FF_VERTICALFLIP, since I've been messing around with sprite stuff.

* flips the sprite ala MFE_VERTICALFLIP except you don't need to flip the direction of gravity for the object just to draw upside down
* stacks properly with reverse gravity

src/dehacked.c

@@ -7046,6 +7046,7 @@ struct {
 
 	// Frame settings
 	{"FF_FRAMEMASK",FF_FRAMEMASK},
+	{"FF_VERTICALFLIP",FF_VERTICALFLIP},
 	{"FF_PAPERSPRITE",FF_PAPERSPRITE},
 	{"FF_ANIMATE",FF_ANIMATE},
 	{"FF_FULLBRIGHT",FF_FULLBRIGHT},

src/hardware/hw_main.c

@@ -5040,6 +5040,8 @@ static void HWR_ProjectSprite(mobj_t *thing)
 	size_t lumpoff;
 	unsigned rot;
 	UINT8 flip;
+	boolean vflip = (!(thing->eflags & MFE_VERTICALFLIP) != !(thing->frame & FF_VERTICALFLIP));
+
 	angle_t ang;
 	INT32 heightsec, phs;
 
@@ -5139,7 +5141,7 @@ static void HWR_ProjectSprite(mobj_t *thing)
 	tx += FIXED_TO_FLOAT(spritecachedinfo[lumpoff].width) * this_scale;
 	x2 = gr_windowcenterx + (tx * gr_centerx / tz);
 
-	if (thing->eflags & MFE_VERTICALFLIP)
+	if (vflip)
 	{
 		gz = FIXED_TO_FLOAT(thing->z+thing->height) - FIXED_TO_FLOAT(spritecachedinfo[lumpoff].topoffset) * this_scale;
 		gzt = gz + FIXED_TO_FLOAT(spritecachedinfo[lumpoff].height) * this_scale;
@@ -5216,10 +5218,7 @@ static void HWR_ProjectSprite(mobj_t *thing)
 	//CONS_Debug(DBG_RENDER, "------------------\nH: sprite  : %d\nH: frame   : %x\nH: type    : %d\nH: sname   : %s\n\n",
 	//            thing->sprite, thing->frame, thing->type, sprnames[thing->sprite]);
 
-	if (thing->eflags & MFE_VERTICALFLIP)
-		vis->vflip = true;
-	else
-		vis->vflip = false;
+	vis->vflip = vflip;
 
 	vis->precip = false;
 }

src/hardware/hw_md2.c

@@ -1230,7 +1230,7 @@ void HWR_DrawMD2(gr_vissprite_t *spr)
 		UINT32 durs = spr->mobj->state->tics;
 		UINT32 tics = spr->mobj->tics;
 		md2_frame_t *curr, *next = NULL;
-		const UINT8 flip = (UINT8)((spr->mobj->eflags & MFE_VERTICALFLIP) == MFE_VERTICALFLIP);
+		const UINT8 flip = (UINT8)(!(spr->mobj->eflags & MFE_VERTICALFLIP) != !(spr->mobj->frame & FF_VERTICALFLIP));
 		spritedef_t *sprdef;
 		spriteframe_t *sprframe;
 		float finalscale;
@@ -1345,7 +1345,7 @@ void HWR_DrawMD2(gr_vissprite_t *spr)
 		p.x = FIXED_TO_FLOAT(spr->mobj->x);
 		p.y = FIXED_TO_FLOAT(spr->mobj->y)+md2->offset;
 
-		if (spr->mobj->eflags & MFE_VERTICALFLIP)
+		if (flip)
 			p.z = FIXED_TO_FLOAT(spr->mobj->z + spr->mobj->height);
 		else
 			p.z = FIXED_TO_FLOAT(spr->mobj->z);

src/p_pspr.h

@@ -37,6 +37,8 @@
 
 /// \brief Frame flags: only the frame number
 #define FF_FRAMEMASK 0x1ff
+/// \brief Frame flags: Flip sprite vertically (relative to what it should be for its gravity)
+#define FF_VERTICALFLIP 0x400
 /// \brief Frame flags: Thin, paper-like sprite (for collision equivalent, see MF_PAPERCOLLISION)
 #define FF_PAPERSPRITE 0x800
 /// \brief Frame flags: Simple stateless animation

src/r_things.c

@@ -1114,6 +1114,7 @@ static void R_ProjectSprite(mobj_t *thing)
 
 	size_t rot;
 	UINT8 flip;
+	boolean vflip = (!(thing->eflags & MFE_VERTICALFLIP) != !(thing->frame & FF_VERTICALFLIP));
 
 	INT32 lindex;
 
@@ -1123,7 +1124,7 @@ static void R_ProjectSprite(mobj_t *thing)
 	fixed_t iscale;
 	fixed_t scalestep;
 	fixed_t offset, offset2;
-	boolean papersprite = (thing->frame & FF_PAPERSPRITE);
+	boolean papersprite = !!(thing->frame & FF_PAPERSPRITE);
 
 	INT32 dispoffset = thing->info->dispoffset;
 
@@ -1355,7 +1356,7 @@ static void R_ProjectSprite(mobj_t *thing)
 	}
 
 	//SoM: 3/17/2000: Disregard sprites that are out of view..
-	if (thing->eflags & MFE_VERTICALFLIP)
+	if (vflip)
 	{
 		// When vertical flipped, draw sprites from the top down, at least as far as offsets are concerned.
 		// sprite height - sprite topoffset is the proper inverse of the vertical offset, of course.
@@ -1516,10 +1517,7 @@ static void R_ProjectSprite(mobj_t *thing)
 
 	vis->precip = false;
 
-	if (thing->eflags & MFE_VERTICALFLIP)
-		vis->vflip = true;
-	else
-		vis->vflip = false;
+	vis->vflip = vflip;
 
 	vis->isScaled = false;