diff --git a/src/gl/dynlights/gl_shadowmap.cpp b/src/gl/dynlights/gl_shadowmap.cpp
index 1585aec82..0f493b751 100644
--- a/src/gl/dynlights/gl_shadowmap.cpp
+++ b/src/gl/dynlights/gl_shadowmap.cpp
@@ -82,6 +82,23 @@ ADD_STAT(shadowmap)
 	return out;
 }
 
+CUSTOM_CVAR(Int, gl_shadowmap_quality, 128, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
+{
+	switch (self)
+	{
+	case 32:
+	case 64:
+	case 128:
+	case 256:
+	case 512:
+	case 1024:
+		break;
+	default:
+		self = 128;
+		break;
+	}
+}
+
 void FShadowMap::Update()
 {
 	UpdateCycles.Reset();
@@ -102,11 +119,12 @@ void FShadowMap::Update()
 	GLRenderer->mBuffers->BindShadowMapFB();
 
 	GLRenderer->mShadowMapShader->Bind();
+	GLRenderer->mShadowMapShader->ShadowmapQuality.Set(gl_shadowmap_quality);
 	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 4, mLightList);
 	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 2, mNodesBuffer);
 	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 3, mLinesBuffer);
 
-	glViewport(0, 0, SHADOWMAP_QUALITY, 1024);
+	glViewport(0, 0, gl_shadowmap_quality, 1024);
 	GLRenderer->RenderScreenQuad();
 
 	const auto &viewport = GLRenderer->mScreenViewport;
diff --git a/src/gl/dynlights/gl_shadowmap.h b/src/gl/dynlights/gl_shadowmap.h
index d6a68198c..281936f80 100644
--- a/src/gl/dynlights/gl_shadowmap.h
+++ b/src/gl/dynlights/gl_shadowmap.h
@@ -8,10 +8,6 @@
 class ADynamicLight;
 struct level_info_t;
 
-// This constant must match the same constant in shadowmap.fp
-//#define SHADOWMAP_QUALITY 1024
-#define SHADOWMAP_QUALITY 128
-
 class FShadowMap
 {
 public:
diff --git a/src/gl/renderer/gl_renderbuffers.cpp b/src/gl/renderer/gl_renderbuffers.cpp
index fbc8294b1..d60045f3e 100644
--- a/src/gl/renderer/gl_renderbuffers.cpp
+++ b/src/gl/renderer/gl_renderbuffers.cpp
@@ -81,6 +81,7 @@ FGLRenderBuffers::~FGLRenderBuffers()
 	ClearBloom();
 	ClearExposureLevels();
 	ClearAmbientOcclusion();
+	ClearShadowMap();
 }
 
 void FGLRenderBuffers::ClearScene()
@@ -759,18 +760,27 @@ void FGLRenderBuffers::BindShadowMapTexture(int texunit)
 	glBindTexture(GL_TEXTURE_2D, mShadowMapTexture);
 }
 
+void FGLRenderBuffers::ClearShadowMap()
+{
+	DeleteFrameBuffer(mShadowMapFB);
+	DeleteTexture(mShadowMapTexture);
+	mCurrentShadowMapSize = 0;
+}
+
 void FGLRenderBuffers::CreateShadowMap()
 {
-	if (mShadowMapTexture != 0)
+	if (mShadowMapTexture != 0 && gl_shadowmap_quality == mCurrentShadowMapSize)
 		return;
 
+	ClearShadowMap();
+
 	GLint activeTex, textureBinding, frameBufferBinding;
 	glGetIntegerv(GL_ACTIVE_TEXTURE, &activeTex);
 	glActiveTexture(GL_TEXTURE0);
 	glGetIntegerv(GL_TEXTURE_BINDING_2D, &textureBinding);
 	glGetIntegerv(GL_FRAMEBUFFER_BINDING, &frameBufferBinding);
 
-	mShadowMapTexture = Create2DTexture("ShadowMap", GL_R32F, SHADOWMAP_QUALITY, 1024);
+	mShadowMapTexture = Create2DTexture("ShadowMap", GL_R32F, gl_shadowmap_quality, 1024);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
@@ -781,6 +791,8 @@ void FGLRenderBuffers::CreateShadowMap()
 	glBindTexture(GL_TEXTURE_2D, textureBinding);
 	glActiveTexture(activeTex);
 	glBindFramebuffer(GL_FRAMEBUFFER, frameBufferBinding);
+
+	mCurrentShadowMapSize = gl_shadowmap_quality;
 }
 
 //==========================================================================
diff --git a/src/gl/renderer/gl_renderbuffers.h b/src/gl/renderer/gl_renderbuffers.h
index 5df3bcca0..c6aec6286 100644
--- a/src/gl/renderer/gl_renderbuffers.h
+++ b/src/gl/renderer/gl_renderbuffers.h
@@ -87,6 +87,7 @@ private:
 	void ClearBloom();
 	void ClearExposureLevels();
 	void ClearAmbientOcclusion();
+	void ClearShadowMap();
 	void CreateScene(int width, int height, int samples, bool needsSceneTextures);
 	void CreatePipeline(int width, int height);
 	void CreateBloom(int width, int height);
@@ -140,6 +141,7 @@ private:
 	// Shadow map texture
 	GLuint mShadowMapTexture = 0;
 	GLuint mShadowMapFB = 0;
+	int mCurrentShadowMapSize = 0;
 
 	static bool FailedCreate;
 	static bool BuffersActive;
diff --git a/src/gl/shaders/gl_shadowmapshader.cpp b/src/gl/shaders/gl_shadowmapshader.cpp
index 674d0a04f..8b81d386a 100644
--- a/src/gl/shaders/gl_shadowmapshader.cpp
+++ b/src/gl/shaders/gl_shadowmapshader.cpp
@@ -40,6 +40,7 @@ void FShadowMapShader::Bind()
 		mShader.SetFragDataLocation(0, "FragColor");
 		mShader.Link("shaders/glsl/shadowmap");
 		mShader.SetAttribLocation(0, "PositionInProjection");
+		ShadowmapQuality.Init(mShader, "ShadowmapQuality");
 	}
 	mShader.Bind();
 }
diff --git a/src/gl/shaders/gl_shadowmapshader.h b/src/gl/shaders/gl_shadowmapshader.h
index 7d01f9974..309dccb52 100644
--- a/src/gl/shaders/gl_shadowmapshader.h
+++ b/src/gl/shaders/gl_shadowmapshader.h
@@ -8,6 +8,8 @@ class FShadowMapShader
 public:
 	void Bind();
 
+	FBufferedUniform1f ShadowmapQuality;
+
 private:
 	FShaderProgram mShader;
 };
diff --git a/src/gl/system/gl_cvars.h b/src/gl/system/gl_cvars.h
index b7122b01c..51ab642de 100644
--- a/src/gl/system/gl_cvars.h
+++ b/src/gl/system/gl_cvars.h
@@ -27,6 +27,7 @@ EXTERN_CVAR (Bool, gl_lights_checkside);
 EXTERN_CVAR (Bool, gl_light_sprites);
 EXTERN_CVAR (Bool, gl_light_particles);
 EXTERN_CVAR (Bool, gl_light_shadowmap);
+EXTERN_CVAR (Int, gl_shadowmap_quality);
 
 EXTERN_CVAR(Int, gl_fogmode)
 EXTERN_CVAR(Int, gl_lightmode)
diff --git a/wadsrc/static/shaders/glsl/shadowmap.fp b/wadsrc/static/shaders/glsl/shadowmap.fp
index 9e4efdd4e..47696aa74 100644
--- a/wadsrc/static/shaders/glsl/shadowmap.fp
+++ b/wadsrc/static/shaders/glsl/shadowmap.fp
@@ -3,8 +3,9 @@ in vec2 TexCoord;
 out vec4 FragColor;
 
 // This constant must match the same constant in gl_shadowmap.h
-// #define SHADOWMAP_QUALITY 1024
-#define SHADOWMAP_QUALITY 128
+// #define ShadowmapQuality 1024
+//#define ShadowmapQuality 128
+uniform float ShadowmapQuality;
 
 struct GPUNode
 {
@@ -144,12 +145,12 @@ void main()
 	if (radius > 0.0)
 	{
 		vec2 pixelpos;
-		switch (int(gl_FragCoord.x) / int(SHADOWMAP_QUALITY/4))
+		switch (int(gl_FragCoord.x) / int(ShadowmapQuality/4.0))
 		{
-		case 0: pixelpos = vec2((gl_FragCoord.x - float(SHADOWMAP_QUALITY/8)) / float(SHADOWMAP_QUALITY/8), 1.0); break;
-		case 1: pixelpos = vec2(1.0, (gl_FragCoord.x - float(SHADOWMAP_QUALITY/4 + SHADOWMAP_QUALITY/8)) / float(SHADOWMAP_QUALITY/8)); break;
-		case 2: pixelpos = vec2(-(gl_FragCoord.x - float(SHADOWMAP_QUALITY/2 + SHADOWMAP_QUALITY/8)) / float(SHADOWMAP_QUALITY/8), -1.0); break;
-		case 3: pixelpos = vec2(-1.0, -(gl_FragCoord.x - float(SHADOWMAP_QUALITY*3/4 + SHADOWMAP_QUALITY/8)) / float(SHADOWMAP_QUALITY/8)); break;
+		case 0: pixelpos = vec2((gl_FragCoord.x - float(ShadowmapQuality/8.0)) / float(ShadowmapQuality/8.0), 1.0); break;
+		case 1: pixelpos = vec2(1.0, (gl_FragCoord.x - float(ShadowmapQuality/4.0 + ShadowmapQuality/8.0)) / float(ShadowmapQuality/8.0)); break;
+		case 2: pixelpos = vec2(-(gl_FragCoord.x - float(ShadowmapQuality/2.0 + ShadowmapQuality/8.0)) / float(ShadowmapQuality/8.0), -1.0); break;
+		case 3: pixelpos = vec2(-1.0, -(gl_FragCoord.x - float(ShadowmapQuality*3.0/4.0 + ShadowmapQuality/8.0)) / float(ShadowmapQuality/8.0)); break;
 		}
 		pixelpos = lightpos + pixelpos * radius;