diff --git a/src/gl/data/gl_data.cpp b/src/gl/data/gl_data.cpp
index e0bb5ee6b..da72f6313 100644
--- a/src/gl/data/gl_data.cpp
+++ b/src/gl/data/gl_data.cpp
@@ -356,7 +356,14 @@ void InitGLRMapinfoData()
 		glset.map_notexturefill = opt->notexturefill;
 		glset.skyrotatevector = opt->skyrotatevector;
 		glset.skyrotatevector2 = opt->skyrotatevector2;
-		if (gl.shadermodel == 2 && glset.map_lightmode ==2) glset.map_lightmode = 3;
+		if (!gl.hasGLSL())
+		{
+			// light modes 2 and 8 require shaders
+			if (glset.map_lightmode == 2 || glset.map_lightmode == 8)
+			{
+				glset.map_lightmode = 3;
+			}
+		}
 	}
 	else
 	{
diff --git a/src/gl/dynlights/gl_dynlight1.cpp b/src/gl/dynlights/gl_dynlight1.cpp
index 0b2ffa43d..e09207411 100644
--- a/src/gl/dynlights/gl_dynlight1.cpp
+++ b/src/gl/dynlights/gl_dynlight1.cpp
@@ -70,7 +70,17 @@ CUSTOM_CVAR (Bool, gl_lights, true, CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_NOIN
 
 CUSTOM_CVAR (Bool, gl_dynlight_shader, false, CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_NOINITCALL)
 {
-	if (self && (gl.maxuniforms < 1024 || gl.shadermodel < 4)) self = false;
+	if (self)
+	{
+		if (!gl.hasGLSL())
+		{
+			self = false;
+		}
+		else if (gl.maxuniforms < 1024 && !(gl.flags & RFL_SHADER_STORAGE_BUFFER))
+		{
+			self = false;
+		}
+	}
 }
 
 CVAR (Bool, gl_attachedlights, true, CVAR_ARCHIVE | CVAR_GLOBALCONFIG);
diff --git a/src/gl/models/gl_models.cpp b/src/gl/models/gl_models.cpp
index 39668cd02..4b8a8e44b 100644
--- a/src/gl/models/gl_models.cpp
+++ b/src/gl/models/gl_models.cpp
@@ -753,7 +753,7 @@ void gl_RenderModel(GLSprite * spr, int cm)
 	if(smf->flags & MDL_INHERITACTORPITCH) pitch += float(static_cast<double>(spr->actor->pitch >> 16) / (1 << 13) * 45 + static_cast<double>(spr->actor->pitch & 0x0000FFFF) / (1 << 29) * 45);
 	if(smf->flags & MDL_INHERITACTORROLL) roll += float(static_cast<double>(spr->actor->roll >> 16) / (1 << 13) * 45 + static_cast<double>(spr->actor->roll & 0x0000FFFF) / (1 << 29) * 45);
 		
-	if (gl.shadermodel < 4)
+	if (!gl.hasGLSL())
 	{
 		glMatrixMode(GL_MODELVIEW);
 		glPushMatrix();
@@ -795,7 +795,7 @@ void gl_RenderModel(GLSprite * spr, int cm)
 	glRotatef(smf->pitchoffset, 0, 0, 1);
 	glRotatef(-smf->rolloffset, 1, 0, 0);
 		
-	if (gl.shadermodel >= 4) glActiveTexture(GL_TEXTURE0);
+	if (gl.hasGLSL()) glActiveTexture(GL_TEXTURE0);
 
 #if 0
 	if (gl_light_models)
@@ -814,7 +814,7 @@ void gl_RenderModel(GLSprite * spr, int cm)
 
 	gl_RenderFrameModels( smf, spr->actor->state, spr->actor->tics, RUNTIME_TYPE(spr->actor), cm, NULL, translation );
 
-	if (gl.shadermodel < 4)
+	if (!gl.hasGLSL())
 	{
 		glMatrixMode(GL_MODELVIEW);
 		glPopMatrix();
diff --git a/src/gl/renderer/gl_lightdata.cpp b/src/gl/renderer/gl_lightdata.cpp
index 9292c765e..1523443c8 100644
--- a/src/gl/renderer/gl_lightdata.cpp
+++ b/src/gl/renderer/gl_lightdata.cpp
@@ -80,12 +80,12 @@ CVAR(Bool, gl_brightfog, false, CVAR_ARCHIVE);
 
 bool gl_BrightmapsActive()
 {
-	return gl.shadermodel == 4 || (gl.shadermodel == 3 && gl_brightmap_shader);
+	return gl.hasGLSL();
 }
 
 bool gl_GlowActive()
 {
-	return gl.shadermodel == 4 || (gl.shadermodel == 3 && gl_glow_shader);
+	return gl.hasGLSL();
 }
 
 //==========================================================================
@@ -125,7 +125,7 @@ CUSTOM_CVAR(Int,gl_fogmode,1,CVAR_ARCHIVE|CVAR_NOINITCALL)
 {
 	if (self>2) self=2;
 	if (self<0) self=0;
-	if (self == 2 && gl.shadermodel < 4) self = 1;
+	if (self == 2 && !gl.hasGLSL()) self = 1;
 }
 
 CUSTOM_CVAR(Int, gl_lightmode, 3 ,CVAR_ARCHIVE|CVAR_NOINITCALL)
@@ -133,7 +133,7 @@ CUSTOM_CVAR(Int, gl_lightmode, 3 ,CVAR_ARCHIVE|CVAR_NOINITCALL)
 	int newself = self;
 	if (newself > 4) newself=8;	// use 8 for software lighting to avoid conflicts with the bit mask
 	if (newself < 0) newself=0;
-	if ((newself == 2 || newself == 8) && gl.shadermodel < 4) newself = 3;
+	if ((newself == 2 || newself == 8) && !gl.hasGLSL()) newself = 3;
 	if (self != newself) self = newself;
 	glset.lightmode = newself;
 }
diff --git a/src/gl/renderer/gl_renderstate.cpp b/src/gl/renderer/gl_renderstate.cpp
index f0ceb40fa..8d3423423 100644
--- a/src/gl/renderer/gl_renderstate.cpp
+++ b/src/gl/renderer/gl_renderstate.cpp
@@ -104,28 +104,13 @@ int FRenderState::SetupShader(bool cameratexture, int &shaderindex, int &cm, flo
 		}
 	}
 
-	if (gl.shadermodel == 4)
+	if (gl.hasGLSL())
 	{
 		usecmshader = cm > CM_DEFAULT && cm < CM_MAXCOLORMAP && mTextureMode != TM_MASK;
 	}
-	else if (gl.shadermodel == 3)
-	{
-		usecmshader = (cameratexture || gl_colormap_shader) && 
-			cm > CM_DEFAULT && cm < CM_MAXCOLORMAP && mTextureMode != TM_MASK;
-
-		if (!gl_brightmap_shader && shaderindex == 3) 
-		{
-			shaderindex = 0;
-		}
-		else if (!gl_warp_shader && shaderindex !=3)
-		{
-			if (shaderindex <= 2) softwarewarp = shaderindex;
-			shaderindex = 0;
-		}
-	}
 	else
 	{
-		usecmshader = cameratexture;
+		usecmshader = false;
 		softwarewarp = shaderindex > 0 && shaderindex < 3? shaderindex : 0;
 		shaderindex = 0;
 	}
@@ -149,43 +134,22 @@ bool FRenderState::ApplyShader()
 	bool useshaders = false;
 	FShader *activeShader = NULL;
 
-	if (mSpecialEffect > 0 && gl.shadermodel > 2)
+	if (mSpecialEffect > 0 && gl.hasGLSL())
 	{
 		activeShader = GLRenderer->mShaderManager->BindEffect(mSpecialEffect);
 	}
-	else
+	else if (gl.hasGLSL())
 	{
-		switch (gl.shadermodel)
+		useshaders = (!m2D || mEffectState != 0 || mColormapState); // all 3D rendering and 2D with texture effects.
+	}
+
+	if (useshaders)
+	{
+		FShaderContainer *shd = GLRenderer->mShaderManager->Get(mTextureEnabled? mEffectState : 4);
+
+		if (shd != NULL)
 		{
-		case 2:
-			useshaders = (mTextureEnabled && mColormapState != CM_DEFAULT);
-			break;
-
-		case 3:
-			useshaders = (
-				mEffectState != 0 ||	// special shaders
-				(mFogEnabled && (gl_fogmode == 2 || gl_fog_shader) && gl_fogmode != 0) || // fog requires a shader
-				(mTextureEnabled && (mEffectState != 0 || mColormapState)) ||		// colormap
-				mGlowEnabled		// glow requires a shader
-				);
-			break;
-
-		case 4:
-			useshaders = (!m2D || mEffectState != 0 || mColormapState); // all 3D rendering and 2D with texture effects.
-			break;
-
-		default:
-			break;
-		}
-
-		if (useshaders)
-		{
-			FShaderContainer *shd = GLRenderer->mShaderManager->Get(mTextureEnabled? mEffectState : 4);
-
-			if (shd != NULL)
-			{
-				activeShader = shd->Bind(mColormapState, mGlowEnabled, mWarpTime, mLightEnabled);
-			}
+			activeShader = shd->Bind(mColormapState, mGlowEnabled, mWarpTime, mLightEnabled);
 		}
 	}
 
diff --git a/src/gl/scene/gl_scene.cpp b/src/gl/scene/gl_scene.cpp
index 1aa3c2b3f..8fe1f180a 100644
--- a/src/gl/scene/gl_scene.cpp
+++ b/src/gl/scene/gl_scene.cpp
@@ -288,7 +288,7 @@ void FGLRenderer::SetProjection(float fov, float ratio, float fovratio)
 
 void FGLRenderer::SetViewMatrix(bool mirror, bool planemirror)
 {
-	if (gl.shadermodel >= 4)
+	if (gl.hasGLSL())
 	{
 		glActiveTexture(GL_TEXTURE7);
 		glMatrixMode(GL_TEXTURE);
diff --git a/src/gl/scene/gl_sprite.cpp b/src/gl/scene/gl_sprite.cpp
index 63efb978e..d018d2eea 100644
--- a/src/gl/scene/gl_sprite.cpp
+++ b/src/gl/scene/gl_sprite.cpp
@@ -218,7 +218,7 @@ void GLSprite::Draw(int pass)
 			// non-black fog with subtractive style needs special treatment
 			if (!gl_isBlack(Colormap.FadeColor))
 			{
-				if (gl.shadermodel >= 4 && !gl_nolayer)
+				if (gl.hasGLSL() && !gl_nolayer)
 				{
 					// fog layer only works on modern hardware. 
 					foglayer = true;
@@ -795,7 +795,7 @@ void GLSprite::Process(AActor* thing,sector_t * sector)
 		RenderStyle.CheckFuzz();
 		if (RenderStyle.BlendOp == STYLEOP_Fuzz)
 		{
-			if (gl.shadermodel >= 4 && gl_fuzztype != 0)
+			if (gl.hasGLSL() && gl_fuzztype != 0)
 			{
 				// Todo: implement shader selection here
 				RenderStyle = LegacyRenderStyles[STYLE_Translucent];
diff --git a/src/gl/scene/gl_walls_draw.cpp b/src/gl/scene/gl_walls_draw.cpp
index 63e5086a7..f060978e4 100644
--- a/src/gl/scene/gl_walls_draw.cpp
+++ b/src/gl/scene/gl_walls_draw.cpp
@@ -338,7 +338,7 @@ void GLWall::RenderFogBoundary()
 	if (gl_fogmode && gl_fixedcolormap == 0)
 	{
 		// with shaders this can be done properly
-		if (gl.shadermodel == 4 || (gl.shadermodel == 3 && gl_fog_shader))
+		if (gl.hasGLSL())
 		{
 			int rel = rellight + getExtraLight();
 			gl_SetFog(lightlevel, rel, &Colormap, false);
diff --git a/src/gl/scene/gl_weapon.cpp b/src/gl/scene/gl_weapon.cpp
index aa991c0a0..fe3aee0ff 100644
--- a/src/gl/scene/gl_weapon.cpp
+++ b/src/gl/scene/gl_weapon.cpp
@@ -313,7 +313,7 @@ void FGLRenderer::DrawPlayerSprites(sector_t * viewsector, bool hudModelStep)
 		vis.RenderStyle.CheckFuzz();
 		if (vis.RenderStyle.BlendOp == STYLEOP_Fuzz)
 		{
-			if (gl.shadermodel >= 4 && gl_fuzztype != 0)
+			if (gl.hasGLSL() && gl_fuzztype != 0)
 			{
 				// Todo: implement shader selection here
 				vis.RenderStyle = LegacyRenderStyles[STYLE_Translucent];
diff --git a/src/gl/shaders/gl_shader.cpp b/src/gl/shaders/gl_shader.cpp
index ca1921bd4..2065768fa 100644
--- a/src/gl/shaders/gl_shader.cpp
+++ b/src/gl/shaders/gl_shader.cpp
@@ -79,7 +79,7 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 	static char buffer[10000];
 	FString error;
 
-	if (gl.shadermodel > 0)
+	if (gl.hasGLSL())
 	{
 		int vp_lump = Wads.CheckNumForFullName(vert_prog_lump);
 		if (vp_lump == -1) I_Error("Unable to load '%s'", vert_prog_lump);
@@ -93,10 +93,6 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 		FString vp_comb;
 		FString fp_comb;
 		vp_comb = defines;
-		if (gl.shadermodel < 4) 
-		{
-			vp_comb << "#define NO_SM4\n";
-		}
 
 		fp_comb = vp_comb;
 		// This uses GetChars on the strings to get rid of terminating 0 characters.
@@ -307,52 +303,40 @@ FShaderContainer::FShaderContainer(const char *ShaderName, const char *ShaderPat
 		I_Error("Unable to load shader %s:\n%s\n", name.GetChars(), err.GetMessage());
 	}
 
-	if (gl.shadermodel > 2)
+	for(int i = 0;i < NUM_SHADERS; i++)
 	{
-		for(int i = 0;i < NUM_SHADERS; i++)
+		FString name;
+
+		name << ShaderName << shaderdesc[i];
+
+		try
 		{
-			FString name;
-
-			name << ShaderName << shaderdesc[i];
-
-			try
+			FString str;
+			if ((i&4) != 0)
 			{
-				FString str;
-				if ((i&4) != 0)
+				if (gl.maxuniforms < 1024)
 				{
-					if (gl.maxuniforms < 1024 || gl.shadermodel != 4)
-					{
-						shader[i] = NULL;
-						continue;
-					}
-					// this can't be in the shader code due to ATI strangeness.
-					str = "#version 120\n#extension GL_EXT_gpu_shader4 : enable\n";
-					if (gl.MaxLights() == 128) str += "#define MAXLIGHTS128\n";
-				}
-				if ((i&8) == 0)
-				{
-					if (gl.shadermodel != 4)
-					{
-						shader[i] = NULL;
-						continue;
-					}
-				}
-				str += shaderdefines[i];
-				shader[i] = new FShader;
-				if (!shader[i]->Load(name, "shaders/glsl/main.vp", "shaders/glsl/main.fp", ShaderPath, str.GetChars()))
-				{
-					delete shader[i];
 					shader[i] = NULL;
+					continue;
 				}
+				// this can't be in the shader code due to ATI strangeness.
+				str = "#version 120\n#extension GL_EXT_gpu_shader4 : enable\n";
+				if (gl.MaxLights() == 128) str += "#define MAXLIGHTS128\n";
 			}
-			catch(CRecoverableError &err)
+			str += shaderdefines[i];
+			shader[i] = new FShader;
+			if (!shader[i]->Load(name, "shaders/glsl/main.vp", "shaders/glsl/main.fp", ShaderPath, str.GetChars()))
 			{
+				delete shader[i];
 				shader[i] = NULL;
-				I_Error("Unable to load shader %s:\n%s\n", name.GetChars(), err.GetMessage());
 			}
 		}
+		catch(CRecoverableError &err)
+		{
+			shader[i] = NULL;
+			I_Error("Unable to load shader %s:\n%s\n", name.GetChars(), err.GetMessage());
+		}
 	}
-	else memset(shader, 0, sizeof(shader));
 }
 
 //==========================================================================
@@ -502,28 +486,15 @@ FShaderManager::~FShaderManager()
 //
 //==========================================================================
 
-void FShaderManager::Recompile()
-{
-	Clean();
-	CompileShaders();
-}
-
-//==========================================================================
-//
-//
-//
-//==========================================================================
-
 void FShaderManager::CompileShaders()
 {
 	mActiveShader = mEffectShaders[0] = mEffectShaders[1] = NULL;
-	if (gl.shadermodel > 0)
+	if (gl.hasGLSL())
 	{
 		for(int i=0;defaultshaders[i].ShaderName != NULL;i++)
 		{
 			FShaderContainer * shc = new FShaderContainer(defaultshaders[i].ShaderName, defaultshaders[i].gettexelfunc);
 			mTextureEffects.Push(shc);
-			if (gl.shadermodel <= 2) return;	// SM2 will only initialize the default shader
 		}
 
 		for(unsigned i = 0; i < usershaders.Size(); i++)
@@ -531,25 +502,19 @@ void FShaderManager::CompileShaders()
 			FString name = ExtractFileBase(usershaders[i]);
 			FName sfn = name;
 
-			if (gl.shadermodel > 2)
-			{
-				FShaderContainer * shc = new FShaderContainer(sfn, usershaders[i]);
-				mTextureEffects.Push(shc);
-			}
+			FShaderContainer * shc = new FShaderContainer(sfn, usershaders[i]);
+			mTextureEffects.Push(shc);
 		}
 
-		if (gl.shadermodel > 2)
+		for(int i=0;i<NUM_EFFECTS;i++)
 		{
-			for(int i=0;i<NUM_EFFECTS;i++)
+			FShader *eff = new FShader();
+			if (!eff->Load(effectshaders[i].ShaderName, effectshaders[i].vp, effectshaders[i].fp1,
+							effectshaders[i].fp2, effectshaders[i].defines))
 			{
-				FShader *eff = new FShader();
-				if (!eff->Load(effectshaders[i].ShaderName, effectshaders[i].vp, effectshaders[i].fp1,
-								effectshaders[i].fp2, effectshaders[i].defines))
-				{
-					delete eff;
-				}
-				else mEffectShaders[i] = eff;
+				delete eff;
 			}
+			else mEffectShaders[i] = eff;
 		}
 	}
 }
@@ -604,7 +569,7 @@ int FShaderManager::Find(const char * shn)
 void FShaderManager::SetActiveShader(FShader *sh)
 {
 	// shadermodel needs to be tested here because without it UseProgram will be NULL.
-	if (gl.shadermodel > 0 && mActiveShader != sh)
+	if (gl.hasGLSL() && mActiveShader != sh)
 	{
 		glUseProgram(sh == NULL? 0 : sh->GetHandle());
 		mActiveShader = sh;
diff --git a/src/gl/shaders/gl_shader.h b/src/gl/shaders/gl_shader.h
index 61053287c..bd3aa0f30 100644
--- a/src/gl/shaders/gl_shader.h
+++ b/src/gl/shaders/gl_shader.h
@@ -153,8 +153,6 @@ public:
 		}
 		return NULL;
 	}
-
-	void Recompile();
 };
 
 #define FIRST_USER_SHADER 12
diff --git a/src/gl/system/gl_framebuffer.cpp b/src/gl/system/gl_framebuffer.cpp
index 99e9bd9a4..d22c6a5ed 100644
--- a/src/gl/system/gl_framebuffer.cpp
+++ b/src/gl/system/gl_framebuffer.cpp
@@ -73,9 +73,9 @@ CVAR(Bool, gl_aalines, false, CVAR_ARCHIVE)
 
 FGLRenderer *GLRenderer;
 
-void gl_SetupMenu();
 void gl_LoadExtensions();
 void gl_PrintStartupLog();
+void gl_SetupMenu();
 
 //==========================================================================
 //
diff --git a/src/gl/system/gl_interface.cpp b/src/gl/system/gl_interface.cpp
index 31176d220..434659a7c 100644
--- a/src/gl/system/gl_interface.cpp
+++ b/src/gl/system/gl_interface.cpp
@@ -133,7 +133,6 @@ void gl_LoadExtensions()
 	// This loads any function pointers and flags that require a vaild render context to
 	// initialize properly
 
-	gl.shadermodel = 0;	// assume no shader support
 	gl.vendorstring=(char*)glGetString(GL_VENDOR);
 
 	if (CheckExtension("GL_ARB_texture_compression")) gl.flags|=RFL_TEXTURE_COMPRESSION;
@@ -141,23 +140,11 @@ void gl_LoadExtensions()
 	if (CheckExtension("GL_ARB_buffer_storage")) gl.flags |= RFL_BUFFER_STORAGE;
 
 	gl.version = strtod((char*)glGetString(GL_VERSION), NULL);
+	gl.glslversion = strtod((char*)glGetString(GL_SHADING_LANGUAGE_VERSION), NULL);
+	if (Args->CheckParm("-noshader")) gl.glslversion = 0.0f;
 
 	glGetIntegerv(GL_MAX_TEXTURE_SIZE,&gl.max_texturesize);
 	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
-	
-	// Rules:
-	// SM4 will always use shaders. No option to switch them off is needed here.
-	// SM3 has shaders optional but they are off by default (they will have a performance impact
-	// SM2 only uses shaders for colormaps on camera textures and has no option to use them in general.
-	//     On SM2 cards the shaders will be too slow and show visual bugs (at least on GF 6800.)
-	if (strcmp((const char*)glGetString(GL_SHADING_LANGUAGE_VERSION), "1.3") >= 0) gl.shadermodel = 4;
-	else if (CheckExtension("GL_NV_vertex_program3")) gl.shadermodel = 3;
-	else if (!strstr(gl.vendorstring, "NVIDIA")) gl.shadermodel = 3;
-	else gl.shadermodel = 2;	// Only for older NVidia cards which had notoriously bad shader support.
-
-	// Command line overrides for testing and problem cases.
-	if (Args->CheckParm("-sm2") && gl.shadermodel > 2) gl.shadermodel = 2;
-	else if (Args->CheckParm("-sm3") && gl.shadermodel > 3) gl.shadermodel = 3;
 
 	if (gl.version >= 3.f)
 	{
@@ -187,7 +174,7 @@ void gl_PrintStartupLog()
 	Printf ("Max. texture units: %d\n", v);
 	glGetIntegerv(GL_MAX_FRAGMENT_UNIFORM_COMPONENTS, &v);
 	Printf ("Max. fragment uniforms: %d\n", v);
-	if (gl.shadermodel == 4) gl.maxuniforms = v;
+	if (gl.hasGLSL()) gl.maxuniforms = v;
 	glGetIntegerv(GL_MAX_VERTEX_UNIFORM_COMPONENTS, &v);
 	Printf ("Max. vertex uniforms: %d\n", v);
 	glGetIntegerv(GL_MAX_VARYING_FLOATS, &v);
diff --git a/src/gl/system/gl_interface.h b/src/gl/system/gl_interface.h
index fdadd67d9..66f96be00 100644
--- a/src/gl/system/gl_interface.h
+++ b/src/gl/system/gl_interface.h
@@ -6,11 +6,12 @@
 enum RenderFlags
 {
 	// [BB] Added texture compression flags.
-	RFL_TEXTURE_COMPRESSION=8,
-	RFL_TEXTURE_COMPRESSION_S3TC=16,
+	RFL_TEXTURE_COMPRESSION=1,
+	RFL_TEXTURE_COMPRESSION_S3TC=2,
 
-	RFL_FRAMEBUFFER = 32,
-	RFL_BUFFER_STORAGE = 64,
+	RFL_FRAMEBUFFER = 4,
+	RFL_BUFFER_STORAGE = 8,
+	RFL_SHADER_STORAGE_BUFFER = 16,
 };
 
 enum TexMode
@@ -30,9 +31,9 @@ enum TexMode
 struct RenderContext
 {
 	unsigned int flags;
-	unsigned int shadermodel;
 	unsigned int maxuniforms;
 	float version;
+	float glslversion;
 	int max_texturesize;
 	char * vendorstring;
 
@@ -40,6 +41,11 @@ struct RenderContext
 	{
 		return maxuniforms>=2048? 128:64;
 	}
+
+	bool hasGLSL() const
+	{
+		return glslversion >= 1.3f;
+	}
 };
 
 extern RenderContext gl;
diff --git a/src/gl/system/gl_menu.cpp b/src/gl/system/gl_menu.cpp
index 75436209c..0518606b9 100644
--- a/src/gl/system/gl_menu.cpp
+++ b/src/gl/system/gl_menu.cpp
@@ -59,7 +59,7 @@ CUSTOM_CVAR (Float, vid_contrast, 1.f, CVAR_ARCHIVE|CVAR_GLOBALCONFIG)
 // when they are actually valid.
 void gl_SetupMenu()
 {
-	if (gl.shadermodel < 4)
+	if (!gl.hasGLSL())
 	{
 		// Radial fog and Doom lighting are not available in SM < 4 cards
 		// The way they are implemented does not work well on older hardware.
@@ -95,28 +95,4 @@ void gl_SetupMenu()
 		if (gl_fogmode == 2) gl_fogmode = 1;
 		if (gl_dynlight_shader) gl_dynlight_shader = false;
 	}
-
-	if (gl.shadermodel != 3)
-	{
-		// The shader menu will only be visible on SM3. 
-		// SM2 won't use shaders unless unavoidable (and then it's automatic) and SM4 will always use shaders.
-		// Find the OpenGLOptions menu and remove the item named GLShaderOptions.
-		
-		FMenuDescriptor **desc = MenuDescriptors.CheckKey("OpenGLOptions");
-		if (desc != NULL && (*desc)->mType == MDESC_OptionsMenu)
-		{
-			FOptionMenuDescriptor *opt = (FOptionMenuDescriptor *)*desc;
-
-			FName shader = "GLShaderOptions";
-			for(unsigned i=0;i<opt->mItems.Size();i++)
-			{
-				FName nm = opt->mItems[i]->GetAction(NULL);
-				if (nm == shader) 
-				{
-					delete opt->mItems[i];
-					opt->mItems.Delete(i);
-				}
-			}
-		}
-	}
 }
diff --git a/src/gl/textures/gl_hqresize.cpp b/src/gl/textures/gl_hqresize.cpp
index 2c5f831f1..837977145 100644
--- a/src/gl/textures/gl_hqresize.cpp
+++ b/src/gl/textures/gl_hqresize.cpp
@@ -225,7 +225,7 @@ unsigned char *gl_CreateUpsampledTextureBuffer ( const FTexture *inputTexture, u
 		return inputBuffer;
 
 	// [BB] Don't upsample non-shader handled warped textures. Needs too much memory and time
-	if (gl.shadermodel == 2 || (gl.shadermodel == 3 && inputTexture->bWarped))
+	if (inputTexture->bWarped && !gl.hasGLSL())
 		return inputBuffer;
 
 	switch (inputTexture->UseType)
diff --git a/src/gl/textures/gl_material.cpp b/src/gl/textures/gl_material.cpp
index 9cb3ef523..5d471fc81 100644
--- a/src/gl/textures/gl_material.cpp
+++ b/src/gl/textures/gl_material.cpp
@@ -624,7 +624,7 @@ FMaterial::FMaterial(FTexture * tx, bool forceexpand)
 	{
 		expanded = false;
 	}
-	else if (gl.shadermodel > 2) 
+	else if (gl.hasGLSL()) 
 	{
 		if (tx->gl_info.shaderindex >= FIRST_USER_SHADER)
 		{
@@ -670,7 +670,7 @@ FMaterial::FMaterial(FTexture * tx, bool forceexpand)
 	tex = tx;
 
 	tx->gl_info.mExpanded = expanded;
-	FTexture *basetex = tx->GetRedirect(gl.shadermodel < 4);
+	FTexture *basetex = tx->GetRedirect(!gl.hasGLSL());
 	if (!expanded && !basetex->gl_info.mExpanded && basetex->UseType != FTexture::TEX_Sprite)
 	{
 		// check if the texture is just a simple redirect to a patch
diff --git a/wadsrc/static/menudef.z b/wadsrc/static/menudef.z
index 329042b74..0db780620 100644
--- a/wadsrc/static/menudef.z
+++ b/wadsrc/static/menudef.z
@@ -14,13 +14,6 @@ OptionValue "EnhancedStealth"
 	3, "Any fixed colormap"
 }
 
-OptionValue "VBOModes"
-{
-	0, "Off"
-	1, "Static"
-	2, "Dynamic"
-}
-
 OptionValue "FilterModes"
 {
 	0, "None"
@@ -186,17 +179,7 @@ OptionMenu "GLPrefOptions"
 	Option "Particle style",			gl_particles_style,				"Particles"
 	Slider "Ambient light level",		gl_light_ambient,				1.0, 255.0, 5.0
 	Option "Rendering quality",			gl_render_precise,				"Precision"
-	Option "Use vertex buffer",			gl_usevbo,						"VBOModes"
-}
-
-OptionMenu "GLShaderOptions"
-{
-	Title "SHADER OPTIONS"
-	Option "Enable brightness maps",	gl_brightmap_shader,			"OnOff"
-	Option "Shaders for texture warp",	gl_warp_shader,					"OnOff"
-	Option "Shaders for fog",			gl_fog_shader,					"OnOff"
-	Option "Shaders for colormaps",		gl_colormap_shader,				"OnOff"
-	Option "Shaders for glowing textures",	gl_glow_shader,				"OnOff"
+	Option "Use vertex buffer",			gl_usevbo,						"OnOff"
 }
 
 OptionMenu "OpenGLOptions"
@@ -204,7 +187,6 @@ OptionMenu "OpenGLOptions"
 	Title "OPENGL OPTIONS"
 	Submenu "Dynamic Light Options",	"GLLightOptions"
 	Submenu "Texture Options", 			"GLTextureGLOptions"
-	Submenu "Shader Options", 			"GLShaderOptions"
 	Submenu "Preferences", 				"GLPrefOptions"
 }
 
diff --git a/wadsrc/static/shaders/glsl/fogboundary.fp b/wadsrc/static/shaders/glsl/fogboundary.fp
index 5b43dfd95..5ab8ac717 100644
--- a/wadsrc/static/shaders/glsl/fogboundary.fp
+++ b/wadsrc/static/shaders/glsl/fogboundary.fp
@@ -18,18 +18,14 @@ void main()
 	//
 	// calculate fog factor
 	//
-	#ifndef NO_SM4
-		if (fogenabled == -1) 
-		{
-			fogdist = pixelpos.w;
-		}
-		else 
-		{
-			fogdist = max(16.0, distance(pixelpos.xyz, camerapos));
-		}
-	#else
+	if (fogenabled == -1) 
+	{
 		fogdist = pixelpos.w;
-	#endif
+	}
+	else 
+	{
+		fogdist = max(16.0, distance(pixelpos.xyz, camerapos));
+	}
 	fogfactor = exp2 (fogparm.z * fogdist);
 	gl_FragColor = vec4(fogcolor.rgb, 1.0 - fogfactor);
 }
diff --git a/wadsrc/static/shaders/glsl/main.fp b/wadsrc/static/shaders/glsl/main.fp
index aa2c33238..6bb17a2ad 100644
--- a/wadsrc/static/shaders/glsl/main.fp
+++ b/wadsrc/static/shaders/glsl/main.fp
@@ -102,7 +102,7 @@ vec4 getLightColor(float fogdist, float fogfactor)
 	//
 	if (fogenabled > 0)
 	{
-		#if (!defined(NO_SM4) || defined(DOOMLIGHT)) && !defined SOFTLIGHT
+		#if (defined(DOOMLIGHT)) && !defined SOFTLIGHT
 			// special lighting mode 'Doom' not available on older cards for performance reasons.
 			if (fogdist < fogparm.y) 
 			{
@@ -197,20 +197,14 @@ void main()
 	//
 	if (fogenabled != 0)
 	{
-		#ifndef NO_SM4
-			if (fogenabled == 1 || fogenabled == -1) 
-			{
-				fogdist = pixelpos.w;
-			}
-			else 
-			{
-				fogdist = max(16.0, distance(pixelpos.xyz, camerapos));
-			}
-		#elif !defined(FOG_RADIAL)
+		if (fogenabled == 1 || fogenabled == -1) 
+		{
 			fogdist = pixelpos.w;
-		#else
+		}
+		else 
+		{
 			fogdist = max(16.0, distance(pixelpos.xyz, camerapos));
-		#endif
+		}
 		fogfactor = exp2 (fogparm.z * fogdist);
 	}
 	#endif
diff --git a/wadsrc/static/shaders/glsl/main.vp b/wadsrc/static/shaders/glsl/main.vp
index 7aebb8171..fc905b753 100644
--- a/wadsrc/static/shaders/glsl/main.vp
+++ b/wadsrc/static/shaders/glsl/main.vp
@@ -19,12 +19,8 @@ void main()
 		lightlevel = lightlevel_in;
 	#endif
 
-	#ifndef NO_SM4
-		// Yes, I know... But using a texture matrix here saves me from the hassle of tracking its state across shaders. ;)
-		vec4 worldcoord = gl_TextureMatrix[7] * gl_Vertex;
-	#else
-		vec4 worldcoord = gl_Vertex;
-	#endif
+	// We use texture matrix 7 as the model matrix and the modelview matrix as the view matrix.
+	vec4 worldcoord = gl_TextureMatrix[7] * gl_Vertex;
 	vec4 eyeCoordPos = gl_ModelViewMatrix * worldcoord;
 
 	gl_FrontColor = gl_Color;
@@ -55,11 +51,7 @@ void main()
 		gl_TexCoord[0].xy = sst;
 	#endif
 	
-	#ifndef NO_SM4
-		gl_Position = gl_ModelViewProjectionMatrix * worldcoord;
-	#else
-		gl_Position = ftransform();
-	#endif
+	gl_Position = gl_ModelViewProjectionMatrix * worldcoord;
     #ifdef __GLSL_CG_DATA_TYPES
 		gl_ClipVertex = eyeCoordPos;
 	#endif
diff --git a/wadsrc/static/shaders/glsl/main_colormap.fp b/wadsrc/static/shaders/glsl/main_colormap.fp
index a64f67bc2..fa0f28f25 100644
--- a/wadsrc/static/shaders/glsl/main_colormap.fp
+++ b/wadsrc/static/shaders/glsl/main_colormap.fp
@@ -16,19 +16,17 @@ vec4 getTexel(vec2 st)
 {
 	vec4 texel = texture2D(tex, st);
 	
-	#ifndef NO_TEXTUREMODE
-		//
-		// Apply texture modes
-		//
-		if (texturemode == 2) 
-		{
-			texel.a = 1.0;
-		}
-		else if (texturemode == 1) 
-		{
-			texel.rgb = vec3(1.0,1.0,1.0);
-		}
-	#endif
+	//
+	// Apply texture modes
+	//
+	if (texturemode == 2) 
+	{
+		texel.a = 1.0;
+	}
+	else if (texturemode == 1) 
+	{
+		texel.rgb = vec3(1.0,1.0,1.0);
+	}
 
 	return texel;
 }
diff --git a/wadsrc/static/shaders/glsl/main_foglayer.fp b/wadsrc/static/shaders/glsl/main_foglayer.fp
index bfe08d327..3802e3d85 100644
--- a/wadsrc/static/shaders/glsl/main_foglayer.fp
+++ b/wadsrc/static/shaders/glsl/main_foglayer.fp
@@ -39,18 +39,14 @@ void main()
 	//
 	// calculate fog factor
 	//
-	#ifndef NO_SM4
-		if (fogenabled == -1) 
-		{
-			fogdist = pixelpos.w;
-		}
-		else 
-		{
-			fogdist = max(16.0, distance(pixelpos.xyz, camerapos));
-		}
-	#else
+	if (fogenabled == -1) 
+	{
 		fogdist = pixelpos.w;
-	#endif
+	}
+	else 
+	{
+		fogdist = max(16.0, distance(pixelpos.xyz, camerapos));
+	}
 	fogfactor = exp2 (fogparm.z * fogdist);
 	
 	vec4 frag = Process(vec4(1.0,1.0,1.0,1.0));