Permit multiple Spray Cans in one map

- Up to 255
- Each Spray Can placed does, in order, the postion in the list from the current head
    - So if there were 3 cans, and your can list was Red Yellow Blue Green, then Red, Yellow, and Blue would be in the level.
- Grabbing the nth colour in the list will swap that colour to the current head of the list
- However, the game will print to the console if you do this outside of GS_TUTORIAL.

src/p_inter.c

@@ -655,6 +655,25 @@ void P_TouchSpecialThing(mobj_t *special, mobj_t *toucher, boolean heightcheck)
 				{
 					// Unassigned, get the next grabbable colour
 					can_id = gamedata->gotspraycans;
+
+					// Multiple cans in one map?
+					if (special->threshold != 0)
+					{
+						UINT16 ref_id = can_id + (special->threshold & UINT8_MAX);
+						if (ref_id >= gamedata->numspraycans)
+							return;
+
+						// Swap this specific can to the head of the list.
+						UINT16 swapcol = gamedata->spraycans[ref_id].col;
+
+						gamedata->spraycans[ref_id].col =
+							gamedata->spraycans[can_id].col;
+						skincolors[gamedata->spraycans[ref_id].col].cache_spraycan = ref_id;
+
+						gamedata->spraycans[can_id].col = swapcol;
+						skincolors[swapcol].cache_spraycan = can_id;
+					}
+
 				}
 
 				if (can_id >= gamedata->numspraycans)
@@ -675,8 +694,30 @@ void P_TouchSpecialThing(mobj_t *special, mobj_t *toucher, boolean heightcheck)
 					gamedata->deferredsave = true;
 				}
 
-				// Don't delete the object, just fade it.
-				P_SprayCanInit(special);
+				{
+					mobj_t *canmo = NULL;
+					mobj_t *next = NULL;
+
+					for (canmo = trackercap; canmo; canmo = next)
+					{
+						next = canmo->itnext;
+
+						if (canmo->type != MT_SPRAYCAN)
+							continue;
+
+						// Don't delete the object(s), just fade it.
+						if (netgame || canmo == special)
+						{
+							P_SprayCanInit(canmo);
+							continue;
+						}
+
+						// Get ready to get rid of these
+						canmo->renderflags |= (tr_trans50 << RF_TRANSSHIFT);
+						canmo->destscale = 0;
+					}
+				}
+
 				return;
 			}
 

src/p_mobj.c

@@ -12443,8 +12443,14 @@ void P_SprayCanInit(mobj_t* mobj)
 	// Prevent footguns - these won't persist when custom levels are unloaded
 	else if (gamemap-1 < basenummapheaders)
 	{
-		// Unassigned, get the next grabbable colour
+		// Unassigned, get the next grabbable colour (offset by threshold)
 		can_id = gamedata->gotspraycans;
+
+		// It's ok if this goes over gamedata->numspraycans, as they're
+		// capped below in this func... but NEVER let this go backwards!!
+		if (mobj->threshold != 0)
+			can_id += (mobj->threshold & UINT8_MAX);
+
 		mobj->renderflags = 0;
 	}
 
@@ -12920,17 +12926,15 @@ static boolean P_SetupSpawnedMapThing(mapthing_t *mthing, mobj_t *mobj)
 	}
 	case MT_SPRAYCAN:
 	{
-		if (nummapspraycans)
+		if (nummapspraycans == UINT8_MAX)
 		{
-			if (nummapspraycans != UINT8_MAX)
-				nummapspraycans++;
-
 			P_RemoveMobj(mobj);
 			return false;
 		}
 
 		P_SetScale(mobj, mobj->destscale = 2*mobj->scale);
 
+		mobj->threshold = nummapspraycans;
 		P_SprayCanInit(mobj);
 		nummapspraycans++;
 		break;

src/p_setup.c

@@ -816,7 +816,8 @@ static void P_SpawnMapThings(boolean spawnemblems)
 
 	Z_Free(loopends);
 
-	if (spawnemblems)
+	if (spawnemblems
+		&& gametype != GT_TUTORIAL)
 	{
 		const UINT8 recommendedcans =
 #ifdef DEVELOP