Merge branch 'ring-burst-reverse-gravity' into 'master'

Fix caltrop dropping in reverse gravity as well as not disappearing under some slope conditions

See merge request KartKrew/Kart!388

src/p_inter.c

@@ -2138,7 +2138,6 @@ boolean P_DamageMobj(mobj_t *target, mobj_t *inflictor, mobj_t *source, INT32 da
 static void P_FlingBurst
 (		player_t *player,
 		angle_t fa,
-		fixed_t z,
 		mobjtype_t objType,
 		tic_t objFuse,
 		fixed_t objScale,
@@ -2149,18 +2148,17 @@ static void P_FlingBurst
 	fixed_t momxy = 5<<FRACBITS, momz = 12<<FRACBITS; // base horizonal/vertical thrusts
 	INT32 mx = (i + 1) >> 1;
 
-	z = player->mo->z;
-	if (player->mo->eflags & MFE_VERTICALFLIP)
-		z += player->mo->height - mobjinfo[objType].height;
-
-	mo = P_SpawnMobj(player->mo->x, player->mo->y, z, objType);
+	mo = P_SpawnMobjFromMobj(player->mo, 0, 0, 0, objType);
 
 	mo->threshold = 10; // not useful for spikes
 	mo->fuse = objFuse;
 	P_SetTarget(&mo->target, player->mo);
 
-	mo->destscale = objScale;
-	P_SetScale(mo, objScale);
+	if (objScale != FRACUNIT)
+	{
+		P_SetScale(mo, FixedMul(objScale, mo->scale));
+		mo->destscale = mo->scale;
+	}
 
 	/*
 	0: 0
@@ -2197,7 +2195,6 @@ void P_PlayerRingBurst(player_t *player, INT32 num_rings)
 	INT32 num_fling_rings;
 	INT32 i;
 	angle_t fa;
-	fixed_t z;
 
 	// Rings shouldn't be in Battle!
 	if (gametyperules & GTR_SPHERES)
@@ -2223,19 +2220,13 @@ void P_PlayerRingBurst(player_t *player, INT32 num_rings)
 	// determine first angle
 	fa = player->mo->angle + ((P_RandomByte() & 1) ? -ANGLE_90 : ANGLE_90);
 
-	z = player->mo->z;
-	if (player->mo->eflags & MFE_VERTICALFLIP)
-		z += player->mo->height - mobjinfo[MT_RING].height;
-
 	for (i = 0; i < num_fling_rings; i++)
 	{
-		P_FlingBurst(player, fa, z,
-				MT_FLINGRING, 60*TICRATE, player->mo->scale, i);
+		P_FlingBurst(player, fa, MT_FLINGRING, 60*TICRATE, FRACUNIT, i);
 	}
 
 	while (i < num_rings)
 	{
-		P_FlingBurst(player, fa, z,
-				MT_DEBTSPIKE, 0, 3 * player->mo->scale / 2, i++);
+		P_FlingBurst(player, fa, MT_DEBTSPIKE, 0, 3 * FRACUNIT / 2, i++);
 	}
 }

src/p_local.h

@@ -158,6 +158,7 @@ boolean P_IsObjectInGoop(mobj_t *mo);
 boolean P_IsObjectOnGround(mobj_t *mo);
 boolean P_IsObjectOnGroundIn(mobj_t *mo, sector_t *sec);
 boolean P_IsObjectOnRealGround(mobj_t *mo, sector_t *sec); // SRB2Kart
+#define P_IsObjectFlipped(o) ((o)->eflags & MFE_VERTICALFLIP)
 boolean P_InQuicksand(mobj_t *mo);
 boolean P_PlayerHitFloor(player_t *player, boolean dorollstuff);
 
@@ -521,5 +522,9 @@ void P_Thrust(mobj_t *mo, angle_t angle, fixed_t move);
 void P_ExplodeMissile(mobj_t *mo);
 void P_CheckGravity(mobj_t *mo, boolean affect);
 void P_SetPitchRollFromSlope(mobj_t *mo, pslope_t *slope);
+fixed_t P_ScaleFromMap(fixed_t n, fixed_t scale);
+fixed_t P_GetMobjHead(const mobj_t *);
+fixed_t P_GetMobjFeet(const mobj_t *);
+fixed_t P_GetMobjGround(const mobj_t *);
 
 #endif // __P_LOCAL__

src/p_mobj.c

@@ -2296,11 +2296,6 @@ boolean P_ZMovement(mobj_t *mo)
 		{
 			mom.x = mom.y = 0;
 			mom.z = -mom.z/2;
-
-			if (mo->fuse == 0)
-			{
-				mo->fuse = 90;
-			}
 		}
 		else if (mo->flags & MF_MISSILE)
 		{
@@ -6267,6 +6262,12 @@ static boolean P_MobjRegularThink(mobj_t *mobj)
 		else
 			A_AttractChase(mobj);
 		break;
+	case MT_DEBTSPIKE:
+		if (mobj->fuse == 0 && P_GetMobjFeet(mobj) == P_GetMobjGround(mobj))
+		{
+			mobj->fuse = 90;
+		}
+		break;
 	case MT_EMBLEM:
 		if (mobj->flags2 & MF2_NIGHTSPULL)
 			P_NightsItemChase(mobj);
@@ -12748,6 +12749,15 @@ void P_FlashPal(player_t *pl, UINT16 type, UINT16 duration)
 	pl->flashpal = type;
 }
 
+//
+// P_ScaleFromMap
+// Scales a number relative to the mapobjectscale.
+//
+fixed_t P_ScaleFromMap(fixed_t n, fixed_t scale)
+{
+	return FixedMul(n, FixedDiv(scale, mapobjectscale));
+}
+
 //
 // P_SpawnMobjFromMobj
 // Spawns an object with offsets relative to the position of another object.
@@ -12765,16 +12775,40 @@ mobj_t *P_SpawnMobjFromMobj(mobj_t *mobj, fixed_t xofs, fixed_t yofs, fixed_t zo
 	if (!newmobj)
 		return NULL;
 
+	newmobj->destscale = P_ScaleFromMap(mobj->destscale, newmobj->destscale);
+	P_SetScale(newmobj, P_ScaleFromMap(mobj->scale, newmobj->scale));
+
 	if (mobj->eflags & MFE_VERTICALFLIP)
 	{
-		fixed_t elementheight = FixedMul(newmobj->info->height, mobj->scale);
-
 		newmobj->eflags |= MFE_VERTICALFLIP;
 		newmobj->flags2 |= MF2_OBJECTFLIP;
-		newmobj->z = mobj->z + mobj->height - zofs - elementheight;
+		newmobj->z = mobj->z + mobj->height - zofs - newmobj->height;
 	}
 
-	newmobj->destscale = mobj->destscale;
-	P_SetScale(newmobj, mobj->scale);
 	return newmobj;
 }
+
+//
+// P_GetMobjHead & P_GetMobjFeet
+// Returns the top and bottom of an object, follows appearance, not physics,
+// in reverse gravity.
+//
+
+fixed_t P_GetMobjHead(const mobj_t *mobj)
+{
+	return P_IsObjectFlipped(mobj) ? mobj->z : mobj->z + mobj->height;
+}
+
+fixed_t P_GetMobjFeet(const mobj_t *mobj)
+{
+	return P_IsObjectFlipped(mobj) ? mobj->z + mobj->height : mobj->z;
+}
+
+//
+// P_GetMobjGround
+// Returns the object's floor, or ceiling in reverse gravity.
+//
+fixed_t P_GetMobjGround(const mobj_t *mobj)
+{
+	return P_IsObjectFlipped(mobj) ? mobj->ceilingz : mobj->floorz;
+}