obs-studio/libobs-winrt/winrt-capture.cpp

extern "C" {
HRESULT __stdcall CreateDirect3D11DeviceFromDXGIDevice(
	::IDXGIDevice *dxgiDevice, ::IInspectable **graphicsDevice);

HRESULT __stdcall CreateDirect3D11SurfaceFromDXGISurface(
	::IDXGISurface *dgxiSurface, ::IInspectable **graphicsSurface);
}

struct __declspec(uuid("A9B3D012-3DF2-4EE3-B8D1-8695F457D3C1"))
	IDirect3DDxgiInterfaceAccess : ::IUnknown {
	virtual HRESULT __stdcall GetInterface(GUID const &id,
					       void **object) = 0;
};

extern "C" EXPORT BOOL winrt_capture_supported()
try {
	/* no contract for IGraphicsCaptureItemInterop, verify 10.0.18362.0 */
	return winrt::Windows::Foundation::Metadata::ApiInformation::
		IsApiContractPresent(L"Windows.Foundation.UniversalApiContract",
				     8);
} catch (const winrt::hresult_error &err) {
	blog(LOG_ERROR, "winrt_capture_supported (0x%08X): %ls", err.to_abi(),
	     err.message().c_str());
	return false;
} catch (...) {
	blog(LOG_ERROR, "winrt_capture_supported (0x%08X)",
	     winrt::to_hresult());
	return false;
}

extern "C" EXPORT BOOL winrt_capture_cursor_toggle_supported()
try {
	return winrt::Windows::Foundation::Metadata::ApiInformation::
		IsPropertyPresent(
			L"Windows.Graphics.Capture.GraphicsCaptureSession",
			L"IsCursorCaptureEnabled");
} catch (const winrt::hresult_error &err) {
	blog(LOG_ERROR, "winrt_capture_cursor_toggle_supported (0x%08X): %ls",
	     err.to_abi(), err.message().c_str());
	return false;
} catch (...) {
	blog(LOG_ERROR, "winrt_capture_cursor_toggle_supported (0x%08X)",
	     winrt::to_hresult());
	return false;
}

template<typename T>
static winrt::com_ptr<T> GetDXGIInterfaceFromObject(
	winrt::Windows::Foundation::IInspectable const &object)
{
	auto access = object.as<IDirect3DDxgiInterfaceAccess>();
	winrt::com_ptr<T> result;
	winrt::check_hresult(
		access->GetInterface(winrt::guid_of<T>(), result.put_void()));
	return result;
}

static bool get_client_box(HWND window, uint32_t width, uint32_t height,
			   D3D11_BOX *client_box)
{
	RECT client_rect{}, window_rect{};
	POINT upper_left{};

	/* check iconic (minimized) twice, ABA is very unlikely */
	bool client_box_available =
		!IsIconic(window) && GetClientRect(window, &client_rect) &&
		!IsIconic(window) && (client_rect.right > 0) &&
		(client_rect.bottom > 0) &&
		(DwmGetWindowAttribute(window, DWMWA_EXTENDED_FRAME_BOUNDS,
				       &window_rect,
				       sizeof(window_rect)) == S_OK) &&
		ClientToScreen(window, &upper_left);
	if (client_box_available) {
		const uint32_t left =
			(upper_left.x > window_rect.left)
				? (upper_left.x - window_rect.left)
				: 0;
		client_box->left = left;

		const uint32_t top = (upper_left.y > window_rect.top)
					     ? (upper_left.y - window_rect.top)
					     : 0;
		client_box->top = top;

		uint32_t texture_width = 1;
		if (width > left) {
			texture_width =
				min(width - left, (uint32_t)client_rect.right);
		}

		uint32_t texture_height = 1;
		if (height > top) {
			texture_height =
				min(height - top, (uint32_t)client_rect.bottom);
		}

		client_box->right = left + texture_width;
		client_box->bottom = top + texture_height;

		client_box->front = 0;
		client_box->back = 1;

		client_box_available = (client_box->right <= width) &&
				       (client_box->bottom <= height);
	}

	return client_box_available;
}

struct winrt_capture {
	HWND window;
	bool client_area;

	bool capture_cursor;
	bool cursor_visible;

	gs_texture_t *texture;
	bool texture_written;
	winrt::Windows::Graphics::Capture::GraphicsCaptureItem item{nullptr};
	winrt::Windows::Graphics::DirectX::Direct3D11::IDirect3DDevice device{
		nullptr};
	ComPtr<ID3D11DeviceContext> context;
	winrt::Windows::Graphics::Capture::Direct3D11CaptureFramePool frame_pool{
		nullptr};
	winrt::Windows::Graphics::Capture::GraphicsCaptureSession session{
		nullptr};
	winrt::Windows::Graphics::SizeInt32 last_size;
	winrt::Windows::Graphics::Capture::GraphicsCaptureItem::Closed_revoker
		closed;
	winrt::Windows::Graphics::Capture::Direct3D11CaptureFramePool::
		FrameArrived_revoker frame_arrived;

	uint32_t texture_width;
	uint32_t texture_height;
	D3D11_BOX client_box;

	bool active;
	struct winrt_capture *next;

	void draw_cursor()
	{
		CURSORINFO ci{};
		ci.cbSize = sizeof(CURSORINFO);
		if (!GetCursorInfo(&ci))
			return;

		if (!(ci.flags & CURSOR_SHOWING))
			return;

		HICON icon = CopyIcon(ci.hCursor);
		if (!icon)
			return;

		ICONINFO ii;
		if (GetIconInfo(icon, &ii)) {
			POINT win_pos{};
			if (window) {
				if (client_area) {
					ClientToScreen(window, &win_pos);
				} else {
					RECT window_rect;
					if (DwmGetWindowAttribute(
						    window,
						    DWMWA_EXTENDED_FRAME_BOUNDS,
						    &window_rect,
						    sizeof(window_rect)) ==
					    S_OK) {
						win_pos.x = window_rect.left;
						win_pos.y = window_rect.top;
					}
				}
			}

			POINT pos;
			pos.x = ci.ptScreenPos.x - (int)ii.xHotspot - win_pos.x;
			pos.y = ci.ptScreenPos.y - (int)ii.yHotspot - win_pos.y;

			HDC hdc = (HDC)gs_texture_get_dc(texture);

			DrawIconEx(hdc, pos.x, pos.y, icon, 0, 0, 0, NULL,
				   DI_NORMAL);

			gs_texture_release_dc(texture);

			DeleteObject(ii.hbmColor);
			DeleteObject(ii.hbmMask);
		}

		DestroyIcon(icon);
	}

	void on_closed(
		winrt::Windows::Graphics::Capture::GraphicsCaptureItem const &,
		winrt::Windows::Foundation::IInspectable const &)
	{
		active = FALSE;
	}

	void on_frame_arrived(winrt::Windows::Graphics::Capture::
				      Direct3D11CaptureFramePool const &sender,
			      winrt::Windows::Foundation::IInspectable const &)
	{
		obs_enter_graphics();

		const winrt::Windows::Graphics::Capture::Direct3D11CaptureFrame
			frame = sender.TryGetNextFrame();
		const winrt::Windows::Graphics::SizeInt32 frame_content_size =
			frame.ContentSize();

		winrt::com_ptr<ID3D11Texture2D> frame_surface =
			GetDXGIInterfaceFromObject<ID3D11Texture2D>(
				frame.Surface());

		/* need GetDesc because ContentSize is not reliable */
		D3D11_TEXTURE2D_DESC desc;
		frame_surface->GetDesc(&desc);

		if (!client_area || get_client_box(window, desc.Width,
						   desc.Height, &client_box)) {
			if (client_area) {
				texture_width =
					client_box.right - client_box.left;
				texture_height =
					client_box.bottom - client_box.top;
			} else {
				texture_width = desc.Width;
				texture_height = desc.Height;
			}

			if (texture) {
				if (texture_width !=
					    gs_texture_get_width(texture) ||
				    texture_height !=
					    gs_texture_get_height(texture)) {
					gs_texture_destroy(texture);
					texture = nullptr;
				}
			}

			if (!texture) {
				texture = gs_texture_create_gdi(texture_width,
								texture_height);
			}

			if (client_area) {
				context->CopySubresourceRegion(
					(ID3D11Texture2D *)gs_texture_get_obj(
						texture),
					0, 0, 0, 0, frame_surface.get(), 0,
					&client_box);
			} else {
				/* if they gave an SRV, we could avoid this copy */
				context->CopyResource(
					(ID3D11Texture2D *)gs_texture_get_obj(
						texture),
					frame_surface.get());
			}

			if (capture_cursor && cursor_visible) {
				draw_cursor();
			}

			texture_written = true;
		}

		if (frame_content_size.Width != last_size.Width ||
		    frame_content_size.Height != last_size.Height) {
			frame_pool.Recreate(
				device,
				winrt::Windows::Graphics::DirectX::
					DirectXPixelFormat::B8G8R8A8UIntNormalized,
				2, frame_content_size);

			last_size = frame_content_size;
		}

		obs_leave_graphics();
	}
};

static struct winrt_capture *capture_list;

static void winrt_capture_device_loss_release(void *data)
{
	winrt_capture *capture = static_cast<winrt_capture *>(data);
	capture->frame_arrived.revoke();
	capture->frame_pool.Close();
	capture->session.Close();

	capture->session = nullptr;
	capture->frame_pool = nullptr;
	capture->context = nullptr;
	capture->device = nullptr;
	capture->item = nullptr;
}

static void winrt_capture_device_loss_rebuild(void *device_void, void *data)
{
	winrt_capture *capture = static_cast<winrt_capture *>(data);

	auto activation_factory = winrt::get_activation_factory<
		winrt::Windows::Graphics::Capture::GraphicsCaptureItem>();
	auto interop_factory =
		activation_factory.as<IGraphicsCaptureItemInterop>();
	winrt::Windows::Graphics::Capture::GraphicsCaptureItem item = {nullptr};
	try {
		interop_factory->CreateForWindow(
			capture->window,
			winrt::guid_of<ABI::Windows::Graphics::Capture::
					       IGraphicsCaptureItem>(),
			reinterpret_cast<void **>(winrt::put_abi(item)));
	} catch (winrt::hresult_error &err) {
		blog(LOG_ERROR, "CreateForWindow (0x%08X): %ls", err.to_abi(),
		     err.message().c_str());
	} catch (...) {
		blog(LOG_ERROR, "CreateForWindow (0x%08X)",
		     winrt::to_hresult());
	}

	ID3D11Device *const d3d_device = (ID3D11Device *)device_void;
	ComPtr<IDXGIDevice> dxgi_device;
	if (FAILED(d3d_device->QueryInterface(&dxgi_device)))
		blog(LOG_ERROR, "Failed to get DXGI device");

	winrt::com_ptr<IInspectable> inspectable;
	if (FAILED(CreateDirect3D11DeviceFromDXGIDevice(dxgi_device.Get(),
							inspectable.put())))
		blog(LOG_ERROR, "Failed to get WinRT device");

	const winrt::Windows::Graphics::DirectX::Direct3D11::IDirect3DDevice
		device = inspectable.as<winrt::Windows::Graphics::DirectX::
						Direct3D11::IDirect3DDevice>();
	const winrt::Windows::Graphics::Capture::Direct3D11CaptureFramePool
		frame_pool = winrt::Windows::Graphics::Capture::
			Direct3D11CaptureFramePool::Create(
				device,
				winrt::Windows::Graphics::DirectX::
					DirectXPixelFormat::B8G8R8A8UIntNormalized,
				2, capture->last_size);
	const winrt::Windows::Graphics::Capture::GraphicsCaptureSession session =
		frame_pool.CreateCaptureSession(item);

	/* disable cursor capture if possible since ours performs better */
	if (winrt_capture_cursor_toggle_supported())
		session.IsCursorCaptureEnabled(false);

	capture->item = item;
	capture->device = device;
	d3d_device->GetImmediateContext(&capture->context);
	capture->frame_pool = frame_pool;
	capture->session = session;
	capture->frame_arrived = frame_pool.FrameArrived(
		winrt::auto_revoke,
		{capture, &winrt_capture::on_frame_arrived});

	session.StartCapture();
}

extern "C" EXPORT struct winrt_capture *
winrt_capture_init(BOOL cursor, HWND window, BOOL client_area)
try {
	ID3D11Device *const d3d_device = (ID3D11Device *)gs_get_device_obj();
	ComPtr<IDXGIDevice> dxgi_device;

	HRESULT hr = d3d_device->QueryInterface(&dxgi_device);
	if (FAILED(hr)) {
		blog(LOG_ERROR, "Failed to get DXGI device");
		return nullptr;
	}

	winrt::com_ptr<IInspectable> inspectable;
	hr = CreateDirect3D11DeviceFromDXGIDevice(dxgi_device.Get(),
						  inspectable.put());
	if (FAILED(hr)) {
		blog(LOG_ERROR, "Failed to get WinRT device");
		return nullptr;
	}

	auto activation_factory = winrt::get_activation_factory<
		winrt::Windows::Graphics::Capture::GraphicsCaptureItem>();
	auto interop_factory =
		activation_factory.as<IGraphicsCaptureItemInterop>();
	winrt::Windows::Graphics::Capture::GraphicsCaptureItem item = {nullptr};
	try {
		interop_factory->CreateForWindow(
			window,
			winrt::guid_of<ABI::Windows::Graphics::Capture::
					       IGraphicsCaptureItem>(),
			reinterpret_cast<void **>(winrt::put_abi(item)));
	} catch (winrt::hresult_error &err) {
		blog(LOG_ERROR, "CreateForWindow (0x%08X): %ls", err.to_abi(),
		     err.message().c_str());
		return nullptr;
	} catch (...) {
		blog(LOG_ERROR, "CreateForWindow (0x%08X)",
		     winrt::to_hresult());
		return nullptr;
	}

	const winrt::Windows::Graphics::DirectX::Direct3D11::IDirect3DDevice
		device = inspectable.as<winrt::Windows::Graphics::DirectX::
						Direct3D11::IDirect3DDevice>();
	const winrt::Windows::Graphics::SizeInt32 size = item.Size();
	const winrt::Windows::Graphics::Capture::Direct3D11CaptureFramePool
		frame_pool = winrt::Windows::Graphics::Capture::
			Direct3D11CaptureFramePool::Create(
				device,
				winrt::Windows::Graphics::DirectX::
					DirectXPixelFormat::B8G8R8A8UIntNormalized,
				2, size);
	const winrt::Windows::Graphics::Capture::GraphicsCaptureSession session =
		frame_pool.CreateCaptureSession(item);

	/* disable cursor capture if possible since ours performs better */
	const BOOL cursor_toggle_supported =
		winrt_capture_cursor_toggle_supported();
	if (cursor_toggle_supported)
		session.IsCursorCaptureEnabled(false);

	struct winrt_capture *capture = new winrt_capture{};
	capture->window = window;
	capture->client_area = client_area;
	capture->capture_cursor = cursor && cursor_toggle_supported;
	capture->item = item;
	capture->device = device;
	d3d_device->GetImmediateContext(&capture->context);
	capture->frame_pool = frame_pool;
	capture->session = session;
	capture->last_size = size;
	capture->closed = item.Closed(winrt::auto_revoke,
				      {capture, &winrt_capture::on_closed});
	capture->frame_arrived = frame_pool.FrameArrived(
		winrt::auto_revoke,
		{capture, &winrt_capture::on_frame_arrived});
	capture->active = TRUE;
	capture->next = capture_list;
	capture_list = capture;

	session.StartCapture();

	gs_device_loss callbacks;
	callbacks.device_loss_release = winrt_capture_device_loss_release;
	callbacks.device_loss_rebuild = winrt_capture_device_loss_rebuild;
	callbacks.data = capture;
	gs_register_loss_callbacks(&callbacks);

	return capture;

} catch (const winrt::hresult_error &err) {
	blog(LOG_ERROR, "winrt_capture_init (0x%08X): %ls", err.to_abi(),
	     err.message().c_str());
	return nullptr;
} catch (...) {
	blog(LOG_ERROR, "winrt_capture_init (0x%08X)", winrt::to_hresult());
	return nullptr;
}

extern "C" EXPORT void winrt_capture_free(struct winrt_capture *capture)
{
	if (capture) {
		struct winrt_capture *current = capture_list;
		if (current == capture) {
			capture_list = capture->next;
		} else {
			struct winrt_capture *previous;
			do {
				previous = current;
				current = current->next;
			} while (current != capture);

			previous->next = current->next;
		}

		obs_enter_graphics();
		gs_unregister_loss_callbacks(capture);
		gs_texture_destroy(capture->texture);
		obs_leave_graphics();

		capture->frame_arrived.revoke();
		capture->closed.revoke();
		capture->frame_pool.Close();
		capture->session.Close();

		delete capture;
	}
}

static void draw_texture(struct winrt_capture *capture, gs_effect_t *effect)
{
	gs_texture_t *const texture = capture->texture;
	gs_technique_t *tech = gs_effect_get_technique(effect, "Draw");
	gs_eparam_t *image = gs_effect_get_param_by_name(effect, "image");
	size_t passes;

	gs_effect_set_texture(image, texture);

	passes = gs_technique_begin(tech);
	for (size_t i = 0; i < passes; i++) {
		if (gs_technique_begin_pass(tech, i)) {
			gs_draw_sprite(texture, 0, 0, 0);

			gs_technique_end_pass(tech);
		}
	}
	gs_technique_end(tech);
}

extern "C" EXPORT BOOL winrt_capture_active(const struct winrt_capture *capture)
{
	return capture->active;
}

extern "C" EXPORT void winrt_capture_show_cursor(struct winrt_capture *capture,
						 BOOL visible)
{
	capture->cursor_visible = visible;
}

extern "C" EXPORT void winrt_capture_render(struct winrt_capture *capture,
					    gs_effect_t *effect)
{
	if (capture->texture_written)
		draw_texture(capture, effect);
}

extern "C" EXPORT uint32_t
winrt_capture_width(const struct winrt_capture *capture)
{
	return capture ? capture->texture_width : 0;
}

extern "C" EXPORT uint32_t
winrt_capture_height(const struct winrt_capture *capture)
{
	return capture ? capture->texture_height : 0;
}

extern "C" EXPORT void winrt_capture_thread_start()
{
	struct winrt_capture *capture = capture_list;
	void *const device = gs_get_device_obj();
	while (capture) {
		winrt_capture_device_loss_rebuild(device, capture);
		capture = capture->next;
	}
}

extern "C" EXPORT void winrt_capture_thread_stop()
{
	struct winrt_capture *capture = capture_list;
	while (capture) {
		winrt_capture_device_loss_release(capture);
		capture = capture->next;
	}
}