Transparent Screensaver Fix 1.0.0 (#869)

* Transparent Screensaver Fix 1.0.0

* Update symbol hooks name

mods/transparent-screensaver-fix.wh.cpp

@@ -0,0 +1,129 @@
+// ==WindhawkMod==
+// @id              transparent-screensaver-fix
+// @name            Transparent Screensaver Fix
+// @description     Allows transparent screensavers to see your desktop again
+// @version         1.0.0
+// @author          aubymori
+// @github          https://github.com/aubymori
+// @include         winlogon.exe
+// @architecture    x86-64
+// ==/WindhawkMod==
+
+// ==WindhawkModReadme==
+/*
+# Transparent Screensaver Fix
+This mod allows transparent screensavers, such as the Bubbles screensaver, to see
+your desktop again, rather than displaying a solid color.
+
+# IMPORTANT: READ!
+Windhawk needs to hook into `winlogon.exe` for this mod to work. Please navigate
+to Windhawk's Settings, Advanced settings, More advanced settings, and make sure
+that `winlogon.exe` is in the Process inclusion list.
+
+**Before**:
+
+![Before](https://raw.githubusercontent.com/aubymori/images/main/transparent-screensaver-fix-before.png)
+
+**After**:
+
+![After](https://raw.githubusercontent.com/aubymori/images/main/transparent-screensaver-fix-after.png)
+*/
+// ==/WindhawkModReadme==
+
+#include <windhawk_utils.h>
+
+bool g_bStartingScreenSaver = false;
+
+/* Only prevent desktop switch when screensaver is being started */
+DWORD (*RunScreenSaver_orig)(struct _WLSM_GLOBAL_CONTEXT *, struct SCREEN_SAVER_DATA *, struct _WINLOGON_JOB **);
+DWORD RunScreenSaver_hook(
+    struct _WLSM_GLOBAL_CONTEXT *pContext,
+    struct SCREEN_SAVER_DATA    *pData,
+    struct _WINLOGON_JOB        **ppJob
+)
+{
+    g_bStartingScreenSaver = true;
+    DWORD result = RunScreenSaver_orig(
+        pContext, pData, ppJob
+    );
+    g_bStartingScreenSaver = false;
+    return result;
+}
+
+/* Prevent screensaver from switching desktop */
+void (*CSession_SwitchDesktop_orig)(void *, UINT, int *, DWORD, DWORD);
+void CSession_SwitchDesktop_hook(
+    void  *pThis,
+    UINT   a1,
+    int   *a2,
+    DWORD  a3,
+    DWORD  a4
+)
+{
+    if (!g_bStartingScreenSaver)
+        return CSession_SwitchDesktop_orig(pThis, a1, a2, a3, a4);
+}
+
+/* Create screensaver on the user desktop */
+DWORD (*CUser_CreateProcessW_orig)(void *, LPCWSTR, LPWSTR, int, STARTUPINFOW *, PROCESS_INFORMATION *, int);
+DWORD CUser_CreateProcessW_hook(
+    void                *pThis,
+    LPCWSTR              a2,
+    LPWSTR               a3,
+    int                  a4,
+    STARTUPINFOW        *psi,
+    PROCESS_INFORMATION *a6,
+    int                  a7
+)
+{
+    if (psi && psi->lpDesktop && psi->lpDesktop[0]
+    && 0 == wcsicmp(psi->lpDesktop, L"Winsta0\\Screen-saver"))
+    {
+        psi->lpDesktop = nullptr;
+    }
+    return CUser_CreateProcessW_orig(
+        pThis, a2, a3, a4, psi, a6, a7
+    );
+}
+
+const WindhawkUtils::SYMBOL_HOOK winlogonExeHooks[] = {
+    {
+        {
+            L"unsigned long __cdecl RunScreenSaver(struct _WLSM_GLOBAL_CONTEXT *,struct SCREEN_SAVER_DATA *,struct _WINLOGON_JOB * *)"
+        },
+        &RunScreenSaver_orig,
+        RunScreenSaver_hook,
+        false
+    },
+    {
+        {
+            L"public: void __cdecl CSession::SwitchDesktop(enum _DESKTOPID,int *,unsigned long,unsigned long)"
+        },
+        &CSession_SwitchDesktop_orig,
+        CSession_SwitchDesktop_hook,
+        false
+    },
+    {
+        {
+            L"public: unsigned long __cdecl CUser::CreateProcessW(unsigned short const *,unsigned short *,unsigned long,struct _STARTUPINFOW *,struct _PROCESS_INFORMATION *,int)"
+        },
+        &CUser_CreateProcessW_orig,
+        CUser_CreateProcessW_hook,
+        false
+    }
+};
+
+BOOL Wh_ModInit(void)
+{
+    if (!WindhawkUtils::HookSymbols(
+        GetModuleHandleW(NULL),
+        winlogonExeHooks,
+        ARRAYSIZE(winlogonExeHooks)
+    ))
+    {
+        Wh_Log(L"Failed to hook one or more symbol functions in winlogon.exe");
+        return FALSE;
+    }
+
+    return TRUE;
+}