diff --git a/src/rendering/hwrenderer/scene/hw_drawinfo.cpp b/src/rendering/hwrenderer/scene/hw_drawinfo.cpp
index 421024947f..3bb41ff422 100644
--- a/src/rendering/hwrenderer/scene/hw_drawinfo.cpp
+++ b/src/rendering/hwrenderer/scene/hw_drawinfo.cpp
@@ -146,8 +146,16 @@ void HWDrawInfo::StartScene(FRenderViewpoint &parentvp, HWViewpointUniforms *uni
 		VPUniforms.mViewMatrix.loadIdentity();
 		VPUniforms.mNormalViewMatrix.loadIdentity();
 		VPUniforms.mViewHeight = viewheight;
-		VPUniforms.mGlobVis = (float)R_GetGlobVis(r_viewwindow, r_visibility) / 32.f;
-		VPUniforms.mPalLightLevels = static_cast<int>(gl_bandedswlight) | (static_cast<int>(gl_fogmode) << 8) | ((int)lightmode << 16);
+		if (gl_lightmode == 5)
+		{
+			VPUniforms.mGlobVis = 1 / 64.f;
+			VPUniforms.mPalLightLevels = 32 | (static_cast<int>(gl_fogmode) << 8) | ((int)lightmode << 16);
+		}
+		else
+		{
+			VPUniforms.mGlobVis = (float)R_GetGlobVis(r_viewwindow, r_visibility) / 32.f;
+			VPUniforms.mPalLightLevels = static_cast<int>(gl_bandedswlight) | (static_cast<int>(gl_fogmode) << 8) | ((int)lightmode << 16);
+		}
 		VPUniforms.mClipLine.X = -10000000.0f;
 		VPUniforms.mShadowmapFilter = gl_shadowmap_filter;
 	}
diff --git a/src/rendering/hwrenderer/scene/hw_lighting.cpp b/src/rendering/hwrenderer/scene/hw_lighting.cpp
index bb45f08561..ca8fa546dd 100644
--- a/src/rendering/hwrenderer/scene/hw_lighting.cpp
+++ b/src/rendering/hwrenderer/scene/hw_lighting.cpp
@@ -185,7 +185,7 @@ float HWDrawInfo::GetFogDensity(int lightlevel, PalEntry fogcolor, int sectorfog
 	else if ((fogcolor.d & 0xffffff) == 0)
 	{
 		// case 2: black fog
-		if ((!isSoftwareLighting() || blendfactor > 0) && !(Level->flags3 & LEVEL3_NOLIGHTFADE))
+		if ((!isDoomSoftwareLighting() || blendfactor > 0) && !(Level->flags3 & LEVEL3_NOLIGHTFADE))
 		{
 			density = distfogtable[lightmode != ELightMode::LinearStandard][hw_ClampLight(lightlevel)];
 		}
diff --git a/src/rendering/hwrenderer/scene/hw_setcolor.cpp b/src/rendering/hwrenderer/scene/hw_setcolor.cpp
index a81db3a1c6..053a43b971 100644
--- a/src/rendering/hwrenderer/scene/hw_setcolor.cpp
+++ b/src/rendering/hwrenderer/scene/hw_setcolor.cpp
@@ -135,6 +135,10 @@ void HWDrawInfo::SetFog(FRenderState &state, int lightlevel, int rellight, bool
 			float light = (float)CalcLightLevel(lightlevel, rellight, false, cmap->BlendFactor);
 			SetShaderLight(state, light, lightlevel);
 		}
+		else if (lightmode == ELightMode::Build)
+		{
+			state.SetLightParms(0.2f * fogdensity, 1.f / 31.f);
+		}
 		else
 		{
 			state.SetLightParms(1.f, 0.f);
diff --git a/wadsrc/static/menudef.txt b/wadsrc/static/menudef.txt
index 1e06d6cd84..14935cb4fe 100644
--- a/wadsrc/static/menudef.txt
+++ b/wadsrc/static/menudef.txt
@@ -2401,6 +2401,7 @@ OptionValue "LightingModes"
 	2, "$OPTVAL_DOOM"
 	3, "$OPTVAL_DARK"
 	4, "$OPTVAL_LEGACY"
+	5, "$OPTVAL_BUILD"
 	8, "$OPTVAL_SOFTWARE"
 	16, "$OPTVAL_VANILLA"
 }
diff --git a/wadsrc/static/shaders/glsl/main.fp b/wadsrc/static/shaders/glsl/main.fp
index 611dbe0b21..009427dd2e 100644
--- a/wadsrc/static/shaders/glsl/main.fp
+++ b/wadsrc/static/shaders/glsl/main.fp
@@ -313,7 +313,7 @@ float R_DoomLightingEquation(float light)
 	{
 		// This is a lot more primitive than Doom's lighting...
 		float numShades = float(uPalLightLevels & 255);
-		float curshade = (1.0 - light) / (numShades - 1.0);
+		float curshade = (1.0 - light) * (numShades - 1.0);
 		float visibility = max(uGlobVis * uLightFactor * z, 0.0);
 		float shade = clamp((curshade + visibility), 0.0, numShades - 1.0);
 		return clamp(shade * uLightDist, 0.0, 1.0);