301 Days (redux)

Day 18 - Who Do You Hate?

by Joe Threeohone

Peek into the AI for some battle insights.

More detailed violence

We can watch the NPCs take damage and eventually expire, but it’s not exactly super-clear where the damage is coming from. If we poke into the server code to see what’s going on:

DragonsSpine/GameObjects/GameLiving/NPC/AI/AI.cslink
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Command.ParseCommand(npc, "poke", npc.mostHated.Name);
DragonsSpine/GameObjects/GameLiving/NPC/AI/AI.cslink
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Command.ParseCommand(npc, "shoot", npc.mostHated.Name);
DragonsSpine/GameObjects/GameLiving/NPC/AI/AI.cslink
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Command.ParseCommand(npc, "kick", npc.mostHated.Name);
DragonsSpine/GameObjects/GameLiving/NPC/AI/AI.cslink
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Command.ParseCommand(npc, "kill", npc.mostHated.Name);
DragonsSpine/GameObjects/GameLiving/NPC/AI/AI.cslink
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Command.ParseCommand(npc, "jumpkick", npc.mostHated.Name + "/Ki Yah!/!");

Ok, I think we see a pattern. If we know the NPC’s mostHated, we can be pretty sure that’s who the NPC is attacking. Luckily we’ve already added it to the LiveNPC table in the database, so it’s just a matter of surfacing it.

Assets/DragonsSpine/DAL/DBNPC.cslink
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npc.hasMostHated = !(dr.IsNull(dtNPCs.Columns["mostHatedId"]));
if (npc.hasMostHated) {
    npc.mostHatedId = Convert.ToInt32(dr["mostHatedId"]);
}
Assets/Managers/NpcManager.cslink
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npcScripts[npc.worldNpcID].hasMostHated = npc.hasMostHated;
npcScripts[npc.worldNpcID].mostHatedId = npc.mostHatedId;

Then we make an angry red arrow to point at the object of most hatred: We need a way to find the position of our foe:

Assets/Managers/NpcManager.cslink
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public Vector3 locateNpc(int npcId) {
    if (npcScripts.ContainsKey(npcId))
        return npcScripts[npcId].transform.position;
    else
        return Vector3.zero;
}

And now we can display our hatred:

Assets/NpcScript.cslink
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// display hatred
if (hasMostHated) {
    if (myHatred == null) {
        myHatred = Instantiate(hatredPrefab,
                               Vector3.zero,
                               Quaternion.identity) as Transform;
        myHatred.parent = this.transform;
        myHatred.localPosition = new Vector3(0f, 0f, 0.2f);
        myHatredRend = myHatred.GetComponent<Renderer>();
    }
    hatedLocation = npcManager.locateNpc(mostHatedId);

    Vector3 hatredDir = hatedLocation - transform.position;
    hatredDir.z = 0f;
    hatredDir = hatredDir.normalized;

    Quaternion qDir = new Quaternion();
    qDir.SetLookRotation(hatredDir, new Vector3(0f, 0f, 1f));
    myHatred.rotation = qDir;

    myHatred.localScale = new Vector3(0.3f, 1f, 1f);
    myHatredRend.enabled = toBeSeen;
} else {
    if (myHatred != null) {
        myHatredRend.enabled = false;
    }
}

Cohatred

That’s cool, but the Update method in NpcScript is getting crowded. Can’t we do this in a cool, coroutine-ish way?

Assets/NpcScript.cslink
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public bool HasMostHated {
    get { return hasMostHated; }
    set {
        if (hasMostHated != value) {
            hasMostHated = value;
            StopCoroutine("Hatred");
            StartCoroutine("Hatred");
        }
    }
}
public int MostHatedId {
    get { return mostHatedId; }
    set {
        if (mostHatedId != value) {
            mostHatedId = value;
            StopCoroutine("Hatred");
            StartCoroutine("Hatred");
        }
    }
}
Assets/NpcScript.cslink
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IEnumerator Hatred () {
    while (hasMostHated && !presumedDead && hits > 0f) {
        if (myHatred == null) {
            myHatred = Instantiate(hatredPrefab,
                                   Vector3.zero,
                                   Quaternion.identity) as Transform;
            myHatred.parent = this.transform;
            myHatred.localPosition = new Vector3(0f, 0f, 0.2f);
            myHatredRend = myHatred.GetComponent<Renderer>();
        }
        hatedLocation = npcManager.locateNpc(mostHatedId);
        
        Vector3 hatredDir = hatedLocation - transform.position;
        hatredDir.z = 0f;
        hatredDir = hatredDir.normalized;
        
        Quaternion qDir = new Quaternion();
        qDir.SetLookRotation(hatredDir, new Vector3(0f, 0f, 1f));
        myHatred.rotation = qDir;
        
        myHatred.localScale = new Vector3(0.3f, 0.1f, 1f);
        Vector3 startPos = transform.position + hatredDir * transform.localScale.x * 0.5f;
        Vector3 endPos = hatedLocation - hatredDir * transform.localScale.x * 0.5f;
        startPos.z += 0.2f; endPos.z += 0.2f;
        myHatred.position = Vector3.Lerp(startPos, endPos, Time.time % 1f);
        myHatredRend.enabled = toBeSeen;

        yield return null;
    } 
    if (myHatred != null) {
        myHatredRend.enabled = false;
    }
}

And while we’re at it, we take advantage of the added efficiency to animate the arrows a bit.

Day 18 code - client