diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index 7ed763d56b..e800d8448c 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -1,4 +1,16 @@
 March 21, 2008 (Changes by Graf Zahl)
+- Disabled scrolling of 3DMIDTEX textures. Due to the special needs this 
+  cannot work properly.
+- Added new Scroll_Wall special to allow more control over wall scrolling.
+  Since it uses fixed point parameters it can only be used in scripts though.
+- Added flags parameters to all wall scroller specials that didn't use
+  all 5 args.
+- Separated scrolling of the 3 different texture parts of a sidedef.
+  While doing this I did some more restructuring of the sidedef structure
+  and changed it so that all state changes to sidedefs that affect rendering 
+  have to be made with access functions. This is not of much use to the
+  software renderer but it allows far easier caching of rendering data
+  for OpenGL because the only place I need to check is in the access functions.
 - Added Karate Chris's ThingCountSector submission.
 - Made texture indices in FSwitchDef full integers. Since that required
   some data restructuring I also eliminated the MAX_FRAMES limit of 128
diff --git a/src/actionspecials.h b/src/actionspecials.h
index 3821b5e3be..9feaa4026a 100644
--- a/src/actionspecials.h
+++ b/src/actionspecials.h
@@ -49,6 +49,7 @@ DEFINE_SPECIAL(Sector_Attach3dMidtex, 48, -1, -1)
 DEFINE_SPECIAL(GlassBreak, 49, 0, 1)
 DEFINE_SPECIAL(ExtraFloor_LightOnly, 50, -1, -1)
 DEFINE_SPECIAL(Sector_SetLink, 51, 4, 4)
+DEFINE_SPECIAL(Scroll_Wall, 52, 5, 5)
 
 DEFINE_SPECIAL(Plat_PerpetualRaise, 60, 3, 3)
 DEFINE_SPECIAL(Plat_Stop, 61, 1, 1)
@@ -128,7 +129,11 @@ DEFINE_SPECIAL(Floor_Waggle, 138, 5, 5)
 DEFINE_SPECIAL(Thing_SpawnFacing, 139, 2, 4)
 DEFINE_SPECIAL(Sector_ChangeSound, 140, 2, 2)
 
-// GZDoom/Vavoom specials (put here so that they don't get accidentally redefined)
+// GZDoom/Vavoom specials 
+// Although ZDoom doesn't support them it's better to have them defined so that
+// WADs using them somewhere can at least be started without aborting due
+// to an error message.
+DEFINE_SPECIAL(FS_Execute, 158, 1, 4)
 DEFINE_SPECIAL(Sector_SetPlaneReflection, 159, 3, 3)
 DEFINE_SPECIAL(Sector_Set3DFloor, 160, -1, -1)
 DEFINE_SPECIAL(Sector_SetContents, 161, -1, -1)
diff --git a/src/decallib.h b/src/decallib.h
index e5e213c586..c829fd11a2 100644
--- a/src/decallib.h
+++ b/src/decallib.h
@@ -46,7 +46,7 @@ class FDecalTemplate;
 struct FDecalAnimator;
 struct PClass;
 class DBaseDecal;
-struct side_s;
+struct side_t;
 
 class FDecalBase
 {
@@ -71,7 +71,7 @@ class FDecalTemplate : public FDecalBase
 public:
 	FDecalTemplate () : Translation (0) {}
 
-	void ApplyToDecal (DBaseDecal *actor, side_s *wall) const;
+	void ApplyToDecal (DBaseDecal *actor, side_t *wall) const;
 	const FDecalTemplate *GetDecal () const;
 	void ReplaceDecalRef (FDecalBase *from, FDecalBase *to);
 
diff --git a/src/g_shared/a_decals.cpp b/src/g_shared/a_decals.cpp
index 811348bc0f..fe125459da 100644
--- a/src/g_shared/a_decals.cpp
+++ b/src/g_shared/a_decals.cpp
@@ -245,7 +245,7 @@ int DBaseDecal::StickToWall (side_t *wall, fixed_t x, fixed_t y)
 			Z -= front->floortexz;
 		else
 			Z -= front->ceilingtexz;
-		tex = wall->midtexture;
+		tex = wall->GetTexture(side_t::mid);
 	}
 	else if (back->floorplane.ZatPoint (x, y) >= Z)
 	{
@@ -254,7 +254,7 @@ int DBaseDecal::StickToWall (side_t *wall, fixed_t x, fixed_t y)
 			Z -= front->ceilingtexz;
 		else
 			Z -= back->floortexz;
-		tex = wall->bottomtexture;
+		tex = wall->GetTexture(side_t::bottom);
 	}
 	else
 	{
@@ -263,7 +263,7 @@ int DBaseDecal::StickToWall (side_t *wall, fixed_t x, fixed_t y)
 			Z -= front->ceilingtexz;
 		else
 			Z -= back->ceilingtexz;
-		tex = wall->toptexture;
+		tex = wall->GetTexture(side_t::top);
 	}
 
 	CalcFracPos (wall, x, y);
diff --git a/src/g_shared/a_sharedglobal.h b/src/g_shared/a_sharedglobal.h
index c8b376ce46..b0accd3fb0 100644
--- a/src/g_shared/a_sharedglobal.h
+++ b/src/g_shared/a_sharedglobal.h
@@ -7,7 +7,7 @@
 
 class FDecalTemplate;
 struct vertex_s;
-struct side_s;
+struct side_t;
 
 extern void P_SpawnDirt (AActor *actor, fixed_t radius);
 
@@ -18,7 +18,7 @@ bool P_MorphMonster (AActor *actor, const PClass *morphClass);
 bool P_UpdateMorphedMonster (AActor *actor);
 
 
-struct side_s;
+struct side_t;
 
 class DBaseDecal : public DThinker
 {
@@ -33,12 +33,12 @@ public:
 
 	void Serialize (FArchive &arc);
 	void Destroy ();
-	int StickToWall (side_s *wall, fixed_t x, fixed_t y);
-	fixed_t GetRealZ (const side_s *wall) const;
+	int StickToWall (side_t *wall, fixed_t x, fixed_t y);
+	fixed_t GetRealZ (const side_t *wall) const;
 	void SetShade (DWORD rgb);
 	void SetShade (int r, int g, int b);
-	void Spread (const FDecalTemplate *tpl, side_s *wall, fixed_t x, fixed_t y, fixed_t z);
-	void GetXY (side_s *side, fixed_t &x, fixed_t &y) const;
+	void Spread (const FDecalTemplate *tpl, side_t *wall, fixed_t x, fixed_t y, fixed_t z);
+	void GetXY (side_t *side, fixed_t &x, fixed_t &y) const;
 
 	static void SerializeChain (FArchive &arc, DBaseDecal **firstptr);
 
@@ -55,12 +55,12 @@ public:
 	FRenderStyle RenderStyle;
 
 protected:
-	virtual DBaseDecal *CloneSelf (const FDecalTemplate *tpl, fixed_t x, fixed_t y, fixed_t z, side_s *wall) const;
-	void CalcFracPos (side_s *wall, fixed_t x, fixed_t y);
+	virtual DBaseDecal *CloneSelf (const FDecalTemplate *tpl, fixed_t x, fixed_t y, fixed_t z, side_t *wall) const;
+	void CalcFracPos (side_t *wall, fixed_t x, fixed_t y);
 	void Remove ();
 
-	static void SpreadLeft (fixed_t r, vertex_s *v1, side_s *feelwall);
-	static void SpreadRight (fixed_t r, side_s *feelwall, fixed_t wallsize);
+	static void SpreadLeft (fixed_t r, vertex_s *v1, side_t *feelwall);
+	static void SpreadRight (fixed_t r, side_t *feelwall, fixed_t wallsize);
 };
 
 class DImpactDecal : public DBaseDecal
@@ -68,10 +68,10 @@ class DImpactDecal : public DBaseDecal
 	DECLARE_CLASS (DImpactDecal, DBaseDecal)
 public:
 	DImpactDecal (fixed_t z);
-	DImpactDecal (side_s *wall, const FDecalTemplate *templ);
+	DImpactDecal (side_t *wall, const FDecalTemplate *templ);
 
-	static DImpactDecal *StaticCreate (const char *name, fixed_t x, fixed_t y, fixed_t z, side_s *wall, PalEntry color=0);
-	static DImpactDecal *StaticCreate (const FDecalTemplate *tpl, fixed_t x, fixed_t y, fixed_t z, side_s *wall, PalEntry color=0);
+	static DImpactDecal *StaticCreate (const char *name, fixed_t x, fixed_t y, fixed_t z, side_t *wall, PalEntry color=0);
+	static DImpactDecal *StaticCreate (const FDecalTemplate *tpl, fixed_t x, fixed_t y, fixed_t z, side_t *wall, PalEntry color=0);
 
 	void BeginPlay ();
 	void Destroy ();
@@ -80,7 +80,7 @@ public:
 	static void SerializeTime (FArchive &arc);
 
 protected:
-	DBaseDecal *CloneSelf (const FDecalTemplate *tpl, fixed_t x, fixed_t y, fixed_t z, side_s *wall) const;
+	DBaseDecal *CloneSelf (const FDecalTemplate *tpl, fixed_t x, fixed_t y, fixed_t z, side_t *wall) const;
 	static void CheckMax ();
 
 private:
diff --git a/src/g_shared/r_interpolate.h b/src/g_shared/r_interpolate.h
new file mode 100644
index 0000000000..3820cb6866
--- /dev/null
+++ b/src/g_shared/r_interpolate.h
@@ -0,0 +1,64 @@
+#ifndef R_INTERPOLATE_H
+#define R_INTERPOLATE_H
+
+#include "doomtype.h"
+
+// BUILD stuff for interpolating between frames, but modified (rather a lot)
+#define INTERPOLATION_BUCKETS 107
+
+
+class FArchive;
+
+enum EInterpType
+{
+	INTERP_SectorFloor,		// Pass a sector_t *
+	INTERP_SectorCeiling,	// Pass a sector_t *
+	INTERP_Vertex,			// Pass a vertex_t *
+	INTERP_FloorPanning,	// Pass a sector_t *
+	INTERP_CeilingPanning,	// Pass a sector_t *
+	INTERP_WallPanning_Top,		// Pass a side_t *
+	INTERP_WallPanning_Mid,
+	INTERP_WallPanning_Bottom,
+};
+
+struct FActiveInterpolation
+{
+	FActiveInterpolation *Next;
+	void *Address;
+	EInterpType Type;
+
+	friend FArchive &operator << (FArchive &arc, FActiveInterpolation *&interp);
+
+	static int CountInterpolations ();
+	static int CountInterpolations (int *usedbuckets, int *minbucketfill, int *maxbucketfill);
+
+private:
+	fixed_t oldipos[2], bakipos[2];
+
+	void CopyInterpToOld();
+	void CopyBakToInterp();
+	void DoAnInterpolation(fixed_t smoothratio);
+
+	static size_t HashKey(EInterpType type, void *interptr);
+	static FActiveInterpolation *FindInterpolation(EInterpType, void *interptr, FActiveInterpolation **&interp_p);
+
+	friend void updateinterpolations();
+	friend void setinterpolation(EInterpType, void *interptr, bool dolinks);
+	friend void stopinterpolation(EInterpType, void *interptr, bool dolinks);
+	friend void dointerpolations(fixed_t smoothratio);
+	friend void restoreinterpolations();
+	friend void clearinterpolations();
+	friend void SerializeInterpolations(FArchive &arc);
+
+	static FActiveInterpolation *curiposhash[INTERPOLATION_BUCKETS];
+};
+
+void updateinterpolations();
+void setinterpolation(EInterpType, void *interptr, bool dolinks = true);
+void stopinterpolation(EInterpType, void *interptr, bool dolinks = true);
+void dointerpolations(fixed_t smoothratio);
+void restoreinterpolations();
+void clearinterpolations();
+void SerializeInterpolations(FArchive &arc);
+
+#endif
\ No newline at end of file
diff --git a/src/g_strife/a_strifeitems.cpp b/src/g_strife/a_strifeitems.cpp
index a2351d9974..6335b823f3 100644
--- a/src/g_strife/a_strifeitems.cpp
+++ b/src/g_strife/a_strifeitems.cpp
@@ -72,8 +72,8 @@ void A_RemoveForceField (AActor *self)
 		{
 			line->flags &= ~(ML_BLOCKING|ML_BLOCKEVERYTHING);
 			line->special = 0;
-			sides[line->sidenum[0]].midtexture = 0;
-			sides[line->sidenum[1]].midtexture = 0;
+			sides[line->sidenum[0]].SetTexture(side_t::mid, 0);
+			sides[line->sidenum[1]].SetTexture(side_t::mid, 0);
 		}
 	}
 }
diff --git a/src/p_3dmidtex.cpp b/src/p_3dmidtex.cpp
index d0c8944d87..a1ca695ab8 100644
--- a/src/p_3dmidtex.cpp
+++ b/src/p_3dmidtex.cpp
@@ -57,8 +57,8 @@ bool P_Scroll3dMidtex(sector_t *sector, int crush, fixed_t move, bool ceiling)
 	{
 		line_t *l = scrollplane.AttachedLines[i];
 
-		sides[l->sidenum[0]].rowoffset += move;
-		sides[l->sidenum[1]].rowoffset += move;
+		sides[l->sidenum[0]].AddTextureYOffset(side_t::mid, move);
+		sides[l->sidenum[1]].AddTextureYOffset(side_t::mid, move);
 	}
 
 	// Second step: Check all sectors whether the move is ok.
@@ -88,8 +88,8 @@ void P_Start3dMidtexInterpolations(sector_t *sector, bool ceiling)
 	{
 		line_t *l = scrollplane.AttachedLines[i];
 
-		setinterpolation(INTERP_WallPanning, &sides[l->sidenum[0]]);
-		setinterpolation(INTERP_WallPanning, &sides[l->sidenum[1]]);
+		sides[l->sidenum[0]].SetInterpolation(side_t::mid);
+		sides[l->sidenum[1]].SetInterpolation(side_t::mid);
 	}
 }
 
@@ -110,8 +110,8 @@ void P_Stop3dMidtexInterpolations(sector_t *sector, bool ceiling)
 	{
 		line_t *l = scrollplane.AttachedLines[i];
 
-		stopinterpolation(INTERP_WallPanning, &sides[l->sidenum[0]]);
-		stopinterpolation(INTERP_WallPanning, &sides[l->sidenum[1]]);
+		sides[l->sidenum[0]].StopInterpolation(side_t::mid);
+		sides[l->sidenum[1]].StopInterpolation(side_t::mid);
 	}
 }
 
@@ -237,28 +237,28 @@ bool P_GetMidTexturePosition(const line_t *line, int sideno, fixed_t *ptextop, f
 {
 	side_t *side = &sides[line->sidenum[sideno]];
 
-	if (line->sidenum[0]==NO_SIDE || line->sidenum[1]==NO_SIDE || !side->midtexture) return false;
+	if (line->sidenum[0]==NO_SIDE || line->sidenum[1]==NO_SIDE || !side->GetTexture(side_t::mid)) return false;
 	
-	FTexture * tex= TexMan(side->midtexture);
+	FTexture * tex= TexMan(side->GetTexture(side_t::mid));
 	if (!tex) return false;
 
-	fixed_t rowoffset = side->rowoffset;
+	fixed_t y_offset = side->GetTextureYOffset(side_t::mid);
 	fixed_t textureheight = tex->GetScaledHeight() << FRACBITS;
 	if (tex->yScale != FRACUNIT && !tex->bWorldPanning)
 	{ 
-		rowoffset = FixedDiv(rowoffset, tex->yScale);
+		y_offset = FixedDiv(y_offset, tex->yScale);
 	}
 
 	if(line->flags & ML_DONTPEGBOTTOM)
 	{
-		*ptexbot = rowoffset +
+		*ptexbot = y_offset +
 				   MAX<fixed_t>(line->frontsector->floortexz, line->backsector->floortexz);
 
 		*ptextop = *ptexbot + textureheight;
 	}
 	else
 	{
-		*ptextop = rowoffset +
+		*ptextop = y_offset +
 				   MIN<fixed_t>(line->frontsector->ceilingtexz, line->backsector->ceilingtexz);
 		
 		*ptexbot = *ptextop - textureheight;
diff --git a/src/p_acs.cpp b/src/p_acs.cpp
index 73b543f4a3..29fa191bab 100644
--- a/src/p_acs.cpp
+++ b/src/p_acs.cpp
@@ -1945,13 +1945,13 @@ void DLevelScript::SetLineTexture (int lineid, int side, int position, int name)
 		switch (position)
 		{
 		case TEXTURE_TOP:
-			sidedef->toptexture = texture;
+			sidedef->SetTexture(side_t::top, texture);
 			break;
 		case TEXTURE_MIDDLE:
-			sidedef->midtexture = texture;
+			sidedef->SetTexture(side_t::mid, texture);
 			break;
 		case TEXTURE_BOTTOM:
-			sidedef->bottomtexture = texture;
+			sidedef->SetTexture(side_t::bottom, texture);
 			break;
 		default:
 			break;
@@ -1978,9 +1978,14 @@ void DLevelScript::ReplaceTextures (int fromnamei, int tonamei, int flags)
 		{
 			side_t *wal = &sides[i];
 
-			if (!(flags & NOT_BOTTOM) && wal->bottomtexture == picnum1)	wal->bottomtexture = picnum2;
-			if (!(flags & NOT_MIDDLE) && wal->midtexture == picnum1)	wal->midtexture = picnum2;
-			if (!(flags & NOT_TOP) && wal->toptexture == picnum1)		wal->toptexture = picnum2;
+			for(int j=0;j<3;j++)
+			{
+				static BYTE bits[]={NOT_TOP, NOT_MIDDLE, NOT_BOTTOM};
+				if (!(flags & bits[j]) && wal->GetTexture(j) == picnum1)
+				{
+					wal->SetTexture(j, picnum2);
+				}
+			}
 		}
 	}
 	if ((flags ^ (NOT_FLOOR | NOT_CEILING)) != 0)
@@ -4694,7 +4699,7 @@ int DLevelScript::RunScript ()
 		case PCD_GETLINEROWOFFSET:
 			if (activationline)
 			{
-				PushToStack (sides[activationline->sidenum[0]].rowoffset >> FRACBITS);
+				PushToStack (sides[activationline->sidenum[0]].GetTextureYOffset(side_t::mid) >> FRACBITS);
 			}
 			else
 			{
diff --git a/src/p_buildmap.cpp b/src/p_buildmap.cpp
index 8671b28338..589f2d5d82 100644
--- a/src/p_buildmap.cpp
+++ b/src/p_buildmap.cpp
@@ -459,21 +459,22 @@ static void LoadWalls (walltype *walls, int numwalls, sectortype *bsec)
 		walls[i].nextwall = LittleShort(walls[i].nextwall);
 		walls[i].nextsector = LittleShort(walls[i].nextsector);
 
-		sides[i].textureoffset = walls[i].xpanning << FRACBITS;
-		sides[i].rowoffset = walls[i].ypanning << FRACBITS;
+		sides[i].SetTextureXOffset(walls[i].xpanning << FRACBITS);
+		sides[i].SetTextureYOffset(walls[i].ypanning << FRACBITS);
 
-		sides[i].toptexture = sides[i].bottomtexture = pic;
+		sides[i].SetTexture(side_t::top, pic);
+		sides[i].SetTexture(side_t::bottom, pic);
 		if (walls[i].nextsector < 0 || (walls[i].cstat & 32))
 		{
-			sides[i].midtexture = pic;
+			sides[i].SetTexture(side_t::mid, pic);
 		}
 		else if (walls[i].cstat & 16)
 		{
-			sides[i].midtexture = overpic;
+			sides[i].SetTexture(side_t::mid, overpic);
 		}
 		else
 		{
-			sides[i].midtexture = 0;
+			sides[i].SetTexture(side_t::mid, 0);
 		}
 
 		sides[i].TexelLength = walls[i].xrepeat * 8;
diff --git a/src/p_doors.cpp b/src/p_doors.cpp
index 5eb427686b..1d92ed3da8 100644
--- a/src/p_doors.cpp
+++ b/src/p_doors.cpp
@@ -265,8 +265,9 @@ void DDoor::DoorSound (bool raise) const
 				if (line->backsector == NULL)
 					continue;
 
-				texname = TexMan[sides[line->sidenum[0]].toptexture]->Name;
-				if (texname[0] == 'D' && texname[1] == 'O' && texname[2] == 'R')
+				FTexture *tex = TexMan[sides[line->sidenum[0]].GetTexture(side_t::top)];
+				texname = tex? tex->Name : NULL;
+				if (texname != NULL && texname[0] == 'D' && texname[1] == 'O' && texname[2] == 'R')
 				{
 					switch (texname[3])
 					{
@@ -606,11 +607,10 @@ void DAnimatedDoor::Tick ()
 				// IF DOOR NEEDS TO ANIMATE TO NEXT FRAME...
 				m_Timer = m_Speed;
 
-				sides[m_Line1->sidenum[0]].midtexture =
-				sides[m_Line1->sidenum[1]].midtexture =
-				sides[m_Line2->sidenum[0]].midtexture =
-				sides[m_Line2->sidenum[1]].midtexture =
-					ani.TextureFrames[m_Frame];
+				sides[m_Line1->sidenum[0]].SetTexture(side_t::mid, ani.TextureFrames[m_Frame]);
+				sides[m_Line1->sidenum[1]].SetTexture(side_t::mid, ani.TextureFrames[m_Frame]);
+				sides[m_Line2->sidenum[0]].SetTexture(side_t::mid, ani.TextureFrames[m_Frame]);
+				sides[m_Line2->sidenum[1]].SetTexture(side_t::mid, ani.TextureFrames[m_Frame]);
 			}
 		}
 		break;
@@ -642,11 +642,10 @@ void DAnimatedDoor::Tick ()
 				// IF DOOR NEEDS TO ANIMATE TO NEXT FRAME...
 				m_Timer = m_Speed;
 
-				sides[m_Line1->sidenum[0]].midtexture =
-				sides[m_Line1->sidenum[1]].midtexture =
-				sides[m_Line2->sidenum[0]].midtexture =
-				sides[m_Line2->sidenum[1]].midtexture =
-					ani.TextureFrames[m_Frame];
+				sides[m_Line1->sidenum[0]].SetTexture(side_t::mid, ani.TextureFrames[m_Frame]);
+				sides[m_Line1->sidenum[1]].SetTexture(side_t::mid, ani.TextureFrames[m_Frame]);
+				sides[m_Line2->sidenum[0]].SetTexture(side_t::mid, ani.TextureFrames[m_Frame]);
+				sides[m_Line2->sidenum[1]].SetTexture(side_t::mid, ani.TextureFrames[m_Frame]);
 			}
 		}
 		break;
@@ -699,7 +698,7 @@ DAnimatedDoor::DAnimatedDoor (sector_t *sec, line_t *line, int speed, int delay)
 	// The DMovingCeiling constructor automatically sets up an interpolation for us.
 	// Stop it, since the ceiling is moving instantly here.
 	stopinterpolation (INTERP_SectorCeiling, sec);
-	m_WhichDoorIndex = P_FindSlidingDoorType (sides[line->sidenum[0]].toptexture);
+	m_WhichDoorIndex = P_FindSlidingDoorType (sides[line->sidenum[0]].GetTexture(side_t::top));
 	if (m_WhichDoorIndex < 0)
 	{
 		Printf ("EV_SlidingDoor: Textures are not defined for sliding door!");
@@ -715,16 +714,16 @@ DAnimatedDoor::DAnimatedDoor (sector_t *sec, line_t *line, int speed, int delay)
 		if (sec->lines[i] == line)
 			continue;
 
-		if (sides[sec->lines[i]->sidenum[0]].toptexture == sides[line->sidenum[0]].toptexture)
+		if (sides[sec->lines[i]->sidenum[0]].GetTexture(side_t::top) == sides[line->sidenum[0]].GetTexture(side_t::top))
 		{
 			m_Line2 = sec->lines[i];
 			break;
 		}
 	}
 
-	picnum = sides[m_Line1->sidenum[0]].toptexture;
-	sides[m_Line1->sidenum[0]].midtexture = picnum;
-	sides[m_Line2->sidenum[0]].midtexture = picnum;
+	picnum = sides[m_Line1->sidenum[0]].GetTexture(side_t::top);
+	sides[m_Line1->sidenum[0]].SetTexture(side_t::mid, picnum);
+	sides[m_Line2->sidenum[0]].SetTexture(side_t::mid, picnum);
 
 	// don't forget texture scaling here!
 	FTexture *tex = TexMan[picnum];
@@ -783,7 +782,7 @@ bool EV_SlidingDoor (line_t *line, AActor *actor, int tag, int speed, int delay)
 			}
 			return false;
 		}
-		if (P_FindSlidingDoorType (sides[line->sidenum[0]].toptexture) >= 0)
+		if (P_FindSlidingDoorType (sides[line->sidenum[0]].GetTexture(side_t::top)) >= 0)
 		{
 			new DAnimatedDoor (sec, line, speed, delay);
 			return true;
@@ -806,7 +805,7 @@ bool EV_SlidingDoor (line_t *line, AActor *actor, int tag, int speed, int delay)
 			{
 				continue;
 			}
-			if (P_FindSlidingDoorType (sides[line->sidenum[0]].toptexture) >= 0)
+			if (P_FindSlidingDoorType (sides[line->sidenum[0]].GetTexture(side_t::top)) >= 0)
 			{
 				rtn = true;
 				new DAnimatedDoor (sec, line, speed, delay);
diff --git a/src/p_lnspec.cpp b/src/p_lnspec.cpp
index cbef22134f..2be3039335 100644
--- a/src/p_lnspec.cpp
+++ b/src/p_lnspec.cpp
@@ -1889,8 +1889,11 @@ FUNC(LS_Sector_SetLink)
 }
 
 
-static void SetWallScroller (int id, int sidechoice, fixed_t dx, fixed_t dy)
+static void SetWallScroller (int id, int sidechoice, fixed_t dx, fixed_t dy, int Where)
 {
+	Where &=7;
+	if (Where == 0) return;
+
 	if ((dx | dy) == 0)
 	{
 		// Special case: Remove the scroller, because the deltas are both 0.
@@ -1902,7 +1905,8 @@ static void SetWallScroller (int id, int sidechoice, fixed_t dx, fixed_t dy)
 			int wallnum = scroller->GetWallNum ();
 
 			if (wallnum >= 0 && lines[sides[wallnum].linenum].id == id &&
-				lines[sides[wallnum].linenum].sidenum[sidechoice] == (DWORD)wallnum)
+				lines[sides[wallnum].linenum].sidenum[sidechoice] == (DWORD)wallnum &&
+				Where == scroller->GetScrollParts())
 			{
 				scroller->Destroy ();
 			}
@@ -1920,7 +1924,8 @@ static void SetWallScroller (int id, int sidechoice, fixed_t dx, fixed_t dy)
 			{
 				if ((collect.RefNum = ((DScroller *)collect.Obj)->GetWallNum ()) != -1 &&
 					lines[sides[collect.RefNum].linenum].id == id &&
-					lines[sides[collect.RefNum].linenum].sidenum[sidechoice] == (DWORD)collect.RefNum)
+					lines[sides[collect.RefNum].linenum].sidenum[sidechoice] == (DWORD)collect.RefNum &&
+					Where == ((DScroller *)collect.Obj)->GetScrollParts())
 				{
 					((DScroller *)collect.Obj)->SetRate (dx, dy);
 					Collection.Push (collect);
@@ -1944,7 +1949,7 @@ static void SetWallScroller (int id, int sidechoice, fixed_t dx, fixed_t dy)
 			{
 				if (lines[linenum].sidenum[sidechoice] != NO_SIDE)
 				{
-					new DScroller (DScroller::sc_side, dx, dy, -1, lines[linenum].sidenum[sidechoice], 0);
+					new DScroller (DScroller::sc_side, dx, dy, -1, lines[linenum].sidenum[sidechoice], 0, Where);
 				}
 			}
 		}
@@ -1972,11 +1977,21 @@ FUNC(LS_Scroll_Texture_Both)
 		sidechoice = 0;
 	}
 
-	SetWallScroller (arg0, sidechoice, dx, dy);
+	SetWallScroller (arg0, sidechoice, dx, dy, 7);
 
 	return true;
 }
 
+FUNC(LS_Scroll_Wall)
+// Scroll_Wall (id, x, y, side, flags)
+{
+	if (arg0 == 0)
+		return false;
+
+	SetWallScroller (arg0, !!arg3, arg1, arg2, arg4);
+	return true;
+}
+
 static void SetScroller (int tag, DScroller::EScrollType type, fixed_t dx, fixed_t dy)
 {
 	TThinkerIterator<DScroller> iterator (STAT_SCROLLER);
@@ -2685,8 +2700,8 @@ FUNC(LS_ClearForceField)
 			{
 				line->flags &= ~(ML_BLOCKING|ML_BLOCKEVERYTHING);
 				line->special = 0;
-				sides[line->sidenum[0]].midtexture = 0;
-				sides[line->sidenum[1]].midtexture = 0;
+				sides[line->sidenum[0]].SetTexture(side_t::mid, 0);
+				sides[line->sidenum[1]].SetTexture(side_t::mid, 0);
 			}
 		}
 	}
@@ -2860,7 +2875,7 @@ lnSpecFunc LineSpecials[256] =
 	LS_GlassBreak,
 	LS_NOP,		// 50: ExtraFloor_LightOnly
 	LS_Sector_SetLink,
-	LS_NOP,		// 52
+	LS_Scroll_Wall,
 	LS_NOP,		// 53
 	LS_NOP,		// 54
 	LS_NOP,		// 55
diff --git a/src/p_lnspec.h b/src/p_lnspec.h
index e6d705618b..6d1d8c8929 100644
--- a/src/p_lnspec.h
+++ b/src/p_lnspec.h
@@ -155,12 +155,12 @@ typedef enum {
 #define FRICTION_MASK	0x0800
 #define PUSH_MASK		0x1000
 
-struct line_s;
+struct line_t;
 class AActor;
 
 FName MODtoDamageType (int mod);
 
-typedef int (*lnSpecFunc)(struct line_s	*line,
+typedef int (*lnSpecFunc)(struct line_t	*line,
 						  class AActor	*activator,
 						  bool			backSide,
 						  int			arg1,
diff --git a/src/p_saveg.cpp b/src/p_saveg.cpp
index ac95be1f34..b6acb28d97 100644
--- a/src/p_saveg.cpp
+++ b/src/p_saveg.cpp
@@ -367,22 +367,10 @@ void P_SerializeWorld (FArchive &arc)
 				continue;
 
 			side_t *si = &sides[li->sidenum[j]];
-			arc << si->textureoffset
-				<< si->rowoffset;
-
-			if (arc.IsStoring ())
-			{
-				TexMan.WriteTexture (arc, si->toptexture);
-				TexMan.WriteTexture (arc, si->bottomtexture);
-				TexMan.WriteTexture (arc, si->midtexture);
-			}
-			else
-			{
-				si->toptexture = TexMan.ReadTexture (arc);
-				si->bottomtexture = TexMan.ReadTexture (arc);
-				si->midtexture = TexMan.ReadTexture (arc);
-			}
-			arc << si->Light
+			arc << si->textures[side_t::top]
+				<< si->textures[side_t::mid]
+				<< si->textures[side_t::bottom]
+				<< si->Light
 				<< si->Flags
 				<< si->LeftSide
 				<< si->RightSide;
diff --git a/src/p_sectors.cpp b/src/p_sectors.cpp
index 3d951957ab..0bbec3929a 100644
--- a/src/p_sectors.cpp
+++ b/src/p_sectors.cpp
@@ -474,8 +474,8 @@ fixed_t sector_t::FindShortestTextureAround () const
 	{
 		if (lines[i]->flags & ML_TWOSIDED)
 		{
-			CheckShortestTex (sides[lines[i]->sidenum[0]].bottomtexture, minsize);
-			CheckShortestTex (sides[lines[i]->sidenum[1]].bottomtexture, minsize);
+			CheckShortestTex (sides[lines[i]->sidenum[0]].GetTexture(side_t::bottom), minsize);
+			CheckShortestTex (sides[lines[i]->sidenum[1]].GetTexture(side_t::bottom), minsize);
 		}
 	}
 	return minsize < FIXED_MAX ? minsize : TexMan[0]->GetHeight() * FRACUNIT;
@@ -500,8 +500,8 @@ fixed_t sector_t::FindShortestUpperAround () const
 	{
 		if (lines[i]->flags & ML_TWOSIDED)
 		{
-			CheckShortestTex (sides[lines[i]->sidenum[0]].toptexture, minsize);
-			CheckShortestTex (sides[lines[i]->sidenum[1]].toptexture, minsize);
+			CheckShortestTex (sides[lines[i]->sidenum[0]].GetTexture(side_t::top), minsize);
+			CheckShortestTex (sides[lines[i]->sidenum[1]].GetTexture(side_t::top), minsize);
 		}
 	}
 	return minsize < FIXED_MAX ? minsize : TexMan[0]->GetHeight() * FRACUNIT;
diff --git a/src/p_setup.cpp b/src/p_setup.cpp
index 8c3d7a44d4..4dccdcb869 100644
--- a/src/p_setup.cpp
+++ b/src/p_setup.cpp
@@ -385,14 +385,15 @@ MapData *P_OpenMapData(const char * mapname)
 //
 //===========================================================================
 
-static void SetTexture (int *texture, DWORD *blend, char *name8)
+static void SetTexture (side_t *side, int position, DWORD *blend, char *name8)
 {
 	char name[9];
 	strncpy (name, name8, 8);
 	name[8] = 0;
+	int texture;
 	if ((*blend = R_ColormapNumForName (name)) == 0)
 	{
-		if ((*texture = TexMan.CheckForTexture (name, FTexture::TEX_Wall,
+		if ((texture = TexMan.CheckForTexture (name, FTexture::TEX_Wall,
 			FTextureManager::TEXMAN_Overridable|FTextureManager::TEXMAN_TryAny)
 			) == -1)
 		{
@@ -401,7 +402,7 @@ static void SetTexture (int *texture, DWORD *blend, char *name8)
 			strncpy (name2, name, 8);
 			name2[8] = 0;
 			*blend = strtoul (name2, &stop, 16);
-			*texture = 0;
+			texture = 0;
 		}
 		else
 		{
@@ -410,16 +411,18 @@ static void SetTexture (int *texture, DWORD *blend, char *name8)
 	}
 	else
 	{
-		*texture = 0;
+		texture = 0;
 	}
+	side->SetTexture(position, texture);
 }
 
-static void SetTextureNoErr (int *texture, DWORD *color, char *name8, bool *validcolor)
+static void SetTextureNoErr (side_t *side, int position, DWORD *color, char *name8, bool *validcolor)
 {
 	char name[9];
+	int texture;
 	strncpy (name, name8, 8);
 	name[8] = 0;
-	if ((*texture = TexMan.CheckForTexture (name, FTexture::TEX_Wall,
+	if ((texture = TexMan.CheckForTexture (name, FTexture::TEX_Wall,
 		FTextureManager::TEXMAN_Overridable|FTextureManager::TEXMAN_TryAny)
 		) == -1)
 	{
@@ -428,13 +431,14 @@ static void SetTextureNoErr (int *texture, DWORD *color, char *name8, bool *vali
 		strncpy (name2, name, 8);
 		name2[8] = 0;
 		*color = strtoul (name2, &stop, 16);
-		*texture = 0;
+		texture = 0;
 		*validcolor = (*stop == 0) && (stop >= name2 + 2) && (stop <= name2 + 6);
 	}
 	else
 	{
 		*validcolor = false;
 	}
+	side->SetTexture(position, texture);
 }
 
 //===========================================================================
@@ -2278,8 +2282,8 @@ void P_LoadSideDefs2 (MapData * map)
 			msd->rowoffset += 102;
 		}
 
-		sd->textureoffset = LittleShort(msd->textureoffset)<<FRACBITS;
-		sd->rowoffset = LittleShort(msd->rowoffset)<<FRACBITS;
+		sd->SetTextureXOffset(LittleShort(msd->textureoffset)<<FRACBITS);
+		sd->SetTextureYOffset(LittleShort(msd->rowoffset)<<FRACBITS);
 		sd->linenum = NO_INDEX;
 
 		// killough 4/4/98: allow sidedef texture names to be overloaded
@@ -2304,9 +2308,9 @@ void P_LoadSideDefs2 (MapData * map)
 			  //	  instead of figuring something out from the colormap.
 			if (sec != NULL)
 			{
-				SetTexture (&sd->bottomtexture, &sec->bottommap, msd->bottomtexture);
-				SetTexture (&sd->midtexture, &sec->midmap, msd->midtexture);
-				SetTexture (&sd->toptexture, &sec->topmap, msd->toptexture);
+				SetTexture (sd, side_t::bottom, &sec->bottommap, msd->bottomtexture);
+				SetTexture (sd, side_t::mid, &sec->midmap, msd->midtexture);
+				SetTexture (sd, side_t::top, &sec->topmap, msd->toptexture);
 			}
 			break;
 
@@ -2318,10 +2322,11 @@ void P_LoadSideDefs2 (MapData * map)
 				DWORD color, fog;
 				bool colorgood, foggood;
 
-				SetTextureNoErr (&sd->bottomtexture, &fog, msd->bottomtexture, &foggood);
-				SetTextureNoErr (&sd->toptexture, &color, msd->toptexture, &colorgood);
+				SetTextureNoErr (sd, side_t::bottom, &fog, msd->bottomtexture, &foggood);
+				SetTextureNoErr (sd, side_t::top, &color, msd->toptexture, &colorgood);
 				strncpy (name, msd->midtexture, 8);
-				sd->midtexture = TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable);
+				sd->SetTexture(side_t::mid, 
+					TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable));
 
 				if (colorgood | foggood)
 				{
@@ -2355,47 +2360,42 @@ void P_LoadSideDefs2 (MapData * map)
 				if (strnicmp ("TRANMAP", msd->midtexture, 8) == 0)
 				{
 					// The translator set the alpha argument already; no reason to do it again.
-					sd->midtexture = 0;
+					sd->SetTexture(side_t::mid, 0);
 				}
 				else if ((lumpnum = Wads.CheckNumForName (msd->midtexture)) > 0 &&
 					Wads.LumpLength (lumpnum) == 65536)
 				{
 					sidetemp[i].a.alpha = P_DetermineTranslucency (lumpnum);
-					sd->midtexture = 0;
+					sd->SetTexture(side_t::mid, 0);
 				}
 				else
 				{
 					strncpy (name, msd->midtexture, 8);
-					sd->midtexture = TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable);
+					sd->SetTexture(side_t::mid, 
+						TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable));
 				}
 
 				strncpy (name, msd->toptexture, 8);
-				sd->toptexture = TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable);
+				sd->SetTexture(side_t::top, TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable));
 
 				strncpy (name, msd->bottomtexture, 8);
-				sd->bottomtexture = TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable);
+				sd->SetTexture(side_t::bottom, TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable));
 				break;
 			}
 			// Fallthrough for Hexen maps is intentional
-#if 0
-			sd->midtexture = strncasecmp("TRANMAP", msd->midtexture, 8) ?
-				(sd->special = W_CheckNumForName(msd->midtexture)) < 0 ||
-				W_LumpLength(sd->special) != 65536 ?
-				sd->special=0, R_TextureNumForName(msd->midtexture) :
-					(sd->special++, 0) : (sd->special=0);
-			sd->toptexture = R_TextureNumForName(msd->toptexture);
-			sd->bottomtexture = R_TextureNumForName(msd->bottomtexture);
-#endif
 
 		default:			// normal cases
 			strncpy (name, msd->midtexture, 8);
-			sd->midtexture = TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable);
+			sd->SetTexture(side_t::mid, 
+				TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable));
 
 			strncpy (name, msd->toptexture, 8);
-			sd->toptexture = TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable);
+			sd->SetTexture(side_t::top, 
+				TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable));
 
 			strncpy (name, msd->bottomtexture, 8);
-			sd->bottomtexture = TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable);
+			sd->SetTexture(side_t::bottom, 
+				TexMan.GetTexture (name, FTexture::TEX_Wall, FTextureManager::TEXMAN_Overridable));
 			break;
 		}
 	}
diff --git a/src/p_spec.cpp b/src/p_spec.cpp
index 620b605f9f..e56393b760 100644
--- a/src/p_spec.cpp
+++ b/src/p_spec.cpp
@@ -92,7 +92,8 @@ void DScroller::Serialize (FArchive &arc)
 		<< m_Control
 		<< m_LastHeight
 		<< m_vdx << m_vdy
-		<< m_Accel;
+		<< m_Accel
+		<< m_Parts;
 }
 
 DPusher::DPusher ()
@@ -1109,8 +1110,22 @@ void DScroller::Tick ()
 	switch (m_Type)
 	{
 		case sc_side:					// killough 3/7/98: Scroll wall texture
-			sides[m_Affectee].textureoffset += dx;
-			sides[m_Affectee].rowoffset += dy;
+			if (m_Parts & scw_top)
+			{
+				sides[m_Affectee].AddTextureXOffset(side_t::top, dx);
+				sides[m_Affectee].AddTextureYOffset(side_t::top, dy);
+			}
+			if (m_Parts & scw_mid && (lines[sides[m_Affectee].linenum].backsector == NULL ||
+				!(lines[sides[m_Affectee].linenum].flags&ML_3DMIDTEX)))
+			{
+				sides[m_Affectee].AddTextureXOffset(side_t::mid, dx);
+				sides[m_Affectee].AddTextureYOffset(side_t::mid, dy);
+			}
+			if (m_Parts & scw_bottom)
+			{
+				sides[m_Affectee].AddTextureXOffset(side_t::bottom, dx);
+				sides[m_Affectee].AddTextureYOffset(side_t::bottom, dy);
+			}
 			break;
 
 		case sc_floor:						// killough 3/7/98: Scroll floor texture
@@ -1153,13 +1168,14 @@ void DScroller::Tick ()
 //
 
 DScroller::DScroller (EScrollType type, fixed_t dx, fixed_t dy,
-					  int control, int affectee, int accel)
+					  int control, int affectee, int accel, int scrollpos)
 	: DThinker (STAT_SCROLLER)
 {
 	m_Type = type;
 	m_dx = dx;
 	m_dy = dy;
 	m_Accel = accel;
+	m_Parts = scrollpos;
 	m_vdx = m_vdy = 0;
 	if ((m_Control = control) != -1)
 		m_LastHeight =
@@ -1173,7 +1189,19 @@ DScroller::DScroller (EScrollType type, fixed_t dx, fixed_t dy,
 
 	case sc_side:
 		sides[affectee].Flags |= WALLF_NOAUTODECALS;
-		setinterpolation (INTERP_WallPanning, &sides[affectee]);
+		if (m_Parts & scw_top)
+		{
+			sides[m_Affectee].SetInterpolation(side_t::top);
+		}
+		if (m_Parts & scw_mid && (lines[sides[m_Affectee].linenum].backsector == NULL ||
+			!(lines[sides[m_Affectee].linenum].flags&ML_3DMIDTEX)))
+		{
+			sides[m_Affectee].SetInterpolation(side_t::mid);
+		}
+		if (m_Parts & scw_bottom)
+		{
+			sides[m_Affectee].SetInterpolation(side_t::bottom);
+		}
 		break;
 
 	case sc_floor:
@@ -1194,7 +1222,19 @@ DScroller::~DScroller ()
 	switch (m_Type)
 	{
 	case sc_side:
-		stopinterpolation (INTERP_WallPanning, &sides[m_Affectee]);
+		if (m_Parts & scw_top)
+		{
+			sides[m_Affectee].StopInterpolation(side_t::top);
+		}
+		if (m_Parts & scw_mid && (lines[sides[m_Affectee].linenum].backsector == NULL ||
+			!(lines[sides[m_Affectee].linenum].flags&ML_3DMIDTEX)))
+		{
+			sides[m_Affectee].StopInterpolation(side_t::mid);
+		}
+		if (m_Parts & scw_bottom)
+		{
+			sides[m_Affectee].StopInterpolation(side_t::bottom);
+		}
 		break;
 
 	case sc_floor:
@@ -1218,7 +1258,7 @@ DScroller::~DScroller ()
 // killough 5/25/98: cleaned up arithmetic to avoid drift due to roundoff
 
 DScroller::DScroller (fixed_t dx, fixed_t dy, const line_t *l,
-					 int control, int accel)
+					 int control, int accel, int scrollpos)
 	: DThinker (STAT_SCROLLER)
 {
 	fixed_t x = abs(l->dx), y = abs(l->dy), d;
@@ -1234,16 +1274,30 @@ DScroller::DScroller (fixed_t dx, fixed_t dy, const line_t *l,
 	m_dy = y;
 	m_vdx = m_vdy = 0;
 	m_Accel = accel;
+	m_Parts = scrollpos;
 	if ((m_Control = control) != -1)
 		m_LastHeight = sectors[control].CenterFloor() + sectors[control].CenterCeiling();
 	m_Affectee = *l->sidenum;
 	sides[m_Affectee].Flags |= WALLF_NOAUTODECALS;
 
-	setinterpolation (INTERP_WallPanning, &sides[m_Affectee]);
+	if (m_Parts & scw_top)
+	{
+		sides[m_Affectee].SetInterpolation(side_t::top);
+	}
+	if (m_Parts & scw_mid && (lines[sides[m_Affectee].linenum].backsector == NULL ||
+		!(lines[sides[m_Affectee].linenum].flags&ML_3DMIDTEX)))
+	{
+		sides[m_Affectee].SetInterpolation(side_t::mid);
+	}
+	if (m_Parts & scw_bottom)
+	{
+		sides[m_Affectee].SetInterpolation(side_t::bottom);
+	}
 }
 
 // Amount (dx,dy) vector linedef is shifted right to get scroll amount
 #define SCROLL_SHIFT 5
+#define SCROLLTYPE(i) ((i)<=0 ? 7:(i))
 
 // Initialize the scrollers
 static void P_SpawnScrollers(void)
@@ -1333,28 +1387,28 @@ static void P_SpawnScrollers(void)
 		case Scroll_Texture_Offsets:
 			// killough 3/2/98: scroll according to sidedef offsets
 			s = lines[i].sidenum[0];
-			new DScroller (DScroller::sc_side, -sides[s].textureoffset,
-						   sides[s].rowoffset, -1, s, accel);
+			new DScroller (DScroller::sc_side, -sides[s].GetTextureXOffset(side_t::mid),
+				sides[s].GetTextureYOffset(side_t::mid), -1, s, accel, SCROLLTYPE(l->args[0]));
 			break;
 
 		case Scroll_Texture_Left:
 			new DScroller (DScroller::sc_side, l->args[0] * (FRACUNIT/64), 0,
-						   -1, lines[i].sidenum[0], accel);
+						   -1, lines[i].sidenum[0], accel, SCROLLTYPE(l->args[1]));
 			break;
 
 		case Scroll_Texture_Right:
 			new DScroller (DScroller::sc_side, l->args[0] * (-FRACUNIT/64), 0,
-						   -1, lines[i].sidenum[0], accel);
+						   -1, lines[i].sidenum[0], accel, SCROLLTYPE(l->args[1]));
 			break;
 
 		case Scroll_Texture_Up:
 			new DScroller (DScroller::sc_side, 0, l->args[0] * (FRACUNIT/64),
-						   -1, lines[i].sidenum[0], accel);
+						   -1, lines[i].sidenum[0], accel, SCROLLTYPE(l->args[1]));
 			break;
 
 		case Scroll_Texture_Down:
 			new DScroller (DScroller::sc_side, 0, l->args[0] * (-FRACUNIT/64),
-						   -1, lines[i].sidenum[0], accel);
+						   -1, lines[i].sidenum[0], accel, SCROLLTYPE(l->args[1]));
 			break;
 
 		case Scroll_Texture_Both:
diff --git a/src/p_spec.h b/src/p_spec.h
index 6ee3ef143a..5b73ace2b1 100644
--- a/src/p_spec.h
+++ b/src/p_spec.h
@@ -52,9 +52,16 @@ public:
 		sc_carry,
 		sc_carry_ceiling,	// killough 4/11/98: carry objects hanging on ceilings
 	};
+	enum EScrollPos
+	{
+		scw_top=1,
+		scw_mid=2,
+		scw_bottom=4,
+		scw_all=7,
+	};
 	
-	DScroller (EScrollType type, fixed_t dx, fixed_t dy, int control, int affectee, int accel);
-	DScroller (fixed_t dx, fixed_t dy, const line_t *l, int control, int accel);
+	DScroller (EScrollType type, fixed_t dx, fixed_t dy, int control, int affectee, int accel, int scrollpos = scw_all);
+	DScroller (fixed_t dx, fixed_t dy, const line_t *l, int control, int accel, int scrollpos = scw_all);
 	~DScroller ();
 
 	void Serialize (FArchive &arc);
@@ -65,6 +72,7 @@ public:
 	void SetRate (fixed_t dx, fixed_t dy) { m_dx = dx; m_dy = dy; }
 	bool IsType (EScrollType type) const { return type == m_Type; }
 	int GetAffectee () const { return m_Affectee; }
+	int GetScrollParts() const { return m_Parts; }
 
 protected:
 	EScrollType m_Type;		// Type of scroll effect
@@ -74,6 +82,7 @@ protected:
 	fixed_t m_LastHeight;	// Last known height of control sector
 	fixed_t m_vdx, m_vdy;	// Accumulated velocity if accelerative
 	int m_Accel;			// Whether it's accelerative
+	int m_Parts;			// Which parts of a sidedef are being scrolled?
 
 private:
 	DScroller ();
diff --git a/src/p_switch.cpp b/src/p_switch.cpp
index 4b059439b3..91f1efe28e 100644
--- a/src/p_switch.cpp
+++ b/src/p_switch.cpp
@@ -58,22 +58,14 @@ class DActiveButton : public DThinker
 {
 	DECLARE_CLASS (DActiveButton, DThinker)
 public:
-	enum EWhere
-	{
-		BUTTON_Top,
-		BUTTON_Middle,
-		BUTTON_Bottom,
-		BUTTON_Nowhere
-	};
-
 	DActiveButton ();
-	DActiveButton (side_t *, EWhere, WORD switchnum, fixed_t x, fixed_t y, bool flippable);
+	DActiveButton (side_t *, int, WORD switchnum, fixed_t x, fixed_t y, bool flippable);
 
 	void Serialize (FArchive &arc);
 	void Tick ();
 
 	side_t	*m_Side;
-	EWhere	m_Where;
+	SBYTE	m_Part;
 	WORD	m_SwitchDef;
 	WORD	m_Frame;
 	WORD	m_Timer;
@@ -82,15 +74,6 @@ public:
 
 protected:
 	bool AdvanceFrame ();
-	void StoreTexture (short tex) const;
-
-	friend FArchive &operator<< (FArchive &arc, EWhere &where)
-	{
-		BYTE val = (BYTE)where;
-		arc << val;
-		where = (EWhere)val;
-		return arc;
-	}
 };
 
 struct FSwitchDef
@@ -435,7 +418,7 @@ static WORD AddSwitchDef (FSwitchDef *def)
 // Start a button counting down till it turns off.
 // [RH] Rewritten to remove MAXBUTTONS limit.
 //
-static bool P_StartButton (side_t *side, DActiveButton::EWhere w, int switchnum,
+static bool P_StartButton (side_t *side, int Where, int switchnum,
 						   fixed_t x, fixed_t y, bool useagain)
 {
 	DActiveButton *button;
@@ -451,14 +434,15 @@ static bool P_StartButton (side_t *side, DActiveButton::EWhere w, int switchnum,
 		}
 	}
 
-	new DActiveButton (side, w, switchnum, x, y, useagain);
+	new DActiveButton (side, Where, switchnum, x, y, useagain);
 	return true;
 }
 
-static int TryFindSwitch (SWORD texture)
+static int TryFindSwitch (side_t *side, int Where)
 {
 	int mid, low, high;
 
+	int texture = side->GetTexture(Where);
 	high = (int)(SwitchList.Size () - 1);
 	if (high >= 0)
 	{
@@ -519,15 +503,15 @@ bool P_CheckSwitchRange(AActor *user, line_t *line, int sideno)
 	P_LineOpening(open, NULL, line, checkx, checky, user->x, user->y);
 	if (open.range <= 0) return true;
 
-	if ((TryFindSwitch (side->toptexture)) != -1)
+	if ((TryFindSwitch (side, side_t::top)) != -1)
 	{
 		return (user->z + user->height >= open.top);
 	}
-	else if ((TryFindSwitch (side->bottomtexture)) != -1)
+	else if ((TryFindSwitch (side, side_t::bottom)) != -1)
 	{
 		return (user->z <= open.bottom);
 	}
-	else if ((line->flags & (ML_3DMIDTEX)) || (TryFindSwitch (side->midtexture)) != -1)
+	else if ((line->flags & (ML_3DMIDTEX)) || (TryFindSwitch (side, side_t::mid)) != -1)
 	{
 		// 3DMIDTEX lines will force a mid texture check if no switch is found on this line
 		// to keep compatibility with Eternity's implementation.
@@ -547,24 +531,20 @@ bool P_CheckSwitchRange(AActor *user, line_t *line, int sideno)
 //
 bool P_ChangeSwitchTexture (side_t *side, int useAgain, BYTE special, bool *quest)
 {
-	DActiveButton::EWhere Where;
-	int *texture;
+	int texture;
 	int i, sound;
 
-	if ((i = TryFindSwitch (side->toptexture)) != -1)
+	if ((i = TryFindSwitch (side, side_t::top)) != -1)
 	{
-		texture = &side->toptexture;
-		Where = DActiveButton::BUTTON_Top;
+		texture = side_t::top;
 	}
-	else if ((i = TryFindSwitch (side->bottomtexture)) != -1)
+	else if ((i = TryFindSwitch (side, side_t::bottom)) != -1)
 	{
-		texture = &side->bottomtexture;
-		Where = DActiveButton::BUTTON_Bottom;
+		texture = side_t::bottom;
 	}
-	else if ((i = TryFindSwitch (side->midtexture)) != -1)
+	else if ((i = TryFindSwitch (side, side_t::mid)) != -1)
 	{
-		texture = &side->midtexture;
-		Where = DActiveButton::BUTTON_Middle;
+		texture = side_t::mid;
 	}
 	else
 	{
@@ -600,9 +580,9 @@ bool P_ChangeSwitchTexture (side_t *side, int useAgain, BYTE special, bool *ques
 
 	pt[0] = line->v1->x + (line->dx >> 1);
 	pt[1] = line->v1->y + (line->dy >> 1);
-	*texture = SwitchList[i]->u[0].Texture;
+	side->SetTexture(texture, SwitchList[i]->u[0].Texture);
 	if (useAgain || SwitchList[i]->NumFrames > 1)
-		playsound = P_StartButton (side, Where, i, pt[0], pt[1], !!useAgain);
+		playsound = P_StartButton (side, texture, i, pt[0], pt[1], !!useAgain);
 	else 
 		playsound = true;
 	if (playsound) S_SoundID (pt, CHAN_VOICE|CHAN_LISTENERZ|CHAN_IMMOBILE, sound, 1, ATTN_STATIC);
@@ -618,7 +598,7 @@ IMPLEMENT_CLASS (DActiveButton)
 DActiveButton::DActiveButton ()
 {
 	m_Side = NULL;
-	m_Where = BUTTON_Nowhere;
+	m_Part = -1;
 	m_SwitchDef = 0;
 	m_Timer = 0;
 	m_X = 0;
@@ -626,11 +606,11 @@ DActiveButton::DActiveButton ()
 	bFlippable = false;
 }
 
-DActiveButton::DActiveButton (side_t *side, EWhere where, WORD switchnum,
+DActiveButton::DActiveButton (side_t *side, int Where, WORD switchnum,
 							  fixed_t x, fixed_t y, bool useagain)
 {
 	m_Side = side;
-	m_Where = where;
+	m_Part = SBYTE(Where);
 	m_X = x;
 	m_Y = y;
 	bFlippable = useagain;
@@ -649,7 +629,7 @@ void DActiveButton::Serialize (FArchive &arc)
 	{
 		sidenum = m_Side ? m_Side - sides : -1;
 	}
-	arc << sidenum << m_Where << m_SwitchDef << m_Frame << m_Timer << bFlippable << m_X << m_Y;
+	arc << sidenum << m_Part << m_SwitchDef << m_Frame << m_Timer << bFlippable << m_X << m_Y;
 	if (arc.IsLoading ())
 	{
 		m_Side = sidenum >= 0 ? sides + sidenum : NULL;
@@ -685,7 +665,7 @@ void DActiveButton::Tick ()
 		}
 		bool killme = AdvanceFrame ();
 
-		StoreTexture (def->u[m_Frame].Texture);
+		m_Side->SetTexture(m_Part, def->u[m_Frame].Texture);
 
 		if (killme)
 		{
@@ -728,23 +708,3 @@ bool DActiveButton::AdvanceFrame ()
 	return ret;
 }
 
-void DActiveButton::StoreTexture (short tex) const
-{
-	switch (m_Where)
-	{
-	case BUTTON_Middle:
-		m_Side->midtexture = tex;
-		break;
-
-	case BUTTON_Bottom:
-		m_Side->bottomtexture = tex;
-		break;
-
-	case BUTTON_Top:
-		m_Side->toptexture = tex;
-		break;
-
-	default:
-		return;
-	}
-}
diff --git a/src/p_writemap.cpp b/src/p_writemap.cpp
index 1f711a6790..637b689a8a 100644
--- a/src/p_writemap.cpp
+++ b/src/p_writemap.cpp
@@ -147,12 +147,12 @@ static int WriteSIDEDEFS (FILE *file)
 
 	for (int i = 0; i < numsides; ++i)
 	{
-		msd.textureoffset = LittleShort(short(sides[i].textureoffset >> FRACBITS));
-		msd.rowoffset = LittleShort(short(sides[i].rowoffset >> FRACBITS));
+		msd.textureoffset = LittleShort(short(sides[i].GetTextureXOffset(side_t::mid) >> FRACBITS));
+		msd.rowoffset = LittleShort(short(sides[i].GetTextureYOffset(side_t::mid) >> FRACBITS));
 		msd.sector = LittleShort(short(sides[i].sector - sectors));
-		uppercopy (msd.toptexture, GetTextureName (sides[i].toptexture));
-		uppercopy (msd.bottomtexture, GetTextureName (sides[i].bottomtexture));
-		uppercopy (msd.midtexture, GetTextureName (sides[i].midtexture));
+		uppercopy (msd.toptexture, GetTextureName (sides[i].GetTexture(side_t::top)));
+		uppercopy (msd.bottomtexture, GetTextureName (sides[i].GetTexture(side_t::bottom)));
+		uppercopy (msd.midtexture, GetTextureName (sides[i].GetTexture(side_t::mid)));
 		fwrite (&msd, sizeof(msd), 1, file);
 	}
 	return numsides * sizeof(msd);
diff --git a/src/r_bsp.cpp b/src/r_bsp.cpp
index e2068767e7..27248e6082 100644
--- a/src/r_bsp.cpp
+++ b/src/r_bsp.cpp
@@ -756,8 +756,8 @@ void R_AddLine (seg_t *line)
 		&& rw_backcz1 <= rw_backfz1 && rw_backcz2 <= rw_backfz2
 
 		// preserve a kind of transparent door/lift special effect:
-		&& ((rw_backcz1 >= rw_frontcz1 && rw_backcz2 >= rw_frontcz2) || line->sidedef->toptexture != 0)
-		&& ((rw_backfz1 <= rw_frontfz1 && rw_backfz2 <= rw_frontfz2) || line->sidedef->bottomtexture != 0))
+		&& ((rw_backcz1 >= rw_frontcz1 && rw_backcz2 >= rw_frontcz2) || line->sidedef->GetTexture(side_t::top) != 0)
+		&& ((rw_backfz1 <= rw_frontfz1 && rw_backfz2 <= rw_frontfz2) || line->sidedef->GetTexture(side_t::bottom) != 0))
 		{
 		// killough 1/18/98 -- This function is used to fix the automap bug which
 		// showed lines behind closed doors simply because the door had a dropoff.
@@ -779,7 +779,7 @@ void R_AddLine (seg_t *line)
 		else if (backsector->lightlevel != frontsector->lightlevel
 			|| backsector->floorpic != frontsector->floorpic
 			|| backsector->ceilingpic != frontsector->ceilingpic
-			|| curline->sidedef->midtexture != 0
+			|| curline->sidedef->GetTexture(side_t::mid) != 0
 
 			// killough 3/7/98: Take flats offsets into account:
 			|| backsector->floor_xoffs != frontsector->floor_xoffs
@@ -834,12 +834,12 @@ void R_AddLine (seg_t *line)
 #if 0	// Maybe later...
 		if (!solid)
 		{
-			if (rw_ceilstat == 12 && line->sidedef->toptexture != 0)
+			if (rw_ceilstat == 12 && line->sidedef->GetTexture(side_t::top) != 0)
 			{
 				rw_mustmarkceiling = true;
 				solid = true;
 			}
-			if (rw_floorstat == 3 && line->sidedef->bottomtexture != 0)
+			if (rw_floorstat == 3 && line->sidedef->GetTexture(side_t::bottom) != 0)
 			{
 				rw_mustmarkfloor = true;
 				solid = true;
diff --git a/src/r_data.cpp b/src/r_data.cpp
index e8d119a150..865d22d748 100644
--- a/src/r_data.cpp
+++ b/src/r_data.cpp
@@ -462,9 +462,9 @@ void R_PrecacheLevel (void)
 
 	for (i = numsides - 1; i >= 0; i--)
 	{
-		hitlist[sides[i].toptexture] =
-			hitlist[sides[i].midtexture] =
-			hitlist[sides[i].bottomtexture] = 1;
+		hitlist[sides[i].GetTexture(side_t::top)] =
+			hitlist[sides[i].GetTexture(side_t::mid)] =
+			hitlist[sides[i].GetTexture(side_t::bottom)] = 1;
 	}
 
 	// Sky texture is always present.
diff --git a/src/r_defs.h b/src/r_defs.h
index 596d058d77..723c1646a7 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -35,6 +35,7 @@
 #include "actor.h"
 
 #include "dthinker.h"
+#include "r_interpolate.h"
 
 
 
@@ -82,7 +83,7 @@ struct vertex_s
 typedef struct vertex_s vertex_t;
 
 // Forward of LineDefs, for Sectors.
-struct line_s;
+struct line_t;
 
 class player_s;
 
@@ -262,12 +263,11 @@ struct FExtraLight
 	WORD NumUsedLights;
 	FLightStack *Lights;	// Lights arranged from top to bottom
 
-	void InsertLight (const secplane_t &plane, line_s *line, int type);
+	void InsertLight (const secplane_t &plane, line_t *line, int type);
 };
 
 // this substructure contains a few sector properties that are stored in dynamic arrays
 // These must not be copied by R_FakeFlat etc. or bad things will happen.
-struct line_s;
 struct sector_t;
 
 struct FLinkedSector
@@ -285,7 +285,7 @@ struct extsector_t
 		struct plane
 		{
 			TArray<sector_t *> AttachedSectors;		// all sectors containing 3dMidtex lines attached to this sector
-			TArray<line_s *> AttachedLines;			// all 3dMidtex lines attached to this sector
+			TArray<line_t *> AttachedLines;			// all 3dMidtex lines attached to this sector
 		} Floor, Ceiling;
 	} Midtex;
 
@@ -386,7 +386,7 @@ struct sector_t
 	SWORD nextsec;		// -1 or number of next step sector
 
 	short linecount;
-	struct line_s **lines;		// [linecount] size
+	struct line_t **lines;		// [linecount] size
 
 	// killough 3/7/98: support flat heights drawn at another sector's heights
 	sector_t *heightsec;		// other sector, or NULL if no other sector
@@ -443,16 +443,28 @@ enum
 	WALLF_ABSLIGHTING	= 1,	// Light is absolute instead of relative
 	WALLF_NOAUTODECALS	= 2,	// Do not attach impact decals to this wall
 	WALLF_ADDTRANS		= 4,	// Use additive instead of normal translucency
-	WALLF_AUTOCONTRAST	= 8,	// Automatically handle fake contrast in side_s::GetLightLevel
+	WALLF_AUTOCONTRAST	= 8,	// Automatically handle fake contrast in side_t::GetLightLevel
 };
 
-struct side_s
+struct side_t
 {
-	fixed_t 	textureoffset;	// add this to the calculated texture column
-	fixed_t 	rowoffset;		// add this to the calculated texture top
+	enum ETexpart
+	{
+		top=0,
+		mid=1,
+		bottom=2
+	};
+	struct part
+	{
+		fixed_t xoffset;
+		fixed_t yoffset;
+		int texture;
+		//int Light;
+	};
+
 	sector_t*	sector;			// Sector the SideDef is facing.
 	DBaseDecal*	AttachedDecals;	// [RH] Decals bound to the wall
-	int			toptexture, bottomtexture, midtexture;	// texture indices
+	part		textures[3];
 	WORD		linenum;
 	DWORD		LeftSide, RightSide;	// [RH] Group walls into loops
 	WORD		TexelLength;
@@ -460,9 +472,66 @@ struct side_s
 	BYTE		Flags;
 
 	int GetLightLevel (bool foggy, int baselight) const;
-};
-typedef struct side_s side_t;
 
+	int GetTexture(int which) const
+	{
+		return textures[which].texture;
+	}
+	void SetTexture(int which, int tex)
+	{
+		textures[which].texture = tex;
+	}
+
+	void SetTextureXOffset(int which, fixed_t offset)
+	{
+		textures[which].xoffset = offset;
+	}
+	void SetTextureXOffset(fixed_t offset)
+	{
+		textures[top].xoffset =
+		textures[mid].xoffset =
+		textures[bottom].xoffset = offset;
+	}
+	fixed_t GetTextureXOffset(int which) const
+	{
+		return textures[which].xoffset;
+	}
+	void AddTextureXOffset(int which, fixed_t delta)
+	{
+		textures[which].xoffset += delta;
+	}
+
+	void SetTextureYOffset(int which, fixed_t offset)
+	{
+		textures[which].yoffset = offset;
+	}
+	void SetTextureYOffset(fixed_t offset)
+	{
+		textures[top].yoffset =
+		textures[mid].yoffset =
+		textures[bottom].yoffset = offset;
+	}
+	fixed_t GetTextureYOffset(int which) const
+	{
+		return textures[which].yoffset;
+	}
+	void AddTextureYOffset(int which, fixed_t delta)
+	{
+		textures[which].yoffset += delta;
+	}
+
+	void SetInterpolation(int position)
+	{
+		setinterpolation(EInterpType(INTERP_WallPanning_Top+position), this);
+	}
+	void StopInterpolation(int position)
+	{
+		setinterpolation(EInterpType(INTERP_WallPanning_Top+position), this);
+	}
+
+};
+
+FArchive &operator<< (FArchive &arc, side_t::part &p);
 
 //
 // Move clipping aid for LineDefs.
@@ -476,7 +545,7 @@ enum slopetype_t
 };
 
 
-struct line_s
+struct line_t
 {
 	vertex_t	*v1, *v2;	// vertices, from v1 to v2
 	fixed_t 	dx, dy;		// precalculated v2 - v1 for side checking
@@ -486,14 +555,13 @@ struct line_s
 	short		id;			// <--- same as tag or set with Line_SetIdentification
 	int			args[5];	// <--- hexen-style arguments (expanded to ZDoom's full width)
 	int			firstid, nextid;
-	DWORD		sidenum[2];	// sidenum[1] will be 0xffffffff if one sided
+	DWORD		sidenum[2];	// sidenum[1] will be NO_SIDE if one sided
 	fixed_t		bbox[4];	// bounding box, for the extent of the LineDef.
 	slopetype_t	slopetype;	// To aid move clipping.
 	sector_t	*frontsector, *backsector;
 	int 		validcount;	// if == validcount, already checked
 
 };
-typedef struct line_s line_t;
 
 // phares 3/14/98
 //
diff --git a/src/r_main.cpp b/src/r_main.cpp
index 150304f5f8..ab61623176 100644
--- a/src/r_main.cpp
+++ b/src/r_main.cpp
@@ -1822,9 +1822,11 @@ void FActiveInterpolation::CopyInterpToOld ()
 		oldipos[0] = ((sector_t*)Address)->ceiling_xoffs;
 		oldipos[1] = ((sector_t*)Address)->ceiling_yoffs;
 		break;
-	case INTERP_WallPanning:
-		oldipos[0] = ((side_t*)Address)->rowoffset;
-		oldipos[1] = ((side_t*)Address)->textureoffset;
+	case INTERP_WallPanning_Top:
+	case INTERP_WallPanning_Mid:
+	case INTERP_WallPanning_Bottom:
+		oldipos[0] = ((side_t*)Address)->GetTextureYOffset(Type - INTERP_WallPanning_Top);
+		oldipos[1] = ((side_t*)Address)->GetTextureXOffset(Type - INTERP_WallPanning_Top);
 		break;
 	}
 }
@@ -1853,9 +1855,11 @@ void FActiveInterpolation::CopyBakToInterp ()
 		((sector_t*)Address)->ceiling_xoffs = bakipos[0];
 		((sector_t*)Address)->ceiling_yoffs = bakipos[1];
 		break;
-	case INTERP_WallPanning:
-		((side_t*)Address)->rowoffset = bakipos[0];
-		((side_t*)Address)->textureoffset = bakipos[1];
+	case INTERP_WallPanning_Top:
+	case INTERP_WallPanning_Mid:
+	case INTERP_WallPanning_Bottom:
+		((side_t*)Address)->SetTextureYOffset(Type - INTERP_WallPanning_Top, bakipos[0]);
+		((side_t*)Address)->SetTextureXOffset(Type - INTERP_WallPanning_Top, bakipos[1]);
 		break;
 	}
 }
@@ -1863,6 +1867,7 @@ void FActiveInterpolation::CopyBakToInterp ()
 void FActiveInterpolation::DoAnInterpolation (fixed_t smoothratio)
 {
 	fixed_t *adr1, *adr2, pos;
+	int v1, v2;
 
 	switch (Type)
 	{
@@ -1886,9 +1891,13 @@ void FActiveInterpolation::DoAnInterpolation (fixed_t smoothratio)
 		adr1 = &((sector_t*)Address)->ceiling_xoffs;
 		adr2 = &((sector_t*)Address)->ceiling_yoffs;
 		break;
-	case INTERP_WallPanning:
-		adr1 = &((side_t*)Address)->rowoffset;
-		adr2 = &((side_t*)Address)->textureoffset;
+	case INTERP_WallPanning_Top:
+	case INTERP_WallPanning_Mid:
+	case INTERP_WallPanning_Bottom:
+		v1 = ((side_t*)Address)->GetTextureYOffset(Type - INTERP_WallPanning_Top);
+		v2 = ((side_t*)Address)->GetTextureXOffset(Type - INTERP_WallPanning_Top);
+		adr1 = &v1;
+		adr2 = &v2;
 		break;
 	default:
 		return;
@@ -1899,6 +1908,19 @@ void FActiveInterpolation::DoAnInterpolation (fixed_t smoothratio)
 
 	pos = bakipos[1] = *adr2;
 	*adr2 = oldipos[1] + FixedMul (pos - oldipos[1], smoothratio);
+
+	switch (Type)
+	{
+	case INTERP_WallPanning_Top:
+	case INTERP_WallPanning_Mid:
+	case INTERP_WallPanning_Bottom:
+		((side_t*)Address)->SetTextureYOffset(Type - INTERP_WallPanning_Top, v1);
+		((side_t*)Address)->SetTextureXOffset(Type - INTERP_WallPanning_Top, v2);
+		break;
+	default:
+		return;
+	}
+
 }
 
 size_t FActiveInterpolation::HashKey (EInterpType type, void *interptr)
@@ -2141,7 +2163,10 @@ FArchive &operator << (FArchive &arc, FActiveInterpolation *&interp)
 		switch (type)
 		{
 		case INTERP_Vertex:			arc << ptr.vert;	break;
-		case INTERP_WallPanning:	arc << ptr.side;	break;
+		case INTERP_WallPanning_Top:	
+		case INTERP_WallPanning_Mid:	
+		case INTERP_WallPanning_Bottom:	
+									arc << ptr.side;	break;
 		default:					arc << ptr.sect;	break;
 		}
 	}
@@ -2153,7 +2178,10 @@ FArchive &operator << (FArchive &arc, FActiveInterpolation *&interp)
 		switch (type)
 		{
 		case INTERP_Vertex:			arc << ptr.vert;	break;
-		case INTERP_WallPanning:	arc << ptr.side;	break;
+		case INTERP_WallPanning_Top:	
+		case INTERP_WallPanning_Mid:	
+		case INTERP_WallPanning_Bottom:	
+									arc << ptr.side;	break;
 		default:					arc << ptr.sect;	break;
 		}
 		interp->Address = ptr.ptr;
diff --git a/src/r_main.h b/src/r_main.h
index c4e9b4a41c..ec0459c8dd 100644
--- a/src/r_main.h
+++ b/src/r_main.h
@@ -207,58 +207,6 @@ void R_SetViewSize (int blocks);
 // [RH] Initialize multires stuff for renderer
 void R_MultiresInit (void);
 
-// BUILD stuff for interpolating between frames, but modified (rather a lot)
-#define INTERPOLATION_BUCKETS 107
-
-enum EInterpType
-{
-	INTERP_SectorFloor,		// Pass a sector_t *
-	INTERP_SectorCeiling,	// Pass a sector_t *
-	INTERP_Vertex,			// Pass a vertex_t *
-	INTERP_FloorPanning,	// Pass a sector_t *
-	INTERP_CeilingPanning,	// Pass a sector_t *
-	INTERP_WallPanning,		// Pass a side_t *
-};
-
-struct FActiveInterpolation
-{
-	FActiveInterpolation *Next;
-	void *Address;
-	EInterpType Type;
-
-	friend FArchive &operator << (FArchive &arc, FActiveInterpolation *&interp);
-
-	static int CountInterpolations ();
-	static int CountInterpolations (int *usedbuckets, int *minbucketfill, int *maxbucketfill);
-
-private:
-	fixed_t oldipos[2], bakipos[2];
-
-	void CopyInterpToOld();
-	void CopyBakToInterp();
-	void DoAnInterpolation(fixed_t smoothratio);
-
-	static size_t HashKey(EInterpType type, void *interptr);
-	static FActiveInterpolation *FindInterpolation(EInterpType, void *interptr, FActiveInterpolation **&interp_p);
-
-	friend void updateinterpolations();
-	friend void setinterpolation(EInterpType, void *interptr, bool dolinks);
-	friend void stopinterpolation(EInterpType, void *interptr, bool dolinks);
-	friend void dointerpolations(fixed_t smoothratio);
-	friend void restoreinterpolations();
-	friend void clearinterpolations();
-	friend void SerializeInterpolations(FArchive &arc);
-
-	static FActiveInterpolation *curiposhash[INTERPOLATION_BUCKETS];
-};
-
-void updateinterpolations();
-void setinterpolation(EInterpType, void *interptr, bool dolinks = true);
-void stopinterpolation(EInterpType, void *interptr, bool dolinks = true);
-void dointerpolations(fixed_t smoothratio);
-void restoreinterpolations();
-void clearinterpolations();
-void SerializeInterpolations(FArchive &arc);
 
 extern void R_FreePastViewers ();
 extern void R_ClearPastViewer (AActor *actor);
diff --git a/src/r_plane.cpp b/src/r_plane.cpp
index 86b445b293..419107e384 100644
--- a/src/r_plane.cpp
+++ b/src/r_plane.cpp
@@ -1276,17 +1276,20 @@ sky1:
 
 		// Sky transferred from first sidedef
 		const side_t *s = *l->sidenum + sides;
+		int pos;
 
 		// Texture comes from upper texture of reference sidedef
 		// [RH] If swapping skies, then use the lower sidedef
-		if (level.flags & LEVEL_SWAPSKIES && s->bottomtexture != 0)
+		if (level.flags & LEVEL_SWAPSKIES && s->GetTexture(side_t::bottom) != 0)
 		{
-			frontskytex = TexMan(s->bottomtexture);
+			pos = side_t::bottom;
 		}
 		else
 		{
-			frontskytex = TexMan(s->toptexture);
+			pos = side_t::top;
 		}
+
+		frontskytex = TexMan(s->GetTexture(pos));
 		if (frontskytex->UseType == FTexture::TEX_Null)
 		{ // [RH] The blank texture: Use normal sky instead.
 			goto sky1;
@@ -1297,10 +1300,10 @@ sky1:
 		// to allow sky rotation as well as careful positioning.
 		// However, the offset is scaled very small, so that it
 		// allows a long-period of sky rotation.
-		frontpos = (-s->textureoffset) >> 6;
+		frontpos = (-s->GetTextureXOffset(pos)) >> 6;
 
 		// Vertical offset allows careful sky positioning.
-		dc_texturemid = s->rowoffset - 28*FRACUNIT;
+		dc_texturemid = s->GetTextureYOffset(pos) - 28*FRACUNIT;
 
 		// We sometimes flip the picture horizontally.
 		//
diff --git a/src/r_polymost.cpp b/src/r_polymost.cpp
index 7adb332196..b184224947 100644
--- a/src/r_polymost.cpp
+++ b/src/r_polymost.cpp
@@ -1275,7 +1275,7 @@ void RP_AddLine (seg_t *line)
 		// preserve a kind of transparent door/lift special effect:
 		&& bcz0 >= fcz0 && bcz1 >= fcz1
 
-		&& ((bfz0 <= ffz0 && bfz1 <= ffz1) || line->sidedef->bottomtexture != 0))
+		&& ((bfz0 <= ffz0 && bfz1 <= ffz1) || line->sidedef->GetTexture(side_t::bottom) != 0))
 		{
 		// killough 1/18/98 -- This function is used to fix the automap bug which
 		// showed lines behind closed doors simply because the door had a dropoff.
@@ -1297,7 +1297,7 @@ void RP_AddLine (seg_t *line)
 		else if (backsector->lightlevel != frontsector->lightlevel
 			|| backsector->floorpic != frontsector->floorpic
 			|| backsector->ceilingpic != frontsector->ceilingpic
-			|| curline->sidedef->midtexture != 0
+			|| curline->sidedef->GetTexture(side_t::mid) != 0
 
 			// killough 3/7/98: Take flats offsets into account:
 			|| backsector->floor_xoffs != frontsector->floor_xoffs
@@ -1342,7 +1342,8 @@ void RP_AddLine (seg_t *line)
 		markceiling = markfloor = true;
 	}
 
-	rw_offset = line->sidedef->textureoffset;
+	// must be fixed in case the polymost renderer ever gets developed further!
+	rw_offset = line->sidedef->GetTextureXOffset(side_t::mid);
 
 	R_NewWall (false);
 	if (rw_markmirror)
diff --git a/src/r_segs.cpp b/src/r_segs.cpp
index 9a3dda538c..5abc48dcb5 100644
--- a/src/r_segs.cpp
+++ b/src/r_segs.cpp
@@ -71,6 +71,9 @@ bool		markceiling;
 FTexture *toptexture;
 FTexture *bottomtexture;
 FTexture *midtexture;
+fixed_t rw_offset_top;
+fixed_t rw_offset_mid;
+fixed_t rw_offset_bottom;
 
 int OWallMost (short *mostbuf, fixed_t z);
 int WallMost (short *mostbuf, const secplane_t &plane);
@@ -219,7 +222,7 @@ void R_RenderMaskedSegRange (drawseg_t *ds, int x1, int x2)
 	frontsector = curline->frontsector;
 	backsector = curline->backsector;
 
-	tex = TexMan(curline->sidedef->midtexture);
+	tex = TexMan(curline->sidedef->GetTexture(side_t::mid));
 
 	// killough 4/13/98: get correct lightlevel for 2s normal textures
 	const sector_t *sec = R_FakeFlat (frontsector, &tempsec, NULL, NULL, false);
@@ -259,11 +262,13 @@ void R_RenderMaskedSegRange (drawseg_t *ds, int x1, int x2)
 	{
 		dc_texturemid = MIN (frontsector->ceilingtexz, backsector->ceilingtexz);
 	}
+
+	fixed_t rowoffset = curline->sidedef->GetTextureYOffset(side_t::mid);
 	if (tex->bWorldPanning)
 	{
 		// rowoffset is added before the MulScale3 so that the masked texture will
 		// still be positioned in world units rather than texels.
-		dc_texturemid += curline->sidedef->rowoffset - viewz;
+		dc_texturemid += rowoffset - viewz;
 		textop = dc_texturemid;
 		dc_texturemid = MulScale16 (dc_texturemid, tex->yScale);
 	}
@@ -271,8 +276,8 @@ void R_RenderMaskedSegRange (drawseg_t *ds, int x1, int x2)
 	{
 		// rowoffset is added outside the multiply so that it positions the texture
 		// by texels instead of world units.
-		textop = dc_texturemid - viewz + SafeDivScale16 (curline->sidedef->rowoffset, tex->yScale);
-		dc_texturemid = MulScale16 (dc_texturemid - viewz, tex->yScale) + curline->sidedef->rowoffset;
+		textop = dc_texturemid - viewz + SafeDivScale16 (rowoffset, tex->yScale);
+		dc_texturemid = MulScale16 (dc_texturemid - viewz, tex->yScale) + rowoffset;
 	}
 
 	if (fixedlightlev)
@@ -1058,7 +1063,11 @@ void R_RenderSegLoop ()
 			}
 			if (midtexture->bWorldPanning)
 			{
-				rw_offset = MulScale16 (xoffset, midtexture->xScale);
+				rw_offset = MulScale16 (rw_offset_mid, midtexture->xScale);
+			}
+			else
+			{
+				rw_offset = rw_offset_mid;
 			}
 			if (fixedlightlev || fixedcolormap || !frontsector->ExtraLights)
 			{
@@ -1092,7 +1101,11 @@ void R_RenderSegLoop ()
 				}
 				if (toptexture->bWorldPanning)
 				{
-					rw_offset = MulScale16 (xoffset, toptexture->xScale);
+					rw_offset = MulScale16 (rw_offset_top, toptexture->xScale);
+				}
+				else
+				{
+					rw_offset = rw_offset_top;
 				}
 				if (fixedlightlev || fixedcolormap || !frontsector->ExtraLights)
 				{
@@ -1129,11 +1142,11 @@ void R_RenderSegLoop ()
 				}
 				if (bottomtexture->bWorldPanning)
 				{
-					rw_offset = MulScale16 (xoffset, bottomtexture->xScale);
+					rw_offset = MulScale16 (rw_offset_bottom, bottomtexture->xScale);
 				}
 				else
 				{
-					rw_offset = xoffset;
+					rw_offset = rw_offset_bottom;
 				}
 				if (fixedlightlev || fixedcolormap || !frontsector->ExtraLights)
 				{
@@ -1179,8 +1192,9 @@ void R_NewWall (bool needlights)
 			// [RH] Horizon lines do not need to be textured
 			if (linedef->special != Line_Horizon)
 			{
-				midtexture = TexMan(sidedef->midtexture);
-				rowoffset = sidedef->rowoffset;
+				midtexture = TexMan(sidedef->GetTexture(side_t::mid));
+				rw_offset_mid = sidedef->GetTextureXOffset(side_t::mid);
+				rowoffset = sidedef->GetTextureYOffset(side_t::mid);
 				if (linedef->flags & ML_DONTPEGBOTTOM)
 				{ // bottom of texture at bottom
 					rw_midtexturemid = frontsector->floortexz + (midtexture->GetHeight() << FRACBITS);
@@ -1271,7 +1285,7 @@ void R_NewWall (bool needlights)
 
 				|| (backsector->floor_angle + backsector->base_floor_angle) != (frontsector->floor_angle + frontsector->base_floor_angle)
 
-				|| (sidedef->midtexture && linedef->flags & (ML_CLIP_MIDTEX|ML_WRAP_MIDTEX))
+				|| (sidedef->GetTexture(side_t::mid) && linedef->flags & (ML_CLIP_MIDTEX|ML_WRAP_MIDTEX))
 				;
 
 			markceiling = (frontsector->ceilingpic != skyflatnum ||
@@ -1300,16 +1314,17 @@ void R_NewWall (bool needlights)
 
 				|| (backsector->ceiling_angle + backsector->base_ceiling_angle) != (frontsector->ceiling_angle + frontsector->base_ceiling_angle)
 
-				|| (sidedef->midtexture && linedef->flags & (ML_CLIP_MIDTEX|ML_WRAP_MIDTEX))
+				|| (sidedef->GetTexture(side_t::mid) && linedef->flags & (ML_CLIP_MIDTEX|ML_WRAP_MIDTEX))
 				);
 		}
 
 		if (rw_havehigh)
 		{ // top texture
-			toptexture = TexMan(sidedef->toptexture);
+			toptexture = TexMan(sidedef->GetTexture(side_t::top));
 			const fixed_t scale = toptexture->yScale;
 
-			rowoffset = sidedef->rowoffset;
+			rw_offset_top = sidedef->GetTextureXOffset(side_t::top);
+			rowoffset = sidedef->GetTextureYOffset(side_t::top);
 			if (linedef->flags & ML_DONTPEGTOP)
 			{ // top of texture at top
 				rw_toptexturemid = MulScale16 (frontsector->ceilingtexz - viewz, scale);
@@ -1333,9 +1348,10 @@ void R_NewWall (bool needlights)
 		}
 		if (rw_havelow)
 		{ // bottom texture
-			bottomtexture = TexMan(sidedef->bottomtexture);
+			bottomtexture = TexMan(sidedef->GetTexture(side_t::bottom));
 
-			rowoffset = sidedef->rowoffset;
+			rw_offset_bottom = sidedef->GetTextureXOffset(side_t::bottom);
+			rowoffset = sidedef->GetTextureYOffset(side_t::bottom);
 			if (linedef->flags & ML_DONTPEGBOTTOM)
 			{ // bottom of texture at bottom
 				rw_bottomtexturemid = rw_frontlowertop;
@@ -1375,12 +1391,14 @@ void R_NewWall (bool needlights)
 			markceiling = false;
 	}
 
-	segtextured = TexMan(sidedef->midtexture) != NULL || toptexture != NULL || bottomtexture != NULL;
+	FTexture *midtex = TexMan(sidedef->GetTexture(side_t::mid));
+
+	segtextured = midtex != NULL || toptexture != NULL || bottomtexture != NULL;
 
 	// calculate light table
 	if (needlights && (segtextured || (backsector && IsFogBoundary (frontsector, backsector))))
 	{
-		lwallscale = TexMan(sidedef->midtexture) ? TexMan(sidedef->midtexture)->xScale :
+		lwallscale = midtex ? midtex->xScale :
 							toptexture ? toptexture->xScale :
 							bottomtexture ? bottomtexture->xScale : FRACUNIT;
 
@@ -1402,7 +1420,7 @@ void R_NewWall (bool needlights)
 	}
 }
 
-int side_s::GetLightLevel (bool foggy, int baselight) const
+int side_t::GetLightLevel (bool foggy, int baselight) const
 {
 	// [RH] Get wall light level
 	if (this->Flags & WALLF_ABSLIGHTING && (!(this->Flags & WALLF_AUTOCONTRAST) || foggy))
@@ -1431,6 +1449,24 @@ int side_s::GetLightLevel (bool foggy, int baselight) const
 	}
 }
 
+FArchive &operator<< (FArchive &arc, side_t::part &p)
+{
+	arc << p.xoffset << p.yoffset;// << p.Light;
+	if (arc.IsStoring())
+	{
+		if (arc.IsStoring ())
+		{
+			TexMan.WriteTexture (arc, p.texture);
+		}
+		else
+		{
+			p.texture = TexMan.ReadTexture (arc);
+		}
+	}
+	return arc;
+}
+
+
 
 //
 // R_CheckDrawSegs
@@ -1491,7 +1527,7 @@ void R_StoreWallRange (int start, int stop)
 		R_NewWall (true);
 	}
 
-	rw_offset = sidedef->textureoffset;
+	rw_offset = sidedef->GetTextureXOffset(side_t::mid);
 	rw_light = rw_lightleft + rw_lightstep * (start - WallSX1);
 
 	ds_p->sx1 = WallSX1;
@@ -1568,9 +1604,9 @@ void R_StoreWallRange (int start, int stop)
 
 		// allocate space for masked texture tables, if needed
 		// [RH] Don't just allocate the space; fill it in too.
-		if ((TexMan(sidedef->midtexture)->UseType != FTexture::TEX_Null || IsFogBoundary (frontsector, backsector)) &&
-			(rw_ceilstat != 12 || sidedef->toptexture == 0) &&
-			(rw_floorstat != 3 || sidedef->bottomtexture == 0) &&
+		if ((TexMan(sidedef->GetTexture(side_t::mid))->UseType != FTexture::TEX_Null || IsFogBoundary (frontsector, backsector)) &&
+			(rw_ceilstat != 12 || sidedef->GetTexture(side_t::top) == 0) &&
+			(rw_floorstat != 3 || sidedef->GetTexture(side_t::bottom) == 0) &&
 			(WallSZ1 >= TOO_CLOSE_Z && WallSZ2 >= TOO_CLOSE_Z))
 		{
 			fixed_t *swal;
@@ -1580,15 +1616,15 @@ void R_StoreWallRange (int start, int stop)
 			maskedtexture = true;
 
 			ds_p->bFogBoundary = IsFogBoundary (frontsector, backsector);
-			if (sidedef->midtexture != 0)
+			if (sidedef->GetTexture(side_t::mid) != 0)
 			{
 				ds_p->maskedtexturecol = R_NewOpening ((stop - start) * 2);
 				ds_p->swall = R_NewOpening ((stop - start) * 2);
 
 				lwal = (fixed_t *)(openings + ds_p->maskedtexturecol);
 				swal = (fixed_t *)(openings + ds_p->swall);
-				int scaley = TexMan(sidedef->midtexture)->yScale;
-				int xoffset = rw_offset;
+				int scaley = TexMan(sidedef->GetTexture(side_t::mid))->yScale;
+				int xoffset = sidedef->GetTextureXOffset(side_t::mid);
 				for (i = start; i < stop; i++)
 				{
 					*lwal++ = lwall[i] + xoffset;
@@ -1667,7 +1703,7 @@ void R_StoreWallRange (int start, int stop)
 		memcpy (openings + ds_p->sprbottomclip, &floorclip[start], sizeof(short)*(stop-start));
 	}
 
-	if (maskedtexture && curline->sidedef->midtexture != 0)
+	if (maskedtexture && curline->sidedef->GetTexture(side_t::mid) != 0)
 	{
 		ds_p->silhouette |= SIL_TOP | SIL_BOTTOM;
 	}
diff --git a/src/version.h b/src/version.h
index 191aed244d..8bf3edc215 100644
--- a/src/version.h
+++ b/src/version.h
@@ -75,7 +75,7 @@
 // SAVESIG should match SAVEVER.
 
 // MINSAVEVER is the minimum level snapshot version that can be loaded.
-#define MINSAVEVER 825
+#define MINSAVEVER 832
 
 #if SVN_REVISION_NUMBER < MINSAVEVER
 // Never write a savegame with a version lower than what we need