WX: Replace SetIcon with SetIcons(wxIconBundle)

Setting a single icon at a single resolution doesn't scale well,
Windows requires a 16x16 icon for the window and a 32x32/48x48 for
the taskbar. Providing all icons produces less pixellated results at
HiDPI.

Source/Core/DolphinWX/Cheats/CheatsWindow.cpp

@@ -61,6 +61,7 @@ wxCheatsWindow::wxCheatsWindow(wxWindow* const parent)
   UpdateGUI();
   wxTheApp->Bind(DOLPHIN_EVT_LOCAL_INI_CHANGED, &wxCheatsWindow::OnLocalGameIniModified, this);
 
+  SetIcons(WxUtils::GetDolphinIconBundle());
   SetLayoutAdaptationMode(wxDIALOG_ADAPTATION_MODE_ENABLED);
   SetLayoutAdaptationLevel(wxDIALOG_ADAPTATION_STANDARD_SIZER);
   Center();

Source/Core/DolphinWX/Frame.cpp

@@ -85,9 +85,7 @@ CRenderFrame::CRenderFrame(wxFrame* parent, wxWindowID id, const wxString& title
     : wxFrame(parent, id, title, pos, size, style)
 {
   // Give it an icon
-  wxIcon IconTemp;
+  SetIcons(WxUtils::GetDolphinIconBundle());
-  IconTemp.CopyFromBitmap(WxUtils::LoadScaledResourceBitmap("Dolphin", this));
-  SetIcon(IconTemp);
 
   DragAcceptFiles(true);
   Bind(wxEVT_DROP_FILES, &CRenderFrame::OnDropFiles, this);

Source/Core/DolphinWX/NetPlay/NetPlaySetupFrame.cpp

@@ -43,11 +43,7 @@ NetPlaySetupFrame::NetPlaySetupFrame(wxWindow* const parent, const CGameListCtrl
   IniFile::Section& netplay_section = *inifile.GetOrCreateSection("NetPlay");
 
   CreateGUI();
-  {
+  SetIcons(WxUtils::GetDolphinIconBundle());
-    wxIcon icon;
-    icon.CopyFromBitmap(WxUtils::LoadScaledResourceBitmap("Dolphin", this));
-    SetIcon(icon);
-  }
 
   {
     std::string temp;

Source/Core/DolphinWX/NetPlay/NetWindow.cpp

@@ -70,6 +70,7 @@ NetPlayDialog::NetPlayDialog(wxWindow* const parent, const CGameListCtrl* const
 {
   Bind(wxEVT_THREAD, &NetPlayDialog::OnThread, this);
   CreateGUI();
+  SetIcons(WxUtils::GetDolphinIconBundle());
   Center();
 
   // Remember the window size and position for NetWindow

Source/Core/DolphinWX/WxUtils.cpp

@@ -28,6 +28,10 @@
 
 #include "DolphinWX/WxUtils.h"
 
+#ifdef _WIN32
+#include <Windows.h>
+#endif
+
 namespace WxUtils
 {
 // Launch a file according to its mime type
@@ -81,6 +85,50 @@ void AddToolbarButton(wxToolBar* toolbar, int toolID, const wxString& label, con
                    wxITEM_NORMAL, shortHelp);
 }
 
+wxIconBundle GetDolphinIconBundle()
+{
+  static wxIconBundle s_bundle;
+  if (!s_bundle.IsEmpty())
+    return s_bundle;
+
+#ifdef _WIN32
+
+  // Convert the Windows ICO file into a wxIconBundle by tearing it apart into each individual
+  // sub-icon using the Win32 API. This is necessary because WX uses its own wxIcons internally
+  // which (unlike QIcon in Qt) only contain 1 image per icon, hence why wxIconBundle exists.
+  HINSTANCE dolphin = GetModuleHandleW(nullptr);
+  for (int size : {16, 32, 48, 256})
+  {
+    // Extract resource from embedded DolphinWX.rc
+    HANDLE win32_icon =
+        LoadImageW(dolphin, L"\"DOLPHIN\"", IMAGE_ICON, size, size, LR_CREATEDIBSECTION);
+    if (win32_icon && win32_icon != INVALID_HANDLE_VALUE)
+    {
+      wxIcon icon;
+      icon.CreateFromHICON(reinterpret_cast<HICON>(win32_icon));
+      s_bundle.AddIcon(icon);
+    }
+  }
+
+#else
+
+  for (const char* fname : {"Dolphin.png", "dolphin_logo.png", "dolphin_logo@2x.png"})
+  {
+    wxImage image{StrToWxStr(File::GetSysDirectory() + RESOURCES_DIR DIR_SEP + fname),
+                  wxBITMAP_TYPE_PNG};
+    if (image.IsOk())
+    {
+      wxIcon icon;
+      icon.CopyFromBitmap(image);
+      s_bundle.AddIcon(icon);
+    }
+  }
+
+#endif
+
+  return s_bundle;
+}
+
 wxRect GetVirtualScreenGeometry()
 {
   wxRect geometry;

Source/Core/DolphinWX/WxUtils.h

@@ -36,6 +36,9 @@ wxBitmap CreateDisabledButtonBitmap(const wxBitmap& original);
 void AddToolbarButton(wxToolBar* toolbar, int toolID, const wxString& label, const wxBitmap& bitmap,
                       const wxString& shortHelp);
 
+// Gets a complete set of window icons at all relevant sizes, use with wxTopLevelWindow::SetIcons
+wxIconBundle GetDolphinIconBundle();
+
 // Get the dimensions of the virtual desktop that spans all monitors.
 // Matches GetSystemMetrics(SM_XVIRTUALSCREEN), etc on Windows.
 wxRect GetVirtualScreenGeometry();