Fan particle generators now suck less!

For the object...
* Tag via its angle field
* Number of objects to spawn per tic around it via its z field, if zero then just spawn at center
* Is flipped if given MTF_OBJECTFLIP.

Now there's a linedef type 15!
* Tag is tag of object(s!)
* Object type set via concatenation of frontside textures, MT_PARTICLE is default
* The length of the linedef is the radius the particle is spawned out (zeroed if z field is 0)
* Frontside x offset is speed upwards
* Frontside y offset is number of degrees to turn each tic (zeroed if z field is 0)
* Frontside floor and ceiling heights are the heights in which the particle is bound through some fun mathematics and/or BDSM

Of course, not every story has a happy ending.
* A_ParticleSpawn no longer accepts objects via its var1 because of how specialised it's gotten. Considering it can be set via abuse of actor->cvmem, I don't consider this an issue. Maybe you might disagree.

src/p_enemy.c

@@ -3359,41 +3359,45 @@ void A_ScoreRise(mobj_t *actor)
 
 // Function: A_ParticleSpawn
 //
-// Description: Spawns a particle at a specified interval
+// Description: Hyper-specialised function for spawning a particle for MT_PARTICLEGEN.
 //
-// var1 = type (if 0, defaults to MT_PARTICLE)
+// var1 = unused
 // var2 = unused
 //
 void A_ParticleSpawn(mobj_t *actor)
 {
-	INT32 locvar1 = var1;
-	fixed_t speed;
-	mobjtype_t type;
+	INT32 i = 0;
 	mobj_t *spawn;
 
 #ifdef HAVE_BLUA
 	if (LUA_CallAction("A_ParticleSpawn", actor))
 		return;
 #endif
-	if (!actor->spawnpoint)
-	{
-		P_RemoveMobj(actor);
+	if (!actor->health)
 		return;
+
+	if ((actor->lastlook) && (actor->cvmem))
+	{
+		for (i = 0; i < actor->lastlook; i++)
+		{
+			spawn = P_SpawnMobj(actor->x + FixedMul(actor->friction, FINECOSINE(actor->angle>>ANGLETOFINESHIFT)),
+				actor->y + FixedMul(actor->friction, FINESINE(actor->angle>>ANGLETOFINESHIFT)),
+				actor->z,
+				(mobjtype_t)actor->cvmem);
+			P_SetScale(spawn, actor->scale);
+			spawn->momz = actor->movefactor;
+			spawn->destscale = spawn->scale/100;
+			spawn->scalespeed = spawn->scale/actor->health;
+			spawn->tics = (tic_t)actor->health;
+			spawn->flags2 |= (actor->flags2 & MF2_OBJECTFLIP);
+			spawn->angle += P_RandomKey(36)*ANG10; // irrelevant for default objects but might make sense for some custom ones
+			if (spawn->frame & FF_ANIMATE)
+				spawn->frame += P_RandomKey(spawn->state->var1);
+
+			actor->angle += actor->movedir;
+		}
+		actor->angle += (angle_t)actor->movecount;
 	}
-
-	if (locvar1)
-		type = (mobjtype_t)locvar1;
-	else
-		type = MT_PARTICLE;
-
-	speed = FixedMul((actor->spawnpoint->angle >> 12)<<FRACBITS, actor->scale);
-
-	spawn = P_SpawnMobj(actor->x, actor->y, actor->z, type);
-	P_SetScale(spawn, actor->scale);
-	spawn->momz = speed;
-	spawn->destscale = FixedDiv(spawn->scale<<FRACBITS, 100<<FRACBITS);
-	spawn->scalespeed = FixedDiv(((actor->spawnpoint->angle >> 8) & 63) << FRACBITS, 100<<FRACBITS);
-	actor->tics = actor->spawnpoint->extrainfo + 1;
 }
 
 // Function: A_BunnyHop

src/p_mobj.c

@@ -9303,6 +9303,85 @@ ML_NOCLIMB : Direction not controllable
 		}
 		break;
 	}
+	case MT_PARTICLEGEN:
+	{
+		fixed_t radius, speed, bottomheight, topheight;
+		INT32 type, numdivisions, time, anglespeed;
+		angle_t angledivision;
+		size_t line;
+		const size_t mthingi = (size_t)(mthing - mapthings);
+
+		for (line = 0; line < numlines; line++)
+		{
+			if (lines[line].special == 15 && lines[line].tag == mthing->angle)
+				break;
+		}
+
+		if (line == numlines)
+		{
+			CONS_Debug(DBG_GAMELOGIC, "Particle generator (mapthing #%s) needs tagged to a #15 parameter line (trying to find tag %d).\n", sizeu1(mthingi), mthing->angle);
+			return;
+		}
+
+		if (sides[lines[line].sidenum[0]].toptexture)
+			type = sides[lines[line].sidenum[0]].toptexture; // Set as object type in p_setup.c...
+		else
+			type = (INT32)MT_PARTICLE;
+
+		speed = abs(sides[lines[line].sidenum[0]].textureoffset);
+		bottomheight = lines[line].frontsector->floorheight;
+		topheight = lines[line].frontsector->ceilingheight - mobjinfo[(mobjtype_t)type].height;
+
+		numdivisions = (mthing->options >> ZSHIFT);
+
+		if (numdivisions)
+		{
+			radius = R_PointToDist2(lines[line].v1->x, lines[line].v1->y, lines[line].v2->x, lines[line].v2->y);
+			anglespeed = (sides[lines[line].sidenum[0]].rowoffset >> FRACBITS) % 360;
+			angledivision = 360/numdivisions;
+		}
+		else
+		{
+			numdivisions = 1; // Simple trick to make A_ParticleSpawn simpler.
+			radius = 0;
+			anglespeed = 0;
+			angledivision = 0;
+		}
+
+		if ((speed) && (topheight > bottomheight))
+			time = (INT32)(FixedDiv((topheight - bottomheight), speed) >> FRACBITS);
+		else
+			time = 1; // There's no reasonable way to set it, so just show the object for one tic and move on.
+
+		if (mthing->options & MTF_OBJECTFLIP)
+		{
+			mobj->z = topheight;
+			speed *= -1;
+		}
+		else
+			mobj->z = bottomheight;
+
+		CONS_Debug(DBG_GAMELOGIC, "Particle Generator (mapthing #%s):\n"
+				"Radius is %d\n"
+				"Speed is %d\n"
+				"Anglespeed is %d\n"
+				"Numdivisions is %d\n"
+				"Angledivision is %d\n"
+				"Time is %d\n"
+				"Type is %d\n",
+				sizeu1(mthingi), radius, speed, anglespeed, numdivisions, angledivision, time, type);
+
+		mobj->angle = 0;
+		mobj->movefactor = speed;
+		mobj->lastlook = numdivisions;
+		mobj->movedir = angledivision*ANG1;
+		mobj->movecount = anglespeed*ANG1;
+		mobj->health = time;
+		mobj->friction = radius;
+		mobj->cvmem = type;
+
+		break;
+	}
 	case MT_ROCKSPAWNER:
 		mobj->threshold = mthing->angle;
 		mobj->movecount = mthing->extrainfo;

src/p_setup.c

@@ -1479,6 +1479,7 @@ static void P_LoadSideDefs2(lumpnum_t lumpnum)
 			}
 
 			case 14: // Bustable block parameters
+			case 15: // Fan particle spawner parameters
 			case 425: // Calls P_SetMobjState on calling mobj
 			case 434: // Custom Power
 			case 442: // Calls P_SetMobjState on mobjs of a given type in the tagged sectors