Combos: cooldown labels on the skill bar, steps follow the arts' current levels

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

src/game/engine/arts.h

@@ -156,6 +156,59 @@ inline ArtCooldown GetArtCooldown(void* creature, uint16_t art) {
     return {remaining, Float(entry, kCooldownTotal), perSecond > 0.0f ? remaining / perSecond : 0.0f};
 }
 
+// Combos (made at the Kombomeister): a vector of 0x26-byte entries at +0x10e /
+// +0x112 of cCreatureArts, at most 4 (cCreatureArts::FindCombo 0x5819a0):
+//   +0    u16    combo id (0x200..0x204, definitions FindComboDef 0x4d2970)
+//   +2    u32[4] art of each step (0: empty)
+//   +0x12 u16[4] level of each step's art, stored when the combo was made
+//   +0x1a float  total (sum of the arts' regeneration at those levels)
+//   +0x1e float  charge rate, recomputed each update while charging:
+//                1 + average of the arts' regeneration speed % / 100
+//   +0x22 float  charge: counts up to the total (ready at total,
+//                cCreatureArts::IsComboReady 0x581920); using the combo
+//                lowers it (cCreatureArts::AddGroupRegen, combo branch)
+// cCreatureArts::SetCombo (0x581290, (index, arts[4], levels[4], id), ret
+// 0x10) fills an entry and computes the total; the charge starts at 0.
+// A taskbar slot of type 4 holds combo 0x200 + index.
+constexpr size_t kCombosBegin = 0x10e;
+constexpr size_t kCombosEnd = 0x112;
+constexpr size_t kComboSize = 0x26;
+constexpr size_t kComboId = 0x0;
+constexpr size_t kComboArts = 0x2;
+constexpr size_t kComboLevels = 0x12;
+constexpr size_t kComboTotal = 0x1a;
+constexpr size_t kComboRate = 0x1e;
+constexpr size_t kComboCharge = 0x22;
+constexpr unsigned kComboSteps = 4;
+constexpr uint32_t kComboRefBase = 0x200;
+constexpr uint32_t kArtSlotTypeCombo = 4;
+
+// Entry `index` of the combo vector of cCreatureArts `arts`, or null.
+inline uint8_t* ComboEntry(uint8_t* arts, unsigned index) {
+    auto* begin = *reinterpret_cast<uint8_t**>(arts + kCombosBegin);
+    auto* end = *reinterpret_cast<uint8_t**>(arts + kCombosEnd);
+    if (!begin || index >= static_cast<unsigned>(end - begin) / kComboSize) {
+        return nullptr;
+    }
+    return begin + index * kComboSize;
+}
+
+// The cooldown of the combo in a taskbar slot (reference 0x200 + index).
+inline ArtCooldown GetComboCooldown(void* creature, uint32_t slotRef) {
+    auto* arts = static_cast<uint8_t*>(creature) + kCreatureArts;
+    uint8_t* entry = slotRef >= kComboRefBase ? ComboEntry(arts, slotRef - kComboRefBase) : nullptr;
+    if (!entry) {
+        return {};
+    }
+    const float total = Float(entry, kComboTotal);
+    const float remaining = total - Float(entry, kComboCharge);
+    if (remaining <= 0.0f) {
+        return {0.0f, total, 0.0f};
+    }
+    const float rate = Float(entry, kComboRate);
+    return {remaining, total, rate > 0.0f ? remaining / rate : 0.0f};
+}
+
 // cCreature::IsAlly (0x548f20): whether object `id` is an ally of `creature`.
 inline bool IsAlly(void* creature, uint32_t id) {
     using Fn = char(__fastcall*)(void*, void*, uint32_t);