diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9b4c0792d..48892e944 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -318,7 +318,7 @@ else()
 
 
 	if( APPLE )
-		set(CMAKE_OSX_DEPLOYMENT_TARGET "10.12")
+		set(CMAKE_OSX_DEPLOYMENT_TARGET "10.13")
 		if( CMAKE_CXX_COMPILER_ID STREQUAL "GNU" )
 			# If we're compiling with a custom GCC on the Mac (which we know since g++-4.2 doesn't support C++11) statically link libgcc.
 			set( ALL_C_FLAGS "-static-libgcc" )
diff --git a/specs/udmf_zdoom.txt b/specs/udmf_zdoom.txt
index 6057c328d..adcfd1239 100644
--- a/specs/udmf_zdoom.txt
+++ b/specs/udmf_zdoom.txt
@@ -233,6 +233,12 @@ Note: All <bool> fields default to false unless mentioned otherwise.
       lm_sampledist_top = <int>;    // ZDRay customizable sampling distance for this sidedef's top part. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0
       lm_sampledist_mid = <int>;    // ZDRay customizable sampling distance for this sidedef's middle part. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0
       lm_sampledist_bot = <int>;    // ZDRay customizable sampling distance for this sidedef's bottom part. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0	  
+	  
+	  skew_top = <int>;             // enables skewing of wall textures, the skewing angle will be aligned to one of the 4 planes touching the floor. 
+      skew_middle = <int>;          // Vertical texture alignment defines the position at the leftmost point of the wall.
+      skew_bottom = <int>;          // Possible values: 0 = no skewing, 1 = align to front floor, 2 = align to front ceiling, 3 = align to back floor, 4 = align to back ceiling.
+	                                // Front/Back are relative to the sidedef, not the owning linedef. Default = 0.
+
    }
 
    sector
@@ -542,6 +548,9 @@ Added/updated ZDRay/lightmap-related properties.
 1.35 15.09.2023
 fixed omissions: Blocklandmonsters and Blockfloaters line flags.
 
+1.36 20.10.2023
+Sidedef skewing properties
+
 ===============================================================================
 EOF
 ===============================================================================
diff --git a/src/common/engine/serializer.cpp b/src/common/engine/serializer.cpp
index 34fd6956b..7fbf7adc6 100644
--- a/src/common/engine/serializer.cpp
+++ b/src/common/engine/serializer.cpp
@@ -1,4 +1,5 @@
 /*
+/*
 ** serializer.cpp
 ** Savegame wrapper around RapidJSON
 **
diff --git a/src/common/models/modelrenderer.h b/src/common/models/modelrenderer.h
index 18c49f641..d921e7100 100644
--- a/src/common/models/modelrenderer.h
+++ b/src/common/models/modelrenderer.h
@@ -17,8 +17,8 @@ public:
 
 	virtual VSMatrix GetViewToWorldMatrix() = 0;
 
-	virtual void BeginDrawHUDModel(FRenderStyle style, const VSMatrix &objectToWorldMatrix, bool mirrored) = 0;
-	virtual void EndDrawHUDModel(FRenderStyle style) = 0;
+	virtual void BeginDrawHUDModel(FRenderStyle style, const VSMatrix &objectToWorldMatrix, bool mirrored, FSpriteModelFrame *smf) = 0;
+	virtual void EndDrawHUDModel(FRenderStyle style, FSpriteModelFrame *smf) = 0;
 
 	virtual void SetInterpolation(double interpolation) = 0;
 	virtual void SetMaterial(FGameTexture *skin, bool clampNoFilter, int translation) = 0;
diff --git a/src/g_game.cpp b/src/g_game.cpp
index 8a20b76a5..3f30a5788 100644
--- a/src/g_game.cpp
+++ b/src/g_game.cpp
@@ -1892,9 +1892,9 @@ bool G_CheckSaveGameWads (FSerializer &arc, bool printwarn)
 	bool printRequires = false;
 	FString text;
 
-	arc("Game WAD", text);
+	text = arc.GetString("Game WAD");
 	CheckSingleWad (text.GetChars(), printRequires, printwarn);
-	arc("Map WAD", text);
+	text = arc.GetString("Map WAD");
 	CheckSingleWad (text.GetChars(), printRequires, printwarn);
 
 	if (printRequires)
diff --git a/src/gamedata/r_defs.h b/src/gamedata/r_defs.h
index f164a92a4..0009c1662 100644
--- a/src/gamedata/r_defs.h
+++ b/src/gamedata/r_defs.h
@@ -1201,6 +1201,15 @@ struct side_t
 		walltop = 0,
 		wallbottom = 1,
 	};
+	enum ESkew
+	{
+		skew_none = 0,
+		skew_front_floor = 1,
+		skew_front_ceiling = 2,
+		skew_back_floor = 3,
+		skew_back_ceiling = 4
+	};
+
 	struct part
 	{
 		enum EPartFlags
@@ -1216,7 +1225,8 @@ struct side_t
 		double xScale;
 		double yScale;
 		TObjPtr<DInterpolation*> interpolation;
-		int flags;
+		int16_t flags;
+		int8_t skew;
 		FTextureID texture;
 		TextureManipulation TextureFx;
 		PalEntry SpecialColors[2];
diff --git a/src/gamedata/umapinfo.cpp b/src/gamedata/umapinfo.cpp
index bb442f78d..08e16d9f8 100644
--- a/src/gamedata/umapinfo.cpp
+++ b/src/gamedata/umapinfo.cpp
@@ -443,11 +443,13 @@ void CommitUMapinfo(level_info_t *defaultinfo)
 		if (map.partime > 0) levelinfo->partime = map.partime;
 		if (map.enterpic[0]) levelinfo->EnterPic = map.enterpic;
 		if (map.exitpic[0]) levelinfo->ExitPic = map.exitpic;
+		/* UMAPINFO's intermusic is for the text screen, not the summary.
 		if (map.intermusic[0])
 		{
 			levelinfo->InterMusic = map.intermusic;
 			levelinfo->intermusicorder = 0;
 		}
+		*/
 		if (map.BossActions.Size() > 0 || map.BossCleared)
 		{
 			// Setting a boss action will deactivate the flag based monster actions.
diff --git a/src/gamedata/xlat/xlat.h b/src/gamedata/xlat/xlat.h
index f488704ff..516104af1 100644
--- a/src/gamedata/xlat/xlat.h
+++ b/src/gamedata/xlat/xlat.h
@@ -82,7 +82,7 @@ struct FBoomTranslator
 {
 	uint16_t FirstLinetype = 0;
 	uint16_t LastLinetype = 0;
-	uint8_t NewSpecial = 0;
+	uint16_t NewSpecial = 0;
 	TArray<FBoomArg> Args;
 } ;
 
diff --git a/src/maploader/udmf.cpp b/src/maploader/udmf.cpp
index bb26f4dce..61416df38 100644
--- a/src/maploader/udmf.cpp
+++ b/src/maploader/udmf.cpp
@@ -104,6 +104,26 @@ static char HexenSectorSpecialOk[256]={
 	1,1,1,1,1,
 };
 
+#if 0
+static const char* udmfsolidskewtypes[] =
+{
+   "none",
+   "front",
+   "back",
+   nullptr
+};
+
+static const char* udmfmaskedskewtypes[] =
+{
+   "none",
+   "front_floor",
+   "front_ceiling",
+   "back_floor",
+   "back_ceiling",
+   nullptr
+};
+#endif
+
 static inline bool P_IsThingSpecial(int specnum)
 {
 	return (specnum >= Thing_Projectile && specnum <= Thing_SpawnNoFog) ||
@@ -282,6 +302,20 @@ const char *UDMFParserBase::CheckString(FName key)
 	return parsedString.GetChars();
 }
 
+int UDMFParserBase::MatchString(FName key, const char* const* strings, int defval)
+{
+	const char* string = CheckString(key);
+	for (int i = 0; *strings != nullptr; i++, strings++)
+	{
+		if (!stricmp(string, *strings))
+		{
+			return i;
+		}
+	}
+	sc.ScriptMessage("Unknown value %s for key '%s'", string, key.GetChars());
+	return defval;
+}
+
 //===========================================================================
 //
 // Storage of UDMF user properties
@@ -1537,6 +1571,38 @@ public:
 				sd->textures[side_t::bottom].LightmapSampleDistance = CheckInt(key);
 				break;
 
+#if 0		// specs are to rough and too vague - needs to be cleared first how this works.
+			case NAME_skew_top_type:
+				CHECK_N(Zd | Zdt)
+				sd->textures[side_t::top].skew = MatchString(key, udmfsolidskewtypes, 0);
+				break;
+
+			case NAME_skew_middle_type:
+				CHECK_N(Zd | Zdt)
+					sd->textures[side_t::mid].skew = MatchString(key, udmfmaskedskewtypes, 0);
+				break;
+
+			case NAME_skew_bottom_type:
+				CHECK_N(Zd | Zdt)
+					sd->textures[side_t::bottom].skew = MatchString(key, udmfsolidskewtypes, 0);
+				break;
+#endif
+
+			case NAME_skew_top:
+				CHECK_N(Zd | Zdt)
+					sd->textures[side_t::top].skew = CheckInt(key);
+				break;
+
+			case NAME_skew_middle:
+				CHECK_N(Zd | Zdt)
+					sd->textures[side_t::mid].skew = CheckInt(key);
+				break;
+
+			case NAME_skew_bottom:
+				CHECK_N(Zd | Zdt)
+					sd->textures[side_t::bottom].skew = CheckInt(key);
+				break;
+
 			default:
 				if (strnicmp("user_", key.GetChars(), 5))
 					DPrintf(DMSG_WARNING, "Unknown UDMF sidedef key %s\n", key.GetChars());
@@ -2262,6 +2328,19 @@ public:
 						sides[side].sector = &Level->sectors[intptr_t(sides[side].sector)];
 						lines[line].sidedef[sd] = &sides[side];
 
+#if 0
+						if (sd == 1)
+						{
+							// fix flags for backside. The definition is linedef relative, not sidedef relative.
+							static const uint8_t swaps[] = { 0, side_t::skew_back, side_t::skew_front };
+							static const uint8_t swapsm[] = {0, side_t::skew_back_floor, side_t::skew_back_ceiling, side_t::skew_front_floor, side_t::skew_front_ceiling};
+
+							sides[side].textures[side_t::top].skew = swaps[sides[side].textures[side_t::top].skew];
+							sides[side].textures[side_t::bottom].skew = swaps[sides[side].textures[side_t::bottom].skew];
+							sides[side].textures[side_t::mid].skew = swapsm[sides[side].textures[side_t::mid].skew];
+						}
+#endif
+
 						loader->ProcessSideTextures(!isExtended, &sides[side], sides[side].sector, &ParsedSideTextures[mapside],
 							lines[line].special, lines[line].args[0], &tempalpha[sd], missingTex);
 
diff --git a/src/maploader/udmf.h b/src/maploader/udmf.h
index ed18345b5..38d904288 100644
--- a/src/maploader/udmf.h
+++ b/src/maploader/udmf.h
@@ -21,6 +21,7 @@ protected:
 	DAngle CheckAngle(FName key);
 	bool CheckBool(FName key);
 	const char *CheckString(FName key);
+	int MatchString(FName key, const char* const* strings, int defval);
 
 	template<typename T>
 	bool Flag(T &value, int mask, FName key)
diff --git a/src/namedef_custom.h b/src/namedef_custom.h
index 2cac59f5d..6f5e281a0 100644
--- a/src/namedef_custom.h
+++ b/src/namedef_custom.h
@@ -858,4 +858,11 @@ xx(lm_sampledist_ceiling)
 xx(lm_suncolor)
 xx(lm_dynamic)
 
+xx(skew_bottom_type)
+xx(skew_middle_type)
+xx(skew_top_type)
+xx(skew_bottom)
+xx(skew_middle)
+xx(skew_top)
+
 xx(Corona)
diff --git a/src/p_saveg.cpp b/src/p_saveg.cpp
index f99a630fb..6088a8f52 100644
--- a/src/p_saveg.cpp
+++ b/src/p_saveg.cpp
@@ -140,6 +140,7 @@ FSerializer &Serialize(FSerializer &arc, const char *key, side_t::part &part, si
 			("texture", part.texture, def->texture)
 			("interpolation", part.interpolation)
 			("flags", part.flags, def->flags)
+			("skew", part.skew, def->skew)
 			("color1", part.SpecialColors[0], def->SpecialColors[0])
 			("color2", part.SpecialColors[1], def->SpecialColors[1])
 			("addcolor", part.AdditiveColor, def->AdditiveColor)
diff --git a/src/playsim/p_3dmidtex.cpp b/src/playsim/p_3dmidtex.cpp
index 315ded0c9..0e2d7e10d 100644
--- a/src/playsim/p_3dmidtex.cpp
+++ b/src/playsim/p_3dmidtex.cpp
@@ -44,6 +44,7 @@
 #include "g_levellocals.h"
 #include "actor.h"
 #include "texturemanager.h"
+#include "vm.h"
 
 
 //============================================================================
@@ -258,6 +259,20 @@ bool P_GetMidTexturePosition(const line_t *line, int sideno, double *ptextop, do
 	return true;
 }
 
+DEFINE_ACTION_FUNCTION(_Line, GetMidTexturePosition)
+{
+	PARAM_SELF_STRUCT_PROLOGUE(line_t);
+	PARAM_INT(side);
+	double top = 0.0;
+	double bottom = 0.0;
+
+	bool res = P_GetMidTexturePosition(self,side,&top,&bottom);
+	if (numret > 2) ret[2].SetFloat(bottom);
+	if (numret > 1) ret[1].SetFloat(top);
+	if (numret > 0) ret[0].SetInt(int(res));
+	return numret;
+}
+
 //============================================================================
 //
 // P_LineOpening_3dMidtex
diff --git a/src/r_data/models.cpp b/src/r_data/models.cpp
index ae409507e..60a3e50ce 100644
--- a/src/r_data/models.cpp
+++ b/src/r_data/models.cpp
@@ -261,11 +261,11 @@ void RenderHUDModel(FModelRenderer *renderer, DPSprite *psp, FVector3 translatio
 
 	float orientation = smf->xscale * smf->yscale * smf->zscale;
 
-	renderer->BeginDrawHUDModel(playermo->RenderStyle, objectToWorldMatrix, orientation < 0);
+	renderer->BeginDrawHUDModel(playermo->RenderStyle, objectToWorldMatrix, orientation < 0, smf);
 	uint32_t trans = psp->GetTranslation() != 0 ? psp->GetTranslation() : 0;
 	if ((psp->Flags & PSPF_PLAYERTRANSLATED)) trans = psp->Owner->mo->Translation;
 	RenderFrameModels(renderer, playermo->Level, smf, psp->GetState(), psp->GetTics(), psp->Caller->modelData != nullptr ? psp->Caller->modelData->modelDef != NAME_None ? PClass::FindActor(psp->Caller->modelData->modelDef) : psp->Caller->GetClass() : psp->Caller->GetClass(), trans, psp->Caller);
-	renderer->EndDrawHUDModel(playermo->RenderStyle);
+	renderer->EndDrawHUDModel(playermo->RenderStyle, smf);
 }
 
 void RenderFrameModels(FModelRenderer *renderer, FLevelLocals *Level, const FSpriteModelFrame *smf, const FState *curState, const int curTics, const PClass *ti, int translation, AActor* actor)
diff --git a/src/rendering/hwrenderer/hw_models.cpp b/src/rendering/hwrenderer/hw_models.cpp
index 4aec7c1ae..5b2f14d9b 100644
--- a/src/rendering/hwrenderer/hw_models.cpp
+++ b/src/rendering/hwrenderer/hw_models.cpp
@@ -88,7 +88,7 @@ void FHWModelRenderer::EndDrawModel(FRenderStyle style, FSpriteModelFrame *smf)
 		state.SetCulling(Cull_None);
 }
 
-void FHWModelRenderer::BeginDrawHUDModel(FRenderStyle style, const VSMatrix &objectToWorldMatrix, bool mirrored)
+void FHWModelRenderer::BeginDrawHUDModel(FRenderStyle style, const VSMatrix &objectToWorldMatrix, bool mirrored, FSpriteModelFrame *smf)
 {
 	state.SetDepthFunc(DF_LEqual);
 	state.SetDepthClamp(true);
@@ -104,7 +104,7 @@ void FHWModelRenderer::BeginDrawHUDModel(FRenderStyle style, const VSMatrix &obj
 	// [BB] In case the model should be rendered translucent, do back face culling.
 	// This solves a few of the problems caused by the lack of depth sorting.
 	// TO-DO: Implement proper depth sorting.
-	if (!(style == DefaultRenderStyle()))
+	if (!(style == DefaultRenderStyle()) || (smf->flags & MDL_FORCECULLBACKFACES))
 	{
 		state.SetCulling((mirrored ^ di->drawctx->portalState.isMirrored()) ? Cull_CW : Cull_CCW);
 	}
@@ -114,13 +114,13 @@ void FHWModelRenderer::BeginDrawHUDModel(FRenderStyle style, const VSMatrix &obj
 	state.SetModelMatrix(objectToWorldMatrix, normalModelMatrix);
 }
 
-void FHWModelRenderer::EndDrawHUDModel(FRenderStyle style)
+void FHWModelRenderer::EndDrawHUDModel(FRenderStyle style, FSpriteModelFrame *smf)
 {
 	state.SetBoneIndexBase(-1);
 	state.SetModelMatrix(VSMatrix::identity(), VSMatrix::identity());
 
 	state.SetDepthFunc(DF_Less);
-	if (!(style == DefaultRenderStyle()))
+	if (!(style == DefaultRenderStyle()) || (smf->flags & MDL_FORCECULLBACKFACES))
 		state.SetCulling(Cull_None);
 }
 
diff --git a/src/rendering/hwrenderer/hw_models.h b/src/rendering/hwrenderer/hw_models.h
index 32248152b..80c9376af 100644
--- a/src/rendering/hwrenderer/hw_models.h
+++ b/src/rendering/hwrenderer/hw_models.h
@@ -50,8 +50,8 @@ public:
 	void EndDrawModel(FRenderStyle style, FSpriteModelFrame *smf) override;
 	IModelVertexBuffer *CreateVertexBuffer(bool needindex, bool singleframe) override;
 	VSMatrix GetViewToWorldMatrix() override;
-	void BeginDrawHUDModel(FRenderStyle style, const VSMatrix &objectToWorldMatrix, bool mirrored) override;
-	void EndDrawHUDModel(FRenderStyle style) override;
+	void BeginDrawHUDModel(FRenderStyle style, const VSMatrix &objectToWorldMatrix, bool mirrored, FSpriteModelFrame *smf) override;
+	void EndDrawHUDModel(FRenderStyle style, FSpriteModelFrame *smf) override;
 	void SetInterpolation(double interpolation) override;
 	void SetMaterial(FGameTexture *skin, bool clampNoFilter, int translation) override;
 	void DrawArrays(int start, int count) override;
diff --git a/src/rendering/hwrenderer/scene/hw_decal.cpp b/src/rendering/hwrenderer/scene/hw_decal.cpp
index 25d3749ed..e1c604c94 100644
--- a/src/rendering/hwrenderer/scene/hw_decal.cpp
+++ b/src/rendering/hwrenderer/scene/hw_decal.cpp
@@ -35,6 +35,7 @@
 #include "hwrenderer/scene/hw_drawinfo.h"
 #include "hw_lighting.h"
 #include "hw_clock.h"
+#include "hw_drawcontext.h"
 #include "flatvertices.h"
 #include "hw_renderstate.h"
 #include "texturemanager.h"
@@ -70,7 +71,7 @@ void HWDecal::DrawDecal(HWDrawInfo *di, FRenderState &state)
 	else state.AlphaFunc(Alpha_Greater, 0.f);
 
 
-	di->SetColor(state, lightlevel, rellight, di->isFullbrightScene(), Colormap, alpha);
+	SetColor(state, di->Level, di->lightmode, lightlevel, rellight, di->isFullbrightScene(), Colormap, alpha);
 	// for additively drawn decals we must temporarily set the fog color to black.
 	PalEntry fc = state.GetFogColor();
 	if (decal->RenderStyle.BlendOp == STYLEOP_Add && decal->RenderStyle.DestAlpha == STYLEALPHA_One)
@@ -101,9 +102,9 @@ void HWDecal::DrawDecal(HWDrawInfo *di, FRenderState &state)
 				FColormap thiscm;
 				thiscm.FadeColor = Colormap.FadeColor;
 				CopyFrom3DLight(thiscm, &lightlist[k]);
-				di->SetColor(state, thisll, rellight, di->isFullbrightScene(), thiscm, alpha);
+				SetColor(state, di->Level, di->lightmode, thisll, rellight, di->isFullbrightScene(), thiscm, alpha);
 				if (di->Level->flags3 & LEVEL3_NOCOLOREDSPRITELIGHTING) thiscm.Decolorize();
-				di->SetFog(state, thisll, rellight, di->isFullbrightScene(), &thiscm, false);
+				SetFog(state, di->Level, di->lightmode, thisll, rellight, di->isFullbrightScene(), &thiscm, false, di->drawctx->portalState.inskybox);
 				SetSplitPlanes(state, lightlist[k].plane, lowplane);
 
 				state.Draw(DT_TriangleStrip, vertindex, 4);
@@ -142,7 +143,7 @@ void HWDrawInfo::DrawDecals(FRenderState &state, TArray<HWDecal *> &decals)
 			else
 			{
 				state.EnableSplit(false);
-				SetFog(state, gldecal->lightlevel, gldecal->rellight, isFullbrightScene(), &gldecal->Colormap, false);
+				SetFog(state, Level, lightmode, gldecal->lightlevel, gldecal->rellight, isFullbrightScene(), &gldecal->Colormap, false, drawctx->portalState.inskybox);
 			}
 		}
 		gldecal->DrawDecal(this, state);
@@ -164,7 +165,7 @@ void HWWall::DrawDecalsForMirror(HWDrawInfo *di, FRenderState &state, TArray<HWD
 {
 	state.SetDepthMask(false);
 	state.SetDepthBias(-1, -128);
-	di->SetFog(state, lightlevel, rellight + getExtraLight(), di->isFullbrightScene(), &Colormap, false);
+	SetFog(state, di->Level, di->lightmode, lightlevel, rellight + getExtraLight(), di->isFullbrightScene(), &Colormap, false, di->drawctx->portalState.inskybox);
 	for (auto gldecal : decals)
 	{
 		if (gldecal->decal->Side == seg->sidedef)
diff --git a/src/rendering/hwrenderer/scene/hw_drawinfo.cpp b/src/rendering/hwrenderer/scene/hw_drawinfo.cpp
index d88c7c757..093a4a2bd 100644
--- a/src/rendering/hwrenderer/scene/hw_drawinfo.cpp
+++ b/src/rendering/hwrenderer/scene/hw_drawinfo.cpp
@@ -599,7 +599,7 @@ void HWDrawInfo::DrawCorona(FRenderState& state, AActor* corona, float coronaFad
 	alpha *= distFade;
 
 	state.SetColorAlpha(0xffffff, alpha, 0);
-	if (isSoftwareLighting()) state.SetSoftLightLevel(255);
+	if (isSoftwareLighting(lightmode)) state.SetSoftLightLevel(255);
 	else state.SetNoSoftLightLevel();
 
 	state.SetLightIndex(-1);
diff --git a/src/rendering/hwrenderer/scene/hw_drawinfo.h b/src/rendering/hwrenderer/scene/hw_drawinfo.h
index 1574d8c86..8ef0155e3 100644
--- a/src/rendering/hwrenderer/scene/hw_drawinfo.h
+++ b/src/rendering/hwrenderer/scene/hw_drawinfo.h
@@ -199,13 +199,6 @@ struct HWDrawInfo
 	void RenderParticles(subsector_t *sub, sector_t *front);
 	void DoSubsector(subsector_t * sub);
 	void DrawPSprite(HUDSprite* huds, FRenderState& state);
-	void SetColor(FRenderState& state, int sectorlightlevel, int rellight, bool fullbright, const FColormap& cm, float alpha, bool weapon = false);
-	void SetFog(FRenderState& state, int lightlevel, int rellight, bool fullbright, const FColormap* cmap, bool isadditive);
-	void SetShaderLight(FRenderState& state, float level, float olight);
-	int CalcLightLevel(int lightlevel, int rellight, bool weapon, int blendfactor);
-	PalEntry CalcLightColor(int light, PalEntry pe, int blendfactor);
-	float GetFogDensity(int lightlevel, PalEntry fogcolor, int sectorfogdensity, int blendfactor);
-	bool CheckFog(sector_t* frontsector, sector_t* backsector);
 	WeaponLighting GetWeaponLighting(sector_t* viewsector, const DVector3& pos, int cm, area_t in_area, const DVector3& playerpos);
 
 	void PreparePlayerSprites2D(sector_t* viewsector, area_t in_area, FRenderState& state);
@@ -334,26 +327,6 @@ public:
 
     HWDecal *AddDecal(bool onmirror);
 
-	bool isSoftwareLighting() const
-	{
-		return lightmode == ELightMode::ZDoomSoftware || lightmode == ELightMode::DoomSoftware || lightmode == ELightMode::Build;
-	}
-
-	bool isBuildSoftwareLighting() const
-	{
-		return lightmode == ELightMode::Build;
-	}
-
-	bool isDoomSoftwareLighting() const
-	{
-		return lightmode == ELightMode::ZDoomSoftware || lightmode == ELightMode::DoomSoftware;
-	}
-
-	bool isDarkLightMode() const
-	{
-		return lightmode == ELightMode::Doom || lightmode == ELightMode::DoomDark;
-	}
-
 	void SetFallbackLightMode()
 	{
 		lightmode = ELightMode::Doom;
@@ -384,3 +357,30 @@ void WriteSavePic(player_t* player, FileWriter* file, int width, int height);
 sector_t* RenderView(player_t* player);
 
 
+inline bool isSoftwareLighting(ELightMode lightmode)
+{
+	return lightmode == ELightMode::ZDoomSoftware || lightmode == ELightMode::DoomSoftware || lightmode == ELightMode::Build;
+}
+
+inline bool isBuildSoftwareLighting(ELightMode lightmode)
+{
+	return lightmode == ELightMode::Build;
+}
+
+inline bool isDoomSoftwareLighting(ELightMode lightmode)
+{
+	return lightmode == ELightMode::ZDoomSoftware || lightmode == ELightMode::DoomSoftware;
+}
+
+inline bool isDarkLightMode(ELightMode lightmode)
+{
+	return lightmode == ELightMode::Doom || lightmode == ELightMode::DoomDark;
+}
+
+int CalcLightLevel(ELightMode lightmode, int lightlevel, int rellight, bool weapon, int blendfactor);
+PalEntry CalcLightColor(ELightMode lightmode, int light, PalEntry pe, int blendfactor);
+float GetFogDensity(FLevelLocals* Level, ELightMode lightmode, int lightlevel, PalEntry fogcolor, int sectorfogdensity, int blendfactor);
+bool CheckFog(FLevelLocals* Level, sector_t* frontsector, sector_t* backsector, ELightMode lightmode);
+void SetColor(FRenderState& state, FLevelLocals* Level, ELightMode lightmode, int sectorlightlevel, int rellight, bool fullbright, const FColormap& cm, float alpha, bool weapon = false);
+void SetShaderLight(FRenderState& state, FLevelLocals* Level, float level, float olight);
+void SetFog(FRenderState& state, FLevelLocals* Level, ELightMode lightmode, int lightlevel, int rellight, bool fullbright, const FColormap* cmap, bool isadditive, bool inskybox);
diff --git a/src/rendering/hwrenderer/scene/hw_drawlist.cpp b/src/rendering/hwrenderer/scene/hw_drawlist.cpp
index f27d4d81f..8b598a2ff 100644
--- a/src/rendering/hwrenderer/scene/hw_drawlist.cpp
+++ b/src/rendering/hwrenderer/scene/hw_drawlist.cpp
@@ -38,6 +38,7 @@
 #include "hw_drawinfo.h"
 #include "hw_fakeflat.h"
 #include "hw_drawcontext.h"
+#include "hw_walldispatcher.h"
 
 //==========================================================================
 //
@@ -373,8 +374,8 @@ void HWDrawList::SortWallIntoWall(HWDrawInfo *di, FRenderState& state, SortNode
 		w->zbottom[0]=ws->zbottom[1]=izb;
 		w->tcs[HWWall::LOLFT].u = w->tcs[HWWall::UPLFT].u = ws->tcs[HWWall::LORGT].u = ws->tcs[HWWall::UPRGT].u = iu;
 		w->lightuv[HWWall::LOLFT].u = w->lightuv[HWWall::UPLFT].u = ws->lightuv[HWWall::LORGT].u = ws->lightuv[HWWall::UPRGT].u = iu;
-		ws->MakeVertices(di, state, false);
-		w->MakeVertices(di, state, false);
+		ws->MakeVertices(state, false);
+		w->MakeVertices(state, false);
 
 		SortNode * sort2=drawctx->SortNodes.GetNew();
 		memset(sort2,0,sizeof(SortNode));
@@ -722,8 +723,9 @@ void HWDrawList::DoDraw(HWDrawInfo *di, FRenderState &state, bool translucent, i
 	case DrawType_WALL:
 		{
 			HWWall * w= walls[drawitems[i].index];
+			HWWallDispatcher dis(di);
 			RenderWall.Clock();
-			w->DrawWall(di, state, translucent);
+			w->DrawWall(&dis, state, translucent);
 			RenderWall.Unclock();
 		}
 		break;
@@ -759,10 +761,11 @@ void HWDrawList::Draw(HWDrawInfo *di, FRenderState &state, bool translucent)
 //==========================================================================
 void HWDrawList::DrawWalls(HWDrawInfo *di, FRenderState &state, bool translucent)
 {
+	HWWallDispatcher dis(di);
 	RenderWall.Clock();
 	for (auto &item : drawitems)
 	{
-		walls[item.index]->DrawWall(di, state, translucent);
+		walls[item.index]->DrawWall(&dis, state, translucent);
 	}
 	RenderWall.Unclock();
 }
diff --git a/src/rendering/hwrenderer/scene/hw_drawlistadd.cpp b/src/rendering/hwrenderer/scene/hw_drawlistadd.cpp
index cf59688c9..a44bc4e35 100644
--- a/src/rendering/hwrenderer/scene/hw_drawlistadd.cpp
+++ b/src/rendering/hwrenderer/scene/hw_drawlistadd.cpp
@@ -80,7 +80,7 @@ void HWDrawInfo::AddMirrorSurface(HWWall *w, FRenderState& state)
 	auto tcs = newwall->tcs;
 	tcs[HWWall::LOLFT].u = tcs[HWWall::LORGT].u = tcs[HWWall::UPLFT].u = tcs[HWWall::UPRGT].u = v.X;
 	tcs[HWWall::LOLFT].v = tcs[HWWall::LORGT].v = tcs[HWWall::UPLFT].v = tcs[HWWall::UPRGT].v = v.Z;
-	newwall->MakeVertices(this, state, false);
+	newwall->MakeVertices(state, false);
 
 	bool hasDecals = newwall->seg->sidedef && newwall->seg->sidedef->AttachedDecals;
 	if (hasDecals && Level->HasDynamicLights && !isFullbrightScene())
diff --git a/src/rendering/hwrenderer/scene/hw_drawstructs.h b/src/rendering/hwrenderer/scene/hw_drawstructs.h
index 374477c8c..0152679cd 100644
--- a/src/rendering/hwrenderer/scene/hw_drawstructs.h
+++ b/src/rendering/hwrenderer/scene/hw_drawstructs.h
@@ -226,7 +226,7 @@ public:
 
 	void SetupLights(HWDrawInfo* di, FRenderState& state, FDynLightData& lightdata);
 
-	void MakeVertices(HWDrawInfo* di, FRenderState& state, bool nosplit);
+	void MakeVertices(FRenderState& state, bool nosplit);
 
 	void SkyPlane(HWWallDispatcher* di, FRenderState& state, sector_t* sector, int plane, bool allowmirror);
 	void SkyLine(HWWallDispatcher* di, FRenderState& state, sector_t* sec, line_t* line);
@@ -237,19 +237,19 @@ public:
 	bool DoHorizon(HWWallDispatcher* di, FRenderState& state, seg_t* seg, sector_t* fs, vertex_t* v1, vertex_t* v2);
 
 	bool SetWallCoordinates(seg_t* seg, FTexCoordInfo* tci, float ceilingrefheight,
-		float topleft, float topright, float bottomleft, float bottomright, float t_ofs);
+		float topleft, float topright, float bottomleft, float bottomright, float t_ofs, float skew);
 
 	void DoTexture(HWWallDispatcher* di, FRenderState& state, int type, seg_t* seg, int peg,
 		float ceilingrefheight, float floorrefheight,
 		float CeilingHeightstart, float CeilingHeightend,
 		float FloorHeightstart, float FloorHeightend,
-		float v_offset);
+		float v_offset, float skew);
 
 	void DoMidTexture(HWWallDispatcher* di, FRenderState& state, seg_t* seg, bool drawfogboundary,
 		sector_t* front, sector_t* back,
 		sector_t* realfront, sector_t* realback,
 		float fch1, float fch2, float ffh1, float ffh2,
-		float bch1, float bch2, float bfh1, float bfh2, float zalign);
+		float bch1, float bch2, float bfh1, float bfh2, float zalign, float skew);
 
 	void GetPlanePos(F3DFloor::planeref* planeref, float& left, float& right);
 
@@ -280,11 +280,11 @@ public:
 
 	int CountVertices();
 
-	void RenderWall(HWDrawInfo* di, FRenderState& state, int textured);
-	void RenderFogBoundary(HWDrawInfo* di, FRenderState& state);
-	void RenderMirrorSurface(HWDrawInfo* di, FRenderState& state);
-	void RenderTexturedWall(HWDrawInfo* di, FRenderState& state, int rflags);
-	void RenderTranslucentWall(HWDrawInfo* di, FRenderState& state);
+	void RenderWall(FRenderState& state, int textured);
+	void RenderFogBoundary(HWWallDispatcher* di, FRenderState& state);
+	void RenderMirrorSurface(HWWallDispatcher* di, FRenderState& state);
+	void RenderTexturedWall(HWWallDispatcher* di, FRenderState& state, int rflags);
+	void RenderTranslucentWall(HWWallDispatcher* di, FRenderState& state);
 	void DrawDecalsForMirror(HWDrawInfo* di, FRenderState& state, TArray<HWDecal*>& decals);
 
 public:
@@ -296,7 +296,7 @@ public:
 		return -((y - glseg.y1) * (glseg.x2 - glseg.x1) - (x - glseg.x1) * (glseg.y2 - glseg.y1));
 	}
 
-	void DrawWall(HWDrawInfo* di, FRenderState& state, bool translucent);
+	void DrawWall(HWWallDispatcher* di, FRenderState& state, bool translucent);
 
 };
 
diff --git a/src/rendering/hwrenderer/scene/hw_flats.cpp b/src/rendering/hwrenderer/scene/hw_flats.cpp
index 902464d16..8e34de67c 100644
--- a/src/rendering/hwrenderer/scene/hw_flats.cpp
+++ b/src/rendering/hwrenderer/scene/hw_flats.cpp
@@ -41,6 +41,7 @@
 #include "hw_clock.h"
 #include "hw_lighting.h"
 #include "hw_material.h"
+#include "hw_drawcontext.h"
 #include "hwrenderer/scene/hw_drawinfo.h"
 #include "flatvertices.h"
 #include "hw_drawstructs.h"
@@ -321,8 +322,8 @@ void HWFlat::DrawFlat(HWDrawInfo *di, FRenderState &state, bool translucent)
 
 	state.SetNormal(plane.plane.Normal().X, plane.plane.Normal().Z, plane.plane.Normal().Y);
 
-	di->SetColor(state, lightlevel, rel, di->isFullbrightScene(), Colormap, alpha);
-	di->SetFog(state, lightlevel, rel, di->isFullbrightScene(), &Colormap, false);
+	SetColor(state, di->Level, di->lightmode, lightlevel, rel, di->isFullbrightScene(), Colormap, alpha);
+	SetFog(state, di->Level, di->lightmode, lightlevel, rel, di->isFullbrightScene(), &Colormap, false, di->drawctx->portalState.inskybox);
 	state.SetObjectColor(FlatColor | 0xff000000);
 	state.SetAddColor(AddColor | 0xff000000);
 	state.ApplyTextureManipulation(TextureFx);
diff --git a/src/rendering/hwrenderer/scene/hw_lighting.cpp b/src/rendering/hwrenderer/scene/hw_lighting.cpp
index e22a359bf..bfcaf5f74 100644
--- a/src/rendering/hwrenderer/scene/hw_lighting.cpp
+++ b/src/rendering/hwrenderer/scene/hw_lighting.cpp
@@ -76,13 +76,13 @@ CUSTOM_CVAR(Int, gl_distfog, 70, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
 //
 //==========================================================================
 
-int HWDrawInfo::CalcLightLevel(int lightlevel, int rellight, bool weapon, int blendfactor)
+int CalcLightLevel(ELightMode lightmode, int lightlevel, int rellight, bool weapon, int blendfactor)
 {
 	int light;
 
 	if (lightlevel <= 0) return 0;
 
-	bool darklightmode = (isDarkLightMode()) || (isSoftwareLighting() && blendfactor > 0);
+	bool darklightmode = (isDarkLightMode(lightmode)) || (isSoftwareLighting(lightmode) && blendfactor > 0);
 
 	if (darklightmode && lightlevel < 192 && !weapon) 
 	{
@@ -119,13 +119,13 @@ int HWDrawInfo::CalcLightLevel(int lightlevel, int rellight, bool weapon, int bl
 //
 //==========================================================================
 
-PalEntry HWDrawInfo::CalcLightColor(int light, PalEntry pe, int blendfactor)
+PalEntry CalcLightColor(ELightMode lightmode, int light, PalEntry pe, int blendfactor)
 {
 	int r,g,b;
 
 	if (blendfactor == 0)
 	{
-		if (isSoftwareLighting())
+		if (isSoftwareLighting(lightmode))
 		{
 			return pe;
 		}
@@ -165,12 +165,12 @@ PalEntry HWDrawInfo::CalcLightColor(int light, PalEntry pe, int blendfactor)
 //
 //==========================================================================
 
-float HWDrawInfo::GetFogDensity(int lightlevel, PalEntry fogcolor, int sectorfogdensity, int blendfactor)
+float GetFogDensity(FLevelLocals* Level, ELightMode lightmode, int lightlevel, PalEntry fogcolor, int sectorfogdensity, int blendfactor)
 {
 	float density;
 
 	auto oldlightmode = lightmode;
-	if (isSoftwareLighting() && blendfactor > 0) lightmode = ELightMode::Doom;	// The blendfactor feature does not work with software-style lighting.
+	if (isSoftwareLighting(lightmode) && blendfactor > 0) lightmode = ELightMode::Doom;	// The blendfactor feature does not work with software-style lighting.
 
 	if (lightmode == ELightMode::DoomLegacy)
 	{
@@ -185,7 +185,7 @@ float HWDrawInfo::GetFogDensity(int lightlevel, PalEntry fogcolor, int sectorfog
 	else if ((fogcolor.d & 0xffffff) == 0)
 	{
 		// case 2: black fog
-		if ((!isDoomSoftwareLighting() || blendfactor > 0) && !(Level->flags3 & LEVEL3_NOLIGHTFADE))
+		if ((!isDoomSoftwareLighting(lightmode) || blendfactor > 0) && !(Level->flags3 & LEVEL3_NOLIGHTFADE))
 		{
 			density = distfogtable[lightmode != ELightMode::LinearStandard][hw_ClampLight(lightlevel)];
 		}
diff --git a/src/rendering/hwrenderer/scene/hw_portal.cpp b/src/rendering/hwrenderer/scene/hw_portal.cpp
index 29dabd443..cfaf2a6f7 100644
--- a/src/rendering/hwrenderer/scene/hw_portal.cpp
+++ b/src/rendering/hwrenderer/scene/hw_portal.cpp
@@ -36,6 +36,7 @@
 #include "flatvertices.h"
 #include "hw_clock.h"
 #include "hw_lighting.h"
+#include "hw_drawcontext.h"
 #include "texturemanager.h"
 
 EXTERN_CVAR(Int, r_mirror_recursions)
@@ -969,14 +970,14 @@ void HWHorizonPortal::DrawContents(HWDrawInfo *di, FRenderState &state)
 	if (texture->isFullbright())
 	{
 		// glowing textures are always drawn full bright without color
-		di->SetColor(state, 255, 0, false, origin->colormap, 1.f);
-		di->SetFog(state, 255, 0, false, &origin->colormap, false);
+		SetColor(state, di->Level, di->lightmode, 255, 0, false, origin->colormap, 1.f);
+		SetFog(state, di->Level, di->lightmode, 255, 0, false, &origin->colormap, false, di->drawctx->portalState.inskybox);
 	}
 	else
 	{
 		int rel = getExtraLight();
-		di->SetColor(state, origin->lightlevel, rel, di->isFullbrightScene(), origin->colormap, 1.0f);
-		di->SetFog(state, origin->lightlevel, rel, di->isFullbrightScene(), &origin->colormap, false);
+		SetColor(state, di->Level, di->lightmode, origin->lightlevel, rel, di->isFullbrightScene(), origin->colormap, 1.0f);
+		SetFog(state, di->Level, di->lightmode, origin->lightlevel, rel, di->isFullbrightScene(), &origin->colormap, false, di->drawctx->portalState.inskybox);
 	}
 
 
diff --git a/src/rendering/hwrenderer/scene/hw_setcolor.cpp b/src/rendering/hwrenderer/scene/hw_setcolor.cpp
index 946be1c68..f8b150f67 100644
--- a/src/rendering/hwrenderer/scene/hw_setcolor.cpp
+++ b/src/rendering/hwrenderer/scene/hw_setcolor.cpp
@@ -38,20 +38,20 @@
 // set current light color
 //
 //==========================================================================
-void HWDrawInfo::SetColor(FRenderState &state, int sectorlightlevel, int rellight, bool fullbright, const FColormap &cm, float alpha, bool weapon)
+void SetColor(FRenderState &state, FLevelLocals* Level, ELightMode lightmode, int sectorlightlevel, int rellight, bool fullbright, const FColormap &cm, float alpha, bool weapon)
 {
 	if (fullbright)
 	{
 		state.SetColorAlpha(0xffffff, alpha, 0);
-		if (isSoftwareLighting()) state.SetSoftLightLevel(255);
+		if (isSoftwareLighting(lightmode)) state.SetSoftLightLevel(255);
 		else state.SetNoSoftLightLevel();
 	}
 	else
 	{
-		int hwlightlevel = CalcLightLevel(sectorlightlevel, rellight, weapon, cm.BlendFactor);
-		PalEntry pe = CalcLightColor(hwlightlevel, cm.LightColor, cm.BlendFactor);
+		int hwlightlevel = CalcLightLevel(lightmode, sectorlightlevel, rellight, weapon, cm.BlendFactor);
+		PalEntry pe = CalcLightColor(lightmode, hwlightlevel, cm.LightColor, cm.BlendFactor);
 		state.SetColorAlpha(pe, alpha, cm.Desaturation);
-		if (isSoftwareLighting()) state.SetSoftLightLevel(hw_ClampLight(sectorlightlevel + rellight), cm.BlendFactor);
+		if (isSoftwareLighting(lightmode)) state.SetSoftLightLevel(hw_ClampLight(sectorlightlevel + rellight), cm.BlendFactor);
 		else state.SetNoSoftLightLevel();
 	}
 }
@@ -62,7 +62,7 @@ void HWDrawInfo::SetColor(FRenderState &state, int sectorlightlevel, int relligh
 //
 //==========================================================================
 
-void HWDrawInfo::SetShaderLight(FRenderState &state, float level, float olight)
+void SetShaderLight(FRenderState &state, FLevelLocals* Level, float level, float olight)
 {
 	const float MAXDIST = 256.f;
 	const float THRESHOLD = 96.f;
@@ -96,7 +96,7 @@ void HWDrawInfo::SetShaderLight(FRenderState &state, float level, float olight)
 //
 //==========================================================================
 
-void HWDrawInfo::SetFog(FRenderState &state, int lightlevel, int rellight, bool fullbright, const FColormap *cmap, bool isadditive)
+void SetFog(FRenderState &state, FLevelLocals* Level, ELightMode lightmode, int lightlevel, int rellight, bool fullbright, const FColormap *cmap, bool isadditive, bool inskybox)
 {
 	PalEntry fogcolor;
 	float fogdensity;
@@ -109,7 +109,7 @@ void HWDrawInfo::SetFog(FRenderState &state, int lightlevel, int rellight, bool
 	else if (cmap != nullptr && !fullbright)
 	{
 		fogcolor = cmap->FadeColor;
-		fogdensity = GetFogDensity(lightlevel, fogcolor, cmap->FogDensity, cmap->BlendFactor);
+		fogdensity = GetFogDensity(Level, lightmode, lightlevel, fogcolor, cmap->FogDensity, cmap->BlendFactor);
 		fogcolor.a = 0;
 	}
 	else
@@ -119,7 +119,7 @@ void HWDrawInfo::SetFog(FRenderState &state, int lightlevel, int rellight, bool
 	}
 
 	// Make fog a little denser when inside a skybox
-	if (drawctx->portalState.inskybox) fogdensity += fogdensity / 2;
+	if (inskybox) fogdensity += fogdensity / 2;
 
 
 	// no fog in enhanced vision modes!
@@ -130,10 +130,10 @@ void HWDrawInfo::SetFog(FRenderState &state, int lightlevel, int rellight, bool
 	}
 	else
 	{
-		if ((lightmode == ELightMode::Doom || (isSoftwareLighting() && cmap && cmap->BlendFactor > 0)) && fogcolor == 0)
+		if ((lightmode == ELightMode::Doom || (isSoftwareLighting(lightmode) && cmap && cmap->BlendFactor > 0)) && fogcolor == 0)
 		{
-			float light = (float)CalcLightLevel(lightlevel, rellight, false, cmap->BlendFactor);
-			SetShaderLight(state, light, lightlevel);
+			float light = (float)CalcLightLevel(lightmode, lightlevel, rellight, false, cmap->BlendFactor);
+			SetShaderLight(state, Level, light, lightlevel);
 		}
 		else if (lightmode == ELightMode::Build)
 		{
@@ -155,7 +155,7 @@ void HWDrawInfo::SetFog(FRenderState &state, int lightlevel, int rellight, bool
 		state.SetFog(fogcolor, fogdensity);
 
 		// Korshun: fullbright fog like in software renderer.
-		if (isSoftwareLighting() && cmap && cmap->BlendFactor == 0 && Level->brightfog && fogdensity != 0 && fogcolor != 0)
+		if (isSoftwareLighting(lightmode) && cmap && cmap->BlendFactor == 0 && Level->brightfog && fogdensity != 0 && fogcolor != 0)
 		{
 			state.SetSoftLightLevel(255);
 		}
diff --git a/src/rendering/hwrenderer/scene/hw_skyportal.cpp b/src/rendering/hwrenderer/scene/hw_skyportal.cpp
index 386b8fc1f..89f83e130 100644
--- a/src/rendering/hwrenderer/scene/hw_skyportal.cpp
+++ b/src/rendering/hwrenderer/scene/hw_skyportal.cpp
@@ -43,7 +43,7 @@ void HWSkyPortal::DrawContents(HWDrawInfo *di, FRenderState &state)
 
 	// We have no use for Doom lighting special handling here, so disable it for this function.
 	auto oldlightmode = di->lightmode;
-	if (di->isSoftwareLighting())
+	if (isSoftwareLighting(oldlightmode))
 	{
 		di->SetFallbackLightMode();
 		state.SetNoSoftLightLevel();
diff --git a/src/rendering/hwrenderer/scene/hw_sprites.cpp b/src/rendering/hwrenderer/scene/hw_sprites.cpp
index 70baef14b..0ad807a3e 100644
--- a/src/rendering/hwrenderer/scene/hw_sprites.cpp
+++ b/src/rendering/hwrenderer/scene/hw_sprites.cpp
@@ -56,6 +56,7 @@
 #include "hw_material.h"
 #include "hw_dynlightdata.h"
 #include "hw_renderstate.h"
+#include "hw_drawcontext.h"
 
 extern TArray<spritedef_t> sprites;
 extern TArray<spriteframe_t> SpriteFrames;
@@ -144,7 +145,7 @@ void HWSprite::DrawSprite(HWDrawInfo *di, FRenderState &state, bool translucent)
 			if (!Colormap.FadeColor.isBlack())
 			{
 				float dist = Dist2(vp.Pos.X, vp.Pos.Y, x, y);
-				int fogd = di->GetFogDensity(lightlevel, Colormap.FadeColor, Colormap.FogDensity, Colormap.BlendFactor);
+				int fogd = GetFogDensity(di->Level, di->lightmode, lightlevel, Colormap.FadeColor, Colormap.FogDensity, Colormap.BlendFactor);
 
 				// this value was determined by trial and error and is scale dependent!
 				float factor = 0.05f + exp(-fogd * dist / 62500.f);
@@ -189,7 +190,7 @@ void HWSprite::DrawSprite(HWDrawInfo *di, FRenderState &state, bool translucent)
 			state.SetObjectColor(finalcol);
 			state.SetAddColor(cursec->AdditiveColors[sector_t::sprites] | 0xff000000);
 		}
-		di->SetColor(state, lightlevel, rel, di->isFullbrightScene(), Colormap, trans);
+		SetColor(state, di->Level, di->lightmode, lightlevel, rel, di->isFullbrightScene(), Colormap, trans);
 	}
 
 
@@ -216,7 +217,7 @@ void HWSprite::DrawSprite(HWDrawInfo *di, FRenderState &state, bool translucent)
 		else RenderStyle.BlendOp = STYLEOP_Fuzz;	// subtractive with models is not going to work.
 	}
 
-	if (!foglayer) di->SetFog(state, foglevel, rel, di->isFullbrightScene(), &Colormap, additivefog);
+	if (!foglayer) SetFog(state, di->Level, di->lightmode, foglevel, rel, di->isFullbrightScene(), &Colormap, additivefog, di->drawctx->portalState.inskybox);
 	else
 	{
 		state.EnableFog(false);
@@ -257,10 +258,10 @@ void HWSprite::DrawSprite(HWDrawInfo *di, FRenderState &state, bool translucent)
 				thiscm.Decolorize();
 			}
 
-			di->SetColor(state, thisll, rel, di->isFullbrightScene(), thiscm, trans);
+			SetColor(state, di->Level, di->lightmode, thisll, rel, di->isFullbrightScene(), thiscm, trans);
 			if (!foglayer)
 			{
-				di->SetFog(state, thislight, rel, di->isFullbrightScene(), &thiscm, additivefog);
+				SetFog(state, di->Level, di->lightmode, thislight, rel, di->isFullbrightScene(), &thiscm, additivefog, di->drawctx->portalState.inskybox);
 			}
 			SetSplitPlanes(state, *topplane, *lowplane);
 		}
@@ -285,7 +286,7 @@ void HWSprite::DrawSprite(HWDrawInfo *di, FRenderState &state, bool translucent)
 			if (foglayer)
 			{
 				// If we get here we know that we have colored fog and no fixed colormap.
-				di->SetFog(state, foglevel, rel, false, &Colormap, additivefog);
+				SetFog(state, di->Level, di->lightmode, foglevel, rel, false, &Colormap, additivefog, di->drawctx->portalState.inskybox);
 				state.SetTextureMode(TM_FOGLAYER);
 				state.SetRenderStyle(STYLE_Translucent);
 				state.Draw(DT_TriangleStrip, vertexindex, 4);
@@ -347,8 +348,8 @@ void HWSprite::DrawSprite(HWDrawInfo *di, FRenderState &state, bool translucent)
 		state.SetDynLight(0, 0, 0);
 		state.SetRenderStyle(STYLE_Normal);
 		state.SetTextureMode(TM_NORMAL);
-		di->SetFog(state, 0, 0, false, &Colormap, true);
-		di->SetColor(state, 255, 0, true, Colormap, true);
+		SetFog(state, di->Level, di->lightmode, 0, 0, false, &Colormap, true, di->drawctx->portalState.inskybox);
+		SetColor(state, di->Level, di->lightmode, 255, 0, true, Colormap, true);
 		state.EnableTexture(false);
 
 		int scales[12][6] =
diff --git a/src/rendering/hwrenderer/scene/hw_walls.cpp b/src/rendering/hwrenderer/scene/hw_walls.cpp
index 0b9fe91c9..ffc7cf1b2 100644
--- a/src/rendering/hwrenderer/scene/hw_walls.cpp
+++ b/src/rendering/hwrenderer/scene/hw_walls.cpp
@@ -82,7 +82,7 @@ void SetSplitPlanes(FRenderState& state, const secplane_t& top, const secplane_t
 //
 //==========================================================================
 
-void HWWall::RenderWall(HWDrawInfo*di, FRenderState &state, int textured)
+void HWWall::RenderWall(FRenderState &state, int textured)
 {
 	assert(vertcount > 0);
 	state.SetLightIndex(dynlightindex);
@@ -96,17 +96,17 @@ void HWWall::RenderWall(HWDrawInfo*di, FRenderState &state, int textured)
 //
 //==========================================================================
 
-void HWWall::RenderFogBoundary(HWDrawInfo*di, FRenderState &state)
+void HWWall::RenderFogBoundary(HWWallDispatcher*di, FRenderState &state)
 {
 	if (gl_fogmode && !di->isFullbrightScene())
 	{
 		int rel = rellight + getExtraLight();
 		state.EnableDrawBufferAttachments(false);
-		di->SetFog(state, lightlevel, rel, false, &Colormap, false);
+		SetFog(state, di->Level, di->lightmode, lightlevel, rel, false, &Colormap, false, di->di ? di->di->drawctx->portalState.inskybox : false);
 		state.SetEffect(EFF_FOGBOUNDARY);
 		state.AlphaFunc(Alpha_GEqual, 0.f);
 		state.SetDepthBias(-1, -128);
-		RenderWall(di, state, HWWall::RWF_BLANK);
+		RenderWall(state, HWWall::RWF_BLANK);
 		state.ClearDepthBias();
 		state.SetEffect(EFF_NONE);
 		state.EnableDrawBufferAttachments(true);
@@ -119,7 +119,7 @@ void HWWall::RenderFogBoundary(HWDrawInfo*di, FRenderState &state)
 // 
 //
 //==========================================================================
-void HWWall::RenderMirrorSurface(HWDrawInfo*di, FRenderState &state)
+void HWWall::RenderMirrorSurface(HWWallDispatcher*di, FRenderState &state)
 {
 	if (!TexMan.mirrorTexture.isValid()) return;
 
@@ -127,8 +127,8 @@ void HWWall::RenderMirrorSurface(HWDrawInfo*di, FRenderState &state)
 
 	// Use sphere mapping for this
 	state.SetEffect(EFF_SPHEREMAP);
-	di->SetColor(state, lightlevel, 0, di->isFullbrightScene(), Colormap, 0.1f);
-	di->SetFog(state, lightlevel, 0, di->isFullbrightScene(), &Colormap, true);
+	SetColor(state, di->Level, di->lightmode, lightlevel, 0, di->isFullbrightScene(), Colormap, 0.1f);
+	SetFog(state, di->Level, di->lightmode, lightlevel, 0, di->isFullbrightScene(), &Colormap, true, di->di ? di->di->drawctx->portalState.inskybox : false);
 	state.SetRenderStyle(STYLE_Add);
 	state.AlphaFunc(Alpha_Greater, 0);
 
@@ -136,7 +136,7 @@ void HWWall::RenderMirrorSurface(HWDrawInfo*di, FRenderState &state)
 	state.SetMaterial(tex, UF_None, 0, CLAMP_NONE, 0, -1); // do not upscale the mirror texture.
 
 	flags &= ~HWWall::HWF_GLOW;
-	RenderWall(di, state, HWWall::RWF_BLANK);
+	RenderWall(state, HWWall::RWF_BLANK);
 
 	state.SetTextureMatrix(VSMatrix::identity());
 	state.SetEffect(EFF_NONE);
@@ -147,9 +147,9 @@ void HWWall::RenderMirrorSurface(HWDrawInfo*di, FRenderState &state)
 	// This is drawn in the translucent pass which is done after the decal pass
 	// As a result the decals have to be drawn here, right after the wall they are on,
 	// because the depth buffer won't get set by translucent items.
-	if (seg->sidedef->AttachedDecals)
+	if (di->di && seg->sidedef->AttachedDecals)
 	{
-		DrawDecalsForMirror(di, state, di->Decals[1]);
+		DrawDecalsForMirror(di->di, state, di->di->Decals[1]);
 	}
 	state.SetRenderStyle(STYLE_Translucent);
 }
@@ -178,7 +178,7 @@ static const uint8_t renderwalltotier[] =
 CVAR(Bool, hw_npottest, false, 0)
 #endif
 
-void HWWall::RenderTexturedWall(HWDrawInfo*di, FRenderState &state, int rflags)
+void HWWall::RenderTexturedWall(HWWallDispatcher*di, FRenderState &state, int rflags)
 {
 	int tmode = state.GetTextureMode();
 	int rel = rellight + getExtraLight();
@@ -214,7 +214,7 @@ void HWWall::RenderTexturedWall(HWDrawInfo*di, FRenderState &state, int rflags)
 
 	if (type == RENDERWALL_M2SNF)
 	{
-		di->SetFog(state, 255, 0, di->isFullbrightScene(), nullptr, false);
+		SetFog(state, di->Level, di->lightmode, 255, 0, di->isFullbrightScene(), nullptr, false, di->di ? di->di->drawctx->portalState.inskybox : false);
 	}
 	if (type != RENDERWALL_COLOR && seg->sidedef != nullptr)
 	{
@@ -262,9 +262,9 @@ void HWWall::RenderTexturedWall(HWDrawInfo*di, FRenderState &state, int rflags)
 	float absalpha = fabsf(alpha);
 	if (lightlist == nullptr)
 	{
-		if (type != RENDERWALL_M2SNF) di->SetFog(state, lightlevel, rel, di->isFullbrightScene(), &Colormap, RenderStyle == STYLE_Add);
-		di->SetColor(state, lightlevel, rel, di->isFullbrightScene(), Colormap, absalpha);
-		RenderWall(di, state, rflags);
+		if (type != RENDERWALL_M2SNF) SetFog(state, di->Level, di->lightmode, lightlevel, rel, di->isFullbrightScene(), &Colormap, RenderStyle == STYLE_Add, di->di ? di->di->drawctx->portalState.inskybox : false);
+		SetColor(state, di->Level, di->lightmode, lightlevel, rel, di->isFullbrightScene(), Colormap, absalpha);
+		RenderWall(state, rflags);
 	}
 	else
 	{
@@ -284,10 +284,10 @@ void HWWall::RenderTexturedWall(HWDrawInfo*di, FRenderState &state, int rflags)
 				thiscm.FadeColor = Colormap.FadeColor;
 				thiscm.FogDensity = Colormap.FogDensity;
 				CopyFrom3DLight(thiscm, &(*lightlist)[i]);
-				di->SetColor(state, thisll, rel, false, thiscm, absalpha);
-				if (type != RENDERWALL_M2SNF) di->SetFog(state, thisll, rel, false, &thiscm, RenderStyle == STYLE_Add);
+				SetColor(state, di->Level, di->lightmode, thisll, rel, false, thiscm, absalpha);
+				if (type != RENDERWALL_M2SNF) SetFog(state, di->Level, di->lightmode, thisll, rel, false, &thiscm, RenderStyle == STYLE_Add, di->di ? di->di->drawctx->portalState.inskybox : false);
 				SetSplitPlanes(state, (*lightlist)[i].plane, lowplane);
-				RenderWall(di, state, rflags);
+				RenderWall(state, rflags);
 			}
 			if (low1 <= zbottom[0] && low2 <= zbottom[1]) break;
 		}
@@ -311,7 +311,7 @@ void HWWall::RenderTexturedWall(HWDrawInfo*di, FRenderState &state, int rflags)
 //
 //==========================================================================
 
-void HWWall::RenderTranslucentWall(HWDrawInfo*di, FRenderState &state)
+void HWWall::RenderTranslucentWall(HWWallDispatcher*di, FRenderState &state)
 {
 	state.SetRenderStyle(RenderStyle);
 	if (texture)
@@ -323,10 +323,10 @@ void HWWall::RenderTranslucentWall(HWDrawInfo*di, FRenderState &state)
 	else
 	{
 		state.AlphaFunc(Alpha_GEqual, 0.f);
-		di->SetColor(state, lightlevel, 0, false, Colormap, fabsf(alpha));
-		di->SetFog(state, lightlevel, 0, false, &Colormap, RenderStyle == STYLE_Add);
+		SetColor(state, di->Level, di->lightmode, lightlevel, 0, false, Colormap, fabsf(alpha));
+		SetFog(state, di->Level, di->lightmode, lightlevel, 0, false, &Colormap, RenderStyle == STYLE_Add, di->di ? di->di->drawctx->portalState.inskybox : false);
 		state.EnableTexture(false);
-		RenderWall(di, state, HWWall::RWF_NOSPLIT);
+		RenderWall(state, HWWall::RWF_NOSPLIT);
 		state.EnableTexture(true);
 	}
 	state.SetRenderStyle(STYLE_Translucent);
@@ -337,13 +337,13 @@ void HWWall::RenderTranslucentWall(HWDrawInfo*di, FRenderState &state)
 // 
 //
 //==========================================================================
-void HWWall::DrawWall(HWDrawInfo*di, FRenderState &state, bool translucent)
+void HWWall::DrawWall(HWWallDispatcher*di, FRenderState &state, bool translucent)
 {
-	if (di->Level->HasDynamicLights && !di->isFullbrightScene() && texture != nullptr)
+	if (di->di && di->Level->HasDynamicLights && !di->isFullbrightScene() && texture != nullptr)
 	{
-		SetupLights(di, state, lightdata);
+		SetupLights(di->di, state, lightdata);
 	}
-	MakeVertices(di, state, !!(flags & HWWall::HWF_TRANSLUCENT));
+	MakeVertices(state, !!(flags & HWWall::HWF_TRANSLUCENT));
 
 	state.SetNormal(glseg.Normal());
 	if (!translucent)
@@ -567,7 +567,7 @@ void HWWall::PutPortal(HWWallDispatcher *di, FRenderState& state, int ptype, int
 	auto ddi = di->di;
 	if (ddi)
 	{
-		MakeVertices(ddi, state, false);
+		MakeVertices(state, false);
 		switch (ptype)
 		{
 			// portals don't go into the draw list.
@@ -893,7 +893,7 @@ static float ZeroLightmapUVs[8] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.
 //
 //==========================================================================
 bool HWWall::SetWallCoordinates(seg_t * seg, FTexCoordInfo *tci, float texturetop,
-	float topleft, float topright, float bottomleft, float bottomright, float t_ofs)
+	float topleft, float topright, float bottomleft, float bottomright, float t_ofs, float skew)
 {
 	//
 	//
@@ -986,8 +986,8 @@ bool HWWall::SetWallCoordinates(seg_t * seg, FTexCoordInfo *tci, float textureto
 
 		if (tci)
 		{
-			tcs[UPRGT].v = tci->FloatToTexV(-ztop[1] + texturetop);
-			tcs[LORGT].v = tci->FloatToTexV(-zbottom[1] + texturetop);
+			tcs[UPRGT].v = tci->FloatToTexV(-ztop[1] + texturetop + skew);
+			tcs[LORGT].v = tci->FloatToTexV(-zbottom[1] + texturetop + skew);
 		}
 
 		lightuv[UPRGT].v = srclightuv[UPRGT].v;
@@ -1009,7 +1009,7 @@ bool HWWall::SetWallCoordinates(seg_t * seg, FTexCoordInfo *tci, float textureto
 		zbottom[1] = ztop[1] = inter_y;
 		if (tci)
 		{
-			tcs[LORGT].v = tcs[UPRGT].v = tci->FloatToTexV(-ztop[1] + texturetop);
+			tcs[LORGT].v = tcs[UPRGT].v = tci->FloatToTexV(-ztop[1] + texturetop + skew);
 		}
 
 		lightuv[UPRGT].v = srclightuv[UPRGT].v + inter_x * (srclightuv[UPRGT].v - srclightuv[UPLFT].v);
@@ -1135,7 +1135,7 @@ void HWWall::DoTexture(HWWallDispatcher *di, FRenderState& state, int _type,seg_
 					   float ceilingrefheight,float floorrefheight,
 					   float topleft,float topright,
 					   float bottomleft,float bottomright,
-					   float v_offset)
+					   float v_offset, float skew)
 {
 	if (topleft<=bottomleft && topright<=bottomright) return;
 
@@ -1181,7 +1181,7 @@ void HWWall::DoTexture(HWWallDispatcher *di, FRenderState& state, int _type,seg_
 	if (peg) floatceilingref += tci.mRenderHeight - flh - v_offset;
 
 	if (!SetWallCoordinates(seg, &tci, floatceilingref, topleft, topright, bottomleft, bottomright, 
-							seg->sidedef->GetTextureXOffset(texpos))) return;
+							seg->sidedef->GetTextureXOffset(texpos), skew)) return;
 
 	if (seg->linedef->special == Line_Mirror && _type == RENDERWALL_M1S && gl_mirrors && !(di->Level->ib_compatflags & BCOMPATF_NOMIRRORS))
 	{
@@ -1213,7 +1213,7 @@ void HWWall::DoMidTexture(HWWallDispatcher *di, FRenderState& state, seg_t * seg
 						  sector_t * front, sector_t * back,
 						  sector_t * realfront, sector_t * realback,
 						  float fch1, float fch2, float ffh1, float ffh2,
-						  float bch1, float bch2, float bfh1, float bfh2, float zalign)
+						  float bch1, float bch2, float bfh1, float bfh2, float zalign, float skew)
 								
 {
 	FTexCoordInfo tci;
@@ -1339,10 +1339,10 @@ void HWWall::DoMidTexture(HWWallDispatcher *di, FRenderState& state, seg_t * seg
 		// if we don't need a fog sheet let's clip away some unnecessary parts of the polygon
 		//
 		//
-		if (!drawfogboundary && !wrap)
+		if (!drawfogboundary && !wrap && skew == 0)
 		{
-			if (texturetop<topleft && texturetop<topright) topleft=topright=texturetop;
-			if (texturebottom>bottomleft && texturebottom>bottomright) bottomleft=bottomright=texturebottom;
+			if (texturetop < topleft && texturetop < topright) topleft = topright = texturetop;
+			if (texturebottom > bottomleft && texturebottom > bottomright) bottomleft = bottomright = texturebottom;
 		}
 	}
 	else
@@ -1355,8 +1355,10 @@ void HWWall::DoMidTexture(HWWallDispatcher *di, FRenderState& state, seg_t * seg
 		// unwanted side effects.
 		//
 		//
-		topleft=topright=texturetop;
-		bottomleft=bottomright=texturebottom;
+		topleft = texturetop;
+		topright = texturetop + skew;
+		bottomleft = texturebottom;
+		bottomright = texturebottom + skew;
 	}
 
 	// nothing visible - skip the rest
@@ -1419,7 +1421,7 @@ void HWWall::DoMidTexture(HWWallDispatcher *di, FRenderState& state, seg_t * seg
 		// mid textures on portal lines need the same offsetting as mid textures on sky lines
 		flags |= HWF_SKYHACK;
 	}
-	SetWallCoordinates(seg, &tci, texturetop, topleft, topright, bottomleft, bottomright, t_ofs);
+	SetWallCoordinates(seg, &tci, texturetop, topleft, topright, bottomleft, bottomright, t_ofs, skew);
 
 	//
 	//
@@ -1478,7 +1480,7 @@ void HWWall::DoMidTexture(HWWallDispatcher *di, FRenderState& state, seg_t * seg
 		FloatRect *splitrect;
 		int v = texture->GetAreas(&splitrect);
 		if (seg->frontsector == seg->backsector) flags |= HWF_NOSPLIT;	// we don't need to do vertex splits if a line has both sides in the same sector
-		if (v>0 && !drawfogboundary && !(seg->linedef->flags&ML_WRAP_MIDTEX) && !(flags & HWF_NOSLICE))
+		if (v>0 && !drawfogboundary && !(seg->linedef->flags&ML_WRAP_MIDTEX) && !(flags & HWF_NOSLICE) && skew == 0)
 		{
 			// split the poly!
 			int i,t=0;
@@ -1934,6 +1936,10 @@ inline int CalcRelLight(int lightlevel, int orglightlevel, int rel)
 	}
 }
 
+CVAR(Int, topskew, 0, 0)
+CVAR(Int, midskew, 0, 0)
+CVAR(Int, bottomskew, 0, 0)
+
 //==========================================================================
 //
 // 
@@ -2090,9 +2096,14 @@ void HWWall::Process(HWWallDispatcher *di, FRenderState& state, seg_t *seg, sect
 			texture = TexMan.GetGameTexture(seg->sidedef->GetTexture(side_t::mid), true);
 			if (texture && texture->isValid())
 			{
+				int skewflag = seg->sidedef->textures[side_t::mid].skew;
+				if (skewflag == 0) skewflag = midskew;
+				float skew = 
+					skewflag == side_t::skew_front_ceiling ? fch2 - fch1 :
+					skewflag == side_t::skew_front_floor ? ffh2 - ffh1 : 0.;
 				DoTexture(di, state, RENDERWALL_M1S, seg, (seg->linedef->flags & ML_DONTPEGBOTTOM) > 0,
 					crefz, frefz,	// must come from the original!
-					fch1, fch2, ffh1, ffh2, 0);
+					fch1, fch2, ffh1, ffh2, 0, skew);
 			}
 		}
 	}
@@ -2160,9 +2171,31 @@ void HWWall::Process(HWWallDispatcher *di, FRenderState& state, seg_t *seg, sect
 				texture = TexMan.GetGameTexture(seg->sidedef->GetTexture(side_t::top), true);
 				if (texture && texture->isValid())
 				{
+					int skewflag = seg->sidedef->textures[side_t::top].skew;
+					float skew;
+					if (skewflag == 0) skewflag = topskew;
+
+					switch (skewflag)
+					{
+					default:
+						skew = 0;
+						break;
+					case side_t::skew_front_ceiling:
+						skew = fch2 - fch1;
+						break;
+					case side_t::skew_back_ceiling:
+						skew = bch2 - bch1;
+						break;
+					case side_t::skew_front_floor:
+						skew = bfh2 - bfh1;
+						break;
+					case side_t::skew_back_floor:
+						skew = ffh2 - ffh1;
+						break;
+					}
 					DoTexture(di, state, RENDERWALL_TOP, seg, (seg->linedef->flags & (ML_DONTPEGTOP)) == 0,
 						crefz, realback->GetPlaneTexZ(sector_t::ceiling),
-						fch1, fch2, bch1a, bch2a, 0);
+						fch1, fch2, bch1a, bch2a, 0, skew);
 				}
 				else if (!(seg->sidedef->Flags & WALLF_POLYOBJ))
 				{
@@ -2175,7 +2208,7 @@ void HWWall::Process(HWWallDispatcher *di, FRenderState& state, seg_t *seg, sect
 						{
 							DoTexture(di, state, RENDERWALL_TOP, seg, (seg->linedef->flags & (ML_DONTPEGTOP)) == 0,
 								crefz, realback->GetPlaneTexZ(sector_t::ceiling),
-								fch1, fch2, bch1a, bch2a, 0);
+								fch1, fch2, bch1a, bch2a, 0, 0);
 						}
 					}
 					else
@@ -2210,6 +2243,28 @@ void HWWall::Process(HWWallDispatcher *di, FRenderState& state, seg_t *seg, sect
 		lightlevel = hw_ClampLight(seg->sidedef->GetLightLevel(foggy, orglightlevel, side_t::mid, false, &rel));
 		rellight = CalcRelLight(lightlevel, orglightlevel, rel);
 
+		float skew;
+		int skewflag = seg->sidedef->textures[side_t::mid].skew;
+		if (skewflag == 0) skewflag = midskew;
+		switch (skewflag)
+		{
+		default:
+			skew = 0;
+			break;
+		case side_t::skew_front_ceiling:
+			skew = fch2 - fch1;
+			break;
+		case side_t::skew_back_ceiling:
+			skew = bch2 - bch1;
+			break;
+		case side_t::skew_front_floor:
+			skew = bfh2 - bfh1;
+			break;
+		case side_t::skew_back_floor:
+			skew = ffh2 - ffh1;
+			break;
+		}
+
 		if (isportal)
 		{
 			lineportal = seg->linedef->getPortal()->mGroup;
@@ -2222,7 +2277,7 @@ void HWWall::Process(HWWallDispatcher *di, FRenderState& state, seg_t *seg, sect
 			if (texture && seg->backsector != nullptr)
 			{
 				DoMidTexture(di, state, seg, drawfogboundary, frontsector, backsector, realfront, realback,
-					fch1, fch2, ffh1, ffh2, bch1, bch2, bfh1, bfh2, zalign);
+					fch1, fch2, ffh1, ffh2, bch1, bch2, bfh1, bfh2, zalign, skew);
 			}
 		}
 		else
@@ -2231,7 +2286,7 @@ void HWWall::Process(HWWallDispatcher *di, FRenderState& state, seg_t *seg, sect
 			if (texture || drawfogboundary)
 			{
 				DoMidTexture(di, state, seg, drawfogboundary, frontsector, backsector, realfront, realback,
-					fch1, fch2, ffh1, ffh2, bch1, bch2, bfh1, bfh2, zalign);
+					fch1, fch2, ffh1, ffh2, bch1, bch2, bfh1, bfh2, zalign, skew);
 			}
 
 			if (backsector->e->XFloor.ffloors.Size() || frontsector->e->XFloor.ffloors.Size())
@@ -2244,6 +2299,7 @@ void HWWall::Process(HWWallDispatcher *di, FRenderState& state, seg_t *seg, sect
 
 		/* bottom texture */
 		// the back sector's ceiling obstructs part of this wall (specially important for sky sectors)
+		float bfh1a = bch1, bfh2a = bch2;
 		if (fch1 < bfh1 && fch2 < bfh2 && (seg->linedef->flags & ML_DRAWFULLHEIGHT) == 0)
 		{
 			bfh1 = fch1;
@@ -2257,12 +2313,34 @@ void HWWall::Process(HWWallDispatcher *di, FRenderState& state, seg_t *seg, sect
 			texture = TexMan.GetGameTexture(seg->sidedef->GetTexture(side_t::bottom), true);
 			if (texture && texture->isValid())
 			{
+				int skewflag = seg->sidedef->textures[side_t::bottom].skew;
+				if (skewflag == 0) skewflag = bottomskew;
+				float skew;
+				switch (skewflag)
+				{
+				default:
+					skew = 0;
+					break;
+				case side_t::skew_front_ceiling:
+					skew = fch2 - fch1;
+					break;
+				case side_t::skew_back_ceiling:
+					skew = bch2 - bch1;
+					break;
+				case side_t::skew_front_floor:
+					skew = bfh2a - bfh1a;
+					break;
+				case side_t::skew_back_floor:
+					skew = ffh2 - ffh1;
+					break;
+				}
+
 				DoTexture(di, state, RENDERWALL_BOTTOM, seg, (seg->linedef->flags & ML_DONTPEGBOTTOM) > 0,
 					realback->GetPlaneTexZ(sector_t::floor), frefz,
 					bfh1, bfh2, ffh1, ffh2,
 					frontsector->GetTexture(sector_t::ceiling) == skyflatnum && backsector->GetTexture(sector_t::ceiling) == skyflatnum ?
 					frefz - realback->GetPlaneTexZ(sector_t::ceiling) :
-					frefz - crefz);
+					frefz - crefz, skew);
 			}
 			else if (!(seg->sidedef->Flags & WALLF_POLYOBJ))
 			{
@@ -2278,7 +2356,7 @@ void HWWall::Process(HWWallDispatcher *di, FRenderState& state, seg_t *seg, sect
 					{
 						DoTexture(di, state, RENDERWALL_BOTTOM, seg, (seg->linedef->flags & ML_DONTPEGBOTTOM) > 0,
 							realback->GetPlaneTexZ(sector_t::floor), frefz,
-							bfh1, bfh2, ffh1, ffh2, frefz - crefz);
+							bfh1, bfh2, ffh1, ffh2, frefz - crefz, 0);
 					}
 				}
 				else if (backsector->GetTexture(sector_t::floor) != skyflatnum)
@@ -2350,7 +2428,7 @@ void HWWall::ProcessLowerMiniseg(HWWallDispatcher *di, FRenderState& state, seg_
 			FTexCoordInfo tci;
 			type = RENDERWALL_BOTTOM;
 			tci.GetFromTexture(texture, 1, 1, false);
-			SetWallCoordinates(seg, &tci, bfh, bfh, bfh, ffh, ffh, 0);
+			SetWallCoordinates(seg, &tci, bfh, bfh, bfh, ffh, ffh, 0, 0);
 			PutWall(di, state, false);
 		}
 	}
diff --git a/src/rendering/hwrenderer/scene/hw_walls_vertex.cpp b/src/rendering/hwrenderer/scene/hw_walls_vertex.cpp
index c66e11105..a92cd7087 100644
--- a/src/rendering/hwrenderer/scene/hw_walls_vertex.cpp
+++ b/src/rendering/hwrenderer/scene/hw_walls_vertex.cpp
@@ -283,7 +283,7 @@ int HWWall::CountVertices()
 //
 //==========================================================================
 
-void HWWall::MakeVertices(HWDrawInfo *di, FRenderState& state, bool nosplit)
+void HWWall::MakeVertices(FRenderState& state, bool nosplit)
 {
 	if (vertcount == 0)
 	{
diff --git a/src/rendering/hwrenderer/scene/hw_weapon.cpp b/src/rendering/hwrenderer/scene/hw_weapon.cpp
index f9f510bde..d4e3f4f06 100644
--- a/src/rendering/hwrenderer/scene/hw_weapon.cpp
+++ b/src/rendering/hwrenderer/scene/hw_weapon.cpp
@@ -68,7 +68,7 @@ void HWDrawInfo::DrawPSprite(HUDSprite *huds, FRenderState &state)
 	}
 	else
 	{
-		SetColor(state, huds->lightlevel, 0, isFullbrightScene(), huds->cm, huds->alpha, true);
+		SetColor(state, Level, lightmode, huds->lightlevel, 0, isFullbrightScene(), huds->cm, huds->alpha, true);
 	}
 	state.SetLightIndex(-1);
 	state.SetRenderStyle(huds->RenderStyle);
@@ -120,7 +120,7 @@ void HWDrawInfo::DrawPSprite(HUDSprite *huds, FRenderState &state)
 void HWDrawInfo::DrawPlayerSprites(bool hudModelStep, FRenderState &state)
 {
 	auto oldlightmode = lightmode;
-	if (!hudModelStep && isSoftwareLighting()) SetFallbackLightMode();	// Software lighting cannot handle 2D content.
+	if (!hudModelStep && isSoftwareLighting(oldlightmode)) SetFallbackLightMode();	// Software lighting cannot handle 2D content.
 	for (auto &hudsprite : hudsprites)
 	{
 		if ((!!hudsprite.mframe) == hudModelStep)
@@ -352,9 +352,9 @@ WeaponLighting HWDrawInfo::GetWeaponLighting(sector_t *viewsector, const DVector
 			if (Level->flags3 & LEVEL3_NOCOLOREDSPRITELIGHTING) l.cm.ClearColor();
 		}
 
-		l.lightlevel = CalcLightLevel(l.lightlevel, getExtraLight(), true, 0);
+		l.lightlevel = CalcLightLevel(lightmode, l.lightlevel, getExtraLight(), true, 0);
 
-		if (isSoftwareLighting() || l.lightlevel < 92)
+		if (isSoftwareLighting(lightmode) || l.lightlevel < 92)
 		{
 			// Korshun: the way based on max possible light level for sector like in software renderer.
 			double min_L = 36.0 / 31.0 - ((l.lightlevel / 255.0) * (63.0 / 31.0)); // Lightlevel in range 0-63
@@ -702,7 +702,7 @@ void HWDrawInfo::PreparePlayerSprites2D(sector_t * viewsector, area_t in_area, F
 	// hack alert! Rather than changing everything in the underlying lighting code let's just temporarily change
 	// light mode here to draw the weapon sprite.
 	auto oldlightmode = lightmode;
-	if (isSoftwareLighting()) SetFallbackLightMode();
+	if (isSoftwareLighting(oldlightmode)) SetFallbackLightMode();
 
 	for (DPSprite *psp = player->psprites; psp != nullptr && psp->GetID() < PSP_TARGETCENTER; psp = psp->GetNext())
 	{
@@ -788,7 +788,7 @@ void HWDrawInfo::PreparePlayerSprites3D(sector_t * viewsector, area_t in_area, F
 	// hack alert! Rather than changing everything in the underlying lighting code let's just temporarily change
 	// light mode here to draw the weapon sprite.
 	auto oldlightmode = lightmode;
-	if (isSoftwareLighting()) SetFallbackLightMode();
+	if (isSoftwareLighting(oldlightmode)) SetFallbackLightMode();
 
 	for (DPSprite *psp = player->psprites; psp != nullptr && psp->GetID() < PSP_TARGETCENTER; psp = psp->GetNext())
 	{
diff --git a/wadsrc/static/zscript/mapdata.zs b/wadsrc/static/zscript/mapdata.zs
index dfe4a7016..8abfe8f1b 100644
--- a/wadsrc/static/zscript/mapdata.zs
+++ b/wadsrc/static/zscript/mapdata.zs
@@ -238,6 +238,7 @@ struct Line native play
 	native clearscope int Index() const;
 	native bool Activate(Actor activator, int side, int type);
 	native bool RemoteActivate(Actor activator, int side, int type, Vector3 pos);
+	native bool, double, double GetMidTexturePosition (int side);
 	
 	clearscope int GetUDMFInt(Name nm) const
 	{