Cross-platform stability fixes and FP-contract standardization

CHANGELOG.md

@@ -264,6 +264,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 - Fixed an issue where if the first objects in the buy cart are items instead of an actor, they would be added to the first actor's inventory- even if it was an actor without an inventory (i.e a crab)
 
+- Fixed a macOS worker-thread message box that could hang, and a libc++ build error formatting save-game timestamps.
+
+- Fixed a divide-by-zero on `AtomGroup` segments with no steps, which could feed bad values into the physics.
+
+- Fixed a couple of uninitialized values (Atom step state and the simulation frame counter) that could cause inconsistent behavior between runs.
+
 </details>
 
 <details><summary><b>Removed</b></summary>

Data/Base.rte/AI/HumanBehaviors.lua

@@ -651,7 +651,11 @@ function HumanBehaviors.WeaponSearch(AI, Owner, Abort)
 		end
 
 		AI.PickupHD = nil;
-		table.sort(devicesToPickUp, function(A,B) return A.score < B.score end);
+		-- Tie-break on deviceId so ordering is stable when scores collide.
+		table.sort(devicesToPickUp, function(A,B)
+			if A.score ~= B.score then return A.score < B.score end
+			return A.deviceId < B.deviceId
+		end);
 		for _, deviceToPickupEntry in ipairs(devicesToPickUp) do
 			local device = MovableMan:FindObjectByUniqueID(deviceToPickupEntry.deviceId);
 			if MovableMan:ValidMO(device) and device:IsDevice() then
@@ -767,7 +771,11 @@ function HumanBehaviors.ToolSearch(AI, Owner, Abort)
 		end
 
 		AI.PickupHD = nil;
-		table.sort(devicesToPickUp, function(A,B) return A.score < B.score end); -- sort the items in order of discounted distance
+		-- Tie-break on deviceId so ordering is stable when scores collide.
+		table.sort(devicesToPickUp, function(A,B)
+			if A.score ~= B.score then return A.score < B.score end
+			return A.deviceId < B.deviceId
+		end); -- sort the items in order of discounted distance
 		for _, deviceToPickupEntry in ipairs(devicesToPickUp) do
 			local device = MovableMan:FindObjectByUniqueID(deviceToPickupEntry.deviceId);
 			if MovableMan:ValidMO(device) and device:IsDevice() then

RTEA.vcxproj

@@ -179,7 +179,7 @@
       <LanguageStandard>stdcpp20</LanguageStandard>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <OmitDefaultLibName>false</OmitDefaultLibName>
-      <FloatingPointModel>Fast</FloatingPointModel>
+      <FloatingPointModel>Precise</FloatingPointModel>
       <ConformanceMode>true</ConformanceMode>
       <AddCodeAfterSourceInclude>#undef GetClassName</AddCodeAfterSourceInclude>
       <IncludeInUnityFile>false</IncludeInUnityFile>
@@ -232,7 +232,7 @@
       <LanguageStandard>stdcpp20</LanguageStandard>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <OmitDefaultLibName>false</OmitDefaultLibName>
-      <FloatingPointModel>Fast</FloatingPointModel>
+      <FloatingPointModel>Precise</FloatingPointModel>
       <ConformanceMode>true</ConformanceMode>
       <IncludeInUnityFile>false</IncludeInUnityFile>
       <AddCodeAfterSourceInclude>#undef GetClassName</AddCodeAfterSourceInclude>
@@ -286,7 +286,7 @@
       <LanguageStandard>stdcpp20</LanguageStandard>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <OmitDefaultLibName>false</OmitDefaultLibName>
-      <FloatingPointModel>Fast</FloatingPointModel>
+      <FloatingPointModel>Precise</FloatingPointModel>
       <ConformanceMode>true</ConformanceMode>
       <IncludeInUnityFile>false</IncludeInUnityFile>
       <AddCodeAfterSourceInclude>#undef GetClassName</AddCodeAfterSourceInclude>
@@ -339,7 +339,7 @@
       <LanguageStandard>stdcpp20</LanguageStandard>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <OmitDefaultLibName>false</OmitDefaultLibName>
-      <FloatingPointModel>Fast</FloatingPointModel>
+      <FloatingPointModel>Precise</FloatingPointModel>
       <ConformanceMode>true</ConformanceMode>
       <IncludeInUnityFile>false</IncludeInUnityFile>
       <AddCodeAfterSourceInclude>#undef GetClassName</AddCodeAfterSourceInclude>
@@ -385,7 +385,7 @@
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <EnableEnhancedInstructionSet>StreamingSIMDExtensions2</EnableEnhancedInstructionSet>
-      <FloatingPointModel>Fast</FloatingPointModel>
+      <FloatingPointModel>Precise</FloatingPointModel>
       <RuntimeTypeInfo>true</RuntimeTypeInfo>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <WarningLevel>Level2</WarningLevel>
@@ -447,7 +447,7 @@
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <EnableEnhancedInstructionSet>StreamingSIMDExtensions2</EnableEnhancedInstructionSet>
-      <FloatingPointModel>Fast</FloatingPointModel>
+      <FloatingPointModel>Precise</FloatingPointModel>
       <RuntimeTypeInfo>true</RuntimeTypeInfo>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <WarningLevel>Level2</WarningLevel>
@@ -510,7 +510,7 @@
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <EnableEnhancedInstructionSet>
       </EnableEnhancedInstructionSet>
-      <FloatingPointModel>Fast</FloatingPointModel>
+      <FloatingPointModel>Precise</FloatingPointModel>
       <RuntimeTypeInfo>true</RuntimeTypeInfo>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <WarningLevel>Level2</WarningLevel>
@@ -573,7 +573,7 @@
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <EnableEnhancedInstructionSet>
       </EnableEnhancedInstructionSet>
-      <FloatingPointModel>Fast</FloatingPointModel>
+      <FloatingPointModel>Precise</FloatingPointModel>
       <RuntimeTypeInfo>true</RuntimeTypeInfo>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <WarningLevel>Level2</WarningLevel>
@@ -635,7 +635,7 @@
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <EnableEnhancedInstructionSet>StreamingSIMDExtensions2</EnableEnhancedInstructionSet>
-      <FloatingPointModel>Fast</FloatingPointModel>
+      <FloatingPointModel>Precise</FloatingPointModel>
       <RuntimeTypeInfo>true</RuntimeTypeInfo>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <WarningLevel>Level2</WarningLevel>
@@ -696,7 +696,7 @@
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <EnableEnhancedInstructionSet>
       </EnableEnhancedInstructionSet>
-      <FloatingPointModel>Fast</FloatingPointModel>
+      <FloatingPointModel>Precise</FloatingPointModel>
       <RuntimeTypeInfo>true</RuntimeTypeInfo>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <WarningLevel>Level2</WarningLevel>

Source/Entities/AtomGroup.cpp

@@ -354,8 +354,8 @@ float AtomGroup::Travel(Vector& position, Vector& velocity, Matrix& rotation, fl
 
 	HitData hitData;
 
-	// Thread locals for performance (avoid memory allocs)
-	thread_local std::unordered_map<MOID, std::vector<Atom*>> hitMOAtoms;
+	// std::map keeps hitMOAtoms iteration MOID-ascending so impulse accumulation order is deterministic.
+	thread_local std::map<MOID, std::vector<Atom*>> hitMOAtoms;
 	hitMOAtoms.clear();
 	thread_local std::vector<Atom*> hitTerrAtoms;
 	hitTerrAtoms.clear();
@@ -450,7 +450,7 @@ float AtomGroup::Travel(Vector& position, Vector& velocity, Matrix& rotation, fl
 		}
 
 		for (Atom* atom: m_Atoms) {
-			atom->SetStepRatio(static_cast<float>(atom->GetStepsLeft()) / static_cast<float>(stepsOnSeg));
+			atom->SetStepRatio(stepsOnSeg != 0 ? static_cast<float>(atom->GetStepsLeft()) / static_cast<float>(stepsOnSeg) : 0.0F);
 		}
 
 		// STEP LOOP ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -800,7 +800,8 @@ Vector AtomGroup::PushTravel(Vector& position, const Vector& velocity, float pus
 	// Thread locals for performance reasons (avoid memory allocs)
 	thread_local std::unordered_map<MOID, std::unordered_set<Atom*>> MOIgnoreMap;
 	MOIgnoreMap.clear();
-	thread_local std::unordered_map<MOID, std::vector<std::pair<Atom*, Vector>>> hitMOAtoms;
+	// std::map keeps hitMOAtoms iteration MOID-ascending so impulse accumulation order is deterministic.
+	thread_local std::map<MOID, std::vector<std::pair<Atom*, Vector>>> hitMOAtoms;
 	hitMOAtoms.clear();
 	thread_local std::deque<std::pair<Atom*, Vector>> hitTerrAtoms;
 	hitTerrAtoms.clear();

Source/Lua/LuaAdapters.cpp

@@ -6,6 +6,8 @@
 
 #include "lj_obj.h"
 
+#include <atomic>
+
 using namespace RTE;
 
 std::unordered_map<std::string, std::function<LuabindObjectWrapper*(Entity*, lua_State*)>> LuaAdaptersEntityCast::s_EntityToLuabindObjectCastFunctions = {};
@@ -293,8 +295,8 @@ void LuaAdaptersScene::CalculatePathAsync(Scene* luaSelfObject, const luabind::o
 	// As such, we need to store this function somewhere safely within our Lua state for us to access later when we need it
 	lua_State* luaState = mainthread(G(callback.interpreter())); // Get the main thread for the state, in case we're a temp lua thread
 
-	static int currentCallbackId = 0;
-	int thisCallbackId = currentCallbackId++;
+	static std::atomic<int> currentCallbackId{0};
+	int thisCallbackId = currentCallbackId.fetch_add(1, std::memory_order_relaxed);
 	if (luabind::type(callback) == LUA_TFUNCTION && callback.is_valid()) {
 		luabind::call_function<void>(luaState, "_AddAsyncPathCallback", thisCallbackId, callback);
 	}

Source/Managers/MovableMan.cpp

@@ -73,6 +73,8 @@ void MovableMan::Clear() {
 	m_MaxDroppedItems = 100;
 	m_SettlingEnabled = true;
 	m_MOSubtractionEnabled = true;
+	// HitWhatMOID / HitWhatTerrMaterial compare against this each tick; it's otherwise only incremented.
+	m_SimUpdateFrameNumber = 0;
 }
 
 int MovableMan::Initialize() {

Source/Menus/SaveLoadMenuGUI.cpp

@@ -180,7 +180,13 @@ void SaveLoadMenuGUI::UpdateSaveGamesGUIList() {
 		const auto saveTime = std::chrono::system_clock::to_time_t(saveFsTime);
 #else
 		// TODO - kill this monstrosity when we move to GCC13
+		// libc++ file_clock rep is wider than system_clock; duration_cast lands it in range first.
+#if defined(_LIBCPP_VERSION)
+		auto saveFsTime = std::chrono::system_clock::time_point(
+		    std::chrono::duration_cast<std::chrono::system_clock::duration>(save.SaveDate.time_since_epoch()));
+#else
 		auto saveFsTime = std::chrono::system_clock::time_point(save.SaveDate.time_since_epoch());
+#endif
 #ifdef _WIN32
 		// Windows epoch time are the number of seconds since... 1601-01-01 00:00:00. Seriously.
 		saveFsTime -= std::chrono::seconds(11644473600LL);

Source/System/Atom.cpp

@@ -91,14 +91,27 @@ void Atom::Clear() {
 	m_StepRatio = 1.0F;
 	m_SegProgress = 0.0F;
 
+	// SetupPos branches on m_IntPos before the first step sets it.
+	m_IntPos[X] = m_IntPos[Y] = 0;
+	m_PrevIntPos[X] = m_PrevIntPos[Y] = 0;
+
 	m_IgnoreMOIDsByGroup = 0;
 
-	// Note: These fields must be cleared to avoid a very edge case bug.
-	// While an AtomGroup is travelling, the OnCollideWithTerrain Lua function can run, which will in turn force Create to run if it hasn't already.
-	// If this Create function adds to an AtomGroup (e.g. adds an Attachable to it), there will be problems.
-	// Setting these values in Clear doesn't help if Atoms are removed at this point, but helps if Atoms are added, since these values mean the added Atoms won't try to step forwards.
-	// m_Dom = 0;
-	// m_Delta[m_Dom] = 0;
+	// Bresenham step state. A fresh Atom can be stepped before SetupSeg runs (an Attachable added
+	// mid-travel by an OnCollideWithTerrain script), so a stale pool value makes StepForward diverge.
+	m_TrailPos[X] = m_TrailPos[Y] = 0;
+	m_HitPos[X] = m_HitPos[Y] = 0;
+	m_Delta[X] = m_Delta[Y] = 0;
+	m_Delta2[X] = m_Delta2[Y] = 0;
+	m_Increment[X] = m_Increment[Y] = 0;
+	m_Error = 0;
+	m_Dom = 0;
+	m_Sub = 0;
+	m_DomSteps = 0;
+	m_SubSteps = 0;
+	m_SubStepped = false;
+	m_StepWasTaken = false;
+	m_SegTraj.Reset();
 }
 
 int Atom::Create(const Vector& offset, Material const* material, MovableObject* owner, Color trailColor, int trailLength) {

Source/System/RTEError.cpp

@@ -13,6 +13,7 @@
 #endif
 
 #include <array>
+#include <cstdio>
 #include <exception>
 #include <regex>
 #include <utility>
@@ -30,6 +31,14 @@
 #include <filesystem>
 #elif defined(__APPLE__) && defined(__MACH__)
 #include <sys/sysctl.h>
+#include <pthread.h>
+#endif
+
+#if defined(__APPLE__) && defined(__MACH__)
+// Cocoa dispatches message boxes onto the main thread, which deadlocks if a worker fires one while the main thread waits on it.
+static bool IsOnAppMainThread() { return pthread_main_np() != 0; }
+#else
+static bool IsOnAppMainThread() { return true; }
 #endif
 
 #include "backward/backward.hpp"
@@ -205,10 +214,18 @@ void RTEError::SetExceptionHandlers() {
 }
 
 void RTEError::ShowMessageBox(const std::string& message) {
+	if (!IsOnAppMainThread()) {
+		std::fprintf(stderr, "RTE Warning (from worker thread): %s\n", message.c_str());
+		return;
+	}
 	SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_WARNING, "RTE Warning! (>_<)", message.c_str(), nullptr);
 }
 
 bool RTEError::ShowAbortMessageBox(const std::string& message) {
+	if (!IsOnAppMainThread()) {
+		std::fprintf(stderr, "RTE Abort (from worker thread): %s\n", message.c_str());
+		return false;
+	}
 	enum AbortMessageButton {
 		ButtonInvalid,
 		ButtonExit,
@@ -242,6 +259,11 @@ bool RTEError::ShowAbortMessageBox(const std::string& message) {
 }
 
 bool RTEError::ShowAssertMessageBox(const std::string& message) {
+	if (!IsOnAppMainThread()) {
+		// Return false (Ignore-once) so the worker can unwind; the main thread sees the assert on its next pass.
+		std::fprintf(stderr, "RTE Assert (from worker thread): %s\n", message.c_str());
+		return false;
+	}
 	enum AssertMessageButton {
 		ButtonInvalid,
 		ButtonAbort,

external/sources/luabind-0.7.1/meson.build

@@ -3,7 +3,8 @@ subdir('src')
 
 luabind_include = include_directories('.', 'luabind')
 
-luabind_args = ['-D_HAS_AUTO_PTR_ETC=1', '-D_LIBCPP_ENABLE_CXX17_REMOVED_FEATURES']
+# libc++ 19 dropped the CXX17-removed umbrella; re-enable the two APIs luabind 0.7.1 + boost 1.75 use.
+luabind_args = ['-D_HAS_AUTO_PTR_ETC=1', '-D_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR', '-D_LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION']
 
 luabind_dependencies = [dependency('luajit', 'LuaJIT-2.1'), dependency('boost-175')]
 

meson.build

@@ -30,12 +30,32 @@ if compiler.get_argument_syntax()== 'gcc' # used for gcc compatible compilers
   # Build against system libraries on linux
   message('gcc detected')
 
+  # Pin floating-point so the same source gives bit-identical results across platforms.
+  if host_machine.cpu_family() in ['x86', 'x86_64']
+    extra_args += ['-msse2']         # baseline ISA — no x87 80-bit drift on Windows
+  endif
+  extra_args += [
+    '-ffp-contract=off',             # forbid FMA/contraction — required on ARM, harmless on x86
+    '-fno-fast-math',
+    '-fno-finite-math-only',
+    '-fno-associative-math',
+    '-fno-reciprocal-math',
+    '-fno-unsafe-math-optimizations',
+    '-frounding-math',
+    '-fsignaling-nans',
+  ]
+
   if host_machine.system() == 'linux'
     build_rpath = '$ORIGIN:$ORIGIN/../external/lib/linux/x86_64' # Set RUNPATH so that CCCP can find libfmod.so without needing to set LD_LIBRARY_PATH
   elif host_machine.system()=='darwin'
     build_rpath = '@executable_path/../external/lib/macos' # Add a new R_PATH CCCP can find libfmod.dylib on Darwin TODO: Confirm and validate this.
   endif
 
+  # Apple's libc++ needs these to expose <execution> (std::execution::par_unseq).
+  if compiler.get_id() == 'clang'
+    extra_args += ['-D_LIBCPP_ENABLE_EXPERIMENTAL', '-D_LIBCPP_PSTL_BACKEND_SERIAL']
+  endif
+
   #suffix = 'x86_64'
   if host_machine.system()=='linux'
     link_args += ['-Wl,--enable-new-dtags'] # Set RUNPATH instead of RPATH
@@ -60,7 +80,7 @@ if compiler.get_argument_syntax()== 'gcc' # used for gcc compatible compilers
       preprocessor_flags += ['-DDEBUG_BUILD', '-DDEBUGMODE'] # enable all debug features; may slow down game
     endif
   else
-    extra_args = ['-w'] # Disable all warnings for release builds
+    extra_args += ['-w'] # Disable all warnings for release builds
     preprocessor_flags += ['-DRELEASE_BUILD', '-DNDEBUG'] # disable all debug features
   endif
   if compiler.get_id() =='gcc' and compiler.version().version_compare('<9')
@@ -70,7 +90,8 @@ elif compiler.get_argument_syntax()== 'msvc'
 #TODO: add MSVC related arguments and stuff in here
   message('cl detected')
   elfname = 'Cortex Command'
-  extra_args += ['-D_HAS_ITERATOR_DEBUGGING=0', '-D_HAS_AUTO_PTR_ETC=1', '-bigobj']
+  # /fp:precise stops MSVC rearranging FP ops; /arch:SSE2 keeps x86 off x87's 80-bit registers.
+  extra_args += ['-D_HAS_ITERATOR_DEBUGGING=0', '-D_HAS_AUTO_PTR_ETC=1', '-bigobj', '/fp:precise', '/arch:SSE2']
   add_global_arguments('-D_ITERATOR_DEBUG_LEVEL=0', language:'cpp')
   add_project_link_arguments(['winmm.lib', 'ws2_32.lib', 'dinput8.lib', 'ddraw.lib', 'dxguid.lib', 'dsound.lib', 'dbghelp.lib'], language:'cpp')
   if host_machine.cpu_family() == 'x86'