ThickFogDistance and ThickFogMultiplier MAPINFO variables adds thicker fog (Vulkan and OpenGL only) beyond ThickFogDistance, as long as it is possible. But default it is -1.f (disabled).

src/common/rendering/gl/gl_shader.cpp

@@ -330,6 +330,9 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 			int uShadowmapFilter;
 			
 			int uLightBlendMode;
+
+			float uThickFogDistance;
+			float uThickFogMultiplier;
 		};
 
 		uniform int uTextureMode;

src/common/rendering/gles/gles_renderstate.cpp

@@ -231,6 +231,8 @@ bool FGLRenderState::ApplyShader()
 		activeShader->cur->muClipHeight.Set(mHwUniforms->mClipHeight);
 		activeShader->cur->muClipHeightDirection.Set(mHwUniforms->mClipHeightDirection);
 		//activeShader->cur->muShadowmapFilter.Set(mHwUniforms->mShadowmapFilter);
+		activeShader->cur->muThickFogDistance.Set(mHwUniforms->mThickFogDistance);
+		activeShader->cur->muThickFogMultiplier.Set(mHwUniforms->mThickFogMultiplier);
 	}
 
 	glVertexAttrib4fv(VATTR_COLOR, &mStreamData.uVertexColor.X);

src/common/rendering/gles/gles_shader.cpp

@@ -284,6 +284,9 @@ bool FShader::Load(const char * name, const char * vert_prog_lump_, const char *
 		uniform	float uClipHeightDirection;
 		uniform	int uShadowmapFilter;
 
+		uniform float uThickFogDistance;
+		uniform float uThickFogMultiplier;
+
 		uniform int uTextureMode;
 		uniform vec2 uClipSplit;
 		uniform float uAlphaThreshold;
@@ -582,6 +585,8 @@ bool FShader::Load(const char * name, const char * vert_prog_lump_, const char *
 	shaderData->muClipHeightDirection.Init(shaderData->hShader, "uClipHeightDirection");
 	shaderData->muShadowmapFilter.Init(shaderData->hShader, "uShadowmapFilter");
 
+	shaderData->muThickFogDistance.Init(shaderData->hShader, "uThickFogDistance");
+	shaderData->muThickFogMultiplier.Init(shaderData->hShader, "uThickFogMultiplier");
 	////
 
 	shaderData->muDesaturation.Init(shaderData->hShader, "uDesaturationFactor");

src/common/rendering/gles/gles_shader.h

@@ -319,6 +319,9 @@ public: class ShaderVariantData
 		FBufferedUniform1f muClipHeight;
 		FBufferedUniform1f muClipHeightDirection;
 		FBufferedUniform1i muShadowmapFilter;
+
+		FBufferedUniform1f muThickFogDistance;
+		FBufferedUniform1f muThickFogMultiplier;
 		/////
 
 		FBufferedUniform1f muDesaturation;

src/common/rendering/hwrenderer/data/hw_viewpointuniforms.h

@@ -30,6 +30,9 @@ struct HWViewpointUniforms
 
 	int mLightBlendMode = 0;
 
+	float mThickFogDistance = -1.f;
+	float mThickFogMultiplier = 30.f;
+
 	void CalcDependencies()
 	{
 		mNormalViewMatrix.computeNormalMatrix(mViewMatrix);

src/common/rendering/vulkan/shaders/vk_shader.cpp

@@ -204,6 +204,9 @@ static const char *shaderBindings = R"(
 		int uShadowmapFilter;
 		
 		int uLightBlendMode;
+
+		float uThickFogDistance;
+		float uThickFogMultiplier;
 	};
 
 	layout(set = 1, binding = 1, std140) uniform MatricesUBO {

src/console/c_cmds.cpp

@@ -952,6 +952,36 @@ CCMD(skymisttoggle)
 	primaryLevel->flags3 ^= LEVEL3_SKYMIST;
 }
 
+//-----------------------------------------------------------------------------
+//
+//
+//
+//-----------------------------------------------------------------------------
+CCMD(thickfogdistance)
+{
+	if (argv.argc() > 1)
+	{
+		// Do this only on the primary level.
+		primaryLevel->thickfogdistance = (float)strtod(argv[1], NULL);
+	}
+	Printf("%f (positive means enabled)\n", primaryLevel->thickfogdistance);
+}
+
+//-----------------------------------------------------------------------------
+//
+//
+//
+//-----------------------------------------------------------------------------
+CCMD(thickfogmultiplier)
+{
+	if (argv.argc() > 1)
+	{
+		// Do this only on the primary level.
+		primaryLevel->thickfogmultiplier = max(0.f, (float)strtod(argv[1], NULL));
+	}
+	Printf("%f\n", primaryLevel->thickfogmultiplier);
+}
+
 //-----------------------------------------------------------------------------
 //
 //

src/g_dumpinfo.cpp

@@ -430,6 +430,7 @@ CCMD(skyfog)
 		// Do this only on the primary level.
 		primaryLevel->skyfog = max(0, (int)strtoull(argv[1], NULL, 0));
 	}
+	Printf("%d\n", primaryLevel->skyfog);
 }
 
 

src/g_level.cpp

@@ -1903,6 +1903,9 @@ void FLevelLocals::Init()
 	skyfog = info->skyfog;
 	deathsequence = info->deathsequence;
 
+	thickfogdistance = info->thickfogdistance;
+	thickfogmultiplier = info->thickfogmultiplier;
+
 	pixelstretch = info->pixelstretch;
 
 	compatflags->Callback();

src/g_levellocals.h

@@ -753,6 +753,8 @@ public:
 	bool		lightadditivesurfaces;
 	bool		notexturefill;
 	int			ImpactDecalCount;
+	float		thickfogdistance;
+	float		thickfogmultiplier;
 
 	FGlobalDLightLists lightlists;
 

src/gamedata/g_mapinfo.cpp

@@ -313,6 +313,8 @@ void level_info_t::Reset()
 	fogdensity = 0;
 	outsidefogdensity = 0;
 	skyfog = 0;
+	thickfogdistance = -1.0f;
+	thickfogmultiplier = 30.0f;
 	pixelstretch = 1.2f;
 
 	specialactions.Clear();
@@ -1575,6 +1577,20 @@ DEFINE_MAP_OPTION(skyfog, false)
 	info->skyfog = parse.sc.Number;
 }
 
+DEFINE_MAP_OPTION(thickfogdistance, false)
+{
+	parse.ParseAssign();
+	parse.sc.MustGetFloat();
+	info->thickfogdistance = (float)parse.sc.Float;
+}
+
+DEFINE_MAP_OPTION(thickfogmultiplier, false)
+{
+	parse.ParseAssign();
+	parse.sc.MustGetFloat();
+	info->thickfogmultiplier = (float)parse.sc.Float;
+}
+
 DEFINE_MAP_OPTION(pixelratio, false)
 {
 	parse.ParseAssign();

src/gamedata/g_mapinfo.h

@@ -382,6 +382,8 @@ struct level_info_t
 	int			fogdensity;
 	int			outsidefogdensity;
 	int			skyfog;
+	float		thickfogdistance;
+	float		thickfogmultiplier;
 	float		pixelstretch;
 
 	// Redirection: If any player is carrying the specified item, then

src/p_saveg.cpp

@@ -982,6 +982,8 @@ void FLevelLocals::Serialize(FSerializer &arc, bool hubload)
 		("fogdensity", fogdensity)
 		("outsidefogdensity", outsidefogdensity)
 		("skyfog", skyfog)
+		("thickfogdistance", thickfogdistance)
+		("thickfogmultiplier", thickfogmultiplier)
 		("deathsequence", deathsequence)
 		("bodyqueslot", bodyqueslot)
 		("spawnindex", spawnindex)

src/rendering/hwrenderer/scene/hw_drawinfo.cpp

@@ -175,6 +175,8 @@ void HWDrawInfo::StartScene(FRenderViewpoint &parentvp, HWViewpointUniforms *uni
 		VPUniforms.mClipLine.X = -10000000.0f;
 		VPUniforms.mShadowmapFilter = gl_shadowmap_filter;
 		VPUniforms.mLightBlendMode = (level.info ? (int)level.info->lightblendmode : 0);
+		VPUniforms.mThickFogDistance = Level->thickfogdistance;
+		VPUniforms.mThickFogMultiplier = Level->thickfogmultiplier;
 	}
 	mClipper->SetViewpoint(Viewpoint);
 	vClipper->SetViewpoint(Viewpoint);

src/scripting/vmthunks.cpp

@@ -2838,6 +2838,8 @@ DEFINE_FIELD_X(LevelInfo, level_info_t, deathsequence)
 DEFINE_FIELD_X(LevelInfo, level_info_t, fogdensity)
 DEFINE_FIELD_X(LevelInfo, level_info_t, outsidefogdensity)
 DEFINE_FIELD_X(LevelInfo, level_info_t, skyfog)
+DEFINE_FIELD_X(LevelInfo, level_info_t, thickfogdistance)
+DEFINE_FIELD_X(LevelInfo, level_info_t, thickfogmultiplier)
 DEFINE_FIELD_X(LevelInfo, level_info_t, pixelstretch)
 DEFINE_FIELD_X(LevelInfo, level_info_t, RedirectType)
 DEFINE_FIELD_X(LevelInfo, level_info_t, RedirectMapName)
@@ -2889,6 +2891,8 @@ DEFINE_FIELD(FLevelLocals, teamdamage)
 DEFINE_FIELD(FLevelLocals, fogdensity)
 DEFINE_FIELD(FLevelLocals, outsidefogdensity)
 DEFINE_FIELD(FLevelLocals, skyfog)
+DEFINE_FIELD(FLevelLocals, thickfogdistance)
+DEFINE_FIELD(FLevelLocals, thickfogmultiplier)
 DEFINE_FIELD(FLevelLocals, pixelstretch)
 DEFINE_FIELD(FLevelLocals, MusicVolume)
 DEFINE_FIELD(FLevelLocals, deathsequence)

wadsrc/static/shaders/glsl/main.fp

@@ -855,6 +855,13 @@ void main()
 			{
 				fogdist = max(16.0, distance(pixelpos.xyz, uCameraPos.xyz));
 			}
+			if (uThickFogDistance > 0.0)
+			{
+				if (fogdist > uThickFogDistance)
+				{
+					fogdist = fogdist + uThickFogMultiplier * (fogdist - uThickFogDistance);
+				}
+			}
 			fogfactor = exp2 (uFogDensity * fogdist);
 		}
 

wadsrc/static/zscript/doombase.zs

@@ -414,6 +414,8 @@ struct LevelInfo native
 	native readonly int fogdensity;
 	native readonly int outsidefogdensity;
 	native readonly int skyfog;
+	native readonly float thickfogdistance;
+	native readonly float thickfogmultiplier;
 	native readonly float pixelstretch;
 	native readonly name RedirectType;
 	native readonly String RedirectMapName;
@@ -527,6 +529,8 @@ struct LevelLocals native
 	native readonly int fogdensity;
 	native readonly int outsidefogdensity;
 	native readonly int skyfog;
+	native readonly float thickfogdistance;
+	native readonly float thickfogmultiplier;
 	native readonly float pixelstretch;
 	native readonly float MusicVolume;
 	native name deathsequence;