add file save dialog on win

src/main.cpp

@@ -278,6 +278,26 @@ std::string win32_open_file(const char* filter)
     return "";
 }
 
+std::string win32_save_file(const char* filter)
+{
+    OPENFILENAMEA ofn;
+    char fileName[MAX_PATH] = "";
+    ZeroMemory(&ofn, sizeof(ofn));
+    ofn.lStructSize = sizeof(OPENFILENAME);
+    ofn.hwndOwner = hWnd;
+    ofn.lpstrFilter = filter;
+    ofn.lpstrFile = fileName;
+    ofn.nMaxFile = MAX_PATH;
+    ofn.Flags = OFN_EXPLORER | OFN_FILEMUSTEXIST | OFN_HIDEREADONLY | OFN_NOCHANGEDIR;
+    ofn.lpstrDefExt = "";
+    ofn.lpstrInitialDir = "";
+    if (GetSaveFileNameA(&ofn) != NULL)
+    {
+        return fileName;
+    }
+    return "";
+}
+
 std::string win32_open_dir()
 {
     BROWSEINFOA bi;