Add Windows and macOS CPU affinity support

- Windows: SetThreadAffinityMask to pin main thread to core 0 and
  exclude workers from core 0
- macOS: thread_policy_set with THREAD_AFFINITY_POLICY tags to hint
  scheduler separation (tag 1 for main, tag 2 for workers)

src/core/application.cpp

@@ -59,6 +59,15 @@
 #ifdef __linux__
 #include <sched.h>
 #include <pthread.h>
+#elif defined(_WIN32)
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <windows.h>
+#elif defined(__APPLE__)
+#include <mach/mach.h>
+#include <mach/thread_policy.h>
+#include <pthread.h>
 #endif
 
 namespace wowee {
@@ -238,11 +247,10 @@ void Application::run() {
     LOG_INFO("Starting main loop");
 
     // Pin main thread to a dedicated CPU core to reduce scheduling jitter
-#ifdef __linux__
     {
         int numCores = static_cast<int>(std::thread::hardware_concurrency());
         if (numCores >= 2) {
-            // Use core 0 for the main thread (typically the highest-clocked core)
+#ifdef __linux__
             cpu_set_t cpuset;
             CPU_ZERO(&cpuset);
             CPU_SET(0, &cpuset);
@@ -252,9 +260,31 @@ void Application::run() {
             } else {
                 LOG_WARNING("Failed to pin main thread to CPU core 0 (error ", rc, ")");
             }
+#elif defined(_WIN32)
+            DWORD_PTR mask = 1; // Core 0
+            DWORD_PTR prev = SetThreadAffinityMask(GetCurrentThread(), mask);
+            if (prev != 0) {
+                LOG_INFO("Main thread pinned to CPU core 0 (", numCores, " cores available)");
+            } else {
+                LOG_WARNING("Failed to pin main thread to CPU core 0 (error ", GetLastError(), ")");
             }
+#elif defined(__APPLE__)
+            // macOS doesn't support hard pinning — use affinity tags to hint
+            // that the main thread should stay on its own core group
+            thread_affinity_policy_data_t policy = { 1 }; // tag 1 = main thread group
+            kern_return_t kr = thread_policy_set(
+                pthread_mach_thread_np(pthread_self()),
+                THREAD_AFFINITY_POLICY,
+                reinterpret_cast<thread_policy_t>(&policy),
+                THREAD_AFFINITY_POLICY_COUNT);
+            if (kr == KERN_SUCCESS) {
+                LOG_INFO("Main thread affinity tag set (", numCores, " cores available)");
+            } else {
+                LOG_WARNING("Failed to set main thread affinity tag (error ", kr, ")");
             }
 #endif
+        }
+    }
 
     const bool frameProfileEnabled = envFlagEnabled("WOWEE_FRAME_PROFILE", false);
     if (frameProfileEnabled) {

src/rendering/terrain_manager.cpp

@@ -25,6 +25,15 @@
 #ifdef __linux__
 #include <sched.h>
 #include <pthread.h>
+#elif defined(_WIN32)
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <windows.h>
+#elif defined(__APPLE__)
+#include <mach/mach.h>
+#include <mach/thread_policy.h>
+#include <pthread.h>
 #endif
 
 namespace wowee {
@@ -922,19 +931,33 @@ bool TerrainManager::advanceFinalization(FinalizingTile& ft) {
 
 void TerrainManager::workerLoop() {
     // Keep worker threads off core 0 (reserved for main thread)
-#ifdef __linux__
     {
         int numCores = static_cast<int>(std::thread::hardware_concurrency());
         if (numCores >= 2) {
+#ifdef __linux__
             cpu_set_t cpuset;
             CPU_ZERO(&cpuset);
             for (int i = 1; i < numCores; i++) {
                 CPU_SET(i, &cpuset);
             }
             pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpuset);
+#elif defined(_WIN32)
+            DWORD_PTR mask = 0;
+            for (int i = 1; i < numCores && i < 64; i++) {
+                mask |= (static_cast<DWORD_PTR>(1) << i);
             }
-    }
+            SetThreadAffinityMask(GetCurrentThread(), mask);
+#elif defined(__APPLE__)
+            // Use affinity tag 2 for workers (separate from main thread tag 1)
+            thread_affinity_policy_data_t policy = { 2 };
+            thread_policy_set(
+                pthread_mach_thread_np(pthread_self()),
+                THREAD_AFFINITY_POLICY,
+                reinterpret_cast<thread_policy_t>(&policy),
+                THREAD_AFFINITY_POLICY_COUNT);
 #endif
+        }
+    }
     LOG_INFO("Terrain worker thread started");
 
     while (workerRunning.load()) {