Add reversed weather

- Negative speed weather will spawn from a floor in a sector with a sky ceiling, and go up into the ceiling.
- (Not really the same as reverse gravity weather in that aspect, because that would be for sky floors.)
- Fixed invert precipitation flag for linedef type 8 being completely unimplemented. (How long has it been like this...?)
- Fix swapping weather on the fly having reversed momz

src/p_local.h

@@ -277,6 +277,7 @@ void P_RespawnSpecials(void);
 
 mobj_t *P_SpawnMobj(fixed_t x, fixed_t y, fixed_t z, mobjtype_t type);
 
+void P_CalculatePrecipFloor(precipmobj_t *mobj);
 void P_RecalcPrecipInSector(sector_t *sector);
 void P_PrecipitationEffects(void);
 

src/p_mobj.c

@@ -3760,19 +3760,22 @@ animonly:
 	P_CyclePlayerMobjState(mobj);
 }
 
-static void CalculatePrecipFloor(precipmobj_t *mobj)
+void P_CalculatePrecipFloor(precipmobj_t *mobj)
 {
 	// recalculate floorz each time
 	const sector_t *mobjsecsubsec;
+
 	if (mobj && mobj->subsector && mobj->subsector->sector)
 		mobjsecsubsec = mobj->subsector->sector;
 	else
 		return;
+
 	mobj->floorz = P_GetSectorFloorZAt(mobjsecsubsec, mobj->x, mobj->y);
+
 	if (mobjsecsubsec->ffloors)
 	{
 		ffloor_t *rover;
-		fixed_t topheight;
+		fixed_t height;
 
 		for (rover = mobjsecsubsec->ffloors; rover; rover = rover->next)
 		{
@@ -3783,9 +3786,9 @@ static void CalculatePrecipFloor(precipmobj_t *mobj)
 			if (!(rover->flags & FF_BLOCKOTHERS) && !(rover->flags & FF_SWIMMABLE))
 				continue;
 
-			topheight = P_GetFFloorTopZAt(rover, mobj->x, mobj->y);
+			height = P_GetFFloorTopZAt(rover, mobj->x, mobj->y);
-			if (topheight > mobj->floorz)
+			if (height > mobj->floorz)
-				mobj->floorz = topheight;
+				mobj->floorz = height;
 		}
 	}
 }
@@ -3800,7 +3803,7 @@ void P_RecalcPrecipInSector(sector_t *sector)
 	sector->moved = true; // Recalc lighting and things too, maybe
 
 	for (psecnode = sector->touching_preciplist; psecnode; psecnode = psecnode->m_thinglist_next)
-		CalculatePrecipFloor(psecnode->m_thing);
+		P_CalculatePrecipFloor(psecnode->m_thing);
 }
 
 //
@@ -3817,13 +3820,15 @@ void P_NullPrecipThinker(precipmobj_t *mobj)
 
 void P_PrecipThinker(precipmobj_t *mobj)
 {
+	boolean flip = (mobj->precipflags & PCF_FLIP);
+
 	P_CycleStateAnimation((mobj_t *)mobj);
 
 	if (mobj->state == &states[S_RAINRETURN])
 	{
 		// Reset to ceiling!
 		P_SetPrecipMobjState(mobj, mobj->info->spawnstate);
-		mobj->z = mobj->ceilingz;
+		mobj->z = (flip) ? (mobj->floorz) : (mobj->ceilingz);
 		mobj->momz = -mobj->info->speed;
 		mobj->precipflags &= ~PCF_SPLASH;
 		R_ResetPrecipitationMobjInterpolationState(mobj);
@@ -3858,18 +3863,20 @@ void P_PrecipThinker(precipmobj_t *mobj)
 	if (mobj->precipflags & PCF_SPLASH)
 		return;
 
+	mobj->z += mobj->momz;
+
 	// adjust height
-	if ((mobj->z += mobj->momz) <= mobj->floorz)
+	if ((flip) ? (mobj->z >= mobj->ceilingz) : (mobj->z <= mobj->floorz))
 	{
 		if ((mobj->info->deathstate == S_NULL) || (mobj->precipflags & PCF_PIT)) // no splashes on sky or bottomless pits
 		{
-			mobj->z = mobj->ceilingz;
+			mobj->z = (flip) ? (mobj->floorz) : (mobj->ceilingz);
 			R_ResetPrecipitationMobjInterpolationState(mobj);
 		}
 		else
 		{
 			P_SetPrecipMobjState(mobj, mobj->info->deathstate);
-			mobj->z = mobj->floorz;
+			mobj->z = (flip) ? (mobj->ceilingz) : (mobj->floorz);
 			mobj->precipflags |= PCF_SPLASH;
 			R_ResetPrecipitationMobjInterpolationState(mobj);
 		}
@@ -10341,8 +10348,8 @@ static precipmobj_t *P_SpawnPrecipMobj(fixed_t x, fixed_t y, fixed_t z, mobjtype
 {
 	const mobjinfo_t *info = &mobjinfo[type];
 	state_t *st;
+	fixed_t start_z = INT32_MIN;
 	precipmobj_t *mobj = Z_Calloc(sizeof (*mobj), PU_LEVEL, NULL);
-	fixed_t starting_floorz;
 
 	mobj->type = type;
 	mobj->info = info;
@@ -10364,8 +10371,8 @@ static precipmobj_t *P_SpawnPrecipMobj(fixed_t x, fixed_t y, fixed_t z, mobjtype
 	// set subsector and/or block links
 	P_SetPrecipitationThingPosition(mobj);
 
-	mobj->floorz   = starting_floorz = P_GetSectorFloorZAt  (mobj->subsector->sector, x, y);
+	mobj->floorz   = P_GetSectorFloorZAt  (mobj->subsector->sector, x, y);
-	mobj->ceilingz                   = P_GetSectorCeilingZAt(mobj->subsector->sector, x, y);
+	mobj->ceilingz = P_GetSectorCeilingZAt(mobj->subsector->sector, x, y);
 
 	mobj->floorrover = NULL;
 	mobj->ceilingrover = NULL;
@@ -10373,17 +10380,34 @@ static precipmobj_t *P_SpawnPrecipMobj(fixed_t x, fixed_t y, fixed_t z, mobjtype
 	mobj->z = z;
 	mobj->momz = -info->speed;
 
+	if (info->speed < 0)
+	{
+		mobj->precipflags |= PCF_FLIP;
+	}
+
+	start_z = mobj->floorz;
+
 	mobj->thinker.function.acp1 = (actionf_p1)P_NullPrecipThinker;
 	P_AddThinker(THINK_PRECIP, &mobj->thinker);
 
-	CalculatePrecipFloor(mobj);
+	P_CalculatePrecipFloor(mobj);
 
-	if (mobj->floorz != starting_floorz)
+	if (mobj->floorz != start_z)
-		mobj->precipflags |= PCF_FOF;
+	{
-	else if (GETSECSPECIAL(mobj->subsector->sector->special, 1) == 7
+		; //mobj->precipflags |= PCF_FOF;
-	 || GETSECSPECIAL(mobj->subsector->sector->special, 1) == 6
+	}
-	 || mobj->subsector->sector->floorpic == skyflatnum)
+	else
-		mobj->precipflags |= PCF_PIT;
+	{
+		INT32 special = GETSECSPECIAL(mobj->subsector->sector->special, 1);
+		boolean sFlag = (mobj->precipflags & PCF_FLIP) ? (mobj->subsector->sector->flags & SF_FLIPSPECIAL_CEILING) : (mobj->subsector->sector->flags & SF_FLIPSPECIAL_FLOOR);
+		boolean pitFloor = ((special == 6 || special == 7) && sFlag);
+		boolean skyFloor = (mobj->precipflags & PCF_FLIP) ? (mobj->subsector->sector->ceilingpic == skyflatnum) : (mobj->subsector->sector->floorpic == skyflatnum);
+
+		if (pitFloor || skyFloor)
+		{
+			mobj->precipflags |= PCF_PIT;
+		}
+	}
 
 	R_ResetPrecipitationMobjInterpolationState(mobj);
 
@@ -10588,13 +10612,19 @@ consvar_t cv_itemrespawn = CVAR_INIT ("respawnitem", "On", CV_NETVAR, CV_OnOff,
 void P_SpawnPrecipitation(void)
 {
 	INT32 i, j, k;
-	mobjtype_t type = precipprops[curWeather].type;
+
-	UINT8 randomstates = (UINT8)mobjinfo[type].damage;
+	const mobjtype_t type = precipprops[curWeather].type;
+	const UINT8 randomstates = (UINT8)mobjinfo[type].damage;
+	const boolean flip = (mobjinfo[type].speed < 0);
+
 	fixed_t basex, basey, x, y, z, height;
+	UINT16 numparticles = 0;
+	boolean condition = false;
+
 	subsector_t *precipsector = NULL;
 	precipmobj_t *rainmo = NULL;
 
-	if (dedicated || !cv_drawdist_precip.value || curWeather == PRECIP_NONE) // SRB2Kart
+	if (dedicated || !cv_drawdist_precip.value || type == MT_NULL)
 		return;
 
 	// Use the blockmap to narrow down our placing patterns
@@ -10603,58 +10633,63 @@ void P_SpawnPrecipitation(void)
 		basex = bmaporgx + (i % bmapwidth) * MAPBLOCKSIZE;
 		basey = bmaporgy + (i / bmapwidth) * MAPBLOCKSIZE;
 
+		x = basex + ((M_RandomKey(MAPBLOCKUNITS << 3) << FRACBITS) >> 3);
+		y = basey + ((M_RandomKey(MAPBLOCKUNITS << 3) << FRACBITS) >> 3);
+
+		precipsector = R_PointInSubsectorOrNull(x, y);
+
+		// No sector? Stop wasting time,
+		// move on to the next entry in the blockmap
+		if (!precipsector)
+			continue;
+
+		// Not in a sector with visible sky?
+		condition = (precipsector->sector->ceilingpic == skyflatnum);
+
+		if (precipsector->sector->flags & SF_INVERTPRECIP)
 		{
-			UINT16 numparticles = 0;
+			condition = !condition;
+		}
 
-			x = basex + ((M_RandomKey(MAPBLOCKUNITS<<3)<<FRACBITS)>>3);
+		if (!condition)
-			y = basey + ((M_RandomKey(MAPBLOCKUNITS<<3)<<FRACBITS)>>3);
+		{
+			continue;
+		}
 
-			precipsector = R_PointInSubsectorOrNull(x, y);
+		height = precipsector->sector->ceilingheight - precipsector->sector->floorheight;
 
-			// No sector? Stop wasting time,
+		// Exists, but is too small for reasonable precipitation.
-			// move on to the next entry in the blockmap
+		if (height < 64<<FRACBITS)
-			if (!precipsector)
+			continue;
-				continue;
 
-			// Not in a sector with visible sky?
+		// Hack around a quirk of this entire system, where taller sectors look like they get less precipitation.
-			if (precipsector->sector->ceilingpic != skyflatnum)
+		numparticles = 1 + (height / (MAPBLOCKUNITS<<4<<FRACBITS));
-				continue;
 
-			height = precipsector->sector->ceilingheight - precipsector->sector->floorheight;
+		// Don't set z properly yet...
+		z = (flip) ? (precipsector->sector->floorheight) : (precipsector->sector->ceilingheight);
 
-			// Exists, but is too small for reasonable precipitation.
+		for (j = 0; j < numparticles; j++)
-			if (height < 64<<FRACBITS)
+		{
-				continue;
+			rainmo = P_SpawnPrecipMobj(x, y, z, type);
 
-			// Hack around a quirk of this entire system, where taller sectors look like they get less precipitation.
+			if (randomstates > 0)
-			numparticles = 1 + (height / (MAPBLOCKUNITS<<4<<FRACBITS));
-
-			// Don't set z properly yet...
-			z = precipsector->sector->ceilingheight;
-
-			for (j = 0; j < numparticles; j++)
 			{
-				rainmo = P_SpawnPrecipMobj(x, y, z, type);
+				UINT8 mrand = M_RandomByte();
+				UINT8 threshold = UINT8_MAX / (randomstates + 1);
+				statenum_t st = mobjinfo[type].spawnstate;
 
-				if (randomstates > 0)
+				for (k = 0; k < randomstates; k++)
 				{
-					UINT8 mrand = M_RandomByte();
+					if (mrand < (threshold * (k+1)))
-					UINT8 threshold = UINT8_MAX / (randomstates + 1);
-					statenum_t st = mobjinfo[type].spawnstate;
-
-					for (k = 0; k < randomstates; k++)
 					{
-						if (mrand < (threshold * (k+1)))
+						P_SetPrecipMobjState(rainmo, st+k+1);
-						{
+						break;
-							P_SetPrecipMobjState(rainmo, st+k+1);
-							break;
-						}
 					}
 				}
-
-				// Randomly assign a height, now that floorz is set.
-				rainmo->z = M_RandomRange(rainmo->floorz>>FRACBITS, rainmo->ceilingz>>FRACBITS)<<FRACBITS;
 			}
+
+			// Randomly assign a height, now that floorz is set.
+			rainmo->z = M_RandomRange(rainmo->floorz >> FRACBITS, rainmo->ceilingz >> FRACBITS) << FRACBITS;
 		}
 	}
 }

src/p_mobj.h

@@ -262,12 +262,11 @@ typedef enum
 // PRECIPITATION flags ?! ?! ?!
 //
 typedef enum {
-	PCF_INVISIBLE = 1, // Don't draw.
+	PCF_THUNK		= 1,		// Ran the thinker this tic.
-	PCF_PIT       = 1<<1, // Above pit.
+	PCF_SPLASH		= 1<<1,		// Splashed on the ground, return to the ceiling after the animation's over
-	PCF_FOF       = 1<<2, // Above FOF.
+	PCF_INVISIBLE	= 1<<2,		// Don't draw.
-	PCF_MOVINGFOF = 1<<3, // Above MOVING FOF (this means we need to keep floorz up to date...)
+	PCF_PIT			= 1<<3,		// Above pit.
-	PCF_SPLASH    = 1<<4, // Splashed on the ground, return to the ceiling after the animation's over
+	PCF_FLIP		= 1<<4,		// Spawning from floor, moving upwards.
-	PCF_THUNK     = 1<<5, // Ran the thinker this tic.
 } precipflag_t;
 
 // Map Object definition.

src/p_spec.c

@@ -1851,8 +1851,13 @@ void P_SwitchWeather(preciptype_t newWeather)
 			precipmobj->sprite = precipmobj->state->sprite;
 			precipmobj->frame = precipmobj->state->frame;
 
-			precipmobj->momz = mobjinfo[swap].speed;
+			precipmobj->momz = -mobjinfo[swap].speed;
-			precipmobj->precipflags &= ~PCF_INVISIBLE;
+			precipmobj->precipflags &= ~(PCF_INVISIBLE|PCF_FLIP);
+
+			if (precipmobj->momz > 0)
+			{
+				precipmobj->precipflags |= PCF_FLIP;
+			}
 		}
 	}