diff --git a/src/gl/data/gl_data.cpp b/src/gl/data/gl_data.cpp
index 37d348bd85..67111ec924 100644
--- a/src/gl/data/gl_data.cpp
+++ b/src/gl/data/gl_data.cpp
@@ -59,6 +59,7 @@ long gl_frameCount;
 
 EXTERN_CVAR(Int, gl_lightmode)
 EXTERN_CVAR(Bool, gl_brightfog)
+EXTERN_CVAR(Bool, gl_lightadditivesurfaces)
 
 CUSTOM_CVAR(Float, maxviewpitch, 90.f, CVAR_ARCHIVE|CVAR_SERVERINFO)
 {
@@ -210,6 +211,7 @@ struct FGLROptions : public FOptionalMapinfoData
 		skyrotatevector = FVector3(0,0,1);
 		skyrotatevector2 = FVector3(0,0,1);
 		pixelstretch = 1.2f;
+		lightadditivesurfaces = false;
 	}
 	virtual FOptionalMapinfoData *Clone() const
 	{
@@ -224,6 +226,7 @@ struct FGLROptions : public FOptionalMapinfoData
 		newopt->skyrotatevector = skyrotatevector;
 		newopt->skyrotatevector2 = skyrotatevector2;
 		newopt->pixelstretch = pixelstretch;
+		newopt->lightadditivesurfaces = lightadditivesurfaces;
 		return newopt;
 	}
 	int			fogdensity;
@@ -231,8 +234,9 @@ struct FGLROptions : public FOptionalMapinfoData
 	int			skyfog;
 	int			lightmode;
 	int			brightfog;
-	SBYTE		nocoloredspritelighting;
-	SBYTE		notexturefill;
+	int8_t		lightadditivesurfaces;
+	int8_t		nocoloredspritelighting;
+	int8_t		notexturefill;
 	FVector3	skyrotatevector;
 	FVector3	skyrotatevector2;
 	float		pixelstretch;
@@ -306,6 +310,20 @@ DEFINE_MAP_OPTION(notexturefill, false)
 	}
 }
 
+DEFINE_MAP_OPTION(lightadditivesurfaces, false)
+{
+	FGLROptions *opt = info->GetOptData<FGLROptions>("gl_renderer");
+	if (parse.CheckAssign())
+	{
+		parse.sc.MustGetNumber();
+		opt->lightadditivesurfaces = !!parse.sc.Number;
+	}
+	else
+	{
+		opt->lightadditivesurfaces = true;
+	}
+}
+
 DEFINE_MAP_OPTION(skyrotate, false)
 {
 	FGLROptions *opt = info->GetOptData<FGLROptions>("gl_renderer");
@@ -360,6 +378,7 @@ void InitGLRMapinfoData()
 	{
 		gl_SetFogParams(opt->fogdensity, level.info->outsidefog, opt->outsidefogdensity, opt->skyfog);
 		glset.map_lightmode = opt->lightmode;
+		glset.map_lightadditivesurfaces = opt->lightadditivesurfaces;
 		glset.map_brightfog = opt->brightfog;
 		glset.map_nocoloredspritelighting = opt->nocoloredspritelighting;
 		glset.map_notexturefill = opt->notexturefill;
@@ -371,6 +390,7 @@ void InitGLRMapinfoData()
 	{
 		gl_SetFogParams(0, level.info->outsidefog, 0, 0);
 		glset.map_lightmode = -1;
+		glset.map_lightadditivesurfaces = -1;
 		glset.map_brightfog = -1;
 		glset.map_nocoloredspritelighting = -1;
 		glset.map_notexturefill = -1;
@@ -387,6 +407,8 @@ void InitGLRMapinfoData()
 	else glset.notexturefill = !!glset.map_notexturefill;
 	if (glset.map_brightfog == -1) glset.brightfog = gl_brightfog;
 	else glset.brightfog = !!glset.map_brightfog;
+	if (glset.map_lightadditivesurfaces == -1) glset.brightfog = gl_brightfog;
+	else glset.lightadditivesurfaces = !!glset.map_lightadditivesurfaces;
 }
 
 CCMD(gl_resetmap)
diff --git a/src/gl/data/gl_data.h b/src/gl/data/gl_data.h
index f1bc27ee4d..d6f789863c 100644
--- a/src/gl/data/gl_data.h
+++ b/src/gl/data/gl_data.h
@@ -12,11 +12,13 @@ struct GLRenderSettings
 	bool nocoloredspritelighting;
 	bool notexturefill;
 	bool brightfog;
+	bool lightadditivesurfaces;
 
-	SBYTE map_lightmode;
-	SBYTE map_nocoloredspritelighting;
-	SBYTE map_notexturefill;
-	SBYTE map_brightfog;
+	int8_t map_lightmode;
+	int8_t map_nocoloredspritelighting;
+	int8_t map_notexturefill;
+	int8_t map_brightfog;
+	int8_t map_lightadditivesurfaces;
 
 	FVector3 skyrotatevector;
 	FVector3 skyrotatevector2;
diff --git a/src/gl/dynlights/a_dynlight.cpp b/src/gl/dynlights/a_dynlight.cpp
index 0e52eedd8a..84e1d9ab1b 100644
--- a/src/gl/dynlights/a_dynlight.cpp
+++ b/src/gl/dynlights/a_dynlight.cpp
@@ -67,6 +67,7 @@
 #include "templates.h"
 #include "doomdata.h"
 #include "r_utility.h"
+#include "p_local.h"
 #include "portal.h"
 #include "doomstat.h"
 #include "serializer.h"
@@ -192,6 +193,7 @@ void ADynamicLight::BeginPlay()
 
 	m_Radius[0] = args[LIGHT_INTENSITY];
 	m_Radius[1] = args[LIGHT_SECONDARY_INTENSITY];
+	specialf1 = DAngle(double(SpawnAngle)).Normalized360().Degrees;
 	visibletoplayer = true;
 }
 
@@ -228,7 +230,7 @@ void ADynamicLight::Activate(AActor *activator)
 
 	if (lighttype == PulseLight)
 	{
-		float pulseTime = Angles.Yaw.Degrees / TICRATE;
+		float pulseTime = specialf1 / TICRATE;
 		
 		m_lastUpdate = level.maptime;
 		m_cycler.SetParams(float(m_Radius[1]), float(m_Radius[0]), pulseTime);
@@ -293,7 +295,7 @@ void ADynamicLight::Tick()
 	case FlickerLight:
 	{
 		BYTE rnd = randLight();
-		float pct = Angles.Yaw.Degrees / 360.f;
+		float pct = specialf1 / 360.f;
 		
 		m_currentRadius = float(m_Radius[rnd >= pct * 255]);
 		break;
@@ -304,12 +306,13 @@ void ADynamicLight::Tick()
 		int flickerRange = m_Radius[1] - m_Radius[0];
 		float amt = randLight() / 255.f;
 		
-		m_tickCount++;
-		
-		if (m_tickCount > Angles.Yaw.Degrees)
+		if (m_tickCount > specialf1)
+		{
+			m_tickCount = 0;
+		}
+		if (m_tickCount++ == 0 || m_currentRadius > m_Radius[1])
 		{
 			m_currentRadius = float(m_Radius[0] + (amt * flickerRange));
-			m_tickCount = 0;
 		}
 		break;
 	}
@@ -319,7 +322,7 @@ void ADynamicLight::Tick()
 	case ColorFlickerLight:
 	{
 		BYTE rnd = randLight();
-		float pct = Angles.Yaw.Degrees/360.f;
+		float pct = specialf1/360.f;
 		
 		m_currentRadius = m_Radius[rnd >= pct * 255];
 		break;
@@ -332,7 +335,7 @@ void ADynamicLight::Tick()
 		
 		m_tickCount++;
 		
-		if (m_tickCount > Angles.Yaw.Degrees)
+		if (m_tickCount > specialf1)
 		{
 			m_currentRadius = m_Radius[0] + (amt * flickerRange);
 			m_tickCount = 0;
@@ -359,7 +362,6 @@ void ADynamicLight::Tick()
 		m_currentRadius = float(m_Radius[0]);
 		break;
 	}
-
 	UpdateLocation();
 }
 
@@ -416,6 +418,7 @@ void ADynamicLight::UpdateLocation()
 			intensity = m_currentRadius;
 		}
 		radius = intensity * 2.0f;
+		assert(radius >= m_currentRadius * 2);
 
 		if (X() != oldx || Y() != oldy || radius != oldradius)
 		{
diff --git a/src/gl/dynlights/gl_dynlight.cpp b/src/gl/dynlights/gl_dynlight.cpp
index 40008e3ad5..63ddfee605 100644
--- a/src/gl/dynlights/gl_dynlight.cpp
+++ b/src/gl/dynlights/gl_dynlight.cpp
@@ -164,7 +164,7 @@ FLightDefaults::FLightDefaults(FName name, ELightType type)
 void FLightDefaults::ApplyProperties(ADynamicLight * light) const
 {
 	light->lighttype = m_type;
-	light->Angles.Yaw.Degrees = m_Param;
+	light->specialf1 = m_Param;
 	light->SetOffset(m_Pos);
 	light->halo = m_halo;
 	for (int a = 0; a < 3; a++) light->args[a] = clamp<int>((int)(m_Args[a]), 0, 255);
@@ -174,6 +174,7 @@ void FLightDefaults::ApplyProperties(ADynamicLight * light) const
 	if (m_subtractive) light->flags4 |= MF4_SUBTRACTIVE;
 	if (m_additive) light->flags4 |= MF4_ADDITIVE;
 	if (m_dontlightself) light->flags4 |= MF4_DONTLIGHTSELF;
+	light->m_tickCount = 0;
 }
 
 
@@ -431,6 +432,14 @@ void gl_ParsePulseLight(FScanner &sc)
 				sc.ScriptError("Unknown tag: %s\n", sc.String);
 			}
 		}
+		if (defaults->GetArg(LIGHT_INTENSITY) > defaults->GetArg(LIGHT_SECONDARY_INTENSITY))
+		{
+			auto i = defaults->GetArg(LIGHT_INTENSITY);
+			auto j = defaults->GetArg(LIGHT_SECONDARY_INTENSITY);
+			defaults->SetArg(LIGHT_INTENSITY, j);
+			defaults->SetArg(LIGHT_SECONDARY_INTENSITY, i);
+		}
+
 		gl_AddLightDefaults(defaults);
 	}
 	else
@@ -1082,7 +1091,7 @@ void gl_AttachLight(AActor *actor, unsigned int count, const FLightDefaults *lig
 		light->target = actor;
 		light->owned = true;
 		light->ObjectFlags |= OF_Transient;
-		light->flags4 |= MF4_ATTENUATE;
+		//light->flags4 |= MF4_ATTENUATE;
 		actor->dynamiclights.Push(light);
 	}
 	light->flags2&=~MF2_DORMANT;
diff --git a/src/gl/dynlights/gl_dynlight.h b/src/gl/dynlights/gl_dynlight.h
index c51e0c79d8..e8448890bc 100644
--- a/src/gl/dynlights/gl_dynlight.h
+++ b/src/gl/dynlights/gl_dynlight.h
@@ -128,12 +128,12 @@ private:
 protected:
 	DVector3 m_off;
 	float m_currentRadius;
-	int m_tickCount;
 	unsigned int m_lastUpdate;
 	FCycler m_cycler;
 	subsector_t * subsector;
 
 public:
+	int m_tickCount;
 	int m_Radius[2];
 	BYTE lightflags;
 	BYTE lighttype;
@@ -143,11 +143,6 @@ public:
 	bool visibletoplayer;
 	int bufferindex;
 
-	// intermediate texture coordinate data
-	// this is stored in the light object to avoid recalculating it
-	// several times during rendering of a flat
-	Vector nearPt, up, right;
-	float scale;
 
 };
 
diff --git a/src/gl/renderer/gl_lightdata.cpp b/src/gl/renderer/gl_lightdata.cpp
index 288af5c088..37f0a2e85b 100644
--- a/src/gl/renderer/gl_lightdata.cpp
+++ b/src/gl/renderer/gl_lightdata.cpp
@@ -63,6 +63,7 @@ CUSTOM_CVAR(Bool, gl_enhanced_nightvision, true, CVAR_ARCHIVE|CVAR_NOINITCALL)
 	}
 }
 CVAR(Bool, gl_brightfog, false, CVAR_ARCHIVE);
+CVAR(Bool, lightadditivesurfaces, false, CVAR_ARCHIVE);
 
 
 
diff --git a/src/gl/scene/gl_flats.cpp b/src/gl/scene/gl_flats.cpp
index c41e7664f9..bc47e448b6 100644
--- a/src/gl/scene/gl_flats.cpp
+++ b/src/gl/scene/gl_flats.cpp
@@ -109,7 +109,7 @@ void GLFlat::SetupSubsectorLights(int pass, subsector_t * sub, int *dli)
 {
 	Plane p;
 
-	if (renderstyle == STYLE_Add) return;	// no lights on additively blended surfaces.
+	if (renderstyle == STYLE_Add && !glset.lightadditivesurfaces) return;	// no lights on additively blended surfaces.
 
 	if (dli != NULL && *dli != -1)
 	{
diff --git a/src/gl/scene/gl_sprite.cpp b/src/gl/scene/gl_sprite.cpp
index e9748fba61..f79549a39a 100644
--- a/src/gl/scene/gl_sprite.cpp
+++ b/src/gl/scene/gl_sprite.cpp
@@ -142,6 +142,9 @@ void GLSprite::CalculateVertices(FVector3 *v)
 		v[1] = mat * FVector3(x1, z, y2);
 		v[2] = mat * FVector3(x2, z, y1);
 		v[3] = mat * FVector3(x1, z, y1);
+
+		glEnable(GL_POLYGON_OFFSET_FILL);
+		glPolygonOffset(-1.0f, -128.0f);
 		return;
 	}
 	
@@ -445,6 +448,11 @@ void GLSprite::Draw(int pass)
 		gl_RenderState.BlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 		gl_RenderState.BlendEquation(GL_FUNC_ADD);
 		gl_RenderState.SetTextureMode(TM_MODULATE);
+		if (actor != nullptr && (actor->renderflags & RF_SPRITETYPEMASK) == RF_FLATSPRITE)
+		{
+			glPolygonOffset(0.0f, 0.0f);
+			glDisable(GL_POLYGON_OFFSET_FILL);
+		}
 	}
 	else if (modelframe == nullptr)
 	{
diff --git a/src/gl/scene/gl_walls_draw.cpp b/src/gl/scene/gl_walls_draw.cpp
index 480ce4e86d..54f1dd75b9 100644
--- a/src/gl/scene/gl_walls_draw.cpp
+++ b/src/gl/scene/gl_walls_draw.cpp
@@ -56,7 +56,7 @@ FDynLightData lightdata;
 
 void GLWall::SetupLights()
 {
-	if (RenderStyle == STYLE_Add) return;	// no lights on additively blended surfaces.
+	if (RenderStyle == STYLE_Add && !glset.lightadditivesurfaces) return;	// no lights on additively blended surfaces.
 
 	// check for wall types which cannot have dynamic lights on them (portal types never get here so they don't need to be checked.)
 	switch (type)
diff --git a/src/gl/scene/gl_weapon.cpp b/src/gl/scene/gl_weapon.cpp
index a2a12f947d..7662c78768 100644
--- a/src/gl/scene/gl_weapon.cpp
+++ b/src/gl/scene/gl_weapon.cpp
@@ -188,8 +188,6 @@ static bool isBright(DPSprite *psp)
 //
 //==========================================================================
 
-EXTERN_CVAR(Bool, gl_brightfog)
-
 void FGLRenderer::DrawPlayerSprites(sector_t * viewsector, bool hudModelStep)
 {
 	bool brightflash = false;