src/dehacked.c

@@ -8277,6 +8277,7 @@ struct {
 
 	// Frame settings
 	{"FF_FRAMEMASK",FF_FRAMEMASK},
+	{"FF_HORIZONTALFLIP",FF_HORIZONTALFLIP},
 	{"FF_PAPERSPRITE",FF_PAPERSPRITE},
 	{"FF_ANIMATE",FF_ANIMATE},
 	{"FF_FULLBRIGHT",FF_FULLBRIGHT},

src/hardware/hw_drv.h

@@ -49,7 +49,7 @@ EXPORT void HWRAPI(SetSpecialState) (hwdspecialstate_t IdState, INT32 Value);
 
 //Hurdler: added for new development
 
-EXPORT void HWRAPI(DrawModel) (model_t *model, INT32 frameIndex, float duration, float tics, INT32 nextFrameIndex, FTransform *pos, float hscale, float vscale, UINT8 flipped, FSurfaceInfo *Surface);
+EXPORT void HWRAPI(DrawModel) (model_t *model, INT32 frameIndex, float duration, float tics, INT32 nextFrameIndex, FTransform *pos, float hscale, float vscale, UINT8 flipped, UINT8 hflipped, FSurfaceInfo *Surface);
 
 EXPORT void HWRAPI(CreateModelVBOs) (model_t *model);
 EXPORT void HWRAPI(SetTransform) (FTransform *stransform);

src/hardware/hw_main.c

@@ -5505,6 +5505,9 @@ void HWR_ProjectSprite(mobj_t *thing)
 	size_t lumpoff;
 	unsigned rot;
 	UINT8 flip;
+	boolean mirrored = thing->mirrored;
+	boolean hflip = (!(thing->frame & FF_HORIZONTALFLIP) != !mirrored);
+	
 	angle_t ang;
 	const boolean papersprite = (thing->frame & FF_PAPERSPRITE);
 	INT32 heightsec, phs;
@@ -5606,6 +5609,8 @@ void HWR_ProjectSprite(mobj_t *thing)
 #endif
 
 	ang = R_PointToAngle (interp.x, interp.y) - interp.angle;
+	if (mirrored)
+		ang = InvAngle(ang);
 
 	if (sprframe->rotate == SRF_SINGLE)
 	{
@@ -5710,6 +5715,8 @@ void HWR_ProjectSprite(mobj_t *thing)
 
 	this_xscale = spritexscale * this_scale;
 	this_yscale = spriteyscale * this_scale;
+	
+	flip = !flip != !hflip;
 
 	if (flip)
 	{

src/hardware/hw_md2.c

@@ -1149,6 +1149,7 @@ void HWR_DrawMD2(gr_vissprite_t *spr)
 		INT32 tics = spr->mobj->tics;
 		//mdlframe_t *next = NULL;
 		const UINT8 flip = (UINT8)((spr->mobj->eflags & MFE_VERTICALFLIP) == MFE_VERTICALFLIP);
+		const UINT8 hflip = (UINT8)(!(spr->mobj->mirrored) != !(spr->mobj->frame & FF_HORIZONTALFLIP));
 		spritedef_t *sprdef;
 		spriteframe_t *sprframe;
 		spriteinfo_t *sprinfo;
@@ -1435,7 +1436,7 @@ void HWR_DrawMD2(gr_vissprite_t *spr)
 			p.y += ox * gr_viewcos;
 			p.z += oy;
 
-			HWD.pfnDrawModel(md2->model, frame, durs, tics, nextFrame, &p, md2->scale * xs, md2->scale * ys, flip, &Surf);
+			HWD.pfnDrawModel(md2->model, frame, durs, tics, nextFrame, &p, md2->scale * xs, md2->scale * ys, flip, hflip, &Surf);
 		}
 	}
 }

src/hardware/r_opengl/r_opengl.c

@@ -3552,7 +3552,7 @@ EXPORT void HWRAPI(CreateModelVBOs) (model_t *model)
 
 #define BUFFER_OFFSET(i) ((char*)(i))
 
-static void DrawModelEx(model_t *model, INT32 frameIndex, float duration, float tics, INT32 nextFrameIndex, FTransform *pos, float hscale, float vscale, UINT8 flipped, FSurfaceInfo *Surface)
+static void DrawModelEx(model_t *model, INT32 frameIndex, float duration, float tics, INT32 nextFrameIndex, FTransform *pos, float hscale, float vscale, UINT8 flipped, UINT8 hflipped, FSurfaceInfo *Surface)
 {
 	static GLRGBAFloat poly = {0,0,0,0};
 	static GLRGBAFloat tint = {0,0,0,0};
@@ -3613,12 +3613,13 @@ static void DrawModelEx(model_t *model, INT32 frameIndex, float duration, float
 	pglEnable(GL_NORMALIZE);
 
 #ifdef USE_FTRANSFORM_MIRROR
-	// flipped is if the object is flipped
+	// flipped is if the object is vertically flipped
+	// hflipped is if the object is horizontally flipped
 	// pos->flip is if the screen is flipped vertically
 	// pos->mirror is if the screen is flipped horizontally
 	// XOR all the flips together to figure out what culling to use!
 	{
-		boolean reversecull = (flipped ^ pos->flip ^ pos->mirror);
+		boolean reversecull = (flipped ^ hflipped ^ pos->flip ^ pos->mirror);
 		if (reversecull)
 			pglCullFace(GL_FRONT);
 		else
@@ -3626,7 +3627,7 @@ static void DrawModelEx(model_t *model, INT32 frameIndex, float duration, float
 	}
 #else
 	// pos->flip is if the screen is flipped too
-	if (flipped != pos->flip) // If either are active, but not both, invert the model's culling
+	if (flipped ^ hflipped ^ pos->flip) // If one or three of these are active, but not two, invert the model's culling
 		pglCullFace(GL_FRONT);
 	else
 		pglCullFace(GL_BACK);
@@ -3636,6 +3637,8 @@ static void DrawModelEx(model_t *model, INT32 frameIndex, float duration, float
 	pglTranslatef(pos->x, pos->z, pos->y);
 	if (flipped)
 		scaley = -scaley;
+	if (hflipped)
+		scalez = -scalez;
 #ifdef USE_FTRANSFORM_ANGLEZ
 	pglRotatef(pos->anglez, 0.0f, 0.0f, -1.0f); // rotate by slope from Kart
 #endif
@@ -3764,9 +3767,9 @@ static void DrawModelEx(model_t *model, INT32 frameIndex, float duration, float
 // -----------------+
 // HWRAPI DrawModel : Draw a model
 // -----------------+
-EXPORT void HWRAPI(DrawModel) (model_t *model, INT32 frameIndex, float duration, float tics, INT32 nextFrameIndex, FTransform *pos, float hscale, float vscale, UINT8 flipped, FSurfaceInfo *Surface)
+EXPORT void HWRAPI(DrawModel) (model_t *model, INT32 frameIndex, float duration, float tics, INT32 nextFrameIndex, FTransform *pos, float hscale, float vscale, UINT8 flipped, UINT8 hflipped, FSurfaceInfo *Surface)
 {
-	DrawModelEx(model, frameIndex, duration, tics, nextFrameIndex, pos, hscale, vscale, flipped, Surface);
+	DrawModelEx(model, frameIndex, duration, tics, nextFrameIndex, pos, hscale, vscale, flipped, hflipped, Surface);
 }
 
 // -----------------+

src/lua_mobjlib.c

@@ -143,6 +143,7 @@ static const udata_field_t mobj_fields[] = {
     FIELD(mobj_t, cvmem,               udatalib_getter_int32,      udatalib_setter_int32),
     FIELD(mobj_t, standingslope,       udatalib_getter_slope,      mobj_standingslope_noset),
     FIELD(mobj_t, colorized,           udatalib_getter_boolean,    udatalib_setter_boolean),
+	FIELD(mobj_t, mirrored,           udatalib_getter_boolean,    udatalib_setter_boolean),
     FIELD(mobj_t, rollmodel,           udatalib_getter_boolean,    udatalib_setter_boolean),
     { NULL },
 };

src/p_mobj.h

@@ -395,6 +395,7 @@ typedef struct mobj_s
 
 	boolean resetinterp; // if true, some fields should not be interpolated (see R_InterpolateMobjState implementation)
 	boolean colorized; // Whether the mobj uses the rainbow colormap
+	boolean mirrored; // The object's rotations will be mirrored left to right, e.g., see frame AL from the right and AR from the left
 	boolean rollmodel; // OpenGL: Should this model rotate?
 
 	tic_t slamsoundtimer;

src/p_pspr.h

@@ -37,6 +37,8 @@
 
 /// \brief Frame flags: only the frame number
 #define FF_FRAMEMASK 0x1ff
+/// \brief Frame flags: Flip sprite horizontally
+#define FF_HORIZONTALFLIP 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/p_saveg.c

@@ -1990,6 +1990,8 @@ static void LoadMobjThinker(actionf_p1 thinker)
 	mobj->stretchslam = 0;
 	mobj->slamsoundtimer = 0;
 	
+	mobj->mirrored = 0;
+	
 	mobj->z = z;
 	mobj->floorz = floorz;
 	mobj->ceilingz = ceilingz;

src/r_things.c

@@ -1315,9 +1315,10 @@ static void R_ProjectSprite(mobj_t *thing)
 
 	size_t rot;
 	UINT8 flip;
-	/*boolean vflip = (!(thing->eflags & MFE_VERTICALFLIP) != !R_ThingVerticallyFlipped(thing));
+	/*boolean vflip = (!(thing->eflags & MFE_VERTICALFLIP) != !R_ThingVerticallyFlipped(thing));*/
+	
 	boolean mirrored = thing->mirrored;
-	boolean hflip = (!R_ThingHorizontallyFlipped(thing) != !mirrored);*/
+	boolean hflip = (!(thing->frame & FF_HORIZONTALFLIP) != !mirrored);
 
 	INT32 lindex;
 
@@ -1445,6 +1446,8 @@ static void R_ProjectSprite(mobj_t *thing)
 	if (sprframe->rotate != SRF_SINGLE || papersprite)
 	{
 		ang = R_PointToAngle (interp.x, interp.y) - interp.angle;
+		if (mirrored)
+			ang = InvAngle(ang);
 		if (papersprite)
 			ang_scale = abs(FINESINE(ang>>ANGLETOFINESHIFT));
 	}
@@ -1539,6 +1542,8 @@ static void R_ProjectSprite(mobj_t *thing)
 		spr_offset += interp.spritexoffset * flipoffset;
 		spr_topoffset += interp.spriteyoffset * flipoffset;
 	}
+	
+	flip = !flip != !hflip;
 
 	if (flip)
 		offset = spr_offset - spr_width;