diff --git a/src/common/rendering/gles/gles_renderstate.cpp b/src/common/rendering/gles/gles_renderstate.cpp
index b29c55d37..c6d4faeda 100644
--- a/src/common/rendering/gles/gles_renderstate.cpp
+++ b/src/common/rendering/gles/gles_renderstate.cpp
@@ -169,6 +169,7 @@ bool FGLRenderState::ApplyShader()
 		}
 
 		flavour.doDesaturate = mStreamData.uDesaturationFactor != 0;
+		flavour.useULightLevel = (mLightParms[3] >= 0); //#define uLightLevel uLightAttr.a
 
 		// Yes create shaders for all combinations of active lights to avoid more branches
 		flavour.dynLightsMod = (modLights > 0);
diff --git a/src/common/rendering/gles/gles_shader.cpp b/src/common/rendering/gles/gles_shader.cpp
index e8c0ce80f..f6ed0d402 100644
--- a/src/common/rendering/gles/gles_shader.cpp
+++ b/src/common/rendering/gles/gles_shader.cpp
@@ -664,7 +664,8 @@ bool FShader::Bind(ShaderFlavourData& flavour)
 		variantConfig.AppendFormat("#define DEF_FOG_ENABLED %d\n", flavour.fogEnabled);
 		variantConfig.AppendFormat("#define DEF_FOG_RADIAL %d\n", flavour.fogEquationRadial);
 		variantConfig.AppendFormat("#define DEF_FOG_COLOURED %d\n", flavour.colouredFog);
-		
+		variantConfig.AppendFormat("#define DEF_USE_U_LIGHT_LEVEL %d\n", flavour.useULightLevel);
+
 		variantConfig.AppendFormat("#define DEF_DO_DESATURATE %d\n", flavour.doDesaturate);
 		variantConfig.AppendFormat("#define DEF_DYNAMIC_LIGHTS_MOD %d\n", flavour.dynLightsMod);
 		variantConfig.AppendFormat("#define DEF_DYNAMIC_LIGHTS_SUB %d\n", flavour.dynLightsSub);
diff --git a/src/common/rendering/gles/gles_shader.h b/src/common/rendering/gles/gles_shader.h
index cb7b99554..e56d1c22f 100644
--- a/src/common/rendering/gles/gles_shader.h
+++ b/src/common/rendering/gles/gles_shader.h
@@ -263,6 +263,7 @@ public:
 	bool dynLightsMod;
 	bool dynLightsSub;
 	bool dynLightsAdd;
+	bool useULightLevel;
 };
 
 class FShader
@@ -391,6 +392,7 @@ public:
 		tag |= (flavour.dynLightsMod & 1) << 12;
 		tag |= (flavour.dynLightsSub & 1) << 13;
 		tag |= (flavour.dynLightsAdd & 1) << 14;
+		tag |= (flavour.useULightLevel & 1) << 15;
 
 		return tag;
 	}
diff --git a/wadsrc/static/shaders_gles/glsl/main.fp b/wadsrc/static/shaders_gles/glsl/main.fp
index 18d27031b..abfe86369 100644
--- a/wadsrc/static/shaders_gles/glsl/main.fp
+++ b/wadsrc/static/shaders_gles/glsl/main.fp
@@ -313,12 +313,12 @@ vec4 getLightColor(Material material, float fogdist, float fogfactor)
 {
 	vec4 color = vColor;
 	
-	if (uLightLevel >= 0.0)
+#if (DEF_USE_U_LIGHT_LEVEL == 1)
 	{
 		float newlightlevel = 1.0 - R_DoomLightingEquation(uLightLevel);
 		color.rgb *= newlightlevel;
 	}
-	else
+#else
 	{
 
 		#if (DEF_FOG_ENABLED == 1) && (DEF_FOG_COLOURED == 0)
@@ -336,7 +336,7 @@ vec4 getLightColor(Material material, float fogdist, float fogfactor)
 		}
 		#endif
 	}
-	
+#endif	
 	//
 	// handle glowing walls
 	//