Add ThingCount

Hexen implements this as ThingCount(int, int), and ZDoom adds ThingCountName(str, int). I decided on simplifying down to ThingCount(str, int).

extras/gdcc/rrspecial.acs

@@ -205,7 +205,7 @@ special
 	void  { 55,  56}:Delay(int),
 	int   { 57,  58}:Random(int, int),
 	fixed { 57,  58}:RandomFixed(fixed, fixed),
-	int   { 59,  60}:ThingCount(int, int),
+	int   { 59,  60}:ThingCount(str, int),
 	void  { 61,  62}:TagWait(int),
 	void  { 63,  64}:PolyWait(int),
 	void  { 65,  66}:ChangeFloor(int, str),

src/k_acs-func.c

@@ -27,6 +27,93 @@
 #include "r_state.h"
 #include "p_polyobj.h"
 #include "taglist.h"
+#include "p_local.h"
+#include "deh_tables.h"
+#include "fastcmp.h"
+
+/*--------------------------------------------------
+	static bool ACS_GetMobjTypeFromString(const char *word, mobjtype_t *type)
+
+		Helper function for ACS_CF_ThingCount. Gets
+		an object type from a string.
+
+	Input Arguments:-
+		word: The mobj class string.
+		type: Variable to store the result in.
+
+	Return:-
+		true if successful, otherwise false.
+--------------------------------------------------*/
+static bool ACS_GetMobjTypeFromString(const char *word, mobjtype_t *type)
+{
+	mobjtype_t i;
+
+	if (fastncmp("MT_", word, 3))
+	{
+		// take off the MT_
+		word += 3;
+	}
+
+	for (i = 0; i < NUMMOBJFREESLOTS; i++)
+	{
+		if (!FREE_MOBJS[i])
+		{
+			break;
+		}
+
+		if (fastcmp(word, FREE_MOBJS[i]))
+		{
+			*type = MT_FIRSTFREESLOT+i;
+			return true;
+		}
+	}
+
+	for (i = 0; i < MT_FIRSTFREESLOT; i++)
+	{
+		if (fastcmp(word, MOBJTYPE_LIST[i]+3))
+		{
+			*type = i;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+/*--------------------------------------------------
+	static bool ACS_CountThing(mobj_t *mobj, mobjtype_t type)
+
+		Helper function for ACS_CF_ThingCount.
+		Returns whenever or not to add this thing
+		to the thing count.
+
+	Input Arguments:-
+		mobj: The mobj we want to count.
+		type: Type exclusion.
+
+	Return:-
+		true if successful, otherwise false.
+--------------------------------------------------*/
+static bool ACS_CountThing(mobj_t *mobj, mobjtype_t type)
+{
+	if (type == MT_NULL || mobj->type == type)
+	{
+		// Don't count dead monsters
+		if (mobj->info->spawnhealth > 0 && mobj->health <= 0)
+		{
+			// Note: Hexen checks for COUNTKILL.
+			// SRB2 does not have an equivalent, so I'm checking
+			// spawnhealth. Feel free to replace this condition
+			// with literally anything else.
+			return false;
+		}
+
+		// Count this object.
+		return true;
+	}
+
+	return false;
+}
 
 /*--------------------------------------------------
 	bool ACS_CF_Random(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Word argC)
@@ -40,13 +127,92 @@ bool ACS_CF_Random(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Word argC
 
 	(void)argC;
 
-	low = (INT32)argV[0];
-	high = (INT32)argV[1];
+	low = argV[0];
+	high = argV[1];
 
 	ACSVM_Thread_DataStk_Push(thread, P_RandomRange(PR_ACS, low, high));
 	return false;
 }
 
+/*--------------------------------------------------
+	bool ACS_CF_ThingCount(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Word argC)
+
+		Counts the number of things of a particular
+		type and tid. Both fields are optional;
+		no type means indescriminate against type,
+		no tid means search thru all thinkers.
+--------------------------------------------------*/
+bool ACS_CF_ThingCount(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Word argC)
+{
+	ACSVM_MapScope *map = NULL;
+	ACSVM_String *str = NULL;
+	const char *className = NULL;
+	size_t classLen = 0;
+
+	mobjtype_t type = MT_NULL;
+	mtag_t tid = 0;
+
+	size_t count = 0;
+
+	(void)argC;
+
+	map = ACSVM_Thread_GetScopeMap(thread);
+	str = ACSVM_MapScope_GetString(map, argV[0]);
+
+	className = ACSVM_String_GetStr(str);
+	classLen = ACSVM_String_GetLen(str);
+
+	if (classLen > 0)
+	{
+		bool success = ACS_GetMobjTypeFromString(className, &type);
+
+		if (success == false)
+		{
+			// Exit early.
+
+			CONS_Alert(CONS_WARNING,
+				"Couldn't find object type \"%s\" for ThingCount.\n",
+				className
+			);
+
+			return false;
+		}
+	}
+
+	tid = argV[1];
+
+	if (tid != 0)
+	{
+		// TODO: Even in SRB2 next's UDMF, tag lists
+		// still aren't attached to mobj_t, only
+		// mapthing_t. Fix this.
+	}
+	else
+	{
+		// Search thinkers instead of tag lists.
+		thinker_t *th = NULL;
+		mobj_t *mobj = NULL;
+
+		for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
+		{
+			if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			{
+				continue;
+			}
+
+			mobj = (mobj_t *)th;
+
+			if (ACS_CountThing(mobj, type) == true)
+			{
+				++count;
+			}
+		}
+	}
+
+	ACSVM_Thread_DataStk_Push(thread, count);
+	return false;
+}
+
 /*--------------------------------------------------
 	bool ACS_CF_TagWait(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Word argC)
 
@@ -99,7 +265,7 @@ bool ACS_CF_ChangeFloor(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Word
 	const char *texName = NULL;
 
 	INT32 secnum = -1;
-	INT32 tag = 0;
+	mtag_t tag = 0;
 
 	(void)argC;
 
@@ -130,7 +296,7 @@ bool ACS_CF_ChangeCeiling(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Wo
 	const char *texName = NULL;
 
 	INT32 secnum = -1;
-	INT32 tag = 0;
+	mtag_t tag = 0;
 
 	(void)argC;
 

src/k_acs.c

@@ -202,7 +202,12 @@ static void ACS_EnvConstruct(ACSVM_Environment *env)
 	// Not that we're adding any modules to it, though. :p
 	ACSVM_GlobalScope_SetActive(global, true);
 
-	// Add the data & function pointers
+	// Add the data & function pointers.
+
+	// Starting with raw ACS0 codes. I'm using this classic-style
+	// format here to have a blueprint for what needs implementing,
+	// but it'd also be fine to move these to new style.
+
 	// See also:
 	// - https://doomwiki.org/wiki/ACS0_instruction_set
 	// - https://github.com/DavidPH/ACSVM/blob/master/ACSVM/CodeData.hpp
@@ -211,7 +216,8 @@ static void ACS_EnvConstruct(ACSVM_Environment *env)
 	//  0 to 56: Implemented by ACSVM
 	ACS_AddCodeDataCallFunc(env,   57, "",        2, ACS_CF_Random);
 	ACS_AddCodeDataCallFunc(env,   58, "WW",      0, ACS_CF_Random);
-
+	ACS_AddCodeDataCallFunc(env,   59, "",        2, ACS_CF_ThingCount);
+	ACS_AddCodeDataCallFunc(env,   60, "WW",      0, ACS_CF_ThingCount);
 	ACS_AddCodeDataCallFunc(env,   61, "",        1, ACS_CF_TagWait);
 	ACS_AddCodeDataCallFunc(env,   62, "W",       0, ACS_CF_TagWait);
 	ACS_AddCodeDataCallFunc(env,   63, "",        1, ACS_CF_PolyWait);

src/k_acs.h

@@ -127,6 +127,7 @@ void ACS_Tick(void);
 --------------------------------------------------*/
 
 bool ACS_CF_Random(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Word argC);
+bool ACS_CF_ThingCount(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Word argC);
 bool ACS_CF_TagWait(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Word argC);
 bool ACS_CF_PolyWait(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Word argC);
 bool ACS_CF_ChangeFloor(ACSVM_Thread *thread, ACSVM_Word const *argV, ACSVM_Word argC);