301 Days

A year of gamedev experiments.

Day 18 - Who Do You Hate?

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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

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