diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 13ef11ec3..d78903973 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1115,6 +1115,7 @@ set( FASTMATH_SOURCES
 	gl/shaders/gl_bloomshader.cpp
 	gl/shaders/gl_ambientshader.cpp
 	gl/shaders/gl_blurshader.cpp
+	gl/shaders/gl_colormapshader.cpp
 	gl/shaders/gl_tonemapshader.cpp
 	gl/shaders/gl_lensshader.cpp
 	gl/system/gl_interface.cpp
diff --git a/src/gl/compatibility/gl_20.cpp b/src/gl/compatibility/gl_20.cpp
index 8e6682f17..fdda99130 100644
--- a/src/gl/compatibility/gl_20.cpp
+++ b/src/gl/compatibility/gl_20.cpp
@@ -66,40 +66,39 @@
 
 void gl_PatchMenu()
 {
-	if (gl.glslversion == 0)
+	// Radial fog and Doom lighting are not available without full shader support.
+
+	FOptionValues **opt = OptionValues.CheckKey("LightingModes");
+	if (opt != NULL) 
 	{
-		// Radial fog and Doom lighting are not available without full shader support.
-
-		FOptionValues **opt = OptionValues.CheckKey("LightingModes");
-		if (opt != NULL) 
+		for(int i = (*opt)->mValues.Size()-1; i>=0; i--)
 		{
-			for(int i = (*opt)->mValues.Size()-1; i>=0; i--)
+			// Delete 'Doom' lighting mode
+			if ((*opt)->mValues[i].Value == 2.0 || (*opt)->mValues[i].Value == 8.0)
 			{
-				// Delete 'Doom' lighting mode
-				if ((*opt)->mValues[i].Value == 2.0 || (*opt)->mValues[i].Value == 8.0)
-				{
-					(*opt)->mValues.Delete(i);
-				}
+				(*opt)->mValues.Delete(i);
 			}
 		}
-
-		opt = OptionValues.CheckKey("FogMode");
-		if (opt != NULL) 
-		{
-			for(int i = (*opt)->mValues.Size()-1; i>=0; i--)
-			{
-				// Delete 'Radial' fog mode
-				if ((*opt)->mValues[i].Value == 2.0)
-				{
-					(*opt)->mValues.Delete(i);
-				}
-			}
-		}
-
-		// disable features that don't work without shaders.
-		if (gl_lightmode == 2 || gl_lightmode == 8) gl_lightmode = 3;
-		if (gl_fogmode == 2) gl_fogmode = 1;
 	}
+
+	opt = OptionValues.CheckKey("FogMode");
+	if (opt != NULL) 
+	{
+		for(int i = (*opt)->mValues.Size()-1; i>=0; i--)
+		{
+			// Delete 'Radial' fog mode
+			if ((*opt)->mValues[i].Value == 2.0)
+			{
+				(*opt)->mValues.Delete(i);
+			}
+		}
+	}
+
+	// disable features that don't work without shaders.
+	if (gl_lightmode == 2 || gl_lightmode == 8) gl_lightmode = 3;
+	if (gl_fogmode == 2) gl_fogmode = 1;
+
+	// todo: remove more unsupported stuff like postprocessing options.
 }
 
 
@@ -378,7 +377,7 @@ void FRenderState::DrawColormapOverlay()
 //==========================================================================
 
 bool gl_SetupLight(int group, Plane & p, ADynamicLight * light, Vector & nearPt, Vector & up, Vector & right,
-	float & scale, int desaturation, bool checkside, bool additive)
+	float & scale, bool checkside, bool additive)
 {
 	Vector fn, pos;
 
@@ -434,14 +433,6 @@ bool gl_SetupLight(int group, Plane & p, ADynamicLight * light, Vector & nearPt,
 	{
 		gl_RenderState.BlendEquation(GL_FUNC_ADD);
 	}
-	if (desaturation > 0 && gl.glslversion > 0)	// no-shader excluded because no desaturated textures.
-	{
-		float gray = (r * 77 + g * 143 + b * 37) / 257;
-
-		r = (r*(32 - desaturation) + gray*desaturation) / 32;
-		g = (g*(32 - desaturation) + gray*desaturation) / 32;
-		b = (b*(32 - desaturation) + gray*desaturation) / 32;
-	}
 	gl_RenderState.SetColor(r, g, b);
 	return true;
 }
@@ -491,11 +482,6 @@ bool GLWall::PutWallCompat(int passflag)
 	bool masked = passflag == 2 && gltexture->isMasked();
 
 	int list = list_indices[masked][foggy];
-	if (list == GLLDL_WALLS_PLAIN)
-	{
-		if (gltexture->tex->gl_info.Brightmap && gl.glslversion >= 0.f) list = GLLDL_WALLS_BRIGHT;
-		//if (flags & GLWF_GLOW) list = GLLDL_WALLS_BRIGHT;
-	}
 	gl_drawinfo->dldrawlists[list].AddWall(this);
 	return true;
 
@@ -520,10 +506,6 @@ bool GLFlat::PutFlatCompat(bool fog)
 
 	
 	int list = list_indices[masked][foggy];
-	if (list == GLLDL_FLATS_PLAIN)
-	{
-		if (gltexture->tex->gl_info.Brightmap && gl.glslversion >= 0.f) list = GLLDL_FLATS_BRIGHT;
-	}
 	gl_drawinfo->dldrawlists[list].AddFlat(this);
 	return true;
 }
@@ -612,7 +594,7 @@ void GLFlat::DrawSubsectorLights(subsector_t * sub, int pass)
 		}
 
 		p.Set(plane.plane);
-		if (!gl_SetupLight(sub->sector->PortalGroup, p, light, nearPt, up, right, scale, CM_DEFAULT, false, pass != GLPASS_LIGHTTEX))
+		if (!gl_SetupLight(sub->sector->PortalGroup, p, light, nearPt, up, right, scale, false, pass != GLPASS_LIGHTTEX))
 		{
 			node = node->nextLight;
 			continue;
@@ -692,7 +674,7 @@ bool GLWall::PrepareLight(ADynamicLight * light, int pass)
 		return false;
 	}
 
-	if (!gl_SetupLight(seg->frontsector->PortalGroup, p, light, nearPt, up, right, scale, CM_DEFAULT, true, pass != GLPASS_LIGHTTEX))
+	if (!gl_SetupLight(seg->frontsector->PortalGroup, p, light, nearPt, up, right, scale, true, pass != GLPASS_LIGHTTEX))
 	{
 		return false;
 	}
@@ -798,9 +780,7 @@ void FGLRenderer::RenderMultipassStuff()
 	gl_RenderState.SetTextureMode(TM_MASK);
 	gl_RenderState.EnableBrightmap(true);
 	gl_RenderState.AlphaFunc(GL_GEQUAL, gl_mask_threshold);
-	gl_drawinfo->dldrawlists[GLLDL_WALLS_BRIGHT].DrawWalls(GLPASS_PLAIN);
 	gl_drawinfo->dldrawlists[GLLDL_WALLS_MASKED].DrawWalls(GLPASS_PLAIN);
-	gl_drawinfo->dldrawlists[GLLDL_FLATS_BRIGHT].DrawFlats(GLPASS_PLAIN);
 	gl_drawinfo->dldrawlists[GLLDL_FLATS_MASKED].DrawFlats(GLPASS_PLAIN);
 
 	// Part 3: The base of fogged surfaces, including the texture
@@ -823,10 +803,8 @@ void FGLRenderer::RenderMultipassStuff()
 			glDepthFunc(GL_EQUAL);
 			if (glset.lightmode == 8) gl_RenderState.SetSoftLightLevel(255);
 			gl_drawinfo->dldrawlists[GLLDL_WALLS_PLAIN].DrawWalls(GLPASS_LIGHTTEX);
-			gl_drawinfo->dldrawlists[GLLDL_WALLS_BRIGHT].DrawWalls(GLPASS_LIGHTTEX);
 			gl_drawinfo->dldrawlists[GLLDL_WALLS_MASKED].DrawWalls(GLPASS_LIGHTTEX);
 			gl_drawinfo->dldrawlists[GLLDL_FLATS_PLAIN].DrawFlats(GLPASS_LIGHTTEX);
-			gl_drawinfo->dldrawlists[GLLDL_FLATS_BRIGHT].DrawFlats(GLPASS_LIGHTTEX);
 			gl_drawinfo->dldrawlists[GLLDL_FLATS_MASKED].DrawFlats(GLPASS_LIGHTTEX);
 			gl_RenderState.BlendEquation(GL_FUNC_ADD);
 		}
@@ -841,8 +819,6 @@ void FGLRenderer::RenderMultipassStuff()
 	glDepthFunc(GL_LEQUAL);
 	gl_drawinfo->dldrawlists[GLLDL_WALLS_PLAIN].DrawWalls(GLPASS_TEXONLY);
 	gl_drawinfo->dldrawlists[GLLDL_FLATS_PLAIN].DrawFlats(GLPASS_TEXONLY);
-	gl_drawinfo->dldrawlists[GLLDL_WALLS_BRIGHT].DrawWalls(GLPASS_TEXONLY);
-	gl_drawinfo->dldrawlists[GLLDL_FLATS_BRIGHT].DrawFlats(GLPASS_TEXONLY);
 	gl_RenderState.AlphaFunc(GL_GREATER, gl_mask_threshold);
 	gl_drawinfo->dldrawlists[GLLDL_WALLS_MASKED].DrawWalls(GLPASS_TEXONLY);
 	gl_drawinfo->dldrawlists[GLLDL_FLATS_MASKED].DrawFlats(GLPASS_TEXONLY);
@@ -854,10 +830,8 @@ void FGLRenderer::RenderMultipassStuff()
 	if (gl_SetupLightTexture())
 	{
 		gl_drawinfo->dldrawlists[GLLDL_WALLS_PLAIN].DrawWalls(GLPASS_LIGHTTEX_ADDITIVE);
-		gl_drawinfo->dldrawlists[GLLDL_WALLS_BRIGHT].DrawWalls(GLPASS_LIGHTTEX_ADDITIVE);
 		gl_drawinfo->dldrawlists[GLLDL_WALLS_MASKED].DrawWalls(GLPASS_LIGHTTEX_ADDITIVE);
 		gl_drawinfo->dldrawlists[GLLDL_FLATS_PLAIN].DrawFlats(GLPASS_LIGHTTEX_ADDITIVE);
-		gl_drawinfo->dldrawlists[GLLDL_FLATS_BRIGHT].DrawFlats(GLPASS_LIGHTTEX_ADDITIVE);
 		gl_drawinfo->dldrawlists[GLLDL_FLATS_MASKED].DrawFlats(GLPASS_LIGHTTEX_ADDITIVE);
 		gl_drawinfo->dldrawlists[GLLDL_WALLS_FOG].DrawWalls(GLPASS_LIGHTTEX_FOGGY);
 		gl_drawinfo->dldrawlists[GLLDL_WALLS_FOGMASKED].DrawWalls(GLPASS_LIGHTTEX_FOGGY);
diff --git a/src/gl/data/gl_vertexbuffer.cpp b/src/gl/data/gl_vertexbuffer.cpp
index 5833d3109..0309b2bcd 100644
--- a/src/gl/data/gl_vertexbuffer.cpp
+++ b/src/gl/data/gl_vertexbuffer.cpp
@@ -75,7 +75,7 @@ FVertexBuffer::~FVertexBuffer()
 void FSimpleVertexBuffer::BindVBO()
 {
 	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
-	if (gl.glslversion > 0)
+	if (!gl.legacyMode)
 	{
 		glVertexAttribPointer(VATTR_VERTEX, 3, GL_FLOAT, false, sizeof(FSimpleVertex), &VSiO->x);
 		glVertexAttribPointer(VATTR_TEXCOORD, 2, GL_FLOAT, false, sizeof(FSimpleVertex), &VSiO->u);
@@ -100,7 +100,7 @@ void FSimpleVertexBuffer::EnableColorArray(bool on)
 {
 	if (on)
 	{
-		if (gl.glslversion > 0)
+		if (!gl.legacyMode)
 		{
 			glEnableVertexAttribArray(VATTR_COLOR);
 		}
@@ -111,7 +111,7 @@ void FSimpleVertexBuffer::EnableColorArray(bool on)
 	}
 	else
 	{
-		if (gl.glslversion > 0)
+		if (!gl.legacyMode)
 		{
 			glDisableVertexAttribArray(VATTR_COLOR);
 		}
@@ -138,7 +138,7 @@ void FSimpleVertexBuffer::set(FSimpleVertex *verts, int count)
 //==========================================================================
 
 FFlatVertexBuffer::FFlatVertexBuffer(int width, int height)
-: FVertexBuffer(gl.buffermethod != BM_CLIENTARRAY)
+: FVertexBuffer(!gl.legacyMode)
 {
 	switch (gl.buffermethod)
 	{
@@ -162,7 +162,7 @@ FFlatVertexBuffer::FFlatVertexBuffer(int width, int height)
 		break;
 	}
 
-	case BM_CLIENTARRAY:
+	default:
 	{
 		map = new FFlatVertex[BUFFER_SIZE];
 		DPrintf(DMSG_NOTIFY, "Using client array buffer\n");
@@ -219,7 +219,7 @@ FFlatVertexBuffer::~FFlatVertexBuffer()
 		glUnmapBuffer(GL_ARRAY_BUFFER);
 		glBindBuffer(GL_ARRAY_BUFFER, 0);
 	}
-	if (gl.buffermethod == BM_CLIENTARRAY)
+	if (gl.legacyMode)
 	{
 		delete[] map;
 	}
@@ -230,19 +230,10 @@ FFlatVertexBuffer::~FFlatVertexBuffer()
 void FFlatVertexBuffer::BindVBO()
 {
 	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
-	if (gl.glslversion > 0)
+	if (!gl.legacyMode)
 	{
-		if (gl.buffermethod != BM_CLIENTARRAY)
-		{
-			glVertexAttribPointer(VATTR_VERTEX, 3, GL_FLOAT, false, sizeof(FFlatVertex), &VTO->x);
-			glVertexAttribPointer(VATTR_TEXCOORD, 2, GL_FLOAT, false, sizeof(FFlatVertex), &VTO->u);
-		}
-		else
-		{
-			// If we cannot use a hardware buffer, use an old-style client array.
-			glVertexAttribPointer(VATTR_VERTEX, 3, GL_FLOAT, false, sizeof(FFlatVertex), &map->x);
-			glVertexAttribPointer(VATTR_TEXCOORD, 2, GL_FLOAT, false, sizeof(FFlatVertex), &map->u);
-		}
+		glVertexAttribPointer(VATTR_VERTEX, 3, GL_FLOAT, false, sizeof(FFlatVertex), &VTO->x);
+		glVertexAttribPointer(VATTR_TEXCOORD, 2, GL_FLOAT, false, sizeof(FFlatVertex), &VTO->u);
 		glEnableVertexAttribArray(VATTR_VERTEX);
 		glEnableVertexAttribArray(VATTR_TEXCOORD);
 		glDisableVertexAttribArray(VATTR_COLOR);
diff --git a/src/gl/models/gl_models.cpp b/src/gl/models/gl_models.cpp
index e686f2cea..22b61ace4 100644
--- a/src/gl/models/gl_models.cpp
+++ b/src/gl/models/gl_models.cpp
@@ -105,7 +105,7 @@ void gl_FlushModels()
 //===========================================================================
 
 FModelVertexBuffer::FModelVertexBuffer(bool needindex, bool singleframe)
-	: FVertexBuffer(singleframe || gl.glslversion > 0)
+	: FVertexBuffer(singleframe || !gl.legacyMode)
 {
 	vbo_ptr = nullptr;
 	ibo_id = 0;
@@ -125,7 +125,7 @@ void FModelVertexBuffer::BindVBO()
 {
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo_id);
 	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
-	if (gl.glslversion > 0)
+	if (!gl.legacyMode)
 	{
 		glEnableVertexAttribArray(VATTR_VERTEX);
 		glEnableVertexAttribArray(VATTR_TEXCOORD);
@@ -170,7 +170,7 @@ FModelVertex *FModelVertexBuffer::LockVertexBuffer(unsigned int size)
 	{
 		glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
 		glBufferData(GL_ARRAY_BUFFER, size * sizeof(FModelVertex), nullptr, GL_STATIC_DRAW);
-		if (gl.version >= 3.0)
+		if (!gl.legacyMode)
 			return (FModelVertex*)glMapBufferRange(GL_ARRAY_BUFFER, 0, size * sizeof(FModelVertex), GL_MAP_WRITE_BIT | GL_MAP_INVALIDATE_BUFFER_BIT);
 		else
 			return (FModelVertex*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
@@ -211,7 +211,7 @@ unsigned int *FModelVertexBuffer::LockIndexBuffer(unsigned int size)
 	{
 		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo_id);
 		glBufferData(GL_ELEMENT_ARRAY_BUFFER, size * sizeof(unsigned int), NULL, GL_STATIC_DRAW);
-		if (gl.version >= 3.0)
+		if (!gl.legacyMode)
 			return (unsigned int*)glMapBufferRange(GL_ELEMENT_ARRAY_BUFFER, 0, size * sizeof(unsigned int), GL_MAP_WRITE_BIT | GL_MAP_INVALIDATE_BUFFER_BIT);
 		else
 			return (unsigned int*)glMapBuffer(GL_ELEMENT_ARRAY_BUFFER, GL_WRITE_ONLY);
@@ -251,7 +251,7 @@ unsigned int FModelVertexBuffer::SetupFrame(unsigned int frame1, unsigned int fr
 	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
 	if (vbo_id > 0)
 	{
-		if (gl.glslversion > 0)
+		if (!gl.legacyMode)
 		{
 			glVertexAttribPointer(VATTR_VERTEX, 3, GL_FLOAT, false, sizeof(FModelVertex), &VMO[frame1].x);
 			glVertexAttribPointer(VATTR_TEXCOORD, 2, GL_FLOAT, false, sizeof(FModelVertex), &VMO[frame1].u);
diff --git a/src/gl/renderer/gl_lightdata.cpp b/src/gl/renderer/gl_lightdata.cpp
index 5d153894f..c2329879c 100644
--- a/src/gl/renderer/gl_lightdata.cpp
+++ b/src/gl/renderer/gl_lightdata.cpp
@@ -71,7 +71,7 @@ CUSTOM_CVAR(Bool, gl_enhanced_nightvision, true, CVAR_ARCHIVE|CVAR_NOINITCALL)
 {
 	// The fixed colormap state needs to be reset because if this happens when
 	// a shader is set to CM_LITE or CM_TORCH it won't register the change in behavior caused by this CVAR.
-	if (GLRenderer != NULL && GLRenderer->mShaderManager != NULL)
+	if (GLRenderer != nullptr && GLRenderer->mShaderManager != nullptr)
 	{
 		GLRenderer->mShaderManager->ResetFixedColormap();
 	}
diff --git a/src/gl/renderer/gl_postprocess.cpp b/src/gl/renderer/gl_postprocess.cpp
index 62815f718..684985074 100644
--- a/src/gl/renderer/gl_postprocess.cpp
+++ b/src/gl/renderer/gl_postprocess.cpp
@@ -72,6 +72,7 @@
 #include "gl/shaders/gl_bloomshader.h"
 #include "gl/shaders/gl_blurshader.h"
 #include "gl/shaders/gl_tonemapshader.h"
+#include "gl/shaders/gl_colormapshader.h"
 #include "gl/shaders/gl_lensshader.h"
 #include "gl/shaders/gl_presentshader.h"
 #include "gl/renderer/gl_2ddrawer.h"
@@ -135,10 +136,11 @@ void FGLRenderer::RenderScreenQuad()
 
 void FGLRenderer::PostProcessScene()
 {
-	if (FGLRenderBuffers::IsEnabled()) mBuffers->BlitSceneToTexture();
+	mBuffers->BlitSceneToTexture();
 	AmbientOccludeScene();
 	BloomScene();
 	TonemapScene();
+	ColormapScene();
 	LensDistortScene();
 }
 
@@ -240,7 +242,7 @@ void FGLRenderer::AmbientOccludeScene()
 void FGLRenderer::BloomScene()
 {
 	// Only bloom things if enabled and no special fixed light mode is active
-	if (!gl_bloom || !FGLRenderBuffers::IsEnabled() || gl_fixedcolormap != CM_DEFAULT || gl_ssao_debug)
+	if (!gl_bloom || gl_fixedcolormap != CM_DEFAULT || gl_ssao_debug)
 		return;
 
 	FGLDebug::PushGroup("BloomScene");
@@ -326,7 +328,7 @@ void FGLRenderer::BloomScene()
 
 void FGLRenderer::TonemapScene()
 {
-	if (gl_tonemap == 0 || !FGLRenderBuffers::IsEnabled())
+	if (gl_tonemap == 0)
 		return;
 
 	FGLDebug::PushGroup("TonemapScene");
@@ -398,6 +400,38 @@ void FGLRenderer::ClearTonemapPalette()
 	mTonemapPalette = nullptr;
 }
 
+//-----------------------------------------------------------------------------
+//
+// Colormap scene texture and place the result in the HUD/2D texture
+//
+//-----------------------------------------------------------------------------
+
+void FGLRenderer::ColormapScene()
+{
+	if (gl_fixedcolormap < CM_FIRSTSPECIALCOLORMAP || gl_fixedcolormap >= CM_MAXCOLORMAP)
+		return;
+
+	FGLDebug::PushGroup("ColormapScene");
+
+	FGLPostProcessState savedState;
+
+	mBuffers->BindNextFB();
+	mBuffers->BindCurrentTexture(0);
+	mColormapShader->Bind();
+	
+	FSpecialColormap *scm = &SpecialColormaps[gl_fixedcolormap - CM_FIRSTSPECIALCOLORMAP];
+	float m[] = { scm->ColorizeEnd[0] - scm->ColorizeStart[0],
+		scm->ColorizeEnd[1] - scm->ColorizeStart[1], scm->ColorizeEnd[2] - scm->ColorizeStart[2], 0.f };
+
+	mColormapShader->MapStart.Set(scm->ColorizeStart[0], scm->ColorizeStart[1], scm->ColorizeStart[2], 0.f);
+	mColormapShader->MapRange.Set(m);
+
+	RenderScreenQuad();
+	mBuffers->NextTexture();
+
+	FGLDebug::PopGroup();
+}
+
 //-----------------------------------------------------------------------------
 //
 // Apply lens distortion and place the result in the HUD/2D texture
@@ -406,7 +440,7 @@ void FGLRenderer::ClearTonemapPalette()
 
 void FGLRenderer::LensDistortScene()
 {
-	if (gl_lens == 0 || !FGLRenderBuffers::IsEnabled())
+	if (gl_lens == 0)
 		return;
 
 	FGLDebug::PushGroup("LensDistortScene");
diff --git a/src/gl/renderer/gl_renderbuffers.cpp b/src/gl/renderer/gl_renderbuffers.cpp
index 6da85bba7..93625722d 100644
--- a/src/gl/renderer/gl_renderbuffers.cpp
+++ b/src/gl/renderer/gl_renderbuffers.cpp
@@ -56,7 +56,14 @@
 #include <random>
 
 CVAR(Int, gl_multisample, 1, CVAR_ARCHIVE|CVAR_GLOBALCONFIG);
-CVAR(Bool, gl_renderbuffers, true, CVAR_ARCHIVE|CVAR_GLOBALCONFIG);
+CUSTOM_CVAR(Bool, gl_renderbuffers, true, CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_NOINITCALL)
+{
+	// this CVAR alters some fixed colormap related settings
+	if (GLRenderer != nullptr && GLRenderer->mShaderManager != nullptr)
+	{
+		//GLRenderer->mShaderManager->ResetFixedColormap();
+	}
+}
 
 //==========================================================================
 //
@@ -95,7 +102,6 @@ void FGLRenderBuffers::ClearScene()
 	DeleteFrameBuffer(mSceneFB);
 	DeleteRenderBuffer(mSceneMSColor);
 	DeleteRenderBuffer(mSceneMSDepthStencil);
-	DeleteRenderBuffer(mSceneMSDepth);
 	DeleteRenderBuffer(mSceneMSStencil);
 }
 
@@ -107,7 +113,6 @@ void FGLRenderBuffers::ClearPipeline()
 		DeleteTexture(mPipelineTexture[i]);
 	}
 	DeleteTexture(mPipelineDepthStencil);
-	DeleteTexture(mPipelineDepth);
 	DeleteTexture(mPipelineStencil);
 }
 
@@ -233,25 +238,12 @@ void FGLRenderBuffers::CreateScene(int width, int height, int samples)
 	if (samples > 1)
 	{
 		mSceneMSColor = CreateRenderBuffer("SceneMSColor", GetHdrFormat(), samples, width, height);
-
-		if ((gl.flags & RFL_NO_DEPTHSTENCIL) != 0)
-		{
-			mSceneMSDepth = CreateRenderBuffer("SceneMSDepth", GL_DEPTH_COMPONENT24, samples, width, height);
-			mSceneMSStencil = CreateRenderBuffer("SceneMSStencil", GL_STENCIL_INDEX8, samples, width, height);
-			mSceneFB = CreateFrameBuffer("SceneFB", mSceneMSColor, mSceneMSDepth, mSceneMSStencil, true);
-		}
-		else
-		{
-			mSceneMSDepthStencil = CreateRenderBuffer("SceneMSDepthStencil", GL_DEPTH24_STENCIL8, samples, width, height);
-			mSceneFB = CreateFrameBuffer("SceneFB", mSceneMSColor, mSceneMSDepthStencil, true);
-		}
+		mSceneMSDepthStencil = CreateRenderBuffer("SceneMSDepthStencil", GL_DEPTH24_STENCIL8, samples, width, height);
+		mSceneFB = CreateFrameBuffer("SceneFB", mSceneMSColor, mSceneMSDepthStencil, true);
 	}
 	else
 	{
-		if ((gl.flags & RFL_NO_DEPTHSTENCIL) != 0)
-			mSceneFB = CreateFrameBuffer("SceneFB", mPipelineTexture[0], mPipelineDepth, mPipelineStencil, false);
-		else
-			mSceneFB = CreateFrameBuffer("SceneFB", mPipelineTexture[0], mPipelineDepthStencil, false);
+		mSceneFB = CreateFrameBuffer("SceneFB", mPipelineTexture[0], mPipelineDepthStencil, false);
 	}
 }
 
@@ -265,23 +257,12 @@ void FGLRenderBuffers::CreatePipeline(int width, int height)
 {
 	ClearPipeline();
 
-	if ((gl.flags & RFL_NO_DEPTHSTENCIL) != 0)
-	{
-		mPipelineDepth = Create2DTexture("PipelineDepth", GL_DEPTH_COMPONENT24, width, height);
-		mPipelineStencil = Create2DTexture("PipelineStencil", GL_STENCIL_INDEX8, width, height);
-	}
-	else
-	{
-		mPipelineDepthStencil = Create2DTexture("PipelineDepthStencil", GL_DEPTH24_STENCIL8, width, height);
-	}
+	mPipelineDepthStencil = Create2DTexture("PipelineDepthStencil", GL_DEPTH24_STENCIL8, width, height);
 
 	for (int i = 0; i < NumPipelineTextures; i++)
 	{
 		mPipelineTexture[i] = Create2DTexture("PipelineTexture", GetHdrFormat(), width, height);
-		if ((gl.flags & RFL_NO_DEPTHSTENCIL) != 0)
-			mPipelineFB[i] = CreateFrameBuffer("PipelineFB", mPipelineTexture[i], mPipelineDepth, mPipelineStencil, false);
-		else
-			mPipelineFB[i] = CreateFrameBuffer("PipelineFB", mPipelineTexture[i], mPipelineDepthStencil, false);
+		mPipelineFB[i] = CreateFrameBuffer("PipelineFB", mPipelineTexture[i], mPipelineDepthStencil, false);
 	}
 }
 
@@ -366,7 +347,7 @@ void FGLRenderBuffers::CreateAmbientOcclusion(int width, int height)
 
 GLuint FGLRenderBuffers::GetHdrFormat()
 {
-	return ((gl.flags & RFL_NO_RGBA16F) != 0) ? GL_RGBA8 : GL_RGBA16F;
+	return GL_RGBA16F;
 }
 
 //==========================================================================
@@ -606,10 +587,7 @@ void FGLRenderBuffers::BindSceneFB()
 void FGLRenderBuffers::BindSceneDepthTexture(int index)
 {
 	glActiveTexture(GL_TEXTURE0 + index);
-	if ((gl.flags & RFL_NO_DEPTHSTENCIL) != 0)
-		glBindTexture(GL_TEXTURE_2D, mPipelineDepth);
-	else
-		glBindTexture(GL_TEXTURE_2D, mPipelineDepthStencil);
+	glBindTexture(GL_TEXTURE_2D, mPipelineDepthStencil);
 }
 
 //==========================================================================
@@ -677,7 +655,7 @@ void FGLRenderBuffers::BindOutputFB()
 
 bool FGLRenderBuffers::IsEnabled()
 {
-	return gl_renderbuffers && gl.glslversion != 0 && !FailedCreate;
+	return gl_renderbuffers && !gl.legacyMode && !FailedCreate;
 }
 
 bool FGLRenderBuffers::FailedCreate = false;
diff --git a/src/gl/renderer/gl_renderbuffers.h b/src/gl/renderer/gl_renderbuffers.h
index 5dc2e49bd..87e20117d 100644
--- a/src/gl/renderer/gl_renderbuffers.h
+++ b/src/gl/renderer/gl_renderbuffers.h
@@ -89,7 +89,6 @@ private:
 	// Buffers for the scene
 	GLuint mSceneMSColor = 0;
 	GLuint mSceneMSDepthStencil = 0;
-	GLuint mSceneMSDepth = 0;
 	GLuint mSceneMSStencil = 0;
 	GLuint mSceneFB = 0;
 
@@ -97,7 +96,6 @@ private:
 	GLuint mPipelineTexture[NumPipelineTextures];
 	GLuint mPipelineFB[NumPipelineTextures];
 	GLuint mPipelineDepthStencil = 0;
-	GLuint mPipelineDepth = 0;
 	GLuint mPipelineStencil = 0;
 
 	// Back buffer frame buffer
diff --git a/src/gl/renderer/gl_renderer.cpp b/src/gl/renderer/gl_renderer.cpp
index 9e64c13b0..2d32f0d20 100644
--- a/src/gl/renderer/gl_renderer.cpp
+++ b/src/gl/renderer/gl_renderer.cpp
@@ -68,6 +68,7 @@
 #include "gl/shaders/gl_bloomshader.h"
 #include "gl/shaders/gl_blurshader.h"
 #include "gl/shaders/gl_tonemapshader.h"
+#include "gl/shaders/gl_colormapshader.h"
 #include "gl/shaders/gl_lensshader.h"
 #include "gl/shaders/gl_presentshader.h"
 #include "gl/textures/gl_texture.h"
@@ -98,21 +99,30 @@ CVAR(Bool, gl_scale_viewport, true, 0);
 FGLRenderer::FGLRenderer(OpenGLFrameBuffer *fb) 
 {
 	framebuffer = fb;
-	mClipPortal = NULL;
-	mCurrentPortal = NULL;
+	mClipPortal = nullptr;
+	mCurrentPortal = nullptr;
 	mMirrorCount = 0;
 	mPlaneMirrorCount = 0;
 	mLightCount = 0;
 	mAngles = FRotator(0.f, 0.f, 0.f);
 	mViewVector = FVector2(0,0);
-	mVBO = NULL;
-	mSkyVBO = NULL;
+	mVBO = nullptr;
+	mSkyVBO = nullptr;
 	gl_spriteindex = 0;
-	mShaderManager = NULL;
-	gllight = glpart2 = glpart = mirrortexture = NULL;
-	mLights = NULL;
+	mShaderManager = nullptr;
+	gllight = glpart2 = glpart = mirrortexture = nullptr;
+	mLights = nullptr;
 	m2DDrawer = nullptr;
 	mTonemapPalette = nullptr;
+	mBuffers = nullptr;
+	mPresentShader = nullptr;
+	mBloomExtractShader = nullptr;
+	mBloomCombineShader = nullptr;
+	mBlurShader = nullptr;
+	mTonemapShader = nullptr;
+	mTonemapPalette = nullptr;
+	mColormapShader = nullptr;
+	mLensShader = nullptr;
 }
 
 void gl_LoadModels();
@@ -127,13 +137,14 @@ void FGLRenderer::Initialize(int width, int height)
 	mBloomCombineShader = new FBloomCombineShader();
 	mBlurShader = new FBlurShader();
 	mTonemapShader = new FTonemapShader();
+	mColormapShader = new FColormapShader();
 	mTonemapPalette = nullptr;
 	mLensShader = new FLensShader();
 	mPresentShader = new FPresentShader();
 	m2DDrawer = new F2DDrawer;
 
-	// Only needed for the core profile, because someone decided it was a good idea to remove the default VAO.
-	if (gl.buffermethod != BM_CLIENTARRAY)
+	// needed for the core profile, because someone decided it was a good idea to remove the default VAO.
+	if (!gl.legacyMode)
 	{
 		glGenVertexArrays(1, &mVAOID);
 		glBindVertexArray(mVAOID);
@@ -148,7 +159,7 @@ void FGLRenderer::Initialize(int width, int height)
 
 	mVBO = new FFlatVertexBuffer(width, height);
 	mSkyVBO = new FSkyVertexBuffer;
-	if (gl.lightmethod != LM_SOFTWARE) mLights = new FLightBuffer();
+	if (!gl.legacyMode) mLights = new FLightBuffer();
 	else mLights = NULL;
 	gl_RenderState.SetVertexBuffer(mVBO);
 	mFBID = 0;
@@ -189,6 +200,7 @@ FGLRenderer::~FGLRenderer()
 	if (mBlurShader) delete mBlurShader;
 	if (mTonemapShader) delete mTonemapShader;
 	if (mTonemapPalette) delete mTonemapPalette;
+	if (mColormapShader) delete mColormapShader;
 	if (mLensShader) delete mLensShader;
 }
 
diff --git a/src/gl/renderer/gl_renderer.h b/src/gl/renderer/gl_renderer.h
index b07870738..c487c4a77 100644
--- a/src/gl/renderer/gl_renderer.h
+++ b/src/gl/renderer/gl_renderer.h
@@ -25,6 +25,7 @@ class FBloomExtractShader;
 class FBloomCombineShader;
 class FBlurShader;
 class FTonemapShader;
+class FColormapShader;
 class FLensShader;
 class FPresentShader;
 class F2DDrawer;
@@ -97,6 +98,7 @@ public:
 	FBloomCombineShader *mBloomCombineShader;
 	FBlurShader *mBlurShader;
 	FTonemapShader *mTonemapShader;
+	FColormapShader *mColormapShader;
 	FHardwareTexture *mTonemapPalette;
 	FLensShader *mLensShader;
 	FPresentShader *mPresentShader;
@@ -172,6 +174,7 @@ public:
 	void AmbientOccludeScene();
 	void BloomScene();
 	void TonemapScene();
+	void ColormapScene();
 	void BindTonemapPalette(int texunit);
 	void ClearTonemapPalette();
 	void LensDistortScene();
diff --git a/src/gl/renderer/gl_renderstate.cpp b/src/gl/renderer/gl_renderstate.cpp
index aa7972f1a..aa41b556d 100644
--- a/src/gl/renderer/gl_renderstate.cpp
+++ b/src/gl/renderer/gl_renderstate.cpp
@@ -49,6 +49,7 @@
 #include "gl/renderer/gl_renderstate.h"
 #include "gl/renderer/gl_colormap.h"
 #include "gl/dynlights//gl_lightbuffer.h"
+#include "gl/renderer/gl_renderbuffers.h"
 
 void gl_SetTextureMode(int type);
 
@@ -221,15 +222,24 @@ bool FRenderState::ApplyShader()
 		{
 			activeShader->muFixedColormap.Set(0);
 		}
-		else if (mColormapState < CM_MAXCOLORMAP)
+		else if (mColormapState > CM_DEFAULT && mColormapState < CM_MAXCOLORMAP)
 		{
-			FSpecialColormap *scm = &SpecialColormaps[gl_fixedcolormap - CM_FIRSTSPECIALCOLORMAP];
-			float m[] = { scm->ColorizeEnd[0] - scm->ColorizeStart[0],
-				scm->ColorizeEnd[1] - scm->ColorizeStart[1], scm->ColorizeEnd[2] - scm->ColorizeStart[2], 0.f };
+			if (FGLRenderBuffers::IsEnabled())
+			{
+				// When using postprocessing to apply the colormap, we must render the image fullbright here.
+				activeShader->muFixedColormap.Set(2);
+				activeShader->muColormapStart.Set(1, 1, 1, 1.f);
+			}
+			else
+			{
+				FSpecialColormap *scm = &SpecialColormaps[gl_fixedcolormap - CM_FIRSTSPECIALCOLORMAP];
+				float m[] = { scm->ColorizeEnd[0] - scm->ColorizeStart[0],
+					scm->ColorizeEnd[1] - scm->ColorizeStart[1], scm->ColorizeEnd[2] - scm->ColorizeStart[2], 0.f };
 
-			activeShader->muFixedColormap.Set(1);
-			activeShader->muColormapStart.Set(scm->ColorizeStart[0], scm->ColorizeStart[1], scm->ColorizeStart[2], 0.f);
-			activeShader->muColormapRange.Set(m);
+				activeShader->muFixedColormap.Set(1);
+				activeShader->muColormapStart.Set(scm->ColorizeStart[0], scm->ColorizeStart[1], scm->ColorizeStart[2], 0.f);
+				activeShader->muColormapRange.Set(m);
+			}
 		}
 		else if (mColormapState == CM_FOGLAYER)
 		{
@@ -315,7 +325,7 @@ void FRenderState::Apply()
 		else mVertexBuffer->BindVBO();
 		mCurrentVertexBuffer = mVertexBuffer;
 	}
-	if (gl.glslversion > 0) 
+	if (!gl.legacyMode) 
 	{
 		ApplyShader();
 	}
@@ -352,7 +362,7 @@ void FRenderState::ApplyMatrices()
 
 void FRenderState::ApplyLightIndex(int index)
 {
-	if (gl.lightmethod != LM_SOFTWARE)
+	if (!gl.legacyMode)
 	{
 		if (index > -1 && GLRenderer->mLights->GetBufferType() == GL_UNIFORM_BUFFER)
 		{
diff --git a/src/gl/renderer/gl_renderstate.h b/src/gl/renderer/gl_renderstate.h
index 3e0729bbe..6acf44026 100644
--- a/src/gl/renderer/gl_renderstate.h
+++ b/src/gl/renderer/gl_renderstate.h
@@ -113,7 +113,7 @@ public:
 		// Without shaders this translation must be applied to any texture.
 		if (alphatexture)
 		{
-			if (mat->tex->UseBasePalette() || gl.glslversion == 0) translation = TRANSLATION(TRANSLATION_Standard, 8);
+			if (mat->tex->UseBasePalette() || gl.legacyMode) translation = TRANSLATION(TRANSLATION_Standard, 8);
 		}
 		mEffectState = overrideshader >= 0? overrideshader : mat->mShaderIndex;
 		mShaderTimer = mat->tex->gl_info.shaderspeed;
diff --git a/src/gl/scene/gl_drawinfo.cpp b/src/gl/scene/gl_drawinfo.cpp
index 842423094..c34d79816 100644
--- a/src/gl/scene/gl_drawinfo.cpp
+++ b/src/gl/scene/gl_drawinfo.cpp
@@ -322,7 +322,7 @@ void GLDrawList::SortWallIntoPlane(SortNode * head,SortNode * sort)
 		AddWall(&w);
 	
 		// Splitting is done in the shader with clip planes, if available
-		if (gl.glslversion < 1.3f)
+		if (gl.flags & RFL_NO_CLIP_PLANES)
 		{
 			GLWall * ws1;
 			ws->vertcount = 0;	// invalidate current vertices.
@@ -382,7 +382,7 @@ void GLDrawList::SortSpriteIntoPlane(SortNode * head,SortNode * sort)
 		AddSprite(&s);	// add a copy to avoid reallocation issues.
 	
 		// Splitting is done in the shader with clip planes, if available
-		if (gl.glslversion < 1.3f)
+		if (gl.flags & RFL_NO_CLIP_PLANES)
 		{
 			GLSprite * ss1;
 			ss1=&sprites[sprites.Size()-1];
@@ -476,9 +476,15 @@ void GLDrawList::SortWallIntoWall(SortNode * head,SortNode * sort)
 
 		ws1->glseg.x1=ws->glseg.x2=ix;
 		ws1->glseg.y1=ws->glseg.y2=iy;
+		ws1->glseg.fracleft = ws->glseg.fracright = ws->glseg.fracleft + r*(ws->glseg.fracright - ws->glseg.fracleft);
 		ws1->ztop[0]=ws->ztop[1]=izt;
 		ws1->zbottom[0]=ws->zbottom[1]=izb;
 		ws1->tcs[GLWall::LOLFT].u = ws1->tcs[GLWall::UPLFT].u = ws->tcs[GLWall::LORGT].u = ws->tcs[GLWall::UPRGT].u = iu;
+		if (gl.buffermethod == BM_DEFERRED)
+		{
+			ws->MakeVertices(false);
+			ws1->MakeVertices(false);
+		}
 
 		SortNode * sort2=SortNodes.GetNew();
 		memset(sort2,0,sizeof(SortNode));
@@ -805,17 +811,19 @@ void GLDrawList::DrawSorted()
 
 	if (!sorted)
 	{
+		GLRenderer->mVBO->Map();
 		MakeSortList();
 		sorted=DoSort(SortNodes[SortNodeStart]);
+		GLRenderer->mVBO->Unmap();
 	}
 	gl_RenderState.ClearClipSplit();
-	if (gl.glslversion >= 1.3f)
+	if (!(gl.flags & RFL_NO_CLIP_PLANES))
 	{
 		glEnable(GL_CLIP_DISTANCE1);
 		glEnable(GL_CLIP_DISTANCE2);
 	}
 	DoDrawSorted(sorted);
-	if (gl.glslversion >= 1.3f)
+	if (!(gl.flags & RFL_NO_CLIP_PLANES))
 	{
 		glDisable(GL_CLIP_DISTANCE1);
 		glDisable(GL_CLIP_DISTANCE2);
@@ -994,7 +1002,7 @@ static FDrawInfoList di_list;
 FDrawInfo::FDrawInfo()
 {
 	next = NULL;
-	if (gl.lightmethod == LM_SOFTWARE)
+	if (gl.legacyMode)
 	{
 		dldrawlists = new GLDrawList[GLLDL_TYPES];
 	}
diff --git a/src/gl/scene/gl_drawinfo.h b/src/gl/scene/gl_drawinfo.h
index 124440eee..0e7296ee3 100644
--- a/src/gl/scene/gl_drawinfo.h
+++ b/src/gl/scene/gl_drawinfo.h
@@ -30,11 +30,9 @@ enum DLDrawListType
 {
 	// These are organized so that the various multipass rendering modes have to be set as few times as possible
 	GLLDL_WALLS_PLAIN,			// dynamic lights on normal walls
-	GLLDL_WALLS_BRIGHT,			// dynamic lights on brightmapped walls
 	GLLDL_WALLS_MASKED,			// dynamic lights on masked midtextures
 
 	GLLDL_FLATS_PLAIN,			// dynamic lights on normal flats
-	GLLDL_FLATS_BRIGHT,			// dynamic lights on brightmapped flats
 	GLLDL_FLATS_MASKED,			// dynamic lights on masked flats
 
 	GLLDL_WALLS_FOG,			// lights on fogged walls
diff --git a/src/gl/scene/gl_flats.cpp b/src/gl/scene/gl_flats.cpp
index 8b665648e..1a3fe994b 100644
--- a/src/gl/scene/gl_flats.cpp
+++ b/src/gl/scene/gl_flats.cpp
@@ -430,7 +430,7 @@ void GLFlat::Draw(int pass, bool trans)	// trans only has meaning for GLPASS_LIG
 		{
 			gl_RenderState.SetMaterial(gltexture, CLAMP_NONE, 0, -1, false);
 			gl_SetPlaneTextureRotation(&plane, gltexture);
-			DrawSubsectors(pass, gl.lightmethod != LM_SOFTWARE, true);
+			DrawSubsectors(pass, !gl.legacyMode, true);
 			gl_RenderState.EnableTextureMatrix(false);
 		}
 		if (renderstyle==STYLE_Add) gl_RenderState.BlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
@@ -468,7 +468,7 @@ inline void GLFlat::PutFlat(bool fog)
 	{
 		Colormap.Clear();
 	}
-	if (gl.lightmethod == LM_SOFTWARE)
+	if (gl.legacyMode)
 	{
 		if (PutFlatCompat(fog)) return;
 	}
diff --git a/src/gl/scene/gl_scene.cpp b/src/gl/scene/gl_scene.cpp
index 7537010b3..109b5fdbe 100644
--- a/src/gl/scene/gl_scene.cpp
+++ b/src/gl/scene/gl_scene.cpp
@@ -409,7 +409,7 @@ void FGLRenderer::RenderScene(int recursion)
 
 	// this is the only geometry type on which decals can possibly appear
 	gl_drawinfo->drawlists[GLDL_PLAINWALLS].DrawDecals();
-	if (gl.lightmethod == LM_SOFTWARE)
+	if (gl.legacyMode)
 	{
 		// also process the render lists with walls and dynamic lights
         gl_drawinfo->dldrawlists[GLLDL_WALLS_PLAIN].DrawDecals();
@@ -480,7 +480,6 @@ void FGLRenderer::RenderTranslucent()
 // stencil, z-buffer and the projection matrix intact!
 //
 //-----------------------------------------------------------------------------
-EXTERN_CVAR(Bool, gl_draw_sync)
 
 void FGLRenderer::DrawScene(int drawmode)
 {
@@ -502,14 +501,6 @@ void FGLRenderer::DrawScene(int drawmode)
 	}
 	GLRenderer->mClipPortal = NULL;	// this must be reset before any portal recursion takes place.
 
-	// Up to this point in the main draw call no rendering is performed so we can wait
-	// with swapping the render buffer until now.
-	if (!gl_draw_sync && drawmode == DM_MAINVIEW)
-	{
-		All.Unclock();
-		static_cast<OpenGLFrameBuffer*>(screen)->Swap();
-		All.Clock();
-	}
 	RenderScene(recursion);
 
 	// Handle all portals after rendering the opaque objects but before
@@ -644,12 +635,14 @@ void FGLRenderer::DrawBlend(sector_t * viewsector)
 		V_AddBlend (player->BlendR, player->BlendG, player->BlendB, player->BlendA, blend);
 	}
 
+	gl_RenderState.BlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 	if (blend[3]>0.0f)
 	{
-		gl_RenderState.BlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 		gl_RenderState.SetColor(blend[0], blend[1], blend[2], blend[3]);
 		gl_FillScreen();
 	}
+	gl_RenderState.ResetColor();
+	gl_RenderState.EnableTexture(true);
 }
 
 
@@ -685,16 +678,19 @@ void FGLRenderer::EndDrawScene(sector_t * viewsector)
 	{
 		DrawPlayerSprites (viewsector, false);
 	}
-	int cm = gl_RenderState.GetFixedColormap();
+	if (gl.legacyMode)
+	{
+		int cm = gl_RenderState.GetFixedColormap();
+		gl_RenderState.SetFixedColormap(cm);
+		gl_RenderState.DrawColormapOverlay();
+	}
+
 	gl_RenderState.SetFixedColormap(CM_DEFAULT);
 	gl_RenderState.SetSoftLightLevel(-1);
 	DrawTargeterSprites();
-	DrawBlend(viewsector);
-	if (gl.glslversion == 0.0)
+	if (FGLRenderBuffers::IsEnabled())
 	{
-		gl_RenderState.SetFixedColormap(cm);
-		gl_RenderState.DrawColormapOverlay();
-		gl_RenderState.SetFixedColormap(CM_DEFAULT);
+		DrawBlend(viewsector);
 	}
 
 	// Restore standard rendering state
@@ -855,7 +851,11 @@ sector_t * FGLRenderer::RenderViewpoint (AActor * camera, GL_IRECT * bounds, flo
 
 		ProcessScene(toscreen);
 		if (mainview && toscreen) EndDrawScene(retval);	// do not call this for camera textures.
-		if (mainview) PostProcessScene();
+		if (mainview && FGLRenderBuffers::IsEnabled())
+		{
+			PostProcessScene();
+			DrawBlend(viewsector);	// This should be done after postprocessing, not before.
+		}
 		mDrawingScene2D = false;
 		eye->TearDown();
 	}
@@ -899,7 +899,7 @@ void FGLRenderer::RenderView (player_t* player)
 
 	P_FindParticleSubsectors ();
 
-	if (gl.lightmethod != LM_SOFTWARE) GLRenderer->mLights->Clear();
+	if (!gl.legacyMode) GLRenderer->mLights->Clear();
 
 	// NoInterpolateView should have no bearing on camera textures, but needs to be preserved for the main view below.
 	bool saved_niv = NoInterpolateView;
@@ -954,7 +954,7 @@ void FGLRenderer::WriteSavePic (player_t *player, FILE *file, int width, int hei
 	SetFixedColormap(player);
 	gl_RenderState.SetVertexBuffer(mVBO);
 	GLRenderer->mVBO->Reset();
-	if (gl.lightmethod != LM_SOFTWARE) GLRenderer->mLights->Clear();
+	if (!gl.legacyMode) GLRenderer->mLights->Clear();
 
 	// Check if there's some lights. If not some code can be skipped.
 	TThinkerIterator<ADynamicLight> it(STAT_DLIGHT);
diff --git a/src/gl/scene/gl_skydome.cpp b/src/gl/scene/gl_skydome.cpp
index 2b6843bdf..97c5cb458 100644
--- a/src/gl/scene/gl_skydome.cpp
+++ b/src/gl/scene/gl_skydome.cpp
@@ -87,7 +87,7 @@ FSkyVertexBuffer::~FSkyVertexBuffer()
 void FSkyVertexBuffer::BindVBO()
 {
 	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
-	if (gl.glslversion > 0)
+	if (!gl.legacyMode)
 	{
 		glVertexAttribPointer(VATTR_VERTEX, 3, GL_FLOAT, false, sizeof(FSkyVertex), &VSO->x);
 		glVertexAttribPointer(VATTR_TEXCOORD, 2, GL_FLOAT, false, sizeof(FSkyVertex), &VSO->u);
@@ -321,7 +321,7 @@ void FSkyVertexBuffer::RenderDome(FMaterial *tex, int mode)
 		RenderRow(GL_TRIANGLE_FAN, rc);
 		gl_RenderState.EnableTexture(true);
 		// The color array can only be activated now if this is drawn without shader
-		if (gl.glslversion == 0)
+		if (gl.legacyMode)
 		{
 			glEnableClientState(GL_COLOR_ARRAY);
 		}
diff --git a/src/gl/scene/gl_sprite.cpp b/src/gl/scene/gl_sprite.cpp
index 0c5b2581a..8a8c89c80 100644
--- a/src/gl/scene/gl_sprite.cpp
+++ b/src/gl/scene/gl_sprite.cpp
@@ -870,7 +870,7 @@ void GLSprite::Process(AActor* thing, sector_t * sector, int thruportal)
 		RenderStyle.CheckFuzz();
 		if (RenderStyle.BlendOp == STYLEOP_Fuzz)
 		{
-			if (gl_fuzztype != 0 && gl.glslversion > 0)
+			if (gl_fuzztype != 0 && !gl.legacyMode)
 			{
 				// Todo: implement shader selection here
 				RenderStyle = LegacyRenderStyles[STYLE_Translucent];
diff --git a/src/gl/scene/gl_walls.cpp b/src/gl/scene/gl_walls.cpp
index 3afde063c..f8bb2a876 100644
--- a/src/gl/scene/gl_walls.cpp
+++ b/src/gl/scene/gl_walls.cpp
@@ -140,9 +140,8 @@ void GLWall::PutWall(bool translucent)
 	}
 	else
 	{
-		if (gl.lightmethod == LM_SOFTWARE && !translucent)
+		if (gl.legacyMode && !translucent)
 		{
-			// This is not yet ready.
 			if (PutWallCompat(passflag[type])) return;
 		}
 
diff --git a/src/gl/scene/gl_walls_draw.cpp b/src/gl/scene/gl_walls_draw.cpp
index 585ced1a8..40145abc4 100644
--- a/src/gl/scene/gl_walls_draw.cpp
+++ b/src/gl/scene/gl_walls_draw.cpp
@@ -216,9 +216,8 @@ void GLWall::RenderWall(int textured)
 	}
 	else if (vertcount == 0)
 	{
-		// in case we get here without valid vertex data and no ability to create them now,
-		// use the quad drawer as fallback (without edge splitting.)
-		// This can only happen in one special situation, when a translucent line got split during sorting.
+		// This should never happen but in case it actually does, use the quad drawer as fallback (without edge splitting.)
+		// This way it at least gets drawn.
 		FQuadDrawer qd;
 		qd.Set(0, glseg.x1, zbottom[0], glseg.y1, tcs[LOLFT].u, tcs[LOLFT].v);
 		qd.Set(1, glseg.x1, ztop[0], glseg.y1, tcs[UPLFT].u, tcs[UPLFT].v);
@@ -242,7 +241,7 @@ void GLWall::RenderFogBoundary()
 {
 	if (gl_fogmode && gl_fixedcolormap == 0)
 	{
-		if (gl.glslversion > 0.f)
+		if (!gl.legacyMode)
 		{
 			int rel = rellight + getExtraLight();
 			gl_SetFog(lightlevel, rel, &Colormap, false);
@@ -276,7 +275,7 @@ void GLWall::RenderMirrorSurface()
 	Vector v(glseg.y2-glseg.y1, 0 ,-glseg.x2+glseg.x1);
 	v.Normalize();
 
-	if (gl.glslversion >= 0.f)
+	if (!gl.legacyMode)
 	{
 		// we use texture coordinates and texture matrix to pass the normal stuff to the shader so that the default vertex buffer format can be used as is.
 		tcs[LOLFT].u = tcs[LORGT].u = tcs[UPLFT].u = tcs[UPRGT].u = v.X();
diff --git a/src/gl/shaders/gl_blurshader.cpp b/src/gl/shaders/gl_blurshader.cpp
index 6154c17ce..bf2e29c7e 100644
--- a/src/gl/shaders/gl_blurshader.cpp
+++ b/src/gl/shaders/gl_blurshader.cpp
@@ -87,20 +87,6 @@ void FBlurShader::Blur(FGLRenderer *renderer, float blurAmount, int sampleCount,
 	else
 		setup->HorizontalShader->Bind();
 
-	if (gl.glslversion < 1.3)
-	{
-		if (vertical)
-		{
-			setup->VerticalScaleX.Set(1.0f / width);
-			setup->VerticalScaleY.Set(1.0f / height);
-		}
-		else
-		{
-			setup->HorizontalScaleX.Set(1.0f / width);
-			setup->HorizontalScaleY.Set(1.0f / height);
-		}
-	}
-
 	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, inputTexture);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
@@ -156,14 +142,6 @@ FBlurShader::BlurSetup *FBlurShader::GetSetup(float blurAmount, int sampleCount)
 	blurSetup.HorizontalShader->Bind();
 	glUniform1i(glGetUniformLocation(*blurSetup.HorizontalShader.get(), "SourceTexture"), 0);
 	
-	if (gl.glslversion < 1.3)
-	{
-		blurSetup.VerticalScaleX.Init(*blurSetup.VerticalShader.get(), "ScaleX");
-		blurSetup.VerticalScaleY.Init(*blurSetup.VerticalShader.get(), "ScaleY");
-		blurSetup.HorizontalScaleX.Init(*blurSetup.HorizontalShader.get(), "ScaleX");
-		blurSetup.HorizontalScaleY.Init(*blurSetup.HorizontalShader.get(), "ScaleY");
-	}
-
 	mBlurSetups.Push(blurSetup);
 
 	return &mBlurSetups[mBlurSetups.Size() - 1];
diff --git a/src/gl/shaders/gl_colormapshader.cpp b/src/gl/shaders/gl_colormapshader.cpp
new file mode 100644
index 000000000..f28003150
--- /dev/null
+++ b/src/gl/shaders/gl_colormapshader.cpp
@@ -0,0 +1,67 @@
+/*
+** gl_colormapshader.cpp
+** Applies a fullscreen colormap to the scene
+**
+**---------------------------------------------------------------------------
+** Copyright 2016 Christoph Oelckers
+** All rights reserved.
+**
+** Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions
+** are met:
+**
+** 1. Redistributions of source code must retain the above copyright
+**    notice, this list of conditions and the following disclaimer.
+** 2. Redistributions in binary form must reproduce the above copyright
+**    notice, this list of conditions and the following disclaimer in the
+**    documentation and/or other materials provided with the distribution.
+** 3. The name of the author may not be used to endorse or promote products
+**    derived from this software without specific prior written permission.
+** 4. When not used as part of GZDoom or a GZDoom derivative, this code will be
+**    covered by the terms of the GNU Lesser General Public License as published
+**    by the Free Software Foundation; either version 2.1 of the License, or (at
+**    your option) any later version.
+** 5. Full disclosure of the entire project's source code, except for third
+**    party libraries is mandatory. (NOTE: This clause is non-negotiable!)
+**
+** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+**---------------------------------------------------------------------------
+**
+*/
+
+#include "gl/system/gl_system.h"
+#include "files.h"
+#include "m_swap.h"
+#include "v_video.h"
+#include "gl/gl_functions.h"
+#include "vectors.h"
+#include "gl/system/gl_interface.h"
+#include "gl/system/gl_framebuffer.h"
+#include "gl/system/gl_cvars.h"
+#include "gl/shaders/gl_colormapshader.h"
+
+void FColormapShader::Bind()
+{
+	auto &shader = mShader;
+	if (!shader)
+	{
+		shader.Compile(FShaderProgram::Vertex, "shaders/glsl/screenquad.vp", "", 330);
+		shader.Compile(FShaderProgram::Fragment, "shaders/glsl/colormap.fp", "", 330);
+		shader.SetFragDataLocation(0, "FragColor");
+		shader.Link("shaders/glsl/colormap");
+		shader.SetAttribLocation(0, "PositionInProjection");
+		MapStart.Init(shader, "uFixedColormapStart");
+		MapRange.Init(shader, "uFixedColormapRange");
+	}
+	shader.Bind();
+}
+
diff --git a/src/gl/shaders/gl_colormapshader.h b/src/gl/shaders/gl_colormapshader.h
new file mode 100644
index 000000000..b20c23a4c
--- /dev/null
+++ b/src/gl/shaders/gl_colormapshader.h
@@ -0,0 +1,20 @@
+#ifndef __GL_COLORMAPSHADER_H
+#define __GL_COLORMAPSHADER_H
+
+#include "gl_shaderprogram.h"
+
+class FColormapShader
+{
+public:
+	void Bind();
+
+	FBufferedUniformSampler SceneTexture;
+	FUniform4f MapStart;
+	FUniform4f MapRange;
+
+private:
+
+	FShaderProgram mShader;
+};
+
+#endif
\ No newline at end of file
diff --git a/src/gl/shaders/gl_shader.cpp b/src/gl/shaders/gl_shader.cpp
index fa4c92933..ef8f19547 100644
--- a/src/gl/shaders/gl_shader.cpp
+++ b/src/gl/shaders/gl_shader.cpp
@@ -91,40 +91,27 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 //
 	FString vp_comb;
 
-	if (gl.lightmethod == LM_SOFTWARE)
+	assert(GLRenderer->mLights != NULL);
+	// On the shader side there is no difference between LM_DEFERRED and LM_DIRECT, it only decides how the buffer is initialized.
+	unsigned int lightbuffertype = GLRenderer->mLights->GetBufferType();
+	unsigned int lightbuffersize = GLRenderer->mLights->GetBlockSize();
+	if (lightbuffertype == GL_UNIFORM_BUFFER)
 	{
-		if (gl.glslversion >= 1.3)
+		// This differentiation is for some Intel drivers which fail on #extension, so use of #version 140 is necessary
+		if (gl.glslversion < 1.4f)
 		{
-			vp_comb = "#version 130\n";
+			vp_comb.Format("#version 130\n#extension GL_ARB_uniform_buffer_object : require\n#define NUM_UBO_LIGHTS %d\n", lightbuffersize);
 		}
 		else
 		{
-			vp_comb = "#define GLSL12_COMPATIBLE\n";
+			vp_comb.Format("#version 140\n#define NUM_UBO_LIGHTS %d\n", lightbuffersize);
 		}
 	}
 	else
 	{
-		assert(GLRenderer->mLights != NULL);
-		// On the shader side there is no difference between LM_DEFERRED and LM_DIRECT, it only matters which buffer type is used by the light buffer.
-		unsigned int lightbuffertype = GLRenderer->mLights->GetBufferType();
-		unsigned int lightbuffersize = GLRenderer->mLights->GetBlockSize();
-		if (lightbuffertype == GL_UNIFORM_BUFFER)
-		{
-			// This differentiation is for some Intel drivers which fail on #extension, so use of #version 140 is necessary
-			if (gl.glslversion < 1.4f || gl.version < 3.1f)
-			{
-				vp_comb.Format("#version 130\n#extension GL_ARB_uniform_buffer_object : require\n#define NUM_UBO_LIGHTS %d\n", lightbuffersize);
-			}
-			else
-			{
-				vp_comb.Format("#version 140\n#define NUM_UBO_LIGHTS %d\n", lightbuffersize);
-			}
-		}
-		else
-		{
-			vp_comb = "#version 400 core\n#extension GL_ARB_shader_storage_buffer_object : require\n#define SHADER_STORAGE_LIGHTS\n";
-		}
+		vp_comb = "#version 400 core\n#extension GL_ARB_shader_storage_buffer_object : require\n#define SHADER_STORAGE_LIGHTS\n";
 	}
+
 	if (gl.buffermethod == BM_DEFERRED)
 	{
 		vp_comb << "#define USE_QUAD_DRAWER\n";
@@ -169,12 +156,7 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 		}
 	}
 
-	if (gl.glslversion < 1.3)
-	{
-		FShaderProgram::PatchVertShader(vp_comb);
-		FShaderProgram::PatchFragShader(fp_comb);
-	}
-	else if (gl.flags & RFL_NO_CLIP_PLANES)
+	if (gl.flags & RFL_NO_CLIP_PLANES)
 	{
 		// On ATI's GL3 drivers we have to disable gl_ClipDistance because it's hopelessly broken.
 		// This will cause some glitches and regressions but is the only way to avoid total display garbage.
@@ -274,7 +256,7 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 	texcoordmatrix_index = glGetUniformLocation(hShader, "uQuadTexCoords");
 	quadmode_index = glGetUniformLocation(hShader, "uQuadMode");
 
-	if (LM_SOFTWARE != gl.lightmethod && !(gl.flags & RFL_SHADER_STORAGE_BUFFER))
+	if (!gl.legacyMode && !(gl.flags & RFL_SHADER_STORAGE_BUFFER))
 	{
 		int tempindex = glGetUniformBlockIndex(hShader, "LightBufferUBO");
 		if (tempindex != -1) glUniformBlockBinding(hShader, tempindex, LIGHTBUF_BINDINGPOINT);
@@ -425,7 +407,7 @@ static const FEffectShader effectshaders[]=
 
 FShaderManager::FShaderManager()
 {
-	if (gl.glslversion > 0) CompileShaders();
+	if (!gl.legacyMode) CompileShaders();
 }
 
 //==========================================================================
@@ -436,7 +418,7 @@ FShaderManager::FShaderManager()
 
 FShaderManager::~FShaderManager()
 {
-	if (gl.glslversion > 0) Clean();
+	if (!gl.legacyMode) Clean();
 }
 
 //==========================================================================
@@ -578,7 +560,7 @@ EXTERN_CVAR(Int, gl_fuzztype)
 
 void FShaderManager::ApplyMatrices(VSMatrix *proj, VSMatrix *view)
 {
-	if (gl.glslversion == 0)
+	if (gl.legacyMode)
 	{
 		glMatrixMode(GL_PROJECTION);
 		glLoadMatrixf(proj->get());
diff --git a/src/gl/shaders/gl_shaderprogram.cpp b/src/gl/shaders/gl_shaderprogram.cpp
index 959315a9d..80a7ea99e 100644
--- a/src/gl/shaders/gl_shaderprogram.cpp
+++ b/src/gl/shaders/gl_shaderprogram.cpp
@@ -240,24 +240,13 @@ FString FShaderProgram::PatchShader(ShaderType type, const FString &code, const
 	if (defines)
 		patchedCode << defines;
 
-	if (gl.glslversion >= 1.3)
-	{
-		// these settings are actually pointless but there seem to be some old ATI drivers that fail to compile the shader without setting the precision here.
-		patchedCode << "precision highp int;\n";
-		patchedCode << "precision highp float;\n";
-	}
+	// these settings are actually pointless but there seem to be some old ATI drivers that fail to compile the shader without setting the precision here.
+	patchedCode << "precision highp int;\n";
+	patchedCode << "precision highp float;\n";
 
 	patchedCode << "#line 1\n";
 	patchedCode << code;
 
-	if (gl.glslversion < 1.3)
-	{
-		if (type == Vertex)
-			PatchVertShader(patchedCode);
-		else if (type == Fragment)
-			PatchFragShader(patchedCode);
-	}
-
 	return patchedCode;
 }
 
@@ -268,36 +257,3 @@ FString FShaderProgram::PatchShader(ShaderType type, const FString &code, const
 //
 //==========================================================================
 
-void FShaderProgram::PatchCommon(FString &code)
-{
-	code.Substitute("precision highp int;", "");
-	code.Substitute("precision highp float;", "");
-}
-
-void FShaderProgram::PatchVertShader(FString &code)
-{
-	PatchCommon(code);
-	code.Substitute("in vec", "attribute vec");
-	code.Substitute("in float", "attribute float");
-	code.Substitute("out vec", "varying vec");
-	code.Substitute("out float", "varying float");
-	code.Substitute("gl_ClipDistance", "//");
-}
-
-void FShaderProgram::PatchFragShader(FString &code)
-{
-	PatchCommon(code);
-	code.Substitute("out vec4 FragColor;", "");
-	code.Substitute("FragColor", "gl_FragColor");
-	code.Substitute("in vec", "varying vec");
-	// this patches the switch statement to if's.
-	code.Substitute("break;", "");
-	code.Substitute("switch (uFixedColormap)", "int i = uFixedColormap;");
-	code.Substitute("case 0:", "if (i == 0)");
-	code.Substitute("case 1:", "else if (i == 1)");
-	code.Substitute("case 2:", "else if (i == 2)");
-	code.Substitute("case 3:", "else if (i == 3)");
-	code.Substitute("case 4:", "else if (i == 4)");
-	code.Substitute("case 5:", "else if (i == 5)");
-	code.Substitute("texture(", "texture2D(");
-}
diff --git a/src/gl/shaders/gl_shaderprogram.h b/src/gl/shaders/gl_shaderprogram.h
index 64a36db49..aabfb1f6f 100644
--- a/src/gl/shaders/gl_shaderprogram.h
+++ b/src/gl/shaders/gl_shaderprogram.h
@@ -26,16 +26,11 @@ public:
 	operator GLuint() const { return mProgram; }
 	explicit operator bool() const { return mProgram != 0; }
 
-	// Needed by FShader
-	static void PatchVertShader(FString &code);
-	static void PatchFragShader(FString &code);
-
 private:
 	FShaderProgram(const FShaderProgram &) = delete;
 	FShaderProgram &operator=(const FShaderProgram &) = delete;
 
 	static FString PatchShader(ShaderType type, const FString &code, const char *defines, int maxGlslVersion);
-	static void PatchCommon(FString &code);
 
 	void CreateShader(ShaderType type);
 	FString GetShaderInfoLog(GLuint handle);
diff --git a/src/gl/system/gl_framebuffer.cpp b/src/gl/system/gl_framebuffer.cpp
index ae1fabaed..158d7f333 100644
--- a/src/gl/system/gl_framebuffer.cpp
+++ b/src/gl/system/gl_framebuffer.cpp
@@ -162,7 +162,7 @@ void OpenGLFrameBuffer::InitializeState()
 	glEnable(GL_BLEND);
 	glEnable(GL_DEPTH_CLAMP);
 	glDisable(GL_DEPTH_TEST);
-	if (gl.glslversion == 0) glEnable(GL_TEXTURE_2D);
+	if (gl.legacyMode) glEnable(GL_TEXTURE_2D);
 	glDisable(GL_LINE_SMOOTH);
 	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
@@ -179,9 +179,6 @@ void OpenGLFrameBuffer::InitializeState()
 //
 //==========================================================================
 
-// Testing only for now. 
-CVAR(Bool, gl_draw_sync, true, 0) //false, CVAR_ARCHIVE|CVAR_GLOBALCONFIG)
-
 void OpenGLFrameBuffer::Update()
 {
 	if (!CanUpdate()) 
@@ -197,10 +194,7 @@ void OpenGLFrameBuffer::Update()
 
 	GLRenderer->SetOutputViewport(nullptr);
 
-	if (gl_draw_sync || !swapped)
-	{
-		Swap();
-	}
+	Swap();
 	swapped = false;
 	Unlock();
 	CheckBench();
diff --git a/src/gl/system/gl_interface.cpp b/src/gl/system/gl_interface.cpp
index c54d96448..9185b63dc 100644
--- a/src/gl/system/gl_interface.cpp
+++ b/src/gl/system/gl_interface.cpp
@@ -154,10 +154,10 @@ void gl_LoadExtensions()
 		else Printf("Emulating OpenGL v %s\n", version);
 	}
 
-	gl.version = strtod(version, NULL) + 0.01f;
+	float gl_version = (float)strtod(version, NULL) + 0.01f;
 
-	// Don't even start if it's lower than 2.0 or no framebuffers are available
-	if ((gl.version < 2.0 || !CheckExtension("GL_EXT_framebuffer_object")) && gl.version < 3.0)
+	// Don't even start if it's lower than 2.0 or no framebuffers are available (The framebuffer extension is needed for glGenerateMipmapsEXT!)
+	if ((gl_version < 2.0f || !CheckExtension("GL_EXT_framebuffer_object")) && gl_version < 3.0f)
 	{
 		I_FatalError("Unsupported OpenGL version.\nAt least OpenGL 2.0 with framebuffer support is required to run " GAMENAME ".\n");
 	}
@@ -166,105 +166,86 @@ void gl_LoadExtensions()
 	gl.glslversion = strtod((char*)glGetString(GL_SHADING_LANGUAGE_VERSION), NULL) + 0.01f;
 
 	gl.vendorstring = (char*)glGetString(GL_VENDOR);
-	gl.lightmethod = LM_SOFTWARE;
-	gl.buffermethod = BM_CLIENTARRAY;
 
-	if ((gl.version >= 3.3f || CheckExtension("GL_ARB_sampler_objects")) && !Args->CheckParm("-nosampler"))
+	// first test for optional features
+	if (CheckExtension("GL_ARB_texture_compression")) gl.flags |= RFL_TEXTURE_COMPRESSION;
+	if (CheckExtension("GL_EXT_texture_compression_s3tc")) gl.flags |= RFL_TEXTURE_COMPRESSION_S3TC;
+
+	if ((gl_version >= 3.3f || CheckExtension("GL_ARB_sampler_objects")) && !Args->CheckParm("-nosampler"))
 	{
 		gl.flags |= RFL_SAMPLER_OBJECTS;
 	}
 	
-	// Buffer lighting is only feasible with GLSL 1.3 and higher, even if 1.2 supports the extension.
-	if (gl.version > 3.0f && (gl.version >= 3.3f || CheckExtension("GL_ARB_uniform_buffer_object")))
+	// The minimum requirement for the modern render path are GL 3.0 + uniform buffers
+	if (gl_version < 3.0f || (gl_version < 3.1f && !CheckExtension("GL_ARB_uniform_buffer_object")))
 	{
-		gl.lightmethod = LM_DEFERRED;
-		gl.buffermethod = BM_DEFERRED;
-	}
-
-	if (CheckExtension("GL_ARB_texture_compression")) gl.flags |= RFL_TEXTURE_COMPRESSION;
-	if (CheckExtension("GL_EXT_texture_compression_s3tc")) gl.flags |= RFL_TEXTURE_COMPRESSION_S3TC;
-
-	if (Args->CheckParm("-noshader")/* || gl.glslversion < 1.2f*/)
-	{
-		gl.version = 2.11f;
+		gl.legacyMode = true;
+		gl.lightmethod = LM_LEGACY;
+		gl.buffermethod = BM_LEGACY;
 		gl.glslversion = 0;
-		gl.lightmethod = LM_SOFTWARE;
 		gl.flags |= RFL_NO_CLIP_PLANES;
 	}
-	else if (gl.version < 3.0f)
-	{
-		if (CheckExtension("GL_NV_GPU_shader4") || CheckExtension("GL_EXT_GPU_shader4")) gl.glslversion = 1.21f;	// for pre-3.0 drivers that support capable hardware. Needed for Apple.
-		else
-		{
-			gl.buffermethod = BM_CLIENTARRAY;
-			gl.glslversion = 0;
-		}
-
-		if (!CheckExtension("GL_EXT_packed_float")) gl.flags |= RFL_NO_RGBA16F;
-		if (!CheckExtension("GL_EXT_packed_depth_stencil")) gl.flags |= RFL_NO_DEPTHSTENCIL;
-		gl.flags |= RFL_NO_CLIP_PLANES;
-	}
-	else if (gl.version < 4.f)
-	{
-#ifdef _WIN32
-		if (strstr(gl.vendorstring, "ATI Tech")) 
-		{
-			gl.flags |= RFL_NO_CLIP_PLANES;	// gl_ClipDistance is horribly broken on ATI GL3 drivers for Windows.
-		}
-#endif
-	}
-	else if (gl.version < 4.5f)
-	{
-		// don't use GL 4.x features when running in GL 3 emulation mode.
-		if (CheckExtension("GL_ARB_buffer_storage"))
-		{
-			// work around a problem with older AMD drivers: Their implementation of shader storage buffer objects is piss-poor and does not match uniform buffers even closely.
-			// Recent drivers, GL 4.4 don't have this problem, these can easily be recognized by also supporting the GL_ARB_buffer_storage extension.
-			if (CheckExtension("GL_ARB_shader_storage_buffer_object"))
-			{
-				// Shader storage buffer objects are broken on current Intel drivers.
-				if (strstr(gl.vendorstring, "Intel") == NULL)
-				{
-					gl.flags |= RFL_SHADER_STORAGE_BUFFER;
-				}
-			}
-			gl.flags |= RFL_BUFFER_STORAGE;
-			gl.lightmethod = LM_DIRECT;
-			gl.buffermethod = BM_PERSISTENT;
-		}
-		else
-		{
-			gl.version = 3.3f;
-		}
-	}
 	else
 	{
-		// Assume that everything works without problems on GL 4.5 drivers where these things are core features.
-		gl.flags |= RFL_SHADER_STORAGE_BUFFER | RFL_BUFFER_STORAGE;
-		gl.lightmethod = LM_DIRECT;
-		gl.buffermethod = BM_PERSISTENT;
-	}
+		gl.legacyMode = false;
+		gl.lightmethod = LM_DEFERRED;
+		gl.buffermethod = BM_DEFERRED;
+		if (gl_version < 4.f)
+		{
+#ifdef _WIN32
+			if (strstr(gl.vendorstring, "ATI Tech"))
+			{
+				gl.flags |= RFL_NO_CLIP_PLANES;	// gl_ClipDistance is horribly broken on ATI GL3 drivers for Windows.
+			}
+#endif
+		}
+		else if (gl_version < 4.5f)
+		{
+			// don't use GL 4.x features when running a GL 3.x context.
+			if (CheckExtension("GL_ARB_buffer_storage"))
+			{
+				// work around a problem with older AMD drivers: Their implementation of shader storage buffer objects is piss-poor and does not match uniform buffers even closely.
+				// Recent drivers, GL 4.4 don't have this problem, these can easily be recognized by also supporting the GL_ARB_buffer_storage extension.
+				if (CheckExtension("GL_ARB_shader_storage_buffer_object"))
+				{
+					// Shader storage buffer objects are broken on current Intel drivers.
+					if (strstr(gl.vendorstring, "Intel") == NULL)
+					{
+						gl.flags |= RFL_SHADER_STORAGE_BUFFER;
+					}
+				}
+				gl.flags |= RFL_BUFFER_STORAGE;
+				gl.lightmethod = LM_DIRECT;
+				gl.buffermethod = BM_PERSISTENT;
+			}
+		}
+		else
+		{
+			// Assume that everything works without problems on GL 4.5 drivers where these things are core features.
+			gl.flags |= RFL_SHADER_STORAGE_BUFFER | RFL_BUFFER_STORAGE;
+			gl.lightmethod =	LM_DIRECT;
+			gl.buffermethod = BM_PERSISTENT;
+		}
 
-	if (gl.version >= 4.3f || CheckExtension("GL_ARB_invalidate_subdata")) gl.flags |= RFL_INVALIDATE_BUFFER;
-	if (gl.version >= 4.3f || CheckExtension("GL_KHR_debug")) gl.flags |= RFL_DEBUG;
+		if (gl_version >= 4.3f || CheckExtension("GL_ARB_invalidate_subdata")) gl.flags |= RFL_INVALIDATE_BUFFER;
+		if (gl_version >= 4.3f || CheckExtension("GL_KHR_debug")) gl.flags |= RFL_DEBUG;
 
-	const char *lm = Args->CheckValue("-lightmethod");
-	if (lm != NULL)
-	{
-		if (!stricmp(lm, "deferred") && gl.lightmethod == LM_DIRECT) gl.lightmethod = LM_DEFERRED;	
-		if (!stricmp(lm, "textured")) gl.lightmethod = LM_SOFTWARE;
-	}
+		const char *lm = Args->CheckValue("-lightmethod");
+		if (lm != NULL)
+		{
+			if (!stricmp(lm, "deferred") && gl.lightmethod == LM_DIRECT) gl.lightmethod = LM_DEFERRED;
+		}
 
-	lm = Args->CheckValue("-buffermethod");
-	if (lm != NULL)
-	{
-		if (!stricmp(lm, "deferred") && gl.buffermethod == BM_PERSISTENT) gl.buffermethod = BM_DEFERRED;
-		if (!stricmp(lm, "clientarray")) gl.buffermethod = BM_CLIENTARRAY;
+		lm = Args->CheckValue("-buffermethod");
+		if (lm != NULL)
+		{
+			if (!stricmp(lm, "deferred") && gl.buffermethod == BM_PERSISTENT) gl.buffermethod = BM_DEFERRED;
+		}
 	}
 
 	int v;
 	
-	if (gl.lightmethod != LM_SOFTWARE && !(gl.flags & RFL_SHADER_STORAGE_BUFFER))
+	if (!gl.legacyMode && !(gl.flags & RFL_SHADER_STORAGE_BUFFER))
 	{
 		glGetIntegerv(GL_MAX_FRAGMENT_UNIFORM_COMPONENTS, &v);
 		gl.maxuniforms = v;
@@ -284,24 +265,27 @@ void gl_LoadExtensions()
 	glGetIntegerv(GL_MAX_TEXTURE_SIZE, &gl.max_texturesize);
 	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 
-	// fudge a bit with the framebuffer stuff to avoid redundancies in the main code. Some of the older cards do not have the ARB stuff but the calls are nearly identical.
-	FUDGE_FUNC(glGenerateMipmap, EXT);
-	FUDGE_FUNC(glGenFramebuffers, EXT);
-	FUDGE_FUNC(glBindFramebuffer, EXT);
-	FUDGE_FUNC(glDeleteFramebuffers, EXT);
-	FUDGE_FUNC(glFramebufferTexture2D, EXT);
-	FUDGE_FUNC(glGenerateMipmap, EXT);
-	FUDGE_FUNC(glGenFramebuffers, EXT);
-	FUDGE_FUNC(glBindFramebuffer, EXT);
-	FUDGE_FUNC(glDeleteFramebuffers, EXT);
-	FUDGE_FUNC(glFramebufferTexture2D, EXT);
-	FUDGE_FUNC(glFramebufferRenderbuffer, EXT);
-	FUDGE_FUNC(glGenRenderbuffers, EXT);
-	FUDGE_FUNC(glDeleteRenderbuffers, EXT);
-	FUDGE_FUNC(glRenderbufferStorage, EXT);
-	FUDGE_FUNC(glBindRenderbuffer, EXT);
-	FUDGE_FUNC(glCheckFramebufferStatus, EXT);
-	gl_PatchMenu();
+	if (gl.legacyMode)
+	{
+		// fudge a bit with the framebuffer stuff to avoid redundancies in the main code. Some of the older cards do not have the ARB stuff but the calls are nearly identical.
+		FUDGE_FUNC(glGenerateMipmap, EXT);
+		FUDGE_FUNC(glGenFramebuffers, EXT);
+		FUDGE_FUNC(glBindFramebuffer, EXT);
+		FUDGE_FUNC(glDeleteFramebuffers, EXT);
+		FUDGE_FUNC(glFramebufferTexture2D, EXT);
+		FUDGE_FUNC(glGenerateMipmap, EXT);
+		FUDGE_FUNC(glGenFramebuffers, EXT);
+		FUDGE_FUNC(glBindFramebuffer, EXT);
+		FUDGE_FUNC(glDeleteFramebuffers, EXT);
+		FUDGE_FUNC(glFramebufferTexture2D, EXT);
+		FUDGE_FUNC(glFramebufferRenderbuffer, EXT);
+		FUDGE_FUNC(glGenRenderbuffers, EXT);
+		FUDGE_FUNC(glDeleteRenderbuffers, EXT);
+		FUDGE_FUNC(glRenderbufferStorage, EXT);
+		FUDGE_FUNC(glBindRenderbuffer, EXT);
+		FUDGE_FUNC(glCheckFramebufferStatus, EXT);
+		gl_PatchMenu();
+	}
 }
 
 //==========================================================================
@@ -313,7 +297,7 @@ void gl_LoadExtensions()
 void gl_PrintStartupLog()
 {
 	int v = 0;
-	if (gl.version >= 3.2) glGetIntegerv(GL_CONTEXT_PROFILE_MASK, &v);
+	if (!gl.legacyMode) glGetIntegerv(GL_CONTEXT_PROFILE_MASK, &v);
 
 	Printf ("GL_VENDOR: %s\n", glGetString(GL_VENDOR));
 	Printf ("GL_RENDERER: %s\n", glGetString(GL_RENDERER));
@@ -332,7 +316,7 @@ void gl_PrintStartupLog()
 	glGetIntegerv(GL_MAX_VARYING_FLOATS, &v);
 	Printf ("Max. varying: %d\n", v);
 	
-	if (gl.lightmethod != LM_SOFTWARE && !(gl.flags & RFL_SHADER_STORAGE_BUFFER))
+	if (!gl.legacyMode && !(gl.flags & RFL_SHADER_STORAGE_BUFFER))
 	{
 		glGetIntegerv(GL_MAX_UNIFORM_BLOCK_SIZE, &v);
 		Printf ("Max. uniform block size: %d\n", v);
@@ -349,7 +333,7 @@ void gl_PrintStartupLog()
 	}
 
 	// For shader-less, the special alphatexture translation must be changed to actually set the alpha, because it won't get translated by a shader.
-	if (gl.glslversion == 0)
+	if (gl.legacyMode)
 	{
 		FRemapTable *remap = translationtables[TRANSLATION_Standard][8];
 		for (int i = 0; i < 256; i++)
diff --git a/src/gl/system/gl_interface.h b/src/gl/system/gl_interface.h
index 8300b9973..edaec58c0 100644
--- a/src/gl/system/gl_interface.h
+++ b/src/gl/system/gl_interface.h
@@ -21,12 +21,10 @@ enum RenderFlags
 	RFL_BUFFER_STORAGE = 8,
 	RFL_SAMPLER_OBJECTS = 16,
 
-	RFL_NO_RGBA16F = 32,
-	RFL_NO_DEPTHSTENCIL = 64,
-	RFL_NO_CLIP_PLANES = 128,
+	RFL_NO_CLIP_PLANES = 32,
 
-	RFL_INVALIDATE_BUFFER = 256,
-	RFL_DEBUG = 512
+	RFL_INVALIDATE_BUFFER = 64,
+	RFL_DEBUG = 128
 };
 
 enum TexMode
@@ -43,15 +41,15 @@ enum TexMode
 
 enum ELightMethod
 {
-	LM_SOFTWARE = 0,	// multi-pass texturing
+	LM_LEGACY = 0,		// placeholder for legacy mode (textured lights), should not be checked anywhere in the code!
 	LM_DEFERRED = 1,	// calculate lights up front in a separate pass
 	LM_DIRECT = 2,		// calculate lights on the fly along with the render data
 };
 
 enum EBufferMethod
 {
-	BM_CLIENTARRAY = 0,	// use a client array instead of a hardware buffer
-	BM_DEFERRED = 1,	// use a temporarily mapped buffer (only necessary on GL 3.x core profile, i.e. Apple)
+	BM_LEGACY = 0,		// placeholder for legacy mode (client arrays), should not be checked anywhere in the code!
+	BM_DEFERRED = 1,	// use a temporarily mapped buffer, for GL 3.x core profile
 	BM_PERSISTENT = 2	// use a persistently mapped buffer
 };
 
@@ -64,10 +62,10 @@ struct RenderContext
 	unsigned int uniformblockalignment;
 	int lightmethod;
 	int buffermethod;
-	float version;
 	float glslversion;
 	int max_texturesize;
 	char * vendorstring;
+	bool legacyMode;
 
 	int MaxLights() const
 	{
diff --git a/src/gl/textures/gl_hqresize.cpp b/src/gl/textures/gl_hqresize.cpp
index 785f3c6e9..0af793e58 100644
--- a/src/gl/textures/gl_hqresize.cpp
+++ b/src/gl/textures/gl_hqresize.cpp
@@ -264,7 +264,7 @@ 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.glslversion == 0 && inputTexture->bWarped)
+	if (gl.legacyMode && inputTexture->bWarped)
 		return inputBuffer;
 
 	// already scaled?
diff --git a/src/gl/textures/gl_material.cpp b/src/gl/textures/gl_material.cpp
index 6ba1fe4b0..bc9dc2f52 100644
--- a/src/gl/textures/gl_material.cpp
+++ b/src/gl/textures/gl_material.cpp
@@ -296,7 +296,7 @@ const FHardwareTexture *FGLTexture::Bind(int texunit, int clampmode, int transla
 	if (translation <= 0) translation = -translation;
 	else
 	{
-		alphatrans = (gl.glslversion == 0 && translation == TRANSLATION(TRANSLATION_Standard, 8));
+		alphatrans = (gl.legacyMode && translation == TRANSLATION(TRANSLATION_Standard, 8));
 		translation = GLTranslationPalette::GetInternalTranslation(translation);
 	}
 
@@ -307,7 +307,7 @@ const FHardwareTexture *FGLTexture::Bind(int texunit, int clampmode, int transla
 	if (hwtex)
 	{
 		// Texture has become invalid
-		if ((!tex->bHasCanvas && (!tex->bWarped || gl.glslversion == 0)) && tex->CheckModified())
+		if ((!tex->bHasCanvas && (!tex->bWarped || gl.legacyMode)) && tex->CheckModified())
 		{
 			Clean(true);
 			hwtex = CreateHwTexture();
@@ -325,7 +325,7 @@ const FHardwareTexture *FGLTexture::Bind(int texunit, int clampmode, int transla
 			if (!tex->bHasCanvas)
 			{
 				buffer = CreateTexBuffer(translation, w, h, hirescheck, true, alphatrans);
-				if (tex->bWarped && gl.glslversion == 0 && w*h <= 256*256)	// do not software-warp larger textures, especially on the old systems that still need this fallback.
+				if (tex->bWarped && gl.legacyMode && w*h <= 256*256)	// do not software-warp larger textures, especially on the old systems that still need this fallback.
 				{
 					// need to do software warping
 					FWarpTexture *wt = static_cast<FWarpTexture*>(tex);
@@ -489,7 +489,7 @@ FMaterial::FMaterial(FTexture * tx, bool expanded)
 	mSpriteU[0] = mSpriteV[0] = 0.f;
 	mSpriteU[1] = mSpriteV[1] = 1.f;
 
-	FTexture *basetex = (tx->bWarped && gl.glslversion == 0)? tx : tx->GetRedirect(false);
+	FTexture *basetex = (tx->bWarped && gl.legacyMode)? tx : tx->GetRedirect(false);
 	// allow the redirect only if the textute is not expanded or the scale matches.
 	if (!expanded || (tx->Scale.X == basetex->Scale.X && tx->Scale.Y == basetex->Scale.Y))
 	{
diff --git a/src/posix/cocoa/i_common.h b/src/posix/cocoa/i_common.h
index 4a558cf24..9cedb0262 100644
--- a/src/posix/cocoa/i_common.h
+++ b/src/posix/cocoa/i_common.h
@@ -190,6 +190,9 @@ typedef NSInteger NSApplicationActivationPolicy;
 
 static const NSWindowCollectionBehavior NSWindowCollectionBehaviorFullScreenAuxiliary = NSWindowCollectionBehavior(1 << 8);
 
+static const NSOpenGLPixelFormatAttribute NSOpenGLPFAOpenGLProfile(96);
+static const NSOpenGLPixelFormatAttribute NSOpenGLProfileVersion3_2Core(0x3200);
+
 #endif // prior to 10.7
 
 #endif // COCOA_I_COMMON_INCLUDED
diff --git a/src/posix/cocoa/i_video.mm b/src/posix/cocoa/i_video.mm
index e2b59449d..f455a5f9f 100644
--- a/src/posix/cocoa/i_video.mm
+++ b/src/posix/cocoa/i_video.mm
@@ -233,7 +233,7 @@ namespace
 class CocoaVideo : public IVideo
 {
 public:
-	explicit CocoaVideo(int multisample);
+	CocoaVideo();
 
 	virtual EDisplayType GetDisplayType() { return DISPLAY_Both; }
 	virtual void SetWindowedScale(float scale);
@@ -465,7 +465,7 @@ CocoaWindow* CreateCocoaWindow(const NSUInteger styleMask)
 // ---------------------------------------------------------------------------
 
 
-CocoaVideo::CocoaVideo(const int multisample)
+CocoaVideo::CocoaVideo()
 : m_window(CreateCocoaWindow(STYLE_MASK_WINDOWED))
 , m_width(-1)
 , m_height(-1)
@@ -492,13 +492,10 @@ CocoaVideo::CocoaVideo(const int multisample)
 		attributes[i++] = NSOpenGLPFAAllowOfflineRenderers;
 	}
 
-	if (multisample)
+	if (NSAppKitVersionNumber >= AppKit10_7)
 	{
-		attributes[i++] = NSOpenGLPFAMultisample;
-		attributes[i++] = NSOpenGLPFASampleBuffers;
-		attributes[i++] = NSOpenGLPixelFormatAttribute(1);
-		attributes[i++] = NSOpenGLPFASamples;
-		attributes[i++] = NSOpenGLPixelFormatAttribute(multisample);
+		attributes[i++] = NSOpenGLPFAOpenGLProfile;
+		attributes[i++] = NSOpenGLProfileVersion3_2Core;
 	}
 
 	attributes[i] = NSOpenGLPixelFormatAttribute(0);
@@ -1254,7 +1251,7 @@ void I_InitGraphics()
 	val.Bool = !!Args->CheckParm("-devparm");
 	ticker.SetGenericRepDefault(val, CVAR_Bool);
 
-	Video = new CocoaVideo(0);
+	Video = new CocoaVideo;
 	atterm(I_ShutdownGraphics);
 }
 
diff --git a/src/win32/win32gliface.cpp b/src/win32/win32gliface.cpp
index 494d94233..7ca001e1e 100644
--- a/src/win32/win32gliface.cpp
+++ b/src/win32/win32gliface.cpp
@@ -748,11 +748,9 @@ bool Win32GLVideo::InitHardware (HWND Window, int multisample)
 	}
 
 	int prof = WGL_CONTEXT_CORE_PROFILE_BIT_ARB;
-	const char *lm = Args->CheckValue("-buffermethod");
-	if (lm != NULL)
-	{
-		if (!stricmp(lm, "clientarray")) prof = WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB;
-	}
+	const char *version = Args->CheckValue("-glversion");
+
+	if (version != nullptr && strcmp(version, "3.0") < 0) prof = WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB;
 
 	for (; prof <= WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB; prof++)
 	{
diff --git a/wadsrc/static/shaders/glsl/colormap.fp b/wadsrc/static/shaders/glsl/colormap.fp
new file mode 100644
index 000000000..e86429c37
--- /dev/null
+++ b/wadsrc/static/shaders/glsl/colormap.fp
@@ -0,0 +1,16 @@
+
+in vec2 TexCoord;
+out vec4 FragColor;
+
+uniform sampler2D tex;
+uniform vec4 uFixedColormapStart;
+uniform vec4 uFixedColormapRange;
+
+void main()
+{
+	vec4 frag = texture(tex, TexCoord);
+	float gray = (frag.r * 0.3 + frag.g * 0.56 + frag.b * 0.14);	
+	vec4 cm = uFixedColormapStart + gray * uFixedColormapRange;
+	FragColor = vec4(clamp(cm.rgb, 0.0, 1.0), frag.a);
+}
+
diff --git a/wadsrc/static/shaders/glsl/main.fp b/wadsrc/static/shaders/glsl/main.fp
index 2a783e00c..84b7f5742 100644
--- a/wadsrc/static/shaders/glsl/main.fp
+++ b/wadsrc/static/shaders/glsl/main.fp
@@ -133,32 +133,6 @@ vec4 desaturate(vec4 texel)
 //
 //===========================================================================
 
-#ifdef GLSL12_COMPATIBLE
-vec4 getTexel(vec2 st)
-{
-	vec4 texel = texture(tex, st);
-	
-	//
-	// Apply texture modes
-	//
-	if (uTextureMode != 0)
-	{
-		if (uTextureMode == 1) texel.rgb = vec3(1.0,1.0,1.0);
-		else if (uTextureMode == 2) texel.a = 1.0;
-		else if (uTextureMode == 3) texel = vec4(1.0-texel.r, 1.0-texel.b, 1.0-texel.g, texel.a);
-		else if (uTextureMode == 4) texel = vec4(1.0, 1.0, 1.0, texel.r*texel.a);
-		else if (uTextureMode == 5)
-		{
-			if (st.t < 0.0 || st.t > 1.0)
-			{
-				texel.a = 0.0;
-			}
-		}
-	}
-	texel *= uObjectColor;
-	return desaturate(texel);
-}
-#else
 vec4 getTexel(vec2 st)
 {
 	vec4 texel = texture(tex, st);
@@ -195,7 +169,6 @@ vec4 getTexel(vec2 st)
 
 	return desaturate(texel);
 }
-#endif
 
 //===========================================================================
 //
diff --git a/wadsrc/static/shaders/glsl/tonemap.fp b/wadsrc/static/shaders/glsl/tonemap.fp
index 5a84ca5a4..c33349a38 100644
--- a/wadsrc/static/shaders/glsl/tonemap.fp
+++ b/wadsrc/static/shaders/glsl/tonemap.fp
@@ -70,17 +70,10 @@ uniform sampler2D PaletteLUT;
 vec3 Tonemap(vec3 color)
 {
 	ivec3 c = ivec3(clamp(color.rgb, vec3(0.0), vec3(1.0)) * 255.0 + 0.5);
-#if __VERSION__ < 130
-	int index = (c.r / 4 * 64 + c.g / 4) * 64 + c.b / 4;
-	float tx = mod(index, 512) / 512.0;
-	float ty = float(index / 512) / 512.0;
-	return texture2D(PaletteLUT, vec2(tx, ty)).rgb;
-#else
 	int index = ((c.r >> 2) * 64 + (c.g >> 2)) * 64 + (c.b >> 2);
 	int tx = index % 512;
 	int ty = index / 512;
 	return texelFetch(PaletteLUT, ivec2(tx, ty), 0).rgb;
-#endif
 }
 
 #else