perf: eliminate double map lookups, dynamic_cast in render loops, div by 255

- Replace count()+operator[] double lookups with find() or try_emplace()
  in gameObjectInstances_, playerTextureSlotsByModelId_, onlinePlayerAppearance_
- Add Entity::isUnit() helper; replace 5 dynamic_cast<Unit*> in per-frame
  UI rendering (nameplates, combat text, pet frame) with isUnit()+static_cast
- Add constexpr kInv255 reciprocal for per-pixel normal map generation loops
  in character_renderer and wmo_renderer

include/game/entity.hpp

@@ -153,6 +153,9 @@ public:
     ObjectType getType() const { return type; }
     void setType(ObjectType t) { type = t; }
 
+    /// True if this entity is a Unit or Player (both derive from Unit).
+    bool isUnit() const { return type == ObjectType::UNIT || type == ObjectType::PLAYER; }
+
     // Fields (for update values)
     void setField(uint16_t index, uint32_t value) {
         fields[index] = value;

src/core/application.cpp

@@ -7155,7 +7155,9 @@ void Application::spawnOnlinePlayer(uint64_t guid,
     }
 
     // Determine texture slots once per model
-    if (!playerTextureSlotsByModelId_.count(modelId)) {
+    {
+        auto [slotIt, inserted] = playerTextureSlotsByModelId_.try_emplace(modelId);
+        if (inserted) {
             PlayerTextureSlots slots;
             if (const auto* md = charRenderer->getModelData(modelId)) {
                 for (size_t ti = 0; ti < md->textures.size(); ti++) {
@@ -7165,7 +7167,8 @@ void Application::spawnOnlinePlayer(uint64_t guid,
                     else if (t == 8 && slots.underwear < 0) slots.underwear = static_cast<int>(ti);
                 }
             }
-        playerTextureSlotsByModelId_[modelId] = slots;
+            slotIt->second = slots;
+        }
     }
 
     // Create instance at server position
@@ -7330,14 +7333,13 @@ void Application::setOnlinePlayerEquipment(uint64_t guid,
     }
 
     // If the player isn't spawned yet, store equipment until spawn.
-    if (!playerInstances_.count(guid) || !onlinePlayerAppearance_.count(guid)) {
+    auto appIt = onlinePlayerAppearance_.find(guid);
+    if (!playerInstances_.count(guid) || appIt == onlinePlayerAppearance_.end()) {
         pendingOnlinePlayerEquipment_[guid] = {displayInfoIds, inventoryTypes};
         return;
     }
 
-    auto it = onlinePlayerAppearance_.find(guid);
+    const OnlinePlayerAppearanceState& st = appIt->second;
-    if (it == onlinePlayerAppearance_.end()) return;
-    const OnlinePlayerAppearanceState& st = it->second;
 
     auto* charRenderer = renderer->getCharacterRenderer();
     if (!charRenderer) return;
@@ -7533,9 +7535,10 @@ void Application::spawnOnlineGameObject(uint64_t guid, uint32_t entry, uint32_t
     }
     if (!gameObjectLookupsBuilt_) return;
 
-    if (gameObjectInstances_.count(guid)) {
+    auto goIt = gameObjectInstances_.find(guid);
+    if (goIt != gameObjectInstances_.end()) {
         // Already have a render instance — update its position (e.g. transport re-creation)
-        auto& info = gameObjectInstances_[guid];
+        auto& info = goIt->second;
         glm::vec3 renderPos = core::coords::canonicalToRender(glm::vec3(x, y, z));
         LOG_DEBUG("GameObject position update: displayId=", displayId, " guid=0x", std::hex, guid, std::dec,
                  " pos=(", x, ", ", y, ", ", z, ")");

src/rendering/character_renderer.cpp

@@ -546,12 +546,13 @@ CharacterRenderer::NormalMapResult CharacterRenderer::generateNormalHeightMapCPU
     const uint8_t* pixels = srcPixels.data();
 
     // Step 1: Compute height from luminance
+    constexpr float kInv255 = 1.0f / 255.0f;
     std::vector<float> heightMap(totalPixels);
     double sumH = 0.0, sumH2 = 0.0;
     for (uint32_t i = 0; i < totalPixels; i++) {
-        float r = pixels[i * 4 + 0] / 255.0f;
+        float r = pixels[i * 4 + 0] * kInv255;
-        float g = pixels[i * 4 + 1] / 255.0f;
+        float g = pixels[i * 4 + 1] * kInv255;
-        float b = pixels[i * 4 + 2] / 255.0f;
+        float b = pixels[i * 4 + 2] * kInv255;
         float h = 0.299f * r + 0.587f * g + 0.114f * b;
         heightMap[i] = h;
         sumH += h;

src/rendering/wmo_renderer.cpp

@@ -2159,12 +2159,13 @@ std::unique_ptr<VkTexture> WMORenderer::generateNormalHeightMap(
     const uint32_t totalPixels = width * height;
 
     // Step 1: Compute height from luminance
+    constexpr float kInv255 = 1.0f / 255.0f;
     std::vector<float> heightMap(totalPixels);
     double sumH = 0.0, sumH2 = 0.0;
     for (uint32_t i = 0; i < totalPixels; i++) {
-        float r = pixels[i * 4 + 0] / 255.0f;
+        float r = pixels[i * 4 + 0] * kInv255;
-        float g = pixels[i * 4 + 1] / 255.0f;
+        float g = pixels[i * 4 + 1] * kInv255;
-        float b = pixels[i * 4 + 2] / 255.0f;
+        float b = pixels[i * 4 + 2] * kInv255;
         float h = 0.299f * r + 0.587f * g + 0.114f * b;
         heightMap[i] = h;
         sumH += h;

src/ui/game_screen.cpp

@@ -3681,7 +3681,7 @@ void GameScreen::renderPetFrame(game::GameHandler& gameHandler) {
 
     auto petEntity = gameHandler.getEntityManager().getEntity(petGuid);
     if (!petEntity) return;
-    auto* petUnit = dynamic_cast<game::Unit*>(petEntity.get());
+    auto* petUnit = petEntity->isUnit() ? static_cast<game::Unit*>(petEntity.get()) : nullptr;
     if (!petUnit) return;
 
     // Position below player frame. If in a group, push below party frames
@@ -11255,7 +11255,7 @@ void GameScreen::renderCombatText(game::GameHandler& gameHandler) {
                 // Fallback to entity canonical position
                 auto entity = gameHandler.getEntityManager().getEntity(entry.dstGuid);
                 if (entity) {
-                    auto* unit = dynamic_cast<game::Unit*>(entity.get());
+                    auto* unit = entity->isUnit() ? static_cast<game::Unit*>(entity.get()) : nullptr;
                     if (unit) {
                         renderPos = core::coords::canonicalToRender(
                             glm::vec3(unit->getX(), unit->getY(), unit->getZ()));
@@ -11540,8 +11540,9 @@ void GameScreen::renderNameplates(game::GameHandler& gameHandler) {
     for (const auto& [guid, entityPtr] : gameHandler.getEntityManager().getEntities()) {
         if (!entityPtr || guid == playerGuid) continue;
 
-        auto* unit = dynamic_cast<game::Unit*>(entityPtr.get());
+        if (!entityPtr->isUnit()) continue;
-        if (!unit || unit->getMaxHealth() == 0) continue;
+        auto* unit = static_cast<game::Unit*>(entityPtr.get());
+        if (unit->getMaxHealth() == 0) continue;
 
         bool isPlayer = (entityPtr->getType() == game::ObjectType::PLAYER);
         bool isTarget = (guid == targetGuid);
@@ -14403,7 +14404,7 @@ void GameScreen::renderGuildRoster(game::GameHandler& gameHandler) {
                 if (sig.playerGuid != 0) {
                     auto entity = gameHandler.getEntityManager().getEntity(sig.playerGuid);
                     if (entity) {
-                        auto* unit = dynamic_cast<game::Unit*>(entity.get());
+                        auto* unit = entity->isUnit() ? static_cast<game::Unit*>(entity.get()) : nullptr;
                         if (unit) sigName = unit->getName();
                     }
                 }
@@ -15801,7 +15802,7 @@ void GameScreen::renderLootWindow(game::GameHandler& gameHandler) {
                     const auto& candidates = gameHandler.getMasterLootCandidates();
                     for (uint64_t candidateGuid : candidates) {
                         auto entity = gameHandler.getEntityManager().getEntity(candidateGuid);
-                        auto* unit = entity ? dynamic_cast<game::Unit*>(entity.get()) : nullptr;
+                        auto* unit = (entity && entity->isUnit()) ? static_cast<game::Unit*>(entity.get()) : nullptr;
                         const char* cName = unit ? unit->getName().c_str() : nullptr;
                         char nameBuf[64];
                         if (!cName || cName[0] == '\0') {