diff --git a/src/gl/scene/gl_walls_draw.cpp b/src/gl/scene/gl_walls_draw.cpp
index bd0388722..a03e53150 100644
--- a/src/gl/scene/gl_walls_draw.cpp
+++ b/src/gl/scene/gl_walls_draw.cpp
@@ -464,10 +464,8 @@ void FDrawInfo::AddPortal(GLWall *wall, int ptype)
 //==========================================================================
 void FDrawInfo::DrawDecal(GLDecal *gldecal)
 {
-	auto wall = gldecal->wall;
 	auto decal = gldecal->decal;
 	auto tex = gldecal->gltexture;
-	auto &seg = wall->seg;
 	
 	// calculate dynamic light effect.
 	if (level.HasDynamicLights && !mDrawer->FixedColormap && gl_light_sprites)
@@ -475,8 +473,8 @@ void FDrawInfo::DrawDecal(GLDecal *gldecal)
 		// Note: This should be replaced with proper shader based lighting.
 		double x, y;
 		float out[3];
-		decal->GetXY(seg->sidedef, x, y);
-		GetDynSpriteLight(nullptr, x, y, gldecal->zcenter, wall->sub, out);
+		decal->GetXY(decal->Side, x, y);
+		GetDynSpriteLight(nullptr, x, y, gldecal->zcenter, decal->Side->lighthead, decal->Side->sector->PortalGroup, out);
 		gl_RenderState.SetDynLight(out[0], out[1], out[2]);
 	}
 
@@ -495,7 +493,7 @@ void FDrawInfo::DrawDecal(GLDecal *gldecal)
 	else gl_RenderState.AlphaFunc(GL_GREATER, 0.f);
 
 
-	mDrawer->SetColor(gldecal->light, gldecal->rel, gldecal->colormap, gldecal->a);
+	mDrawer->SetColor(gldecal->lightlevel, gldecal->rellight, gldecal->Colormap, gldecal->alpha);
 	// for additively drawn decals we must temporarily set the fog color to black.
 	PalEntry fc = gl_RenderState.GetFogColor();
 	if (decal->RenderStyle.BlendOp == STYLEOP_Add && decal->RenderStyle.DestAlpha == STYLEALPHA_One)
@@ -503,20 +501,20 @@ void FDrawInfo::DrawDecal(GLDecal *gldecal)
 		gl_RenderState.SetFog(0, -1);
 	}
 
-	gl_RenderState.SetNormal(wall->glseg.Normal());
+	gl_RenderState.SetNormal(gldecal->Normal);
 
-	if (wall->lightlist == nullptr)
+	if (gldecal->lightlist == nullptr)
 	{
 		gl_RenderState.Apply();
 		GLRenderer->mVBO->RenderArray(GL_TRIANGLE_FAN, gldecal->vertindex, 4);
 	}
 	else
 	{
-		auto &lightlist = *wall->lightlist;
+		auto &lightlist = *gldecal->lightlist;
 
 		for (unsigned k = 0; k < lightlist.Size(); k++)
 		{
-			secplane_t &lowplane = k == lightlist.Size() - 1 ? wall->bottomplane : lightlist[k + 1].plane;
+			secplane_t &lowplane = k == lightlist.Size() - 1 ? gldecal->bottomplane : lightlist[k + 1].plane;
 
 			DecalVertex *dv = gldecal->dv;
 			float low1 = lowplane.ZatPoint(dv[1].x, dv[1].y);
@@ -524,13 +522,13 @@ void FDrawInfo::DrawDecal(GLDecal *gldecal)
 
 			if (low1 < dv[1].z || low2 < dv[2].z)
 			{
-				int thisll = lightlist[k].caster != NULL ? hw_ClampLight(*lightlist[k].p_lightlevel) : wall->lightlevel;
+				int thisll = lightlist[k].caster != NULL ? hw_ClampLight(*lightlist[k].p_lightlevel) : gldecal->lightlevel;
 				FColormap thiscm;
-				thiscm.FadeColor = wall->Colormap.FadeColor;
+				thiscm.FadeColor = gldecal->Colormap.FadeColor;
 				thiscm.CopyFrom3DLight(&lightlist[k]);
-				mDrawer->SetColor(thisll, gldecal->rel, thiscm, gldecal->a);
+				mDrawer->SetColor(thisll, gldecal->rellight, thiscm, gldecal->alpha);
 				if (level.flags3 & LEVEL3_NOCOLOREDSPRITELIGHTING) thiscm.Decolorize();
-				mDrawer->SetFog(thisll, gldecal->rel, &thiscm, wall->RenderStyle == STYLE_Add);
+				mDrawer->SetFog(thisll, gldecal->rellight, &thiscm, false);
 				gl_RenderState.SetSplitPlanes(lightlist[k].plane, lowplane);
 
 				gl_RenderState.Apply();
@@ -554,25 +552,28 @@ void FDrawInfo::DrawDecal(GLDecal *gldecal)
 //==========================================================================
 void FDrawInfo::DrawDecals()
 {
-	GLWall *wall = nullptr;
+	side_t *wall = nullptr;
+	bool splitting = false;
 	for (auto gldecal : decals[0])
 	{
-		if (gldecal->wall != wall)
+		if (gldecal->decal->Side != wall)
 		{
-			wall = gldecal->wall;
-			if (wall->lightlist != nullptr)
+			wall = gldecal->decal->Side;
+			if (gldecal->lightlist != nullptr)
 			{
 				gl_RenderState.EnableSplit(true);
+				splitting = true;
 			}
 			else
 			{
 				gl_RenderState.EnableSplit(false);
-				mDrawer->SetFog(wall->lightlevel, wall->rellight + getExtraLight(), &wall->Colormap, false);
+				splitting = false;
+				mDrawer->SetFog(gldecal->lightlevel, gldecal->rellight, &gldecal->Colormap, false);
 			}
 		}
 		DrawDecal(gldecal);
 	}
-	if (wall && wall->lightlist != nullptr) gl_RenderState.EnableSplit(false);
+	if (splitting) gl_RenderState.EnableSplit(false);
 }
 
 //==========================================================================
@@ -585,7 +586,7 @@ void FDrawInfo::DrawDecalsForMirror(GLWall *wall)
 	mDrawer->SetFog(wall->lightlevel, wall->rellight + getExtraLight(), &wall->Colormap, false);
 	for (auto gldecal : decals[1])
 	{
-		if (gldecal->wall == wall)
+		if (gldecal->decal->Side == wall->seg->sidedef)
 		{
 			DrawDecal(gldecal);
 		}
diff --git a/src/hwrenderer/scene/hw_decal.cpp b/src/hwrenderer/scene/hw_decal.cpp
index 423d11276..fca5b9ef3 100644
--- a/src/hwrenderer/scene/hw_decal.cpp
+++ b/src/hwrenderer/scene/hw_decal.cpp
@@ -36,7 +36,7 @@
 #include "hwrenderer/utility/hw_lighting.h"
 #include "hwrenderer/data/flatvertices.h"
 
-void GLWall::ProcessDecal(HWDrawInfo *di, DBaseDecal *decal)
+void GLWall::ProcessDecal(HWDrawInfo *di, DBaseDecal *decal, const FVector3 &normal)
 {
 	line_t * line = seg->linedef;
 	side_t * side = seg->sidedef;
@@ -228,35 +228,37 @@ void GLWall::ProcessDecal(HWDrawInfo *di, DBaseDecal *decal)
 		for (i = 0; i < 4; i++) dv[i].v = vb - dv[i].v;
 	}
 
-	GLDecal &gldecal = *di->AddDecal(type == RENDERWALL_MIRRORSURFACE);
-	gldecal.gltexture = tex;
-	gldecal.wall = this;
-	gldecal.decal = decal;
+	GLDecal *gldecal = di->AddDecal(type == RENDERWALL_MIRRORSURFACE);
+	gldecal->gltexture = tex;
+	gldecal->decal = decal;
 
 	if (decal->RenderFlags & RF_FULLBRIGHT)
 	{
-		gldecal.light = 255;
-		gldecal.rel = 0;
+		gldecal->lightlevel = 255;
+		gldecal->rellight = 0;
 	}
 	else
 	{
-		gldecal.light = lightlevel;
-		gldecal.rel = rellight + getExtraLight();
+		gldecal->lightlevel = lightlevel;
+		gldecal->rellight = rellight + getExtraLight();
 	}
 
-	gldecal.colormap = Colormap;
+	gldecal->Colormap = Colormap;
 
 	if (level.flags3 & LEVEL3_NOCOLOREDSPRITELIGHTING)
 	{
-		gldecal.colormap.Decolorize();
+		gldecal->Colormap.Decolorize();
 	}
 
-	gldecal.a = decal->Alpha;
-	gldecal.zcenter = zpos - decalheight * 0.5f;
-	memcpy(gldecal.dv, dv, sizeof(dv));
+	gldecal->alpha = decal->Alpha;
+	gldecal->zcenter = zpos - decalheight * 0.5f;
+	gldecal->bottomplane = bottomplane;
+	gldecal->Normal = normal;
+	gldecal->lightlist = lightlist;
+	memcpy(gldecal->dv, dv, sizeof(dv));
 	
 	auto verts = di->AllocVertices(4);
-	gldecal.vertindex = verts.second;
+	gldecal->vertindex = verts.second;
 	
 	for (i = 0; i < 4; i++)
 	{
@@ -274,10 +276,14 @@ void GLWall::ProcessDecals(HWDrawInfo *di)
 	if (seg->sidedef != nullptr)
 	{
 		DBaseDecal *decal = seg->sidedef->AttachedDecals;
-		while (decal)
+		if (decal)
 		{
-			ProcessDecal(di, decal);
-			decal = decal->WallNext;
+			auto normal = glseg.Normal();	// calculate the normal only once per wall because it requires a square root.
+			while (decal)
+			{
+				ProcessDecal(di, decal, normal);
+				decal = decal->WallNext;
+			}
 		}
 	}
 }
diff --git a/src/hwrenderer/scene/hw_drawinfo.h b/src/hwrenderer/scene/hw_drawinfo.h
index 38218c46d..2914a7a9c 100644
--- a/src/hwrenderer/scene/hw_drawinfo.h
+++ b/src/hwrenderer/scene/hw_drawinfo.h
@@ -12,6 +12,7 @@ class GLSprite;
 struct GLDecal;
 class IShadowMap;
 struct particle_t;
+struct FDynLightData;
 
 //==========================================================================
 //
@@ -140,7 +141,7 @@ public:
 	void AddOtherFloorPlane(int sector, gl_subsectorrendernode * node);
 	void AddOtherCeilingPlane(int sector, gl_subsectorrendernode * node);
 
-	void GetDynSpriteLight(AActor *self, float x, float y, float z, subsector_t * subsec, float *out);
+	void GetDynSpriteLight(AActor *self, float x, float y, float z, FLightNode *node, int portalgroup, float *out);
 	void GetDynSpriteLight(AActor *thing, particle_t *particle, float *out);
 
 	virtual void DrawWall(GLWall *wall, int pass) = 0;
diff --git a/src/hwrenderer/scene/hw_drawstructs.h b/src/hwrenderer/scene/hw_drawstructs.h
index 5407512ce..b70db68fb 100644
--- a/src/hwrenderer/scene/hw_drawstructs.h
+++ b/src/hwrenderer/scene/hw_drawstructs.h
@@ -247,7 +247,7 @@ public:
 					  float fch1, float fch2, float ffh1, float ffh2,
 					  float bch1, float bch2, float bfh1, float bfh2);
 
-    void ProcessDecal(HWDrawInfo *di, DBaseDecal *decal);
+    void ProcessDecal(HWDrawInfo *di, DBaseDecal *decal, const FVector3 &normal);
     void ProcessDecals(HWDrawInfo *di);
 
 	void CreateVertices(FFlatVertex *&ptr, bool nosplit);
@@ -412,16 +412,19 @@ struct DecalVertex
 struct GLDecal
 {
 	FMaterial *gltexture;
-	GLWall *wall;
+	TArray<lightlist_t> *lightlist;
 	DBaseDecal *decal;
 	DecalVertex dv[4];
 	float zcenter;
 	unsigned int vertindex;
 
-	int light;
-	int rel;
-	float a;
-	FColormap colormap;
+	FRenderStyle renderstyle;
+	int lightlevel;
+	int rellight;
+	float alpha;
+	FColormap Colormap;
+	secplane_t bottomplane;
+	FVector3 Normal;
 
 };
 
diff --git a/src/hwrenderer/scene/hw_spritelight.cpp b/src/hwrenderer/scene/hw_spritelight.cpp
index 21037adfc..cd3e8a293 100644
--- a/src/hwrenderer/scene/hw_spritelight.cpp
+++ b/src/hwrenderer/scene/hw_spritelight.cpp
@@ -49,7 +49,7 @@ T smoothstep(const T edge0, const T edge1, const T x)
 //
 //==========================================================================
 
-void HWDrawInfo::GetDynSpriteLight(AActor *self, float x, float y, float z, subsector_t * subsec, float *out)
+void HWDrawInfo::GetDynSpriteLight(AActor *self, float x, float y, float z, FLightNode *node, int portalgroup, float *out)
 {
 	ADynamicLight *light;
 	float frac, lr, lg, lb;
@@ -57,7 +57,6 @@ void HWDrawInfo::GetDynSpriteLight(AActor *self, float x, float y, float z, subs
 	
 	out[0] = out[1] = out[2] = 0.f;
 	// Go through both light lists
-	FLightNode * node = subsec->lighthead;
 	while (node)
 	{
 		light=node->lightsource;
@@ -71,7 +70,7 @@ void HWDrawInfo::GetDynSpriteLight(AActor *self, float x, float y, float z, subs
 			if (level.Displacements.size > 0)
 			{
 				int fromgroup = light->Sector->PortalGroup;
-				int togroup = subsec->sector->PortalGroup;
+				int togroup = portalgroup;
 				if (fromgroup == togroup || fromgroup == 0 || togroup == 0) goto direct;
 
 				DVector2 offset = level.Displacements.getOffset(fromgroup, togroup);
@@ -132,11 +131,11 @@ void HWDrawInfo::GetDynSpriteLight(AActor *thing, particle_t *particle, float *o
 {
 	if (thing != NULL)
 	{
-		GetDynSpriteLight(thing, thing->X(), thing->Y(), thing->Center(), thing->subsector, out);
+		GetDynSpriteLight(thing, thing->X(), thing->Y(), thing->Center(), thing->subsector->lighthead, thing->Sector->PortalGroup, out);
 	}
 	else if (particle != NULL)
 	{
-		GetDynSpriteLight(NULL, particle->Pos.X, particle->Pos.Y, particle->Pos.Z, particle->subsector, out);
+		GetDynSpriteLight(NULL, particle->Pos.X, particle->Pos.Y, particle->Pos.Z, particle->subsector->lighthead, particle->subsector->sector->PortalGroup, out);
 	}
 }