diff --git a/src/common/rendering/hwrenderer/data/hw_shadowmap.cpp b/src/common/rendering/hwrenderer/data/hw_shadowmap.cpp
index cb5630594a..f3e37ed614 100644
--- a/src/common/rendering/hwrenderer/data/hw_shadowmap.cpp
+++ b/src/common/rendering/hwrenderer/data/hw_shadowmap.cpp
@@ -85,7 +85,7 @@ CUSTOM_CVAR(Int, gl_shadowmap_quality, 512, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
 
 bool IShadowMap::ShadowTest(const DVector3 &lpos, const DVector3 &pos)
 {
-	if (mAABBTree && gl_light_shadowmap)
+	if (mAABBTree)
 		return mAABBTree->RayTest(lpos, pos) >= 1.0f;
 	else
 		return true;
@@ -98,7 +98,7 @@ bool IShadowMap::PerformUpdate()
 	LightsProcessed = 0;
 	LightsShadowmapped = 0;
 
-	if (gl_light_shadowmap && (screen->hwcaps & RFL_SHADER_STORAGE_BUFFER) && CollectLights != nullptr)
+	if (CollectLights != nullptr)
 	{
 		UpdateCycles.Clock();
 		UploadAABBTree();
diff --git a/src/gamedata/g_mapinfo.cpp b/src/gamedata/g_mapinfo.cpp
index ac76ee0767..28b83f3088 100644
--- a/src/gamedata/g_mapinfo.cpp
+++ b/src/gamedata/g_mapinfo.cpp
@@ -1657,8 +1657,10 @@ MapFlagHandlers[] =
 	{ "nolightfade",					MITYPE_SETFLAG3,	LEVEL3_NOLIGHTFADE, 0 },
 	{ "nocoloredspritelighting",		MITYPE_SETFLAG3,	LEVEL3_NOCOLOREDSPRITELIGHTING, 0 },
 	{ "forceworldpanning",				MITYPE_SETFLAG3,	LEVEL3_FORCEWORLDPANNING, 0 },
-	{ "propermonsterfallingdamage",			MITYPE_SETFLAG3,	LEVEL3_PROPERMONSTERFALLINGDAMAGE, 0 },
-	{ "enableskyboxao",				MITYPE_SETFLAG3,	LEVEL3_SKYBOXAO, 0 },
+	{ "propermonsterfallingdamage",		MITYPE_SETFLAG3,	LEVEL3_PROPERMONSTERFALLINGDAMAGE, 0 },
+	{ "disableshadowmap",				MITYPE_SETFLAG3,	LEVEL3_NOSHADOWMAP, 0 },
+	{ "enableshadowmap",				MITYPE_CLRFLAG3,	LEVEL3_NOSHADOWMAP, 0 },
+	{ "enableskyboxao",					MITYPE_SETFLAG3,	LEVEL3_SKYBOXAO, 0 },
 	{ "disableskyboxao",				MITYPE_CLRFLAG3,	LEVEL3_SKYBOXAO, 0 },
 	{ "nobotnodes",						MITYPE_IGNORE,	0, 0 },		// Skulltag option: nobotnodes
 	{ "compat_shorttex",				MITYPE_COMPATFLAG, COMPATF_SHORTTEX, 0 },
diff --git a/src/gamedata/g_mapinfo.h b/src/gamedata/g_mapinfo.h
index a572fcce60..8e73229107 100644
--- a/src/gamedata/g_mapinfo.h
+++ b/src/gamedata/g_mapinfo.h
@@ -257,6 +257,7 @@ enum ELevelFlags : unsigned int
 	LEVEL3_E3M8SPECIAL			= 0x00002000,
 	LEVEL3_E4M8SPECIAL			= 0x00004000,
 	LEVEL3_E4M6SPECIAL			= 0x00008000,
+	LEVEL3_NOSHADOWMAP			= 0x00010000,	// disables shadowmaps for a given level.
 };
 
 
diff --git a/src/rendering/hwrenderer/hw_dynlightdata.cpp b/src/rendering/hwrenderer/hw_dynlightdata.cpp
index dddc9ad4df..f65b031726 100644
--- a/src/rendering/hwrenderer/hw_dynlightdata.cpp
+++ b/src/rendering/hwrenderer/hw_dynlightdata.cpp
@@ -107,10 +107,9 @@ void AddLightToList(FDynLightData &dld, int group, FDynamicLight * light, bool f
 	}
 
 	float shadowIndex;
-	if (gl_light_shadowmap)
+	if (gl_light_shadowmap) // note: with gl_light_shadowmap switched off, we cannot rely on properly set indices anymore.
 	{
 		shadowIndex = light->mShadowmapIndex + 1.0f;
-
 	}
 	else shadowIndex = 1025.f;
 	// Store attenuate flag in the sign bit of the float.
diff --git a/src/rendering/hwrenderer/hw_entrypoint.cpp b/src/rendering/hwrenderer/hw_entrypoint.cpp
index 5485cedc08..1845f051c5 100644
--- a/src/rendering/hwrenderer/hw_entrypoint.cpp
+++ b/src/rendering/hwrenderer/hw_entrypoint.cpp
@@ -107,7 +107,7 @@ sector_t* RenderViewpoint(FRenderViewpoint& mainvp, AActor* camera, IntRect* bou
 
 	R_SetupFrame(mainvp, r_viewwindow, camera);
 
-	if (mainview && toscreen)
+	if (mainview && toscreen && !(camera->Level->flags3 & LEVEL3_NOSHADOWMAP) && gl_light_shadowmap && (screen->hwcaps & RFL_SHADER_STORAGE_BUFFER))
 	{
 		screen->SetAABBTree(camera->Level->aabbTree);
 		screen->mShadowMap.SetCollectLights([=] {
@@ -115,6 +115,12 @@ sector_t* RenderViewpoint(FRenderViewpoint& mainvp, AActor* camera, IntRect* bou
 		});
 		screen->UpdateShadowMap();
 	}
+	else
+	{
+		// null all references to the level if we do not need a shadowmap. This will shortcut all internal calculations without further checks.
+		screen->SetAABBTree(nullptr);
+		screen->mShadowMap.SetCollectLights(nullptr);
+	}
 
 	// Update the attenuation flag of all light defaults for each viewpoint.
 	// This function will only do something if the setting differs.