From dea5168998e2ecc7350367d6db7d42b8e07a17a8 Mon Sep 17 00:00:00 2001
From: Marco Cawthorne <marco@vera-visions.com>
Date: Thu, 27 Jul 2023 13:29:58 -0700
Subject: [PATCH] NSProjectile: Implement "thrust", "thrust_start" and
 "thrust_end" spawn keys, as well as "thrust_homing" NSTimer: Destroy when
 receiver becomes invalidated.

---
 src/shared/NSProjectile.h  |  6 ++++
 src/shared/NSProjectile.qc | 58 ++++++++++++++++++++++++++++++++++++++
 src/shared/NSTimer.qc      |  5 ++++
 3 files changed, 69 insertions(+)

diff --git a/src/shared/NSProjectile.h b/src/shared/NSProjectile.h
index 40745fad..e093b3bf 100644
--- a/src/shared/NSProjectile.h
+++ b/src/shared/NSProjectile.h
@@ -100,9 +100,15 @@ private:
 	/* Nuclide additions */
 	bool m_bStickToWorld;
 	bool m_bStickToActor;
+	bool m_bThrustHoming;
+
+	NSTimer m_thrustHandler;
 
 	nonvirtual void _AnimateThink(void);
+	nonvirtual void _ThrustThink(void);
 	nonvirtual void _AnimateThinkDead(void);
+
+	virtual void OnRemoveEntity(void);
 #endif
 
 public:
diff --git a/src/shared/NSProjectile.qc b/src/shared/NSProjectile.qc
index 19b9f73f..dff1e081 100644
--- a/src/shared/NSProjectile.qc
+++ b/src/shared/NSProjectile.qc
@@ -217,6 +217,9 @@ NSProjectile::SpawnKey(string strKey, string strValue)
 	case "maxs":
 		m_vecSpawnMaxs = ReadVector(strValue);
 		break;
+	case "thrust_homing":
+		m_bThrustHoming = ReadBool(strValue);
+		break;
 	default:
 		super::SpawnKey(strKey, strValue);
 		break;
@@ -272,6 +275,8 @@ NSProjectile::Save(float handle)
 	SaveBool(handle, "m_bStickToActor", m_bStickToActor);
 	SaveVector(handle, "m_vecSpawnMins", m_vecSpawnMins);
 	SaveVector(handle, "m_vecSpawnMaxs", m_vecSpawnMaxs);
+	SaveBool(handle, "m_bThrustHoming", m_bThrustHoming);
+	SaveEntity(handle, "m_thrustHandler", m_thrustHandler);
 }
 
 void
@@ -410,6 +415,12 @@ NSProjectile::Restore(string strKey, string strValue)
 	case "m_vecSpawnMaxs":
 		m_vecSpawnMaxs = ReadVector(strValue);
 		break;
+	case "m_bThrustHoming":
+		m_bThrustHoming = ReadBool(strValue);
+		break;
+	case "m_thrustHandler":
+		m_thrustHandler = (NSTimer)ReadEntity(strValue);
+		break;
 	default:
 		super::Restore(strKey, strValue);
 		break;
@@ -595,6 +606,49 @@ NSProjectile::_LaunchHitscan(vector startPos, vector launchDir, float dmgMultipl
 	
 }
 
+void
+NSProjectile::_ThrustThink(void)
+{
+	vector currentVelocity;
+	float currentSpeed;
+	float newSpeed;
+	vector newVelocity;
+
+	currentVelocity = GetVelocity();
+	currentSpeed = vlen(currentVelocity);
+	newSpeed = (currentSpeed + (m_flThrust * frametime));
+
+	/* homing mode */
+	if (m_bThrustHoming) {
+		NSSurfacePropEntity projectileOwner = (NSSurfacePropEntity)GetOwner();
+		vector ownerPos = projectileOwner.GetEyePos();
+		makevectors(projectileOwner.v_angle);
+		traceline(ownerPos, ownerPos + v_forward * 8096, FALSE, projectileOwner);
+		SetAngles(vectoangles(trace_endpos - GetOrigin()));
+	}
+
+	makevectors(GetAngles());
+	newVelocity = v_forward * (newSpeed);
+
+	/* prevent thrusting early */
+	if ((m_flThrustStart > 0) && GetSpawnAge() < m_flThrustStart) { 
+		return;
+	}
+
+	/* stop thrusting when we reach the end time */
+	if ((m_flThrustEnd > 0) && (GetSpawnAge() > m_flThrustEnd)) {
+		m_thrustHandler.Destroy(); /* invalidate */
+		return;
+	}
+
+	SetVelocity(newVelocity);
+}
+
+void
+NSProjectile::OnRemoveEntity(void)
+{
+}
+
 void
 NSProjectile::Launch(vector startPos, vector launchDir, float fuseOffset, float powerMultiplier, float dmgMultiplier)
 {
@@ -656,6 +710,10 @@ NSProjectile::Launch(vector startPos, vector launchDir, float fuseOffset, float
 		ScheduleThink(_FuseEnded, m_flFuse + fuseOffset);
 	}
 
+	if (m_flThrust != 0) {
+		m_thrustHandler = NSTimer::TemporaryTimer(this, _ThrustThink, 0.0, true);
+	}
+
 	StartSoundDef(m_sndFly, CHAN_BODY, true);
 	SendFlags = (-1);
 	//SendEntity = 0; /* HACK: remove this once Spike fixes CSQC-set traileffectnum etc. */
diff --git a/src/shared/NSTimer.qc b/src/shared/NSTimer.qc
index c4e59163..4049b1b8 100644
--- a/src/shared/NSTimer.qc
+++ b/src/shared/NSTimer.qc
@@ -36,6 +36,11 @@ _NSTimerWrapper(entity receiver, void() func)
 void
 NSTimer::_TimerThink(void)
 {
+	if (!m_eReceiver) {
+		Destroy();
+		return;
+	}
+
 	_NSTimerWrapper(m_eReceiver, _m_NSTimerFunc);
 
 	if (m_bRepeats == true)