement(delta);
-		if (capture_frame)
-		{
+	window->SetRenderLoop([&](float dt) {
+
+		bool capture_frame = engine::recorder.ShouldCaptureAndIncrement(dt);
+		if (capture_frame) {
 			fg_manager::Get()->SaveTaskToDisc<wr::PostProcessingData>(engine::recorder.GetNextFilename(".tga"), 0);
 		}
 
@@ -170,7 +169,7 @@ int WispEntry()
 			fg_manager::Get()->SetShouldExecute<wr::CubemapConvolutionTaskData>(true);
 		}
 
-		current_scene->Update(delta);
+		current_scene->Update(dt);
 
 #ifdef ENABLE_PHYSICS
 		phys_engine.UpdateSim(delta, *current_scene->GetSceneGraph());
diff --git a/tests/demo/scene_emibl.cpp b/tests/demo/scene_emibl.cpp
index 6cbce68f..5a84286d 100644
--- a/tests/demo/scene_emibl.cpp
+++ b/tests/demo/scene_emibl.cpp
@@ -321,7 +321,7 @@ void EmiblScene::BuildScene(unsigned int width, unsigned int height, void* extra
 	dir_light->SetDirectional({ 360_deg - 136_deg, 0, 0 }, { 4, 4, 4 });
 }
 
-void EmiblScene::Update(float delta)
+void EmiblScene::Update(float dt)
 {
-	m_camera->Update(delta);
+	m_camera->Update(dt);
 }
\ No newline at end of file
diff --git a/tests/demo/scene_emibl.hpp b/tests/demo/scene_emibl.hpp
index c0dccae8..991adfdf 100644
--- a/tests/demo/scene_emibl.hpp
+++ b/tests/demo/scene_emibl.hpp
@@ -29,7 +29,7 @@ class EmiblScene : public Scene
 	EmiblScene();
 	~EmiblScene();
 
-	void Update(float delta = 0) final;
+	void Update(float delta_time) final;
 
 protected:
 	void LoadResources() final;
diff --git a/tests/demo/scene_sponza.cpp b/tests/demo/scene_sponza.cpp
index 659f2bcd..f409a3bc 100644
--- a/tests/demo/scene_sponza.cpp
+++ b/tests/demo/scene_sponza.cpp
@@ -136,8 +136,8 @@ void SponzaScene::BuildScene(unsigned int width, unsigned int height, void* extr
 	LoadLightsFromJSON();
 }
 
-void SponzaScene::Update(float delta)
+void SponzaScene::Update(float dt)
 {
-	m_camera->Update(delta);
-	m_camera_spline_node->UpdateSplineNode(delta, m_camera);
+	m_camera->Update(dt);
+	m_camera_spline_node->UpdateSplineNode(dt, m_camera);
 }
\ No newline at end of file
diff --git a/tests/demo/scene_sponza.hpp b/tests/demo/scene_sponza.hpp
index 5cf5034e..3ca4fe0b 100644
--- a/tests/demo/scene_sponza.hpp
+++ b/tests/demo/scene_sponza.hpp
@@ -31,7 +31,7 @@ class SponzaScene : public Scene
 	SponzaScene();
 	~SponzaScene();
 
-	void Update(float delta = 0) final;
+	void Update(float delta_time) final;
 
 protected:
 	void LoadResources() final;
diff --git a/tests/demo/scene_viknell.cpp b/tests/demo/scene_viknell.cpp
index f9d6f4f0..06e8a72a 100644
--- a/tests/demo/scene_viknell.cpp
+++ b/tests/demo/scene_viknell.cpp
@@ -140,8 +140,8 @@ void ViknellScene::BuildScene(unsigned int width, unsigned int height, void* ext
 	LoadLightsFromJSON();
 }
 
-void ViknellScene::Update(float delta)
+void ViknellScene::Update(float dt)
 {
-	m_camera->Update(delta);
-	m_camera_spline_node->UpdateSplineNode(ImGui::GetIO().DeltaTime, m_camera);
+	m_camera->Update(dt);
+	m_camera_spline_node->UpdateSplineNode(dt, m_camera);
 }
\ No newline at end of file
diff --git a/tests/demo/scene_viknell.hpp b/tests/demo/scene_viknell.hpp
index a8efc6ae..d68269b5 100644
--- a/tests/demo/scene_viknell.hpp
+++ b/tests/demo/scene_viknell.hpp
@@ -31,7 +31,7 @@ class ViknellScene : public Scene
 	ViknellScene();
 	~ViknellScene();
 
-	void Update(float delta = 0) final;
+	void Update(float delta_time) final;
 
 protected:
 	void LoadResources() final;
diff --git a/tests/graphics_benchmark/spheres_scene.cpp b/tests/graphics_benchmark/spheres_scene.cpp
index 1c41ade0..a9a1fd7b 100644
--- a/tests/graphics_benchmark/spheres_scene.cpp
+++ b/tests/graphics_benchmark/spheres_scene.cpp
@@ -61,7 +61,7 @@ void SpheresScene::BuildScene(unsigned int width, unsigned int height)
 	dir_light->SetDirectional({ 136._deg, 0, 0 }, { 4, 4, 4 });
 }
 
-void SpheresScene::Update()
+void SpheresScene::Update(float dt)
 {
 
 }
diff --git a/tests/graphics_benchmark/spheres_scene.hpp b/tests/graphics_benchmark/spheres_scene.hpp
index c4f12a98..03e4adca 100644
--- a/tests/graphics_benchmark/spheres_scene.hpp
+++ b/tests/graphics_benchmark/spheres_scene.hpp
@@ -7,7 +7,7 @@ class SpheresScene : public Scene
 public:
 	SpheresScene();
 
-	void Update() final;
+	void Update(float dt) final;
 
 protected:
 	void LoadResources() final;