hook opengl

OpenGL 是一个状态机，程序每一帧都会调用 glFlush、glFinish 或 Windows 特有的 wglSwapBuffers 来结束当前帧的绘制。 我们要做的就是：

  1. 定位目标程序调用的 wglSwapBuffers 地址。
  2. 劫持（Hook）这个地址，指向我们自己的函数。
  3. 在我们的函数里，先用 OpenGL 画一个方框，然后再调用原有的函数完成显示。

dll

dllamin.cpp

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
#include <windows.h>
#include <GL/gl.h>
#include <wrl/client.h>
#include "imgui.h"
#include "imgui_impl_win32.h"
#include "imgui_impl_opengl3.h"
#include <MinHook.h>

// 原始函数定义
typedef BOOL(WINAPI* twglSwapBuffers)(HDC hdc);
twglSwapBuffers oSwapBuffers = nullptr;

bool g_Initialized = false;

// 绘制逻辑：画一个方框
void DrawOverlay() {
    ImGui::NewFrame();

    // 获取后台绘制列表，这样方框就不会被 ImGui 窗口挡住
    ImDrawList* drawList = ImGui::GetBackgroundDrawList();

    // 定义方框：左上角 (100, 100)，右下角 (300, 300)，颜色红色 (ABGR)
    ImVec2 p1 = ImVec2(100, 100);
    ImVec2 p2 = ImVec2(300, 300);
    ImU32 color = IM_COL32(255, 0, 0, 255); // 纯红

    // 绘制空心方框，线条粗细为 2.0
    drawList->AddRect(p1, p2, color, 0.0f, 0, 2.0f);

    // 如果你想画实心方框：
    // drawList->AddRectFilled(p1, p2, IM_COL32(255, 0, 0, 100));

    ImGui::Render();
    ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
}

BOOL WINAPI hSwapBuffers(HDC hdc) {
    if (!g_Initialized) {
        HWND hWnd = WindowFromDC(hdc);
        ImGui::CreateContext();
        ImGui_ImplWin32_Init(hWnd);
        ImGui_ImplOpenGL3_Init();
        g_Initialized = true;
    }

    ImGui_ImplOpenGL3_NewFrame();
    ImGui_ImplWin32_NewFrame();

    DrawOverlay();

    return oSwapBuffers(hdc);
}

DWORD WINAPI MainThread(LPVOID lpReserved) {
    // MinHook 通过 vcpkg 安装后，直接使用 MH_ 系列函数
    if (MH_Initialize() == MH_OK) {
        void* pTarget = (void*)GetProcAddress(GetModuleHandleA("opengl32.dll"), "wglSwapBuffers");
        MH_CreateHook(pTarget, &hSwapBuffers, reinterpret_cast<LPVOID*>(&oSwapBuffers));
        MH_EnableHook(pTarget);
    }
    return 0;
}

BOOL APIENTRY DllMain(HMODULE hModule, DWORD reason, LPVOID reserved) {
    if (reason == DLL_PROCESS_ATTACH) {
        DisableThreadLibraryCalls(hModule);
        CloseHandle(CreateThread(nullptr, 0, MainThread, hModule, 0, nullptr));
    }
    return TRUE;
}

CMakeLists.txt

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

# 【核心】禁用 vcpkg 所有的自动集成行为
set(VCPKG_MANIFEST_MODE OFF CACHE BOOL "Disable vcpkg manifest" FORCE)
set(X_VCPKG_APPLOCAL_DEPS_INSTALL OFF CACHE BOOL "Disable applocal copy" FORCE)

project(GLBoxHook LANGUAGES CXX)

set(CMAKE_CXX_STANDARD 17)

# 1. 统一输出目录到 bin
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)

# 2. ImGui 路径 (保持不变)
set(IMGUI_DIR "C:/D/test/CCpp/ccpplib/imgui")
include_directories(${IMGUI_DIR} ${IMGUI_DIR}/backends)

set(IMGUI_SOURCES
    ${IMGUI_DIR}/imgui.cpp
    ${IMGUI_DIR}/imgui_draw.cpp
    ${IMGUI_DIR}/imgui_widgets.cpp
    ${IMGUI_DIR}/imgui_tables.cpp
    ${IMGUI_DIR}/imgui_demo.cpp
    ${IMGUI_DIR}/backends/imgui_impl_win32.cpp
    ${IMGUI_DIR}/backends/imgui_impl_opengl3.cpp
)

# 3. 手动链接 vcpkg 下的 MinHook (硬路径)
set(VCPKG_BASE "C:/D/test/CCpp/ccpplib/vcpkg/vcpkg/installed/x64-windows-static")
include_directories("${VCPKG_BASE}/include")
link_directories("${VCPKG_BASE}/lib")

# 4. 生成 DLL
add_library(${PROJECT_NAME} SHARED dllmain.cpp ${IMGUI_SOURCES})

# 5. 链接系统库和 minhook
# 注意：如果链接报错，请检查 lib 目录下是否叫 minhook.lib 还是 libMinHook.x64.lib
target_link_libraries(${PROJECT_NAME} PRIVATE 
    minhook.x64.lib
    opengl32
    gdi32
    dwmapi
)

add_definitions(-DUNICODE -D_UNICODE -D_CRT_SECURE_NO_WARNINGS)
if(MSVC)
    add_compile_options("/utf-8")
endif()
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)