Skill hotkeys cast the skill; skills on 1-5, weapon sets on 6-0

A digit that selects a combat-art slot now also presses the right mouse
button (posted WM_RBUTTONDOWN, released with the key), so the game casts
the art at the cursor like a right-click. SwapDigits trades the digit
rows; the key rewrite shares the WASD remap in the engine/UI receivers.

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

src/mods/skillkeys.cpp

@@ -0,0 +1,147 @@
+// Skill hotkeys cast the skill, not only select it.
+//
+// Digits 6-9 and 0 select one of the five combat-art slots on the taskbar
+// (cUI_Taskbar2::HandleEvent -> cUI_Taskbar2::SelectSkillSlot 0x6e17d0); the
+// selected art is then used with the right mouse button. With this mod a
+// digit also presses the right mouse button: a WM_RBUTTONDOWN is posted to the
+// game window, so the game handles it exactly like a real right-click at the
+// cursor (UI hit tests, target under the cursor, cEvent_creature 0x105). The
+// button is released when the digit is, so holding the digit is holding the
+// button.
+//
+// SwapDigits trades 1-5 (weapon sets) and 6-0 (combat-art slots), so the
+// skills sit on 1-5. Key events are rewritten where the WASD mod rewrites its
+// keys (Engine/UI manager ReceiveEvent, src/mods/wasd.cpp).
+//
+// sacred_re.ini:
+//   [skillkeys]
+//   Enabled=1
+//   SwapDigits=1
+
+#include <atomic>
+#include <cstdint>
+#include <thread>
+
+#include <windows.h>
+
+#include "mods/skillkeys.h"
+#include "re/config.h"
+#include "re/hook.h"
+#include "re/log.h"
+#include "re/patch.h"
+
+namespace mods::skillkeys {
+namespace {
+
+// cUI_Taskbar2 fields.
+constexpr size_t kTaskbarSlotCount = 0x15c;  // uint16: combat-art slots the hero has
+constexpr size_t kTaskbarSkillSlots = 0x178;  // 5 slot controls (null: none)
+constexpr unsigned kSlots = 5;
+
+bool Enabled() {
+    static const bool enabled = re::ConfigInt("skillkeys", "Enabled", 1) != 0;
+    return enabled;
+}
+
+bool SwapDigits() {
+    static const bool swap = re::ConfigInt("skillkeys", "SwapDigits", 1) != 0;
+    return swap;
+}
+
+// Digit the player presses to select a slot: 6 7 8 9 0, or 1-5 when swapped.
+int SlotKey(unsigned slot) {
+    if (SwapDigits()) {
+        return '1' + static_cast<int>(slot);
+    }
+    return slot < 4 ? '6' + static_cast<int>(slot) : '0';
+}
+
+bool KeyDown(int key) {
+    return (GetAsyncKeyState(key) & 0x8000) != 0;
+}
+
+// The game window, if it has the focus (it does while a hotkey is pressed).
+HWND GameWindow() {
+    HWND window = GetForegroundWindow();
+    DWORD process = 0;
+    if (!window || !GetWindowThreadProcessId(window, &process) || process != GetCurrentProcessId()) {
+        return nullptr;
+    }
+    return window;
+}
+
+LPARAM CursorClientPos(HWND window) {
+    POINT cursor = {};
+    GetCursorPos(&cursor);
+    ScreenToClient(window, &cursor);
+    return MAKELPARAM(cursor.x, cursor.y);
+}
+
+std::atomic<bool> g_held{false};
+
+// Presses the right mouse button and releases it once `key` is released.
+void PressRightButtonWhileHeld(int key) {
+    HWND window = GameWindow();
+    if (!window || g_held.exchange(true)) {
+        return;  // not focused, or already held (key repeat)
+    }
+    PostMessageW(window, WM_RBUTTONDOWN, MK_RBUTTON, CursorClientPos(window));
+    std::thread([window, key] {
+        while (KeyDown(key) && IsWindow(window)) {
+            Sleep(10);
+        }
+        PostMessageW(window, WM_RBUTTONUP, 0, CursorClientPos(window));
+        g_held = false;
+    }).detach();
+}
+
+void Startup() {
+    if (Enabled()) {
+        re::Log("skillkeys: digits %s cast the skill in their slot", SwapDigits() ? "1-5" : "6-0");
+    }
+}
+RE_STARTUP(SkillKeysStartup, Startup);
+
+} // namespace
+
+uint16_t RemapKey(uint16_t key) {
+    if (!Enabled() || !SwapDigits() || key < '0' || key > '9') {
+        return key;
+    }
+    static constexpr char kSwapped[] = "5678901234";  // indexed by key - '0'
+    return static_cast<uint16_t>(kSwapped[key - '0']);
+}
+
+// After a slot was selected: cast if its digit is what selected it (the slot
+// can also be clicked with the mouse).
+void OnSlotSelected(void* taskbar, unsigned slot) {
+    if (!Enabled() || slot >= kSlots) {
+        return;
+    }
+    const auto* bar = static_cast<const uint8_t*>(taskbar);
+    if (slot >= *reinterpret_cast<const uint16_t*>(bar + kTaskbarSlotCount) ||
+        !reinterpret_cast<void* const*>(bar + kTaskbarSkillSlots)[slot]) {
+        return;  // empty slot: nothing was selected
+    }
+    const int key = SlotKey(slot);
+    if (KeyDown(key)) {
+        PressRightButtonWhileHeld(key);
+    }
+}
+
+} // namespace mods::skillkeys
+
+namespace game {
+
+// cUI_Taskbar2::SelectSkillSlot (0x6e17d0): makes combat-art slot `slot` the
+// right mouse button's art (digits 6-0, clicks on the slot).
+void __fastcall UiTaskbar_SelectSkillSlot(void* self, void* edx, unsigned slot, int notify);
+RE_HOOK(0x006e17d0, UiTaskbar_SelectSkillSlot);
+void __fastcall UiTaskbar_SelectSkillSlot(void* self, void* edx, unsigned slot, int notify) {
+    UiTaskbar_SelectSkillSlot_original(self, edx, slot, notify);
+    if (self) {
+        mods::skillkeys::OnSlotSelected(self, slot & 0xffff);
+    }
+}
+
+} // namespace game