CoopAllTheThings/tests/present_hook_test.cpp

// In-process self-test for the Present-hook video path (hook/src/present_hook.cpp).
// This process plays both "game" and "host": it installs the Present hook, then
// creates its own D3D11 swapchain, clears the backbuffer to a known color, and
// calls Present -- exactly as a game would. With the hook live, that Present must
// (1) fire the detour, (2) copy the backbuffer into the shared keyed-mutex
// texture, and (3) publish the descriptor to the IPC video channel. A second
// device then opens the shared texture by name and reads it back, proving the
// CreateSharedHandle / OpenSharedResourceByName / keyed-mutex / CopyResource
// contract both the hook and the host rely on -- with no game and no Steam.
//
// Requires a D3D11 device; on a headless / no-GPU machine it reports SKIP and
// exits 0 (mirrors audio_hook_test).

#include <cstdint>
#include <cstdio>
#include <vector>

#include <windows.h>

#include <d3d11_1.h>
#include <dxgi1_2.h>

#include "coop/protocol.hpp"
#include "coop/shared_memory.hpp"
#include "ipc_client.hpp"
#include "present_hook.hpp"
#include "present_overhead.hpp"

using namespace coop;

namespace {

int g_failures = 0;

void check(bool ok, const char* what)
{
	if (!ok) {
		std::printf("  FAIL: %s\n", what);
		++g_failures;
	}
}

template <typename T>
void release(T*& p)
{
	if (p) {
		p->Release();
		p = nullptr;
	}
}

constexpr UINT kW = 256;
constexpr UINT kH = 256;
// Distinctive clear color; UNORM bytes are ~ {51, 102, 153, 255}.
constexpr float kClear[4] = {0.20f, 0.40f, 0.60f, 1.0f};

bool near_byte(std::uint8_t got, int expected)
{
	return std::abs(static_cast<int>(got) - expected) <= 2;
}

} // namespace

int main()
{
	// --- Host side: SharedBlock (named by our pid) so the hook's IpcClient connects.
	SharedMemory shm;
	if (!shm.create(shared_memory_name(GetCurrentProcessId()), sizeof(SharedBlock))) {
		std::printf("FAIL: create shared memory\n");
		return 1;
	}
	auto* block = shm.as<SharedBlock>(); // OS zero-fills the mapping
	block->version = kProtocolVersion;
	block->sequence.store(0, std::memory_order_relaxed);
	block->magic = kProtocolMagic;

	hook::IpcClient ipc;
	check(ipc.connect(10, 5), "IPC client connect");

	// --- Install the Present hook (inline-hooks IDXGISwapChain::Present). ---
	if (!hook::install_present_hooks(ipc)) {
		std::printf("SKIP: could not install the Present hook (no D3D11 device?)\n");
		return 0;
	}

	// --- Game side: our own swapchain on a hidden window; render + Present. ---
	WNDCLASSEXW wc{};
	wc.cbSize = sizeof(wc);
	wc.lpfnWndProc = DefWindowProcW;
	wc.hInstance = GetModuleHandleW(nullptr);
	wc.lpszClassName = L"coop_present_test";
	RegisterClassExW(&wc);
	HWND hwnd = CreateWindowExW(0, wc.lpszClassName, L"", WS_OVERLAPPEDWINDOW, 0, 0, kW, kH, nullptr, nullptr,
	                            wc.hInstance, nullptr);

	DXGI_SWAP_CHAIN_DESC scd{};
	scd.BufferCount = 2;
	scd.BufferDesc.Width = kW;
	scd.BufferDesc.Height = kH;
	scd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
	scd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
	scd.OutputWindow = hwnd;
	scd.SampleDesc.Count = 1;
	scd.Windowed = TRUE;
	scd.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;

	IDXGISwapChain* swapchain = nullptr;
	ID3D11Device* device = nullptr;
	ID3D11DeviceContext* ctx = nullptr;
	HRESULT hr = D3D11CreateDeviceAndSwapChain(nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, 0, nullptr, 0,
	                                           D3D11_SDK_VERSION, &scd, &swapchain, &device, nullptr, &ctx);
	if (FAILED(hr) || swapchain == nullptr) {
		std::printf("SKIP: could not create a D3D11 swapchain (hr=0x%08lX)\n", static_cast<unsigned long>(hr));
		hook::remove_present_hooks();
		return 0;
	}

	// Clear the backbuffer to the known color, then Present (fires the detour).
	for (int frame = 0; frame < 3; ++frame) {
		ID3D11Texture2D* back = nullptr;
		if (SUCCEEDED(swapchain->GetBuffer(0, __uuidof(ID3D11Texture2D), reinterpret_cast<void**>(&back)))) {
			ID3D11RenderTargetView* rtv = nullptr;
			if (SUCCEEDED(device->CreateRenderTargetView(back, nullptr, &rtv))) {
				ctx->ClearRenderTargetView(rtv, kClear);
				ctx->Flush();
				rtv->Release();
			}
			back->Release();
		}
		swapchain->Present(0, 0);
	}

	std::printf("present_calls=%llu frames_shared=%llu video{gen=%u %ux%u fmt=%u}\n",
	            static_cast<unsigned long long>(hook::present_calls()),
	            static_cast<unsigned long long>(hook::present_frames_shared()), block->video.generation.load(),
	            block->video.width, block->video.height, block->video.format);

	check(hook::present_calls() >= 3, "Present detour fired");
	check(hook::present_frames_shared() > 0, "backbuffer copied into the shared texture");
	check(block->video.generation.load() > 0, "video generation published to IPC");
	check(block->video.present_qpc > 0, "present QPC stamped for the latency metric");
	check(block->video.width == kW && block->video.height == kH, "shared dimensions published");
	check(block->video.format == DXGI_FORMAT_R8G8B8A8_UNORM, "shared format published");

	// --- Consumer side: open the shared texture by name (second device), copy it
	//     into a staging texture, map it, and verify the clear color survived. ---
	{
		ID3D11Device* devB = nullptr;
		ID3D11DeviceContext* ctxB = nullptr;
		if (SUCCEEDED(D3D11CreateDevice(nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, 0, nullptr, 0, D3D11_SDK_VERSION,
		                                &devB, nullptr, &ctxB))) {
			ID3D11Device1* dev1 = nullptr;
			devB->QueryInterface(IID_PPV_ARGS(&dev1));
			const std::wstring name = video_share_name(GetCurrentProcessId());
			ID3D11Texture2D* sharedB = nullptr;
			IDXGIKeyedMutex* km = nullptr;
			if (dev1 != nullptr
			    && SUCCEEDED(dev1->OpenSharedResourceByName(
			        name.c_str(), DXGI_SHARED_RESOURCE_READ | DXGI_SHARED_RESOURCE_WRITE, IID_PPV_ARGS(&sharedB)))) {
				sharedB->QueryInterface(IID_PPV_ARGS(&km));

				D3D11_TEXTURE2D_DESC sd{};
				sharedB->GetDesc(&sd);
				sd.Usage = D3D11_USAGE_STAGING;
				sd.BindFlags = 0;
				sd.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
				sd.MiscFlags = 0;
				ID3D11Texture2D* staging = nullptr;
				check(SUCCEEDED(devB->CreateTexture2D(&sd, nullptr, &staging)), "create staging texture");

				if (km != nullptr && staging != nullptr && km->AcquireSync(kVideoMutexKey, 1000) == S_OK) {
					ctxB->CopyResource(staging, sharedB);
					km->ReleaseSync(kVideoMutexKey);

					D3D11_MAPPED_SUBRESOURCE mapped{};
					if (SUCCEEDED(ctxB->Map(staging, 0, D3D11_MAP_READ, 0, &mapped))) {
						const auto* px = static_cast<const std::uint8_t*>(mapped.pData);
						std::printf("readback pixel0 = {%u,%u,%u,%u}\n", px[0], px[1], px[2], px[3]);
						check(near_byte(px[0], 51) && near_byte(px[1], 102) && near_byte(px[2], 153),
						      "shared texture carries the rendered color");
						ctxB->Unmap(staging, 0);
					} else {
						check(false, "map staging texture");
					}
				} else {
					check(false, "acquire keyed mutex + copy shared texture");
				}
				release(staging);
			} else {
				check(false, "open shared texture by name");
			}
			release(km);
			release(sharedB);
			release(dev1);
		}
		release(ctxB);
		release(devB);
	}

	// --- Performance regression guard: the Present hook's backbuffer copy must stay off the present
	//     thread's critical path (measure the present cost with the hook live vs. removed). ---
	{
		auto render = [&] {
			ID3D11Texture2D* back = nullptr;
			if (SUCCEEDED(swapchain->GetBuffer(0, __uuidof(ID3D11Texture2D), reinterpret_cast<void**>(&back)))) {
				ID3D11RenderTargetView* rtv = nullptr;
				if (SUCCEEDED(device->CreateRenderTargetView(back, nullptr, &rtv))) {
					ctx->ClearRenderTargetView(rtv, kClear);
					ctx->Flush();
					rtv->Release();
				}
				back->Release();
			}
		};
		auto present = [&] { swapchain->Present(0, 0); };
		const double hooked = cooptest::avg_present_ms(120, render, present);
		hook::remove_present_hooks(); // baseline: same swapchain, hook removed
		const double base = cooptest::avg_present_ms(120, render, present);
		std::printf("present-thread: hooked %.3f ms, unhooked %.3f ms, capture overhead %.3f ms\n", hooked, base,
		            hooked - base);
		check(hooked - base < cooptest::kPresentOverheadBudgetMs,
		      "Present-hook capture stays off the present thread (overhead < one 60 Hz frame)");
	}

	release(swapchain);
	release(ctx);
	release(device);
	DestroyWindow(hwnd);
	UnregisterClassW(wc.lpszClassName, wc.hInstance);

	std::printf(g_failures == 0 ? "PRESENT HOOK TEST PASS\n" : "PRESENT HOOK TEST FAILED (%d)\n", g_failures);
	return g_failures == 0 ? 0 : 1;
}