Implemented creeper abilities

* Creepers now explode with a sound effect
* Creepers drop a music disc on the unlikely event of being killed by a
skeleton's arrow

Inspired by @maniak89's PR #132.

src/Mobs/Creeper.cpp

@@ -3,6 +3,7 @@
 
 #include "Creeper.h"
 #include "../World.h"
+#include "../Entities/ProjectileEntity.h"
 
 
 
@@ -11,7 +12,8 @@
 cCreeper::cCreeper(void) :
 	super("Creeper", mtCreeper, "mob.creeper.say", "mob.creeper.say", 0.6, 1.8),
 	m_bIsBlowing(false),
-	m_bIsCharged(false)
+	m_bIsCharged(false),
+	m_ExplodingTimer(0)
 {
 }
 
@@ -19,11 +21,34 @@ cCreeper::cCreeper(void) :
 
 
 
+void cCreeper::Tick(float a_Dt, cChunk & a_Chunk)
+{
+	super::Tick(a_Dt, a_Chunk);
+
+	if (!ReachedFinalDestination())
+	{
+		m_ExplodingTimer = 0;
+		m_bIsBlowing = false;
+		m_World->BroadcastEntityMetadata(*this);
+	}
+}
+
+
+
+
+
 void cCreeper::GetDrops(cItems & a_Drops, cEntity * a_Killer)
 {
 	AddRandomDropItem(a_Drops, 0, 2, E_ITEM_GUNPOWDER);
 
-	// TODO Check if killed by a skeleton, then drop random music disk
+	if ((a_Killer != NULL) && (a_Killer->IsProjectile()))
+	{
+		if (((cMonster *)((cProjectileEntity *)a_Killer)->GetCreator())->GetMobType() == mtSkeleton)
+		{
+			// 12 music discs. TickRand starts from 0, so range = 11. Disk IDs start at 2256, so add that. There.
+			AddRandomDropItem(a_Drops, 1, 1, (short)m_World->GetTickRandomNumber(11) + 2256);
+		}
+	}
 }
 
 
@@ -45,3 +70,23 @@ void cCreeper::DoTakeDamage(TakeDamageInfo & a_TDI)
 
 
 
+
+void cCreeper::Attack(float a_Dt)
+{
+	UNUSED(a_Dt);
+
+	m_ExplodingTimer += 1;
+
+	if (!m_bIsBlowing)
+	{
+		m_World->BroadcastSoundEffect("random.fuse", (int)GetPosX() * 8, (int)GetPosY() * 8, (int)GetPosZ() * 8, 1.f, (float)(0.75 + ((float)((GetUniqueID() * 23) % 32)) / 64));
+		m_bIsBlowing = true;
+		m_World->BroadcastEntityMetadata(*this);
+	}
+
+	if (m_ExplodingTimer == 20)
+	{
+		m_World->DoExplosionAt((m_bIsCharged ? 5 : 3), GetPosX(), GetPosY(), GetPosZ(), false, esMonster, this);
+		Destroy();
+	}
+}