Added facing check to auto attack LoS code

The Mob::InFrontMob check uses 56 degrees which is where the
client will generate the "You cannon see your target." message.
There were still a few weird angles that I was able to still
attack, but in like 99% of the cases it should work ...

zone/client.cpp

@@ -284,11 +284,13 @@ Client::Client(EQStreamInterface* ieqs)
 	aa_los_me.x = 0;
 	aa_los_me.y = 0;
 	aa_los_me.z = 0;
+	aa_los_me_heading = 0;
 	aa_los_them.x = 0;
 	aa_los_them.y = 0;
 	aa_los_them.z = 0;
 	aa_los_them_mob = nullptr;
 	los_status = false;
+	los_status_facing = false;
 	qGlobals = nullptr;
 	HideCorpseMode = HideCorpseNone;
 	PendingGuildInvitation = false;

zone/client.h

@@ -1200,6 +1200,8 @@ protected:
 	VERTEX aa_los_them;
 	Mob *aa_los_them_mob;
 	bool los_status;
+	float aa_los_me_heading;
+	bool los_status_facing;
 	QGlobalCache *qGlobals;
 
 	/** Adventure Variables **/

zone/client_packet.cpp

@@ -1303,6 +1303,7 @@ void Client::Handle_OP_AutoAttack(const EQApplicationPacket *app)
 		aa_los_me.x = 0;
 		aa_los_me.y = 0;
 		aa_los_me.z = 0;
+		aa_los_me_heading = 0;
 		aa_los_them.x = 0;
 		aa_los_them.y = 0;
 		aa_los_them.z = 0;
@@ -1322,24 +1323,25 @@ void Client::Handle_OP_AutoAttack(const EQApplicationPacket *app)
 			aa_los_me.x = GetX();
 			aa_los_me.y = GetY();
 			aa_los_me.z = GetZ();
+			aa_los_me_heading = GetHeading();
 			aa_los_them.x = aa_los_them_mob->GetX();
 			aa_los_them.y = aa_los_them_mob->GetY();
 			aa_los_them.z = aa_los_them_mob->GetZ();
-			if(CheckLosFN(aa_los_them_mob))
+			los_status = CheckLosFN(aa_los_them_mob);
-				los_status = true;
+			los_status_facing = aa_los_them_mob->InFrontMob(this, aa_los_them.x, aa_los_them.y);
-			else
-				los_status = false;
 		}
 		else
 		{
 			aa_los_me.x = GetX();
 			aa_los_me.y = GetY();
 			aa_los_me.z = GetZ();
+			aa_los_me_heading = GetHeading();
 			aa_los_them.x = 0;
 			aa_los_them.y = 0;
 			aa_los_them.z = 0;
 			aa_los_them_mob = nullptr;
 			los_status = false;
+			los_status_facing = false;
 		}
 	}
 }

zone/client_process.cpp

@@ -299,7 +299,7 @@ bool Client::Process() {
 				if(ranged->GetItem() && ranged->GetItem()->ItemType == ItemTypeBow){
 					if(ranged_timer.Check(false)){
 						if(GetTarget() && (GetTarget()->IsNPC() || GetTarget()->IsClient())){
-							if(!GetTarget()->BehindMob(this, GetTarget()->GetX(), GetTarget()->GetY())){
+							if(GetTarget()->InFrontMob(this, GetTarget()->GetX(), GetTarget()->GetY())){
 								if(CheckLosFN(GetTarget())){
 									//client has built in los check, but auto fire does not.. done last.
 									RangedAttack(GetTarget());
@@ -319,7 +319,7 @@ bool Client::Process() {
 				else if(ranged->GetItem() && (ranged->GetItem()->ItemType == ItemTypeLargeThrowing || ranged->GetItem()->ItemType == ItemTypeSmallThrowing)){
 					if(ranged_timer.Check(false)){
 						if(GetTarget() && (GetTarget()->IsNPC() || GetTarget()->IsClient())){
-							if(!GetTarget()->BehindMob(this, GetTarget()->GetX(), GetTarget()->GetY())){
+							if(GetTarget()->InFrontMob(this, GetTarget()->GetX(), GetTarget()->GetY())){
 								if(CheckLosFN(GetTarget())){
 									//client has built in los check, but auto fire does not.. done last.
 									ThrowingAttack(GetTarget());
@@ -359,10 +359,15 @@ bool Client::Process() {
 					aa_los_them.x = aa_los_them_mob->GetX();
 					aa_los_them.y = aa_los_them_mob->GetY();
 					aa_los_them.z = aa_los_them_mob->GetZ();
-					if(CheckLosFN(auto_attack_target))
+					los_status = CheckLosFN(auto_attack_target);
-						los_status = true;
+					aa_los_me_heading = GetHeading();
-					else
+					los_status_facing = aa_los_them_mob->InFrontMob(this, aa_los_them.x, aa_los_them.y);
-						los_status = false;
+				}
+				// If only our heading changes, we can skip the CheckLosFN call
+				// but above we still need to update los_status_facing
+				if (aa_los_me_heading != GetHeading()) {
+					aa_los_me_heading = GetHeading();
+					los_status_facing = aa_los_them_mob->InFrontMob(this, aa_los_them.x, aa_los_them.y);
 				}
 			}
 			else
@@ -371,25 +376,23 @@ bool Client::Process() {
 				aa_los_me.x = GetX();
 				aa_los_me.y = GetY();
 				aa_los_me.z = GetZ();
+				aa_los_me_heading = GetHeading();
 				aa_los_them.x = aa_los_them_mob->GetX();
 				aa_los_them.y = aa_los_them_mob->GetY();
 				aa_los_them.z = aa_los_them_mob->GetZ();
-				if(CheckLosFN(auto_attack_target))
+				los_status = CheckLosFN(auto_attack_target);
-					los_status = true;
+				los_status_facing = aa_los_them_mob->InFrontMob(this, aa_los_them.x, aa_los_them.y);
-				else
-					los_status = false;
 			}
 
 			if (!CombatRange(auto_attack_target))
 			{
-				//duplicate message not wanting to see it.
+				Message_StringID(MT_TooFarAway,TARGET_TOO_FAR);
-				//Message_StringID(MT_TooFarAway,TARGET_TOO_FAR);
 			}
 			else if (auto_attack_target == this)
 			{
 				Message_StringID(MT_TooFarAway,TRY_ATTACKING_SOMEONE);
 			}
-			else if (!los_status)
+			else if (!los_status || !los_status_facing)
 			{
 				//you can't see your target
 			}
@@ -482,13 +485,13 @@ bool Client::Process() {
 			// Range check
 			if(!CombatRange(auto_attack_target)) {
 				// this is a duplicate message don't use it.
-				Message_StringID(MT_TooFarAway,TARGET_TOO_FAR);
+				//Message_StringID(MT_TooFarAway,TARGET_TOO_FAR);
 			}
 			// Don't attack yourself
 			else if(auto_attack_target == this) {
-				Message_StringID(MT_TooFarAway,TRY_ATTACKING_SOMEONE);
+				//Message_StringID(MT_TooFarAway,TRY_ATTACKING_SOMEONE);
 			}
-			else if (!los_status)
+			else if (!los_status || !los_status_facing)
 			{
 				//you can't see your target
 			}

zone/mob.cpp

@@ -1876,35 +1876,43 @@ void Mob::SetOwnerID(uint16 NewOwnerID) {
 		this->Depop();
 }
 
-//heko: for backstab
+// used in checking for behind (backstab) and checking in front (melee LoS)
-bool Mob::BehindMob(Mob* other, float playerx, float playery) const {
+float Mob::MobAngle(Mob *other, float ourx, float oury) const {
-	if (!other)
+	if (!other || other == this)
-		return true; // sure your behind your invisible friend?? (fall thru for sneak)
+		return 0.0f;
-	//see if player is behind mob
+
-	float angle, lengthb, vectorx, vectory;
+	float angle, lengthb, vectorx, vectory, dotp;
-	float mobx = -(other->GetX());	// mob xlocation (inverse because eq is confused)
+	float mobx = -(other->GetX());	// mob xloc (inverse because eq)
-	float moby = other->GetY();		// mobylocation
+	float moby = other->GetY();		// mob yloc
 	float heading = other->GetHeading();	// mob heading
 	heading = (heading * 360.0f) / 256.0f;	// convert to degrees
 	if (heading < 270)
 		heading += 90;
 	else
 		heading -= 270;
+
 	heading = heading * 3.1415f / 180.0f;	// convert to radians
 	vectorx = mobx + (10.0f * cosf(heading));	// create a vector based on heading
 	vectory = moby + (10.0f * sinf(heading));	// of mob length 10
 
-	//length of mob to player vector
+	// length of mob to player vector
-	//lengthb = (float)sqrtf(pow((-playerx-mobx),2) + pow((playery-moby),2));
+	lengthb = (float) sqrtf(((-ourx - mobx) * (-ourx - mobx)) + ((oury - moby) * (oury - moby)));
-	lengthb = (float) sqrtf( ( (-playerx-mobx) * (-playerx-mobx) ) + ( (playery-moby) * (playery-moby) ) );
 
 	// calculate dot product to get angle
-	angle = acosf(((vectorx-mobx)*(-playerx-mobx)+(vectory-moby)*(playery-moby)) / (10 * lengthb));
+	// Handle acos domain errors due to floating point rounding errors
+	dotp = ((vectorx - mobx) * (-ourx - mobx) +
+			(vectory - moby) * (oury - moby)) / (10 * lengthb);
+	// I haven't seen any errors that  cause problems that weren't slightly
+	// larger/smaller than 1/-1, so only handle these cases for now
+	if (dotp > 1)
+		return 0.0f;
+	else if (dotp < -1)
+		return 180.0f;
+
+	angle = acosf(dotp);
 	angle = angle * 180.0f / 3.1415f;
-	if (angle > 90.0f) //not sure what value to use (90*2=180 degrees is front)
+
-		return true;
+	return angle;
-	else
-		return false;
 }
 
 void Mob::SetZone(uint32 zone_id, uint32 instance_id)

zone/mob.h

@@ -106,7 +106,13 @@ public:
 	//Attack
 	virtual void RogueBackstab(Mob* other, bool min_damage = false, int ReuseTime = 10);
 	virtual void RogueAssassinate(Mob* other); // solar
-	bool BehindMob(Mob* other = 0, float playerx = 0.0f, float playery = 0.0f) const;
+	float MobAngle(Mob *other = 0, float ourx = 0.0f, float oury = 0.0f) const;
+	// greater than 90 is behind
+	inline bool BehindMob(Mob *other = 0, float ourx = 0.0f, float oury = 0.0f) const
+		{ return (!other || other == this) ? true : MobAngle(other, ourx, oury) > 90.0f; }
+	// less than 56 is in front, greater than 56 is usually where the client generates the messages
+	inline bool InFrontMob(Mob *other = 0, float ourx = 0.0f, float oury = 0.0f) const
+		{ return (!other || other == this) ? true : MobAngle(other, ourx, oury) < 56.0f; }
 	virtual void RangedAttack(Mob* other) { }
 	virtual void ThrowingAttack(Mob* other) { }
 	uint16 GetThrownDamage(int16 wDmg, int32& TotalDmg, int& minDmg);