3.主程序预留接口搜索框写成dll注入

1. 核心原理

要实现“注入并显示”，DLL 必须能把自己挂载到主程序的渲染循环里。在 raylib 中，由于它是顺序执行的，最简单的“注入”方式是：

1. 主程序提供一个入口（类似一个“插件槽位”）。

2. DLL 端代码：

searchbox_dll.cpp

#include "IPlugin.h"
#include <vector>

// 插件内部私有变量（被封存在 DLL 内存空间中）
static char inputText[64] = { 0 };
static int letterCount = 0;
static bool active = false;

// --- 接口实现函数 ---

void SearchOnInit() {
    // 可以在这里初始化资源，比如加载搜索框专用的字体或音效
    TraceLog(LOG_INFO, "[SearchBox DLL] Plugin Initialized.");
}

void SearchOnTick() {
    if (IsKeyPressed(KEY_F2)) active = !active;
    if (!active) return;

    // --- 原有的输入处理逻辑 ---
    int key = GetCharPressed();
    while (key > 0) {
        if (key >= 32 && key <= 125 && letterCount < 63) {
            inputText[letterCount++] = (char)key;
            inputText[letterCount] = '\0';
        }
        key = GetCharPressed();
    }
    if (IsKeyPressed(KEY_BACKSPACE) && letterCount > 0) inputText[--letterCount] = '\0';

    // --- 新增：回车事件处理 ---
    if (IsKeyPressed(KEY_ENTER)) {
        if (letterCount > 0) {
            // 1. 打印输出（会显示在主程序的控制台里）
            TraceLog(LOG_INFO, "[SearchBox] Searching for: %s", inputText);

            // 2. 这里可以添加更多反应，比如：
            // - 改变一个全局状态
            // - 触发搜索逻辑
            // - 甚至是调用主程序传进来的回调函数

            // 3. 执行完后清空并关闭
            letterCount = 0;
            inputText[0] = '\0';
            active = false;
        }
    }

    // --- 绘图逻辑保持不变 ---
    Rectangle box = { GetScreenWidth() / 2.0f - 200, 20, 400, 40 };
    DrawRectangleRounded(box, 0.3f, 8, Fade(BLACK, 0.8f));
    DrawRectangleRoundedLines(box, 0.3f, 8,  active ? SKYBLUE : GRAY);
    DrawText(inputText, (int)box.x + 15, (int)box.y + 10, 20, RAYWHITE);
}

void SearchOnUnload() {
    // 清理资源
    TraceLog(LOG_INFO, "[SearchBox DLL] Plugin Unloaded.");
}

// --- 唯一的导出函数：将上述函数打包交给宿主 ---

extern "C" __declspec(dllexport) PluginInterface* GetPluginAPI() {
    static PluginInterface api = {
        {"Global Search", "1.0"},
        SearchOnInit,
        SearchOnTick,
        SearchOnUnload
    };
    return &api;
}

IPlugin.h

#ifndef IPLUGIN_H
#define IPLUGIN_H

#include "raylib.h"

// 插件元数据
struct PluginInfo {
    const char* name;
    const char* version;
};
typedef struct {
	PluginInfo info;
    void (*OnInit)();
    void (*OnTick)();
    void (*OnUnload)();
} PluginInterface;

typedef PluginInterface* (*GetPluginAPI_Func)();

#endif

dllmain.cpp

// dllmain.cpp : Defines the entry point for the DLL application.
#include <windows.h>

BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
                     )
{
    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        break;
    }
    return TRUE;
}

3. 主程序端代码：预留“注入接口”

在主程序渲染中调用dll

main.cpp

#include "raylib.h"
#include "PluginLoader.h"

int main() {
    InitWindow(800, 600, "Clean Plugin System");
    SetTargetFPS(60);

    PluginInstance searchBox("searchbox.dll");
    searchBox.Load();

    while (!WindowShouldClose()) {
        if (IsKeyPressed(KEY_F5)) searchBox.Reload();

        BeginDrawing();
        ClearBackground(DARKGRAY);

        // 状态检查
        if (searchBox.IsLoaded()) {
            DrawCircle(780, 20, 10, GREEN); // 右上角绿灯
            searchBox.Update();
        }
        else {
            DrawCircle(780, 20, 10, RED);   // 右上角红灯
            DrawText("PLUGIN NOT LOADED!", 600, 40, 10, RED);
        }
        EndDrawing();
    }

    CloseWindow();
    return 0;
}

PluginLoader.h

#ifndef PLUGIN_LOADER_H
#define PLUGIN_LOADER_H

#include "IPlugin.h"
#include <string>

class PluginInstance {
public:
    explicit PluginInstance(const std::string& path);
    ~PluginInstance();

    bool Load();
    void Unload();
    void Reload();
    void Update();
    bool IsLoaded() const;
private:
    std::string dllPath;
    void* hModule;      // 内部封装 HMODULE
    PluginInterface* api;
};

#endif

PluginLoader.cpp

#include "PluginLoader.h"

// 只有在这里才包含 Windows 头文件
#define NOGDI
#define NOUSER
#define WIN32_LEAN_AND_MEAN
#include <windows.h>

PluginInstance::PluginInstance(const std::string& path)
    : dllPath(path), hModule(nullptr), api(nullptr) {
}

PluginInstance::~PluginInstance() {
    Unload();
}

bool PluginInstance::Load() {
    hModule = (void*)LoadLibraryA(dllPath.c_str());

    if (!hModule) {
        DWORD error = GetLastError();
        TraceLog(LOG_ERROR, "[Loader] LoadLibraryA failed. Error Code: %lu. Path: %s", error, dllPath.c_str());
        // 常见错误码：126 (找不到模块), 193 (不是有效的 Win32 应用程序/位数不匹配)
        return false;
    }

    auto GetAPI = (GetPluginAPI_Func)GetProcAddress((HMODULE)hModule, "GetPluginAPI");
    if (!GetAPI) {
        TraceLog(LOG_ERROR, "[Loader] GetProcAddress failed. Could not find 'GetPluginAPI' in %s", dllPath.c_str());
        Unload();
        return false;
    }

    api = GetAPI();
    if (api && api->OnInit) {
        api->OnInit();
        TraceLog(LOG_INFO, "[Loader] Plugin %s loaded and initialized.", dllPath.c_str());
    }
    return true;
}

void PluginInstance::Unload() {
    if (api && api->OnUnload) api->OnUnload();
    if (hModule) {
        FreeLibrary((HMODULE)hModule);
        hModule = nullptr;
    }
    api = nullptr;
}

void PluginInstance::Reload() {
    Unload();
    Load();
}

void PluginInstance::Update() {
    if (api && api->OnTick) api->OnTick();
}

bool PluginInstance::IsLoaded() const {
    // 只要模块句柄不为空，且 API 函数表拿到了，就认为加载成功
    return (hModule != nullptr && api != nullptr);
}

IPlugin.h

#ifndef IPLUGIN_H
#define IPLUGIN_H

#include "raylib.h"

// 插件元数据
struct PluginInfo {
    const char* name;
    const char* version;
};
typedef struct {
    PluginInfo info;
    void (*OnInit)();
    void (*OnTick)();
    void (*OnUnload)();
} PluginInterface;

typedef PluginInterface* (*GetPluginAPI_Func)();

#endif