Preferred monitor: chosen in Optionen > Allgemein, used at the next start

The Internet-Optionen frame becomes Bildschirm with a Monitor dropdown
(Hauptmonitor or a connected monitor, kept by device path in
[display] Monitor=). The borderless window and the render size use that
monitor, falling back to the main monitor when it is not connected.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/mods/borderless.cpp

@@ -3,7 +3,7 @@
 // The game renders at a fixed resolution (1024x768). Unmodified, windowed mode
 // shows that as a 1024x768 popup centred on the desktop; fullscreen mode
 // switches the display mode. With this mod the game always runs windowed, the
-// popup covers the whole monitor, and each frame is scaled up into the largest
+// popup covers the whole monitor (mods/monitor.h: the preferred one), and each frame is scaled up into the largest
 // centred rectangle with the game's aspect ratio (black bars elsewhere).
 //
 // Mouse positions are mapped back from that rectangle to game pixels, both in
@@ -35,6 +35,7 @@
 #include "game/render/dx_driver7.h"
 #include "mods/hud.h"
 #include "mods/input.h"
+#include "mods/monitor.h"
 #include "mods/widescreen.h"
 #include "re/config.h"
 #include "game/addresses.h"
@@ -90,9 +91,7 @@ RECT FitRect(int areaWidth, int areaHeight, int width, int height, bool integerS
 
 void ApplyBorderless(game::DxDriver7* driver) {
     HWND window = driver->window;
-    MONITORINFO monitor = {sizeof(monitor)};
-    GetMonitorInfoW(MonitorFromWindow(window, MONITOR_DEFAULTTONEAREST), &monitor);
-    const RECT& area = monitor.rcMonitor;
+    const RECT area = mods::monitor::GameMonitorRect();
     const int areaWidth = area.right - area.left;
     const int areaHeight = area.bottom - area.top;
 
@@ -171,7 +170,7 @@ int __fastcall DxDriver7_SetDisplayMode(DxDriver7* self, void* edx, void* device
     }
     DxDisplayMode windowed = *mode;
     windowed.fullscreen = 0;
-    mods::widescreen::ApplyRenderSize(windowed, self->window);
+    mods::widescreen::ApplyRenderSize(windowed);
     g_viewport.active = false;
     const int result = DxDriver7_SetDisplayMode_original(self, edx, deviceCaps, &windowed, unknown);
     if (result) {

src/mods/monitor.cpp

@@ -0,0 +1,160 @@
+// Preferred monitor (request of 2026-10-25): a setting in the graphics options
+// picks the monitor the game starts on; with none set, or the preferred one
+// not connected, the system's main monitor.
+//
+// The game window and its render size are decided when the display mode is
+// set at startup (borderless.cpp, widescreen.cpp ApplyRenderSize): both ask
+// GameMonitorRect. A change applies at the next start.
+//
+// Monitors are told apart by their device path (DisplayConfigGetDeviceInfo,
+// target name: "\\?\DISPLAY#GSM5B7F#..."), which survives restarts, monitor
+// order changes and other ports' changes, unlike the GDI names \\.\DISPLAYn.
+//
+// sacredK.ini:
+//   [display]
+//   Monitor=<device path>   ; empty: the main monitor
+
+#include "mods/monitor.h"
+
+#include <algorithm>
+
+#include "re/config.h"
+#include "re/log.h"
+
+namespace mods::monitor {
+namespace {
+
+constexpr const char* kSection = "display";
+constexpr const char* kKey = "Monitor";
+
+std::string Utf8(const wchar_t* text) {
+    const int size = WideCharToMultiByte(CP_UTF8, 0, text, -1, nullptr, 0, nullptr, nullptr);
+    if (size <= 1) {
+        return {};
+    }
+    std::string result(static_cast<size_t>(size - 1), '\0');
+    WideCharToMultiByte(CP_UTF8, 0, text, -1, result.data(), size, nullptr, nullptr);
+    return result;
+}
+
+struct Target {
+    std::wstring gdiName;  // \\.\DISPLAYn of the source showing it
+    std::string id;
+    std::wstring name;
+};
+
+// The active display paths: which monitor shows which GDI display.
+std::vector<Target> Targets() {
+    UINT32 pathCount = 0;
+    UINT32 modeCount = 0;
+    std::vector<DISPLAYCONFIG_PATH_INFO> paths;
+    std::vector<DISPLAYCONFIG_MODE_INFO> modes;
+    LONG result;
+    do {
+        if (GetDisplayConfigBufferSizes(QDC_ONLY_ACTIVE_PATHS, &pathCount, &modeCount) != ERROR_SUCCESS) {
+            return {};
+        }
+        paths.resize(pathCount);
+        modes.resize(modeCount);
+        result = QueryDisplayConfig(QDC_ONLY_ACTIVE_PATHS, &pathCount, paths.data(), &modeCount, modes.data(),
+                                    nullptr);
+    } while (result == ERROR_INSUFFICIENT_BUFFER);
+    if (result != ERROR_SUCCESS) {
+        return {};
+    }
+    paths.resize(pathCount);
+    std::vector<Target> targets;
+    for (const DISPLAYCONFIG_PATH_INFO& path : paths) {
+        DISPLAYCONFIG_SOURCE_DEVICE_NAME source = {};
+        source.header.type = DISPLAYCONFIG_DEVICE_INFO_GET_SOURCE_NAME;
+        source.header.size = sizeof(source);
+        source.header.adapterId = path.sourceInfo.adapterId;
+        source.header.id = path.sourceInfo.id;
+        DISPLAYCONFIG_TARGET_DEVICE_NAME target = {};
+        target.header.type = DISPLAYCONFIG_DEVICE_INFO_GET_TARGET_NAME;
+        target.header.size = sizeof(target);
+        target.header.adapterId = path.targetInfo.adapterId;
+        target.header.id = path.targetInfo.id;
+        if (DisplayConfigGetDeviceInfo(&source.header) != ERROR_SUCCESS ||
+            DisplayConfigGetDeviceInfo(&target.header) != ERROR_SUCCESS) {
+            continue;
+        }
+        targets.push_back({source.viewGdiDeviceName, Utf8(target.monitorDevicePath), target.monitorFriendlyDeviceName});
+    }
+    return targets;
+}
+
+BOOL CALLBACK AddMonitor(HMONITOR handle, HDC, LPRECT, LPARAM data) {
+    auto* gdi = reinterpret_cast<std::vector<MONITORINFOEXW>*>(data);
+    MONITORINFOEXW info = {};
+    info.cbSize = sizeof(info);
+    if (GetMonitorInfoW(handle, &info)) {
+        gdi->push_back(info);
+    }
+    return TRUE;
+}
+
+}  // namespace
+
+std::vector<Monitor> List() {
+    std::vector<MONITORINFOEXW> gdi;
+    EnumDisplayMonitors(nullptr, nullptr, &AddMonitor, reinterpret_cast<LPARAM>(&gdi));
+    const std::vector<Target> targets = Targets();
+    std::vector<Monitor> monitors;
+    for (const MONITORINFOEXW& info : gdi) {
+        Monitor monitor{"", L"", info.rcMonitor, (info.dwFlags & MONITORINFOF_PRIMARY) != 0};
+        for (const Target& target : targets) {
+            if (target.gdiName == info.szDevice) {  // mirrored displays: the first monitor
+                monitor.id = target.id;
+                monitor.name = target.name;
+                break;
+            }
+        }
+        if (monitor.id.empty()) {
+            monitor.id = Utf8(info.szDevice);  // no display config (remote desktop, ...)
+        }
+        if (monitor.name.empty()) {
+            monitor.name = L"Monitor " + std::to_wstring(monitors.size() + 1);
+        }
+        monitors.push_back(monitor);
+    }
+    std::stable_sort(monitors.begin(), monitors.end(),
+                     [](const Monitor& a, const Monitor& b) { return a.primary && !b.primary; });
+    return monitors;
+}
+
+std::string PreferredId() {
+    return re::ConfigString(kSection, kKey, "");
+}
+
+void SetPreferredId(const std::string& id) {
+    re::SetConfigString(kSection, kKey, id.c_str());
+}
+
+RECT GameMonitorRect() {
+    const std::vector<Monitor> monitors = List();
+    const std::string preferred = PreferredId();
+    const Monitor* chosen = nullptr;
+    for (const Monitor& monitor : monitors) {
+        if ((!preferred.empty() && monitor.id == preferred) || (!chosen && monitor.primary)) {
+            chosen = &monitor;
+        }
+    }
+    if (!chosen) {
+        // No monitor reported: the main monitor's rectangle as Windows has it.
+        MONITORINFO info = {sizeof(info)};
+        GetMonitorInfoW(MonitorFromPoint({0, 0}, MONITOR_DEFAULTTOPRIMARY), &info);
+        return info.rcMonitor;
+    }
+    const bool found = !preferred.empty() && chosen->id == preferred;
+    static bool logged = false;
+    if (!logged) {
+        logged = true;
+        re::Log("monitor: %ls %ldx%ld at (%ld,%ld)%s", chosen->name.c_str(), chosen->rect.right - chosen->rect.left,
+                chosen->rect.bottom - chosen->rect.top, chosen->rect.left, chosen->rect.top,
+                found ? "" : preferred.empty() ? ", main monitor" : ", preferred monitor not connected: main monitor");
+    }
+    return chosen->rect;
+}
+
+}  // namespace mods::monitor

src/mods/monitor.h

@@ -0,0 +1,31 @@
+#pragma once
+// The monitor the game runs on (request of 2026-10-25): a preferred monitor
+// from the options, or the system's main monitor when none is set or the
+// preferred one is not connected. See monitor.cpp.
+
+#include <string>
+#include <vector>
+
+#include <windows.h>
+
+namespace mods::monitor {
+
+struct Monitor {
+    std::string id;     // stable across restarts and reordering: the monitor's device path
+    std::wstring name;  // the monitor's own name (EDID), e.g. "LG ULTRAGEAR"
+    RECT rect;          // desktop coordinates
+    bool primary;
+};
+
+// The connected monitors, the main monitor first.
+std::vector<Monitor> List();
+
+// The preferred monitor's id from sacredK.ini, empty for none.
+std::string PreferredId();
+void SetPreferredId(const std::string& id);
+
+// The rectangle of the monitor to run on: the preferred one if connected,
+// else the main monitor.
+RECT GameMonitorRect();
+
+}  // namespace mods::monitor

src/mods/options.cpp

@@ -41,6 +41,7 @@
 #include "mods/hud.h"
 #include "mods/input.h"
 #include "mods/lootfilter.h"
+#include "mods/monitor.h"
 #include "re/hook.h"
 #include "re/log.h"
 
@@ -684,6 +685,160 @@ bool HandleSavesEvent(Window& w, void* event) {
     }
 }
 
+// --- monitor (Allgemein page) ----------------------------------------------------
+
+// Preferred monitor (request of 2026-10-25, mods/monitor.h) in place of the
+// Internet-Optionen frame (Datendurchsatz, multiplayer only; the user's
+// choice): its controls are hidden (the game keeps the saved value), its title
+// reads "Bildschirm" (text UI_CFG_WAN, set by 0x672a20 / 0x724d50 when the
+// window is made). One row: "Monitor" and a dropdown box; the list opens
+// upwards (the frame is the lowest one), a click picks, a click elsewhere
+// closes it. OK saves the choice, which applies at the next start.
+constexpr const char* kScreenFrameName = "UI_FRAME_INTERNET";
+constexpr const char* kScreenTitleName = "UI_LABEL_WAN";
+constexpr const char* kScreenTitleKey = "UI_CFG_WAN";
+constexpr int kScreenLabelWidth = 0x70;
+constexpr int kArrowWidth = 9;  // the box's down arrow, 5 rows
+
+struct ScreenChoice {
+    std::string id;  // empty: the main monitor
+    std::wstring text;
+};
+
+game::UiRect g_screenFrame = {};
+std::vector<ScreenChoice> g_screenChoices;
+std::string g_screenPending;
+bool g_screenOpen = false;
+int g_screenHover = -1;  // list entry under the mouse
+
+void CreateScreenControls(Window& w) {
+    for (const Control& c : w.controls) {
+        if (IsFrame(c.control) && game::ControlNamed(c.control, kScreenFrameName)) {
+            g_screenFrame = *reinterpret_cast<const game::UiRect*>(c.control + game::kControlRect);
+        }
+    }
+    for (Control& c : w.controls) {
+        const game::UiRect r = *reinterpret_cast<const game::UiRect*>(c.control + game::kControlRect);
+        const bool inside = r.x >= g_screenFrame.x && r.y >= g_screenFrame.y &&
+                            r.x < g_screenFrame.x + g_screenFrame.w && r.y < g_screenFrame.y + g_screenFrame.h;
+        if (c.group == Group::Common &&
+            (game::ControlNamed(c.control, kScreenTitleName) || (inside && !IsFrame(c.control)))) {
+            c.group = Group::Hidden;
+        }
+    }
+}
+
+void LoadScreenPending() {
+    g_screenChoices = {{"", L"Hauptmonitor"}};
+    for (const mods::monitor::Monitor& m : mods::monitor::List()) {
+        g_screenChoices.push_back({m.id, m.name + L" (" + std::to_wstring(m.rect.right - m.rect.left) + L"x" +
+                                             std::to_wstring(m.rect.bottom - m.rect.top) + L")"});
+    }
+    g_screenPending = mods::monitor::PreferredId();
+    g_screenOpen = false;
+    g_screenHover = -1;
+}
+
+const wchar_t* ScreenPendingText() {
+    for (const ScreenChoice& choice : g_screenChoices) {
+        if (choice.id == g_screenPending) {
+            return choice.text.c_str();
+        }
+    }
+    return L"Nicht verbunden";
+}
+
+game::UiRect ScreenRowRect(void* window, int dx, int width) {
+    const game::UiRect origin = game::ControlScreenRect(window);
+    return {origin.x + g_screenFrame.x + kTextInset + dx,
+            origin.y + g_screenFrame.y + (g_screenFrame.h - kBoxHeight) / 2, static_cast<int16_t>(width),
+            static_cast<int16_t>(kBoxHeight)};
+}
+
+game::UiRect ScreenBoxRect(void* window) {
+    return ScreenRowRect(window, kScreenLabelWidth, g_screenFrame.w - 2 * kTextInset - kScreenLabelWidth);
+}
+
+// List entry `index`, upwards from the box: the last entry right above it.
+game::UiRect ScreenEntryRect(void* window, int index) {
+    game::UiRect r = ScreenBoxRect(window);
+    r.y -= static_cast<int>(g_screenChoices.size() - index) * kBoxHeight;
+    return r;
+}
+
+int ScreenEntryAt(void* window, int x, int y) {
+    for (int i = 0; i < static_cast<int>(g_screenChoices.size()); ++i) {
+        if (game::Inside(ScreenEntryRect(window, i), x, y)) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+void DrawScreen(const Window& w, void* device) {
+    void* window = w.window;
+    game::DrawText(device, kFont, game::CenterLineVertically(kFont, ScreenRowRect(window, 0, kScreenLabelWidth)),
+                   L"Monitor", kTextColour, 0);
+    const game::UiRect box = ScreenBoxRect(window);
+    FillBox(device, box, g_screenOpen ? kSavesBoxHoverColour : kSavesBoxColour);
+    game::UiRect text = box;
+    text.x += 6;
+    text.w = static_cast<int16_t>(text.w - 6 - kArrowWidth - 8);
+    game::DrawText(device, kFont, game::CenterLineVertically(kFont, text), ScreenPendingText(), kTextColour, 0);
+    // The arrow: rows narrowing to a point.
+    const int arrowX = box.x + box.w - kArrowWidth - 6;
+    const int arrowY = box.y + (box.h - 5) / 2;
+    for (int row = 0; row < 5; ++row) {
+        FillBox(device, {arrowX + row, arrowY + row, static_cast<int16_t>(kArrowWidth - 2 * row), 1}, kTextColour);
+    }
+    if (g_screenPending != mods::monitor::PreferredId()) {
+        game::UiRect hint = {box.x, box.y + box.h + 2, box.w, static_cast<int16_t>(game::FontLineHeight(kFont))};
+        game::DrawText(device, kFont, hint, L"Ab dem nächsten Spielstart", kUnboundColour, 0);
+    }
+    if (!g_screenOpen) {
+        return;
+    }
+    for (int i = 0; i < static_cast<int>(g_screenChoices.size()); ++i) {
+        const game::UiRect entry = ScreenEntryRect(window, i);
+        const bool selected = g_screenChoices[i].id == g_screenPending;
+        FillBox(device, entry, selected ? kBoxSelectedColour : i == g_screenHover ? kBoxHoverColour : kBoxColour);
+        game::UiRect label = entry;
+        label.x += 6;
+        game::DrawText(device, kFont, game::CenterLineVertically(kFont, label), g_screenChoices[i].text.c_str(),
+                       kTextColour, 0);
+    }
+}
+
+bool HandleScreenEvent(Window& w, void* event) {
+    switch (game::MouseEventKind(event)) {
+    case game::MouseEvent::Move:
+        g_screenHover =
+            g_screenOpen ? ScreenEntryAt(w.window, game::EventField(event, 0xc), game::EventField(event, 0x10)) : -1;
+        return false;
+    case game::MouseEvent::ButtonDown: {
+        const int x = game::EventField(event, game::kMouseButtonX);
+        const int y = game::EventField(event, game::kMouseButtonY);
+        if (g_screenOpen) {
+            const int entry = ScreenEntryAt(w.window, x, y);
+            if (entry >= 0 && game::EventField(event, game::kMouseButton) == game::kLeftButton) {
+                g_screenPending = g_screenChoices[entry].id;
+            }
+            g_screenOpen = false;
+            g_screenHover = -1;
+            return true;  // the click only closes the list
+        }
+        if (game::EventField(event, game::kMouseButton) == game::kLeftButton &&
+            game::Inside(ScreenBoxRect(w.window), x, y)) {
+            g_screenOpen = true;
+            return true;
+        }
+        return false;
+    }
+    default:
+        return false;
+    }
+}
+
 // --- hooks ---------------------------------------------------------------------
 
 struct RenderCall {
@@ -706,6 +861,7 @@ int RenderBody(void* context) {
         LoadPending();
         LoadLootPending();
         g_autosavePending = mods::characters::AutosaveMinutes();
+        LoadScreenPending();
     }
     w->wasVisible = visible;
     const uint16_t page = game::ActiveTab(w->sheet);
@@ -720,6 +876,8 @@ int RenderBody(void* context) {
     }
     if (!visible || page != kPageCommon) {
         g_savesHover = -1;
+        g_screenOpen = false;
+        g_screenHover = -1;
     }
     if (!visible) {
         return result;
@@ -731,6 +889,7 @@ int RenderBody(void* context) {
         DrawLootPage(*w, call->device);
     } else if (page == kPageCommon && g_pendingLoaded) {
         DrawSaves(*w, call->device);
+        DrawScreen(*w, call->device);
     }
     return result;
 }
@@ -773,7 +932,7 @@ int EventBody(void* context) {
         return 1;
     }
     if (w && w->sheet && game::ControlShown(call->window) && game::ActiveTab(w->sheet) == kPageCommon &&
-        g_pendingLoaded && HandleSavesEvent(*w, call->event)) {
+        g_pendingLoaded && (HandleScreenEvent(*w, call->event) || HandleSavesEvent(*w, call->event))) {
         return 1;
     }
     if (w && w->sheet && game::ControlShown(call->window) && game::ActiveTab(w->sheet) == kPageKeys &&
@@ -824,11 +983,16 @@ void* __fastcall UiOptions_Construct(void* self, void* edx, const char* name, Ui
 RE_HOOK(0x00716570, UiOptions_Construct);
 void* __fastcall UiOptions_Construct(void* self, void* edx, const char* name, UiRect rect, void* parent,
                                      uint32_t flags) {
+    static const bool titled = [] {
+        game::SetTextOverride(game::GameTextIdByKey(kScreenTitleKey), L"Bildschirm");
+        return true;
+    }();
     void* window = UiOptions_Construct_original(self, edx, name, rect, parent, flags);
     if (window) {
         g_windows.push_back({static_cast<uint8_t*>(window)});
         Window& w = g_windows.back();
         Classify(w);
+        CreateScreenControls(w);
         CreateKeyControls(w);
         CreateLootControls(w);
         CreateSavesControls(w);
@@ -873,6 +1037,7 @@ void __fastcall UiOptions_Apply(void* self, void* edx) {
         mods::input::SetBindingKeys(g_pending);
         mods::lootfilter::SetModes(g_lootPending);
         mods::characters::SetAutosaveMinutes(g_autosavePending);
+        mods::monitor::SetPreferredId(g_screenPending);
     }
 }
 

src/mods/widescreen.cpp

@@ -26,6 +26,7 @@
 #include "mods/hud.h"
 #include "mods/loadingscreen.h"
 #include "mods/megamap.h"
+#include "mods/monitor.h"
 
 #include <algorithm>
 #include <atomic>
@@ -270,17 +271,16 @@ void PatchLetterbox(int width) {
 
 } // namespace
 
-void ApplyRenderSize(game::DxDisplayMode& mode, HWND window) {
+void ApplyRenderSize(game::DxDisplayMode& mode) {
     if (!Enabled()) {
         return;
     }
-    MONITORINFO monitor = {sizeof(monitor)};
-    GetMonitorInfoW(MonitorFromWindow(window, MONITOR_DEFAULTTOPRIMARY), &monitor);
+    const RECT monitor = mods::monitor::GameMonitorRect();
     // Default: keep the original 768 pixels of world height (so everything
     // keeps its on-screen size once scaled to the monitor) and extend the width
     // to the monitor's aspect ratio. Height=0 renders at the monitor height 1:1.
-    const int monitorWidth = monitor.rcMonitor.right - monitor.rcMonitor.left;
-    const int monitorHeight = monitor.rcMonitor.bottom - monitor.rcMonitor.top;
+    const int monitorWidth = monitor.right - monitor.left;
+    const int monitorHeight = monitor.bottom - monitor.top;
     int height = re::ConfigInt("widescreen", "Height", static_cast<int>(kOriginalHeight));
     if (height <= 0) {
         height = monitorHeight;

src/mods/widescreen.h

@@ -9,7 +9,7 @@ namespace mods::widescreen {
 // Called by the borderless mod before the renderer creates its surfaces:
 // sets the render size to the monitor (or the configured size) and resizes
 // the world view to match. No-op when disabled.
-void ApplyRenderSize(game::DxDisplayMode& mode, HWND window);
+void ApplyRenderSize(game::DxDisplayMode& mode);
 
 // True while the current thread draws the load / save progress screen.
 bool IsLoadingScreen();