git-svn-id: http://mancubus.net/svn/hosted/gzdoom/trunk@126 b0f79afe-0144-0410-b225-9a4edf0717df

src/g_shared/a_randomspawner.cpp

@@ -0,0 +1,86 @@
+#include "actor.h"
+#include "info.h"
+#include "m_random.h"
+#include "p_local.h"
+#include "p_enemy.h"
+#include "s_sound.h"
+#include "a_doomglobal.h"
+#include "statnums.h"
+#include "gstrings.h"
+#include "a_action.h"
+#include "thingdef/thingdef.h"
+
+/*
+- in the decorate definition define multiple drop items
+- use the function GetDropItems to get the first drop item, then iterate over them and count how many dropitems are defined.
+- with M_Random( ) % NUMBEROFDROPITEMS you get a random drop item number (let's call it n)
+- use GetDropItems again to get the first drop item, then iterate to the n-th drop item
+*/
+static FRandom pr_randomspawn("RandomSpawn");
+
+class ARandomSpawner : public AActor
+{
+	DECLARE_STATELESS_ACTOR (ARandomSpawner, AActor)
+
+	void PostBeginPlay()
+	{
+		AActor *newmobj;
+		FDropItem *di;   // di will be our drop item list iterator
+		FDropItem *drop; // while drop stays as the reference point.
+		int n=0;
+
+		Super::PostBeginPlay();
+
+		drop = di = GetDropItems(RUNTIME_TYPE(this));
+		// Always make sure it actually exists.
+		if (di != NULL)
+		{
+			// First, we get the size of the array...
+			while (di != NULL)
+			{
+				if (di->Name != NAME_None)
+				{
+					if (di->amount < 0) di->amount = 1; // default value is -1, we need a positive value.
+					n += di->amount; // this is how we can weight the list.
+					di = di->Next;
+				}
+			}
+			// Then we reset the iterator to the start position...
+			di = drop;
+			// Take a random number...
+			n = pr_randomspawn(n);
+			// And iterate in the array up to the random number chosen.
+			while (n > 0)
+			{
+				if (di->Name != NAME_None)
+				{
+					n -= di->amount;
+					di = di->Next;
+				}
+			}
+			// So now we can spawn the dropped item.
+			if (pr_randomspawn() <= di->probability) // prob 255 = always spawn, prob 0 = never spawn.
+			{
+				newmobj = Spawn(di->Name, x, y, z, ALLOW_REPLACE);
+				// copy everything relevant
+				newmobj->SpawnAngle = newmobj->angle = angle;
+				newmobj->special    = special;
+				newmobj->args[0]    = args[0];
+				newmobj->args[1]    = args[1];
+				newmobj->args[2]    = args[2];
+				newmobj->args[3]    = args[3];
+				newmobj->args[4]    = args[4];
+				newmobj->SpawnFlags = SpawnFlags;
+				newmobj->HandleSpawnFlags();
+				newmobj->momx = momx;
+				newmobj->momy = momy;
+				newmobj->momz = momz;
+				newmobj->CopyFriendliness(this, false);
+			}
+		}
+	}
+};
+
+IMPLEMENT_STATELESS_ACTOR (ARandomSpawner, Any, -1, 0)
+END_DEFAULTS
+