356 lines
9.7 KiB
JavaScript
356 lines
9.7 KiB
JavaScript
/*
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This is currently just a very simplistic state machine that lets units be commanded around
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and then autonomously carry out the orders. It might need to be entirely redesigned.
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*/
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const STATE_IDLE = 0;
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const STATE_WALKING = 1;
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const STATE_ATTACKING = 2;
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const STATE_GATHERING = 3;
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/* Attack process:
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* When starting attack:
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* Activate attack animation (with appropriate repeat speed and offset)
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* Set this.attackTimer to run at maximum of:
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* GetTimers().prepare msec from now
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* this.attackRechargeTime
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* Loop:
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* Wait for the timer
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* Perform the attack
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* Set this.attackRechargeTime to now plus GetTimers().recharge
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* Set this.attackTimer to run after GetTimers().repeat
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* At any point it's safe to cancel the attack and switch to a different action
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* (The rechargeTime is to prevent people spamming the attack command and getting
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* faster-than-normal attacks)
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*/
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/* Gather process is about the same, except with less synchronisation - the action
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* is just performed 1sec after initiated, and then repeated every 1sec.
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* (TODO: it'd be nice to avoid most of the duplication between Attack and Gather code)
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*/
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function UnitAI() {}
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UnitAI.prototype.Init = function()
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{
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this.state = STATE_IDLE;
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// The earliest time at which we'll have 'recovered' from the previous attack, and
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// can start preparing a new attack
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this.attackRechargeTime = 0;
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// Timer for AttackTimeout
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this.attackTimer = undefined;
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// Current target entity ID
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this.attackTarget = undefined;
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// Timer for GatherTimeout
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this.gatherTimer = undefined;
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// Current target entity ID
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this.gatherTarget = undefined;
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};
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//// Interface functions ////
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UnitAI.prototype.Walk = function(x, z)
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{
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var cmpMotion = Engine.QueryInterface(this.entity, IID_UnitMotion);
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if (!cmpMotion)
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return;
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this.SelectAnimation("walk", false, cmpMotion.GetSpeed());
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cmpMotion.MoveToPoint(x, z, 0, 0);
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this.state = STATE_WALKING;
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};
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UnitAI.prototype.Attack = function(target)
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{
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// Verify that we're able to respond to Attack commands
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var cmpAttack = Engine.QueryInterface(this.entity, IID_Attack);
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if (!cmpAttack)
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return;
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// TODO: verify that this is a valid target
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// Stop any previous action timers
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this.CancelTimers();
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// Remember the target, and start moving towards it
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this.attackTarget = target;
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this.MoveToTarget(target, cmpAttack.GetRange());
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this.state = STATE_ATTACKING;
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};
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UnitAI.prototype.Gather = function(target)
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{
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// Verify that we're able to respond to Gather commands
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var cmpResourceGatherer = Engine.QueryInterface(this.entity, IID_ResourceGatherer);
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if (!cmpResourceGatherer)
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return;
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// TODO: verify that this is a valid target
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// Stop any previous action timers
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this.CancelTimers();
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// Remember the target, and start moving towards it
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this.gatherTarget = target;
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this.MoveToTarget(target, cmpResourceGatherer.GetRange());
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this.state = STATE_GATHERING;
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};
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//// Message handlers ////
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UnitAI.prototype.OnDestroy = function()
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{
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// Clean up any timers that are now obsolete
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this.CancelTimers();
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};
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UnitAI.prototype.OnMotionChanged = function(msg)
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{
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if (msg.speed)
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{
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// Started moving
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// => play the appropriate animation
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this.SelectAnimation("walk", false, msg.speed);
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}
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else
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{
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if (this.state == STATE_WALKING)
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{
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// Stopped walking
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this.state = STATE_IDLE;
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this.SelectAnimation("idle");
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}
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else if (this.state == STATE_ATTACKING)
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{
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// We were attacking, and have stopped moving
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// => check if we can still reach the target now
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if (!this.MoveIntoAttackRange())
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return;
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// In range, so perform the attack,
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// after the prepare time but not before the previous attack's recharge
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var cmpAttack = Engine.QueryInterface(this.entity, IID_Attack);
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var cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
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var timers = cmpAttack.GetTimers();
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var time = Math.max(timers.prepare, this.attackRechargeTime - cmpTimer.GetTime());
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this.attackTimer = cmpTimer.SetTimeout(this.entity, IID_UnitAI, "AttackTimeout", time, {});
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// Start the idle animation before we switch to the attack
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this.SelectAnimation("idle");
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}
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else if (this.state == STATE_GATHERING)
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{
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// We were gathering, and have stopped moving
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// => check if we can still reach the target now
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if (!this.MoveIntoGatherRange())
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return;
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// In range, so perform the gathering
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var cmpResourceSupply = Engine.QueryInterface(this.gatherTarget, IID_ResourceSupply);
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var cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
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this.gatherTimer = cmpTimer.SetTimeout(this.entity, IID_UnitAI, "GatherTimeout", 1000, {});
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// Start the gather animation
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var type = cmpResourceSupply.GetType();
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var anim = "gather_" + (type.specific || type.generic);
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this.SelectAnimation(anim);
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}
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}
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};
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//// Private functions ////
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function hypot2(x, y)
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{
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return x*x + y*y;
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}
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UnitAI.prototype.CheckRange = function(target, range)
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{
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// Target must be in the world
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var cmpPositionTarget = Engine.QueryInterface(target, IID_Position);
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if (!cmpPositionTarget || !cmpPositionTarget.IsInWorld())
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return { "error": "not-in-world" };
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// We must be in the world
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var cmpPositionSelf = Engine.QueryInterface(this.entity, IID_Position);
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if (!cmpPositionSelf || !cmpPositionSelf.IsInWorld())
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return { "error": "not-in-world" };
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// Target must be within range
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var posTarget = cmpPositionTarget.GetPosition();
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var posSelf = cmpPositionSelf.GetPosition();
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var dist2 = hypot2(posTarget.x - posSelf.x, posTarget.z - posSelf.z);
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// TODO: ought to be distance to closest point in footprint, not to center
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// The +4 is a hack to give a ~1 tile tolerance, because the pathfinder doesn't
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// always get quite close enough to the target
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if (dist2 > (range.max+4)*(range.max+4))
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return { "error": "out-of-range" };
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return {};
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}
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UnitAI.prototype.CancelTimers = function()
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{
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if (this.attackTimer)
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{
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var cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
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cmpTimer.CancelTimer(this.attackTimer);
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this.attackTimer = undefined;
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}
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if (this.gatherTimer)
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{
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var cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
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cmpTimer.CancelTimer(this.gatherTimer);
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this.gatherTimer = undefined;
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}
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};
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/**
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* Tries to move into range of the attack target.
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* Returns true if it's already in range.
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*/
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UnitAI.prototype.MoveIntoAttackRange = function()
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{
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var cmpAttack = Engine.QueryInterface(this.entity, IID_Attack);
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var range = cmpAttack.GetRange();
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var rangeStatus = this.CheckRange(this.attackTarget, range);
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if (rangeStatus.error)
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{
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if (rangeStatus.error == "out-of-range")
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{
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// Out of range => need to move closer
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// (The target has probably moved while we were chasing it)
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this.MoveToTarget(this.attackTarget, range);
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return false;
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}
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// Otherwise it's impossible to reach the target, so give up
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// and switch back to idle
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this.state = STATE_IDLE;
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this.SelectAnimation("idle");
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return false;
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}
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return true;
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};
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UnitAI.prototype.MoveIntoGatherRange = function()
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{
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var cmpResourceGatherer = Engine.QueryInterface(this.entity, IID_ResourceGatherer);
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var range = cmpResourceGatherer.GetRange();
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var rangeStatus = this.CheckRange(this.gatherTarget, range);
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if (rangeStatus.error)
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{
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if (rangeStatus.error == "out-of-range")
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{
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// Out of range => need to move closer
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// (The target has probably moved while we were chasing it)
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this.MoveToTarget(this.gatherTarget, range);
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return false;
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}
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// Otherwise it's impossible to reach the target, so give up
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// and switch back to idle
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this.state = STATE_IDLE;
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this.SelectAnimation("idle");
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return false;
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}
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return true;
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};
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UnitAI.prototype.SelectAnimation = function(name, once, speed)
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{
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var cmpVisual = Engine.QueryInterface(this.entity, IID_Visual);
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if (!cmpVisual)
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return;
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cmpVisual.SelectAnimation(name, once, speed);
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};
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UnitAI.prototype.MoveToTarget = function(target, range)
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{
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var cmpPositionTarget = Engine.QueryInterface(target, IID_Position);
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if (!cmpPositionTarget || !cmpPositionTarget.IsInWorld())
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return;
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var cmpMotion = Engine.QueryInterface(this.entity, IID_UnitMotion);
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var pos = cmpPositionTarget.GetPosition();
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cmpMotion.MoveToPoint(pos.x, pos.z, range.min, range.max);
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};
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UnitAI.prototype.AttackTimeout = function(data)
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{
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// If we stopped attacking before this timeout, then don't do any processing here
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if (this.state != STATE_ATTACKING)
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return;
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var cmpAttack = Engine.QueryInterface(this.entity, IID_Attack);
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// Check if we can still reach the target
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if (!this.MoveIntoAttackRange())
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return;
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// Play the attack animation
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this.SelectAnimation("melee", false, 1);
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// Hit the target
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cmpAttack.PerformAttack(this.attackTarget);
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// Set a timer to hit the target again
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var cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
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var timers = cmpAttack.GetTimers();
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this.attackRechargeTime = cmpTimer.GetTime() + timers.recharge;
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this.attackTimer = cmpTimer.SetTimeout(this.entity, IID_UnitAI, "AttackTimeout", timers.repeat, data);
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};
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UnitAI.prototype.GatherTimeout = function(data)
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{
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// If we stopped gathering before this timeout, then don't do any processing here
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if (this.state != STATE_GATHERING)
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return;
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var cmpResourceGatherer = Engine.QueryInterface(this.entity, IID_ResourceGatherer);
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// Check if we can still reach the target
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if (!this.MoveIntoGatherRange())
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return;
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// Gather from the target
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var status = cmpResourceGatherer.PerformGather(this.gatherTarget);
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// If the resource is exhausted, then stop and go back to idle
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if (status.exhausted)
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{
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this.state = STATE_IDLE;
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this.SelectAnimation("idle");
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return;
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}
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// Set a timer to gather again
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var cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
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this.gatherTimer = cmpTimer.SetTimeout(this.entity, IID_UnitAI, "GatherTimeout", 1000, data);
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};
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Engine.RegisterComponentType(IID_UnitAI, "UnitAI", UnitAI);
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