Distance calculation for melee-attacks and Following

[Schmoozerd]

Hi guys.

Current Code situation:

every unit has a model, which has some data stored in creature_model_info

These are

- modelid - linked with creature_template.modelid_X (usally 1)

- bounding_radius a float value, used for distance calculation, assumption this is the 'radius' of the modell

- combat_reach a float values, used for spell range check

Scematic of these values:

http://img96.imageshack.us/i/distancecalculations.png/

Atm in clean core spells are checked with GetCombatDistance

       float dist = m_caster->GetCombatDistance(target);

       if(dist > max_range) // max_range is max range of spell (from DBC)
           return SPELL_FAILED_OUT_OF_RANGE;
       if(min_range && dist < min_range) // min_range is min range of spell (from DBC)
           return SPELL_FAILED_TOO_CLOSE;

And melee-range is checked with IsWithinDistInMap ~~> GetDistance, that is takes bounding_radius information into account

       //If we are within range melee the target
       if (m_creature->IsWithinDistInMap(m_creature->getVictim(), ATTACK_DISTANCE))

Also default MoveChase distance is defined by bounding_radius, as the default distance is 0 (which means, the bounding-boxes are near)

My idea is to change this, such that melee-range check is similar to spell range also dependen on combat reach,

this gives in my opinion way better results.

Suggested check:

The icons for spells turn dark-gray if you are out of range, so this is client based, and hence a very good reference.

Example mobs:

- Murmur, Ragnaros, 16441, Maexxna

Base patches:

http://paste2.org/p/1205717 (for core)

http://paste2.org/p/1205718 (for SD2, might give small conflicts, as I wasn't testing on clean)

Problems

* A few mobs like supremus, 16441 have most likely wrong MoveChase behaviour, as of extremely large bounding_radius

* The melee-range now seems to be too big, don't understand which reasons for decreasing there could be!

Any input & feedback is welcome

[Feanordev]

I have patch for it, lemme look on my branch...

Not sure if you meant it.

This makes players melee attacks based on enemy attack-box (makes for example being possible to hit Thaddius from large distance so Negative / Positive charges arent hitting players on both sides.

diff --git a/src/game/Player.cpp b/src/game/Player.cpp
index 3f09b8e..82ae7ae 100644
--- a/src/game/Player.cpp
+++ b/src/game/Player.cpp
@@ -1250,11 +1250,13 @@ void Player::Update( uint32 p_time )
            // default combat reach 10
            // TODO add weapon,skill check

-            float pldistance = ATTACK_DISTANCE;
+            float dist = pVictim->GetTypeId() == TYPEID_PLAYER ? ATTACK_DISTANCE : (GetFloatValue(UNIT_FIELD_COMBATREACH) + pVictim->GetFloatValue(UNIT_FIELD_COMBATREACH));
+            // Check for creatures that somehow have lower combat-reach than minimal attack distance
+            if (dist < ATTACK_DISTANCE) dist = ATTACK_DISTANCE;

            if (isAttackReady(BASE_ATTACK))
            {
-                if(!IsWithinDistInMap(pVictim, pldistance))
+                if(!IsWithinDistInMap(pVictim, dist))
                {
                    setAttackTimer(BASE_ATTACK,100);
                    if(m_swingErrorMsg != 1)                // send single time (client auto repeat)
@@ -1291,7 +1293,7 @@ void Player::Update( uint32 p_time )

            if ( haveOffhandWeapon() && isAttackReady(OFF_ATTACK))
            {
-                if(!IsWithinDistInMap(pVictim, pldistance))
+                if(!IsWithinDistInMap(pVictim, dist))
                {
                    setAttackTimer(OFF_ATTACK,100);
                }

[Schmoozerd]

yes, this does basicly the same as I did (in the player part).

However with this patch the Problem

"The melee-range now seems to be too big, don't understand which reasons for decreasing there could be"

will be worsened even more, as the IsWithinDistInMap check adds the bounding_box values.

I cannot yet tell if the additional check: if < ATTACK_DISTANCE then = ATTACKDISTANCE is important, therefore I haven't explored enough yet

[Feanordev]

Well Im using this change for almost year already, havent really noticed too-big melee range actually, the dist < attack_dist check is needed becouse sometime becouse of box-calculation distance was almost close-to 0

[Schmoozerd]

indeed it seems that it must be taken the maximum of GetCombatDistance and ATTACK_DISTANCE

and it also looks like that in these small distance cases, the combat range is (again) calculated without bounding_box

(I test with 24219, faction changed to 14, values BB=0.748, CR=0.6)

Also some of the model infos which have 0 entries for BB and CR are linked (modelid_other_genger) to some modelids which have reasonablevalues for these fields - so this suggests to also try to implement some additional feature to get the better values