fix: Replace sqrt with deterministic Sqrt in GameLogic to fix x87 FPU lockstep desyncs

Author: Okladnoj

Core/Libraries/Include/Lib/trig.h

@@ -29,3 +29,4 @@ Real Tan(Real);
 Real ACos(Real);
 Real ASin(Real x);
 Real Atan2(Real y, Real x);
+Real Sqrt(Real x);

GeneralsMD/Code/GameEngine/Source/Common/System/Trig.cpp

@@ -77,6 +77,11 @@ Real Atan2(Real y, Real x)
 	return WWMath::Atan2(y, x);
 }
 
+Real Sqrt(Real x)
+{
+	return WWMath::Sqrt(x);
+}
+
 #ifdef REGENERATE_TRIG_TABLES
 void initTrig()
 {

GeneralsMD/Code/GameEngine/Source/GameLogic/AI/AI.cpp

@@ -719,7 +719,7 @@ Object *AI::findClosestEnemy( const Object *me, Real range, UnsignedInt qualifie
 		}
 
 		Real distSqr = ThePartitionManager->getDistanceSquared(me, theEnemy, FROM_BOUNDINGSPHERE_2D);
-		Real dist = sqrt(distSqr);
+		Real dist = Sqrt(distSqr);
 		Int modifier = dist/getAiData()->m_attackPriorityDistanceModifier;
 		Int modPriority = curPriority-modifier;
 		if (modPriority < 1)

GeneralsMD/Code/GameEngine/Source/GameLogic/AI/AIPlayer.cpp

@@ -647,7 +647,7 @@ Object *AIPlayer::buildStructureWithDozer(const ThingTemplate *bldgPlan, BuildLi
 		dx = dozer->getPosition()->x - pos.x;
 		dy = dozer->getPosition()->y - pos.y;
 
-		Int count = sqrt(dx*dx+dy*dy)/(PATHFIND_CELL_SIZE_F/2);
+		Int count = Sqrt(dx*dx+dy*dy)/(PATHFIND_CELL_SIZE_F/2);
 		if (count<2) count = 2;
 		Int i;
 		color.green = 1;
@@ -1350,7 +1350,7 @@ Int AIPlayer::getPlayerSuperweaponValue(Coord3D *center, Int playerNdx, Real rad
 				Real dy = center->y - pos.y;
 				if (dx*dx+dy*dy<radSqr)
 				{
-					Real dist = sqrt(dx*dx+dy*dy);
+					Real dist = Sqrt(dx*dx+dy*dy);
 					Real factor = 1.0f - (dist/(2*radius)); // 1.0 in center, 0.5 on edges.
 					Real value = pObj->getTemplate()->calcCostToBuild(pPlayer);
 					if (pObj->isKindOf(KINDOF_COMMANDCENTER))
@@ -3136,7 +3136,7 @@ void AIPlayer::computeCenterAndRadiusOfBase(Coord3D *center, Real *radius)
 		Real radSqr = dx*dx+dy*dy;
 		if (radSqr>maxRadSqr) maxRadSqr=radSqr;
 	}
-	*radius = sqrt(maxRadSqr);
+	*radius = Sqrt(maxRadSqr);
 }
 
 //----------------------------------------------------------------------------------------------------------

GeneralsMD/Code/GameEngine/Source/GameLogic/AI/AIStates.cpp

@@ -3678,7 +3678,7 @@ StateReturnType AIAttackMoveToState::update()
 		if (distSqr < sqr(ATTACK_CLOSE_ENOUGH_CELLS*PATHFIND_CELL_SIZE_F)) {
 			return ret;
 		}
-		DEBUG_LOG(("AIAttackMoveToState::update Distance from goal %f, retrying.", sqrt(distSqr)));
+		DEBUG_LOG(("AIAttackMoveToState::update Distance from goal %f, retrying.", Sqrt(distSqr)));
 
 		ret = STATE_CONTINUE;
 		m_retryCount--;

GeneralsMD/Code/GameEngine/Source/GameLogic/Map/PolygonTrigger.cpp

@@ -286,7 +286,7 @@ void PolygonTrigger::updateBounds()	const
 	Real halfWidth = (m_bounds.hi.x - m_bounds.lo.x) / 2.0f;
 	Real halfHeight = (m_bounds.hi.y + m_bounds.lo.y) / 2.0f;
 
-	m_radius = sqrt(halfHeight*halfHeight + halfWidth*halfWidth);
+	m_radius = Sqrt(halfHeight*halfHeight + halfWidth*halfWidth);
 }
 
 

GeneralsMD/Code/GameEngine/Source/GameLogic/Map/TerrainLogic.cpp

@@ -2369,7 +2369,7 @@ void TerrainLogic::setWaterHeight( const WaterHandle *water, Real height, Real d
 		center.z = 0.0f;  // irrelevant
 
 		// the max radius to scan around us is the diagonal of the bounding region
-		Real maxDist = sqrt( affectedRegion.width() * affectedRegion.width() +
+		Real maxDist = Sqrt( affectedRegion.width() * affectedRegion.width() +
 												 affectedRegion.height() * affectedRegion.height() );
 
 		// scan the objects in the area of the water affected
@@ -2879,7 +2879,7 @@ void TerrainLogic::createCraterInTerrain(Object *obj)
 			deltaX = ( i * MAP_XY_FACTOR ) - pos->x;
 			deltaY = ( j * MAP_XY_FACTOR ) - pos->y;
 
-      Real distance = sqrt( sqr( deltaX ) + sqr( deltaY ) );
+      Real distance = Sqrt( sqr( deltaX ) + sqr( deltaY ) );
 
 			if ( distance < radius ) //inside circle
       {

GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Behavior/DumbProjectileBehavior.cpp

@@ -176,7 +176,7 @@ static Bool calcTrajectory(
 
 	// calculating the pitch requires a bit more effort.
 	Real horizDistSqr = sqr(dx) + sqr(dy);
-	Real horizDist = sqrt(horizDistSqr);
+	Real horizDist = Sqrt(horizDistSqr);
 
 	// calc the two possible pitches that will cover the given horizontal range.
 	// (this is actually only true if dz==0, but is a good first guess)
@@ -290,7 +290,7 @@ static Bool calcTrajectory(
 #endif
 
 		vx = velocity*cosPitches[preferred];
-		Real actualRange = (vx*(vz + sqrt(root)))/gravity;
+		Real actualRange = (vx*(vz + Sqrt(root)))/gravity;
 		const Real CLOSE_ENOUGH_RANGE = 5.0f;
 		if (tooClose || (actualRange < horizDist - CLOSE_ENOUGH_RANGE))
 		{
@@ -369,7 +369,7 @@ void DumbProjectileBehavior::projectileFireAtObjectOrPosition( const Object *vic
 		// Some weapons want to scale their start speed to the range
 		Real minRange = detWeap->getMinimumAttackRange();
 		Real maxRange = detWeap->getUnmodifiedAttackRange();
-		Real range = sqrt(ThePartitionManager->getDistanceSquared( projectile, &victimPosToUse, FROM_CENTER_2D ) );
+		Real range = Sqrt(ThePartitionManager->getDistanceSquared( projectile, &victimPosToUse, FROM_CENTER_2D ) );
 		Real rangeRatio = (range - minRange) / (maxRange - minRange);
 		m_flightPathSpeed = (rangeRatio * (weaponSpeed - minWeaponSpeed)) + minWeaponSpeed;
 	}
@@ -611,7 +611,7 @@ UpdateSleepTime DumbProjectileBehavior::update()
 			Real distVictimMovedSqr = sqr(delta.x) + sqr(delta.y) + sqr(delta.z);
 			if (distVictimMovedSqr > 0.1f)
 			{
-				Real distVictimMoved = sqrtf(distVictimMovedSqr);
+				Real distVictimMoved = Sqrt(distVictimMovedSqr);
 				if (distVictimMoved > d->m_flightPathAdjustDistPerFrame)
 					distVictimMoved = d->m_flightPathAdjustDistPerFrame;
 				delta.normalize();

GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Behavior/GenerateMinefieldBehavior.cpp

@@ -248,7 +248,7 @@ void GenerateMinefieldBehavior::placeMinesAlongLine(const Coord3D& posStart, con
 
 	Real dx = posEnd.x - posStart.x;
 	Real dy = posEnd.y - posStart.y;
-	Real len = sqrt(sqr(dx) + sqr(dy));
+	Real len = Sqrt(sqr(dx) + sqr(dy));
 	Real mineRadius = mineTemplate->getTemplateGeometryInfo().getBoundingCircleRadius();
 	Real mineDiameter = mineRadius * 2.0f;
 	Real mineJitter = mineRadius*d->m_randomJitter;

GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Behavior/MinefieldBehavior.cpp

@@ -570,7 +570,7 @@ void MinefieldBehavior::setScootParms(const Coord3D& start, const Coord3D& end)
 	if (start.z > endOnGround.z)
 	{
 		// figure out how long it will take to fall, and replace scoot time with that
-		UnsignedInt fallingTime = REAL_TO_INT_CEIL(sqrtf(2.0f * (start.z - endOnGround.z) / fabs(TheGlobalData->m_gravity)));
+		UnsignedInt fallingTime = REAL_TO_INT_CEIL(Sqrt(2.0f * (start.z - endOnGround.z) / fabs(TheGlobalData->m_gravity)));
 		// we can scoot after we land, but don't want to stop scooting before we land
 		if (scootFromStartingPointTime < fallingTime)
 			scootFromStartingPointTime = fallingTime;
@@ -588,7 +588,7 @@ void MinefieldBehavior::setScootParms(const Coord3D& start, const Coord3D& end)
 		Real dx = endOnGround.x - start.x;
 		Real dy = endOnGround.y - start.y;
 		Real dz = endOnGround.z - start.z;
-		Real dist = sqrt(sqr(dx) + sqr(dy));
+		Real dist = Sqrt(sqr(dx) + sqr(dy));
 		if (dist <= 0.1f && fabs(dz) <= 0.1f)
 		{
 			obj->setPosition(&endOnGround);