Auto-attack: next target, melee/ranged rule after arts; chain range = cast range

- autoattack: when the target dies, the nearest enemy within close range
  (contact distance + a step) takes over; after an art the hero auto-attacks
  if the art was melee (walked up / cast close by), or ranged with a ranged
  weapon, or ranged with an enemy already in melee range; measured action
  codes and weapon classes in game/engine/orders.h
- chainlightning: jumps reach Blitzschlag's cast range (20 ray segments of
  30, the art code's hit check) via the shared NearestHostile search
- guards: burning bone render hook had the wrong signature (device plus a
  4x4 matrix by value, ret 0x44) and corrupted the stack when fire arrows hit
- crash reports follow the ebp chain before the raw stack scan

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

src/mods/autoattack.cpp

@@ -8,13 +8,22 @@
 // becomes the hero's combat target if it is a living creature and not an ally.
 // Every engine tick in which the hero is idle, no mouse button and no skill
 // key is held, the attack order a left click sends goes to the target again.
-// A walk order (mouse move, WASD, stop) or the target's death ends it.
+// A walk order (mouse move, WASD, stop) ends it. When the target dies the
+// hero takes the nearest enemy within close range (weapon reach and a step).
+// After an art: a melee art (the hero walked up to cast it, or casts it from
+// close by) always leads to auto-attacking (its target, else the nearest
+// enemy close by); a ranged art (cast from beyond close range) only with a
+// ranged weapon, or with a melee weapon when an enemy is in melee range. Which arts are ranged is seen when the hero starts them and
+// remembered per art. User requests of 2026-10-16.
 // Between swings the hero does not go idle at all: the end-of-swing check for
 // a held mouse button is answered "held" for the auto-attack target.
 // Measured with an order log, see docs/auto-attack.md.
 
 #include <atomic>
 #include <cstdint>
+#include <unordered_map>
+
+#include <windows.h>
 
 #include "game/engine/arts.h"
 #include "game/engine/events.h"
@@ -30,11 +39,27 @@ namespace {
 // After an attack order, wait this many ticks for the hero to start it before
 // sending another one (it takes about 2 ticks).
 constexpr int kStartTicks = 5;
-constexpr int32_t kActionAttack = 3;  // +0x150 low word
+// "Close range": where the hero touches a creature (game::ContactDistance,
+// heroes swing from 117..149) plus a step.
+constexpr int kStep = 100;
+// TODO(measure): the reach of ranged weapons (no ranged hero measured yet).
+constexpr int kRangedWeaponReach = 600;
+// An art order that has not started after this long is forgotten.
+constexpr DWORD kCastStartMs = 5000;
 
 std::atomic<uint32_t> g_target{0};
 int g_waitTicks = 0;
 
+// The hero's last art order until the hero starts it.
+struct CastWatch {
+    uint16_t art = 0;
+    uint32_t target = 0;  // an enemy, or 0
+    bool walked = false;
+    DWORD since = 0;
+};
+CastWatch g_cast;
+std::unordered_map<uint16_t, bool> g_artRanged;
+
 bool IsEnemy(void* hero, uint32_t id) {
     if (id == 0 || id == static_cast<uint32_t>(game::CreatureField(hero, game::kCreatureId))) {
         return false;
@@ -43,19 +68,89 @@ bool IsEnemy(void* hero, uint32_t id) {
 }
 
 bool Idle(void* creature) {
-    return (game::CreatureField(creature, game::kCreatureAction) & 0xffff) == 0;
+    return game::CurrentAction(creature) == game::kActionIdle;
+}
+
+// How far the hero looks for its next target.
+double CloseRange(void* hero) {
+    if (game::HasRangedWeapon(hero)) {
+        return kRangedWeaponReach;
+    }
+    return game::ContactDistance(hero, hero) + kStep;
+}
+
+uint32_t NearestCloseEnemy(void* hero, uint32_t except) {
+    return game::NearestHostile(hero, hero, CloseRange(hero), except);
+}
+
+// The hero started the watched art: decide what it auto-attacks afterwards.
+void OnCastStarted(void* hero) {
+    const CastWatch cast = g_cast;
+    g_cast = {};
+    void* target = cast.target ? game::GetCreature(cast.target) : nullptr;
+    bool ranged = false;
+    if (cast.walked) {
+        g_artRanged[cast.art] = false;
+    } else if (target && static_cast<int>(game::DistanceTo(hero, cast.target)) >
+                             game::ContactDistance(hero, target) + kStep) {
+        g_artRanged[cast.art] = ranged = true;
+    } else {
+        const auto known = g_artRanged.find(cast.art);
+        ranged = known != g_artRanged.end() && known->second;
+    }
+    if (ranged && !game::HasRangedWeapon(hero)) {
+        // A ranged art with a melee weapon: auto-attack only what is in melee
+        // range already (its target if that close, else the nearest enemy).
+        const bool targetClose = target && game::DistanceTo(hero, cast.target) <= CloseRange(hero);
+        g_target = targetClose ? cast.target : NearestCloseEnemy(hero, 0);
+        return;
+    }
+    g_target = target ? cast.target : NearestCloseEnemy(hero, 0);
+}
+
+void WatchCast(void* hero) {
+    if (!g_cast.since) {
+        return;
+    }
+    if (GetTickCount() - g_cast.since > kCastStartMs) {
+        g_cast = {};
+        return;
+    }
+    switch (game::CurrentAction(hero)) {
+    case game::kActionWalk:
+        g_cast.walked = true;
+        break;
+    case game::kActionCastSpell:
+    case game::kActionCombatMove:
+        OnCastStarted(hero);
+        break;
+    default:
+        break;
+    }
 }
 
 void OnTick(uint8_t* engine) {
-    const uint32_t id = g_target.load();
+    void* hero = game::ControlledCreature(engine);
+    if (!hero) {
+        g_target = 0;
+        return;
+    }
+    WatchCast(hero);
+    if (g_cast.since) {
+        return;  // the art decides once it starts
+    }
+    uint32_t id = g_target.load();
     if (!id) {
         return;
     }
-    void* hero = game::ControlledCreature(engine);
     void* target = game::GetCreature(id);
-    if (!hero || !target || !game::IsAlive(target)) {
-        g_target = 0;
-        return;
+    if (!target || !game::IsAlive(target)) {
+        id = NearestCloseEnemy(hero, id);
+        g_target = id;
+        target = id ? game::GetCreature(id) : nullptr;
+        if (!target) {
+            return;
+        }
     }
     if (!Idle(hero)) {
         g_waitTicks = 0;
@@ -129,7 +224,7 @@ char __fastcall AttackHeld(void* cursor, void*) {
     const uint32_t id = g_target.load();
     void* hero = game::GetPlayerHero();
     if (!id || !hero || mods::skillkeys::KeyHeld() ||
-        (game::CreatureField(hero, game::kCreatureAction) & 0xffff) != kActionAttack) {
+        game::CurrentAction(hero) != game::kActionAttack) {
         return 0;
     }
     void* target = game::GetCreature(id);
@@ -161,12 +256,17 @@ void OnOrder(void* creature, const game::CreatureOrder& order, void*) {
             g_target = static_cast<uint32_t>(order.a);
         }
         break;
-    case game::kOrderUseArt:
-        if (IsEnemy(hero, order.target)) {
-            g_target = order.target;
+    case game::kOrderUseArt: {
+        // Buffs and the like (aimed at the hero or an ally) leave the target.
+        const auto launch = game::ArtLaunchType(static_cast<uint16_t>(order.art));
+        if (launch == game::LaunchType::SelfOrAlly || launch == game::LaunchType::Corpse) {
+            break;
         }
+        g_cast = {static_cast<uint16_t>(order.art), IsEnemy(hero, order.target) ? order.target : 0u, false,
+                  GetTickCount()};
         break;
     }
+    }
 }
 
 struct OrderRegistration {

src/mods/chainlightning.cpp

@@ -11,7 +11,8 @@
 //
 // This mod keeps all of that and decides:
 // - hits per chain N = 3 + level / 5: the first bolt's [14];
-// - the next target: the nearest enemy within the game's range that this
+// - the next target: the nearest enemy within Blitzschlag's cast range (see
+//   below; the game's own jump search used about 316) that this
 //   chain has not hit yet; else another enemy; else the current target again
 //   (a lone enemy takes all N hits);
 // - chains B = 1 + level / 10: B - 1 more chains start at the first target,
@@ -43,7 +44,16 @@ namespace {
 constexpr uint32_t kBoltObjectType = 0x368;  // 872
 constexpr uint32_t kJumpSearchCall = 0x005b469f;  // in the bolt update
 constexpr uint32_t kFindJumpTarget = 0x006005d0;  // cObjectManager::FindJumpTarget
-constexpr uint32_t kJumpRange = 100000;  // the game's argument (a squared distance)
+// Blitzschlag's cast range: the art code (cCreature art switch 0x5222c0,
+// case 0x21) lays the ray from the caster towards the target in segments of
+// 30, at most 20, each on passable ground (0x636b60); only if the target is
+// reached is the bolt created on it. A jump may go as far as a cast. One place,
+// so it can become dynamic (levels, attributes) later.
+constexpr double kRaySegmentLength = 30.0;
+constexpr int kRaySegments = 20;
+double CastRange() {
+    return kRaySegmentLength * kRaySegments;
+}
 constexpr size_t kObjectOwnerPlayer = 0x39;  // u8, copied from the caster like the game does
 constexpr size_t kCreaturePosition = 0x18;  // 4 dwords, as effects are placed
 constexpr size_t kEventHitsLeft = 14;
@@ -84,44 +94,10 @@ unsigned ArtLevel(void* creature, uint16_t art) {
     return entry ? entry[game::kCooldownLevel] + entry[game::kCooldownBonusLevels] : 0;
 }
 
-bool Contains(const std::vector<uint32_t>& ids, uint32_t id) {
-    for (uint32_t i : ids) {
-        if (i == id) {
-            return true;
-        }
-    }
-    return false;
-}
-
-bool IsTarget(void* caster, uint32_t id) {
-    return !game::IsPlayerHeroId(id) && game::IsHostileTo(caster, game::GetCreature(id));
-}
-
-// The nearest living enemy of `caster` within `range` (squared) of `from`, not
-// `current`; one not in `avoid` if there is any. 0 if none.
-uint32_t Nearest(void* caster, void* from, uint32_t range, uint32_t current, const std::vector<uint32_t>& avoid) {
-    uint32_t best = 0;
-    double bestDistance = 0.0;
-    bool bestFresh = false;
-    const int count = game::NearbyCreatureCount();
-    for (int i = 0; i < count; ++i) {
-        const uint32_t id = game::NearbyCreatureId(i);
-        if (id == current || !IsTarget(caster, id)) {
-            continue;
-        }
-        const double d = static_cast<double>(game::DistanceTo(from, id));
-        if (d * d > static_cast<double>(range)) {
-            continue;
-        }
-        const bool fresh = !Contains(avoid, id);
-        if (best && ((bestFresh && !fresh) || (bestFresh == fresh && d >= bestDistance))) {
-            continue;
-        }
-        best = id;
-        bestDistance = d;
-        bestFresh = fresh;
-    }
-    return best;
+// The nearest living enemy of `caster` within the cast range of `from`, not
+// `current`; one not in `avoid` if there is any.
+uint32_t Nearest(void* caster, void* from, uint32_t current, const std::vector<uint32_t>& avoid) {
+    return game::NearestHostile(caster, from, CastRange(), current, avoid.data(), avoid.size());
 }
 
 void Forget() {
@@ -194,7 +170,7 @@ void BeforeFxEvent(uint8_t* fx, uint32_t* event) {
     // More chains: each starts with a bolt at its own first jump target.
     std::vector<uint32_t> taken{target};
     for (unsigned c = 1; c < chains && hits > 1; ++c) {
-        const uint32_t next = Nearest(caster, first, kJumpRange, target, taken);
+        const uint32_t next = Nearest(caster, first, target, taken);
         const uint32_t branchTarget = next ? next : target;
         taken.push_back(branchTarget);
         auto branch = std::make_shared<Chain>();
@@ -252,7 +228,7 @@ uint32_t __fastcall NextTarget(void* manager, void*, const int32_t* position, ui
         return 0;
     }
     const std::shared_ptr<Chain> chain = it->second.chain;
-    uint32_t next = Nearest(casterCreature, from, range, current, chain->hit);
+    uint32_t next = Nearest(casterCreature, from, current, chain->hit);
     if (!next) {
         next = current;  // nobody else: hit the same enemy again
     }

src/mods/guards.cpp

@@ -13,9 +13,13 @@ namespace game {
 // pressed while walking; Windows reported sacred.exe+0x374e39). Who renders
 // it without a device is not known yet (sacred_re_crash.txt will tell). With
 // no device there is nothing to draw.
-void __fastcall BurningBone_Render(void* self, void* edx, void* device);
+// (device, a 4x4 matrix by value; ret 0x44).
+struct Matrix4 {
+    float m[16];
+};
+void __fastcall BurningBone_Render(void* self, void* edx, void* device, Matrix4 transform);
 RE_HOOK(0x00774e10, BurningBone_Render);
-void __fastcall BurningBone_Render(void* self, void* edx, void* device) {
+void __fastcall BurningBone_Render(void* self, void* edx, void* device, Matrix4 transform) {
     if (!device) {
         static bool logged = false;
         if (!logged) {
@@ -24,7 +28,7 @@ void __fastcall BurningBone_Render(void* self, void* edx, void* device) {
         }
         return;
     }
-    BurningBone_Render_original(self, edx, device);
+    BurningBone_Render_original(self, edx, device, transform);
 }
 
 } // namespace game