From b7ec26335f8c8fd0e223e3f268c2b7d2258e5b07 Mon Sep 17 00:00:00 2001
From: "alexey.lysiuk" <alexey.lysiuk@gmail.com>
Date: Mon, 29 Aug 2016 22:03:25 +0300
Subject: [PATCH 1/8] Enabled OpenGL Core Profile on macOS

---
 src/posix/cocoa/i_common.h | 3 +++
 src/posix/cocoa/i_video.mm | 6 ++++++
 2 files changed, 9 insertions(+)

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..b026fa9b9 100644
--- a/src/posix/cocoa/i_video.mm
+++ b/src/posix/cocoa/i_video.mm
@@ -501,6 +501,12 @@ CocoaVideo::CocoaVideo(const int multisample)
 		attributes[i++] = NSOpenGLPixelFormatAttribute(multisample);
 	}
 
+	if (NSAppKitVersionNumber >= AppKit10_7)
+	{
+		attributes[i++] = NSOpenGLPFAOpenGLProfile;
+		attributes[i++] = NSOpenGLProfileVersion3_2Core;
+	}
+
 	attributes[i] = NSOpenGLPixelFormatAttribute(0);
 
 	// Create OpenGL context and view

From 3ba3149df35f858e135b1d49cceeecc6d6910d1a Mon Sep 17 00:00:00 2001
From: "alexey.lysiuk" <alexey.lysiuk@gmail.com>
Date: Mon, 29 Aug 2016 22:08:57 +0300
Subject: [PATCH 2/8] Deleted remains of obsolete multisampling in Cocoa
 backend

---
 src/posix/cocoa/i_video.mm | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/src/posix/cocoa/i_video.mm b/src/posix/cocoa/i_video.mm
index b026fa9b9..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)
@@ -492,15 +492,6 @@ CocoaVideo::CocoaVideo(const int multisample)
 		attributes[i++] = NSOpenGLPFAAllowOfflineRenderers;
 	}
 
-	if (multisample)
-	{
-		attributes[i++] = NSOpenGLPFAMultisample;
-		attributes[i++] = NSOpenGLPFASampleBuffers;
-		attributes[i++] = NSOpenGLPixelFormatAttribute(1);
-		attributes[i++] = NSOpenGLPFASamples;
-		attributes[i++] = NSOpenGLPixelFormatAttribute(multisample);
-	}
-
 	if (NSAppKitVersionNumber >= AppKit10_7)
 	{
 		attributes[i++] = NSOpenGLPFAOpenGLProfile;
@@ -1260,7 +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);
 }
 

From 45ff15559dc713248bcde7fa44a68f5b78219d68 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Tue, 30 Aug 2016 00:33:02 +0200
Subject: [PATCH 3/8] - removed gl_draw_synv because with the postprocessing
 this is no longer useful.

---
 src/gl/scene/gl_scene.cpp        | 9 ---------
 src/gl/scene/gl_walls.cpp        | 1 -
 src/gl/system/gl_framebuffer.cpp | 8 +-------
 3 files changed, 1 insertion(+), 17 deletions(-)

diff --git a/src/gl/scene/gl_scene.cpp b/src/gl/scene/gl_scene.cpp
index 08591283c..c2812db0f 100644
--- a/src/gl/scene/gl_scene.cpp
+++ b/src/gl/scene/gl_scene.cpp
@@ -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
diff --git a/src/gl/scene/gl_walls.cpp b/src/gl/scene/gl_walls.cpp
index 3afde063c..5b2271433 100644
--- a/src/gl/scene/gl_walls.cpp
+++ b/src/gl/scene/gl_walls.cpp
@@ -142,7 +142,6 @@ void GLWall::PutWall(bool translucent)
 	{
 		if (gl.lightmethod == LM_SOFTWARE && !translucent)
 		{
-			// This is not yet ready.
 			if (PutWallCompat(passflag[type])) return;
 		}
 
diff --git a/src/gl/system/gl_framebuffer.cpp b/src/gl/system/gl_framebuffer.cpp
index ae1fabaed..ec77cfd14 100644
--- a/src/gl/system/gl_framebuffer.cpp
+++ b/src/gl/system/gl_framebuffer.cpp
@@ -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();

From 4a0e0828366dda0fb6de69b734c4e190ba9c6026 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Wed, 31 Aug 2016 23:26:49 +0200
Subject: [PATCH 4/8] - fixed: The wall splitter in the translucent sorting
 code needs to set fracleft and fracright so that vertex generation is done
 correctly for the split segments.

---
 src/gl/scene/gl_drawinfo.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/gl/scene/gl_drawinfo.cpp b/src/gl/scene/gl_drawinfo.cpp
index 842423094..d5ed62755 100644
--- a/src/gl/scene/gl_drawinfo.cpp
+++ b/src/gl/scene/gl_drawinfo.cpp
@@ -476,6 +476,7 @@ 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;

From 3389a5a74edbc240a6618336b1cf917cea4144b1 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Thu, 1 Sep 2016 11:52:52 +0200
Subject: [PATCH 5/8] - removed most of the specific options for legacy
 hardware and consolidated them in one variable (does not work yet.)

---
 src/gl/compatibility/gl_20.cpp        |  35 +----
 src/gl/data/gl_vertexbuffer.cpp       |  27 ++--
 src/gl/models/gl_models.cpp           |  10 +-
 src/gl/renderer/gl_postprocess.cpp    |   6 +-
 src/gl/renderer/gl_renderbuffers.cpp  |  17 +--
 src/gl/renderer/gl_renderer.cpp       |   6 +-
 src/gl/renderer/gl_renderstate.cpp    |   4 +-
 src/gl/renderer/gl_renderstate.h      |   2 +-
 src/gl/scene/gl_drawinfo.cpp          |  17 ++-
 src/gl/scene/gl_drawinfo.h            |   2 -
 src/gl/scene/gl_flats.cpp             |   4 +-
 src/gl/scene/gl_scene.cpp             |  12 +-
 src/gl/scene/gl_skydome.cpp           |   4 +-
 src/gl/scene/gl_sprite.cpp            |   2 +-
 src/gl/scene/gl_walls.cpp             |   2 +-
 src/gl/scene/gl_walls_draw.cpp        |   9 +-
 src/gl/shaders/gl_blurshader.cpp      |  22 ---
 src/gl/shaders/gl_shader.cpp          |  50 +++----
 src/gl/shaders/gl_shaderprogram.cpp   |  50 +------
 src/gl/shaders/gl_shaderprogram.h     |   5 -
 src/gl/system/gl_framebuffer.cpp      |   2 +-
 src/gl/system/gl_interface.cpp        | 194 ++++++++++++--------------
 src/gl/system/gl_interface.h          |  16 +--
 src/gl/textures/gl_hqresize.cpp       |   2 +-
 src/gl/textures/gl_material.cpp       |   8 +-
 wadsrc/static/shaders/glsl/main.fp    |  27 ----
 wadsrc/static/shaders/glsl/tonemap.fp |   7 -
 27 files changed, 182 insertions(+), 360 deletions(-)

diff --git a/src/gl/compatibility/gl_20.cpp b/src/gl/compatibility/gl_20.cpp
index 8e6682f17..97abc0d82 100644
--- a/src/gl/compatibility/gl_20.cpp
+++ b/src/gl/compatibility/gl_20.cpp
@@ -66,7 +66,7 @@
 
 void gl_PatchMenu()
 {
-	if (gl.glslversion == 0)
+	if (gl.legacyMode)
 	{
 		// Radial fog and Doom lighting are not available without full shader support.
 
@@ -99,6 +99,8 @@ void gl_PatchMenu()
 		// 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 +380,7 @@ 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 +436,6 @@ 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 +485,6 @@ 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 +509,6 @@ 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 +597,7 @@ 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 +677,7 @@ 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 +783,7 @@ 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 +806,8 @@ 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 +822,6 @@ 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 +833,8 @@ 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_postprocess.cpp b/src/gl/renderer/gl_postprocess.cpp
index 3a83f4caf..047153554 100644
--- a/src/gl/renderer/gl_postprocess.cpp
+++ b/src/gl/renderer/gl_postprocess.cpp
@@ -126,7 +126,7 @@ void FGLRenderer::RenderScreenQuad()
 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)
+	if (!gl_bloom || gl_fixedcolormap != CM_DEFAULT)
 		return;
 
 	FGLDebug::PushGroup("BloomScene");
@@ -212,7 +212,7 @@ void FGLRenderer::BloomScene()
 
 void FGLRenderer::TonemapScene()
 {
-	if (gl_tonemap == 0 || !FGLRenderBuffers::IsEnabled())
+	if (gl_tonemap == 0)
 		return;
 
 	FGLDebug::PushGroup("TonemapScene");
@@ -292,7 +292,7 @@ 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 fd98522d8..f8b5dfcdd 100644
--- a/src/gl/renderer/gl_renderbuffers.cpp
+++ b/src/gl/renderer/gl_renderbuffers.cpp
@@ -218,17 +218,8 @@ void FGLRenderBuffers::CreateScene(int width, int height, int samples)
 	if (samples > 1)
 		mSceneMultisample = CreateRenderBuffer("SceneMultisample", GetHdrFormat(), samples, width, height);
 
-	if ((gl.flags & RFL_NO_DEPTHSTENCIL) != 0)
-	{
-		mSceneDepth = CreateRenderBuffer("SceneDepth", GL_DEPTH_COMPONENT24, samples, width, height);
-		mSceneStencil = CreateRenderBuffer("SceneStencil", GL_STENCIL_INDEX8, samples, width, height);
-		mSceneFB = CreateFrameBuffer("SceneFB", samples > 1 ? mSceneMultisample : mPipelineTexture[0], mSceneDepth, mSceneStencil, samples > 1);
-	}
-	else
-	{
-		mSceneDepthStencil = CreateRenderBuffer("SceneDepthStencil", GL_DEPTH24_STENCIL8, samples, width, height);
-		mSceneFB = CreateFrameBuffer("SceneFB", samples > 1 ? mSceneMultisample : mPipelineTexture[0], mSceneDepthStencil, samples > 1);
-	}
+	mSceneDepthStencil = CreateRenderBuffer("SceneDepthStencil", GL_DEPTH24_STENCIL8, samples, width, height);
+	mSceneFB = CreateFrameBuffer("SceneFB", samples > 1 ? mSceneMultisample : mPipelineTexture[0], mSceneDepthStencil, samples > 1);
 }
 
 //==========================================================================
@@ -288,7 +279,7 @@ void FGLRenderBuffers::CreateBloom(int width, int height)
 
 GLuint FGLRenderBuffers::GetHdrFormat()
 {
-	return ((gl.flags & RFL_NO_RGBA16F) != 0) ? GL_RGBA8 : GL_RGBA16F;
+	return GL_RGBA16F;
 }
 
 //==========================================================================
@@ -559,7 +550,7 @@ 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_renderer.cpp b/src/gl/renderer/gl_renderer.cpp
index c8f2eb224..20126ba77 100644
--- a/src/gl/renderer/gl_renderer.cpp
+++ b/src/gl/renderer/gl_renderer.cpp
@@ -129,8 +129,8 @@ void FGLRenderer::Initialize(int width, int height)
 	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);
@@ -145,7 +145,7 @@ 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;
diff --git a/src/gl/renderer/gl_renderstate.cpp b/src/gl/renderer/gl_renderstate.cpp
index 7fda92428..caf276d37 100644
--- a/src/gl/renderer/gl_renderstate.cpp
+++ b/src/gl/renderer/gl_renderstate.cpp
@@ -314,7 +314,7 @@ void FRenderState::Apply()
 		else mVertexBuffer->BindVBO();
 		mCurrentVertexBuffer = mVertexBuffer;
 	}
-	if (gl.glslversion > 0) 
+	if (!gl.legacyMode) 
 	{
 		ApplyShader();
 	}
@@ -351,7 +351,7 @@ 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 d5ed62755..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];
@@ -480,6 +480,11 @@ void GLDrawList::SortWallIntoWall(SortNode * head,SortNode * sort)
 		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));
@@ -806,17 +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);
@@ -995,7 +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 c2812db0f..7d634054a 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();
@@ -681,7 +681,7 @@ void FGLRenderer::EndDrawScene(sector_t * viewsector)
 	gl_RenderState.SetSoftLightLevel(-1);
 	DrawTargeterSprites();
 	DrawBlend(viewsector);
-	if (gl.glslversion == 0.0)
+	if (gl.legacyMode)
 	{
 		gl_RenderState.SetFixedColormap(cm);
 		gl_RenderState.DrawColormapOverlay();
@@ -846,9 +846,9 @@ 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)
+		if (mainview && FGLRenderBuffers::IsEnabled())
 		{
-			if (FGLRenderBuffers::IsEnabled()) mBuffers->BlitSceneToTexture();
+			mBuffers->BlitSceneToTexture();
 			BloomScene();
 			TonemapScene();
 			LensDistortScene();
@@ -896,7 +896,7 @@ 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;
@@ -951,7 +951,7 @@ 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 5b2271433..f8bb2a876 100644
--- a/src/gl/scene/gl_walls.cpp
+++ b/src/gl/scene/gl_walls.cpp
@@ -140,7 +140,7 @@ void GLWall::PutWall(bool translucent)
 	}
 	else
 	{
-		if (gl.lightmethod == LM_SOFTWARE && !translucent)
+		if (gl.legacyMode && !translucent)
 		{
 			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_shader.cpp b/src/gl/shaders/gl_shader.cpp
index 8ac2b7093..3c574bd62 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.
@@ -273,7 +255,7 @@ 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);
@@ -424,7 +406,7 @@ static const FEffectShader effectshaders[]=
 
 FShaderManager::FShaderManager()
 {
-	if (gl.glslversion > 0) CompileShaders();
+	if (!gl.legacyMode) CompileShaders();
 }
 
 //==========================================================================
@@ -435,7 +417,7 @@ FShaderManager::FShaderManager()
 
 FShaderManager::~FShaderManager()
 {
-	if (gl.glslversion > 0) Clean();
+	if (!gl.legacyMode) Clean();
 }
 
 //==========================================================================
@@ -577,7 +559,7 @@ 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 ec77cfd14..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);
 
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/wadsrc/static/shaders/glsl/main.fp b/wadsrc/static/shaders/glsl/main.fp
index b10c99a17..95ac874b7 100644
--- a/wadsrc/static/shaders/glsl/main.fp
+++ b/wadsrc/static/shaders/glsl/main.fp
@@ -51,32 +51,6 @@ 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);
@@ -113,7 +87,6 @@ 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

From 7efae2c8f8c5940d2bfb27047e6f87f1c1249088 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Thu, 1 Sep 2016 12:14:20 +0200
Subject: [PATCH 6/8] - fixed: When requesting GL version 2.x, do not try to
 create a core profile context, because that can not support legacy features.

---
 src/win32/win32gliface.cpp | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

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++)
 	{

From 589936f570b43a75df8c44892e1fdd917956e915 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Thu, 1 Sep 2016 17:14:51 +0200
Subject: [PATCH 7/8] - draw the colormap blend after postprocessing, not
 before it. - added colormap shader to postprocessing.

This replaces the in-place application of fullscreen colormaps if renderbuffers are active. This way the fully composed scene gets inverted, not each element on its own which is highly problematic for additively blended things.
---
 src/CMakeLists.txt                     |  1 +
 src/gl/compatibility/gl_20.cpp         | 57 +++++++++++-----------
 src/gl/renderer/gl_lightdata.cpp       |  2 +-
 src/gl/renderer/gl_postprocess.cpp     | 33 +++++++++++++
 src/gl/renderer/gl_renderbuffers.cpp   |  9 +++-
 src/gl/renderer/gl_renderer.cpp        | 26 +++++++---
 src/gl/renderer/gl_renderer.h          |  3 ++
 src/gl/renderer/gl_renderstate.cpp     | 24 ++++++---
 src/gl/scene/gl_scene.cpp              | 19 +++++---
 src/gl/shaders/gl_colormapshader.cpp   | 67 ++++++++++++++++++++++++++
 src/gl/shaders/gl_colormapshader.h     | 20 ++++++++
 wadsrc/static/shaders/glsl/colormap.fp | 16 ++++++
 12 files changed, 224 insertions(+), 53 deletions(-)
 create mode 100644 src/gl/shaders/gl_colormapshader.cpp
 create mode 100644 src/gl/shaders/gl_colormapshader.h
 create mode 100644 wadsrc/static/shaders/glsl/colormap.fp

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 03f3372f0..dfac22fe0 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1114,6 +1114,7 @@ set( FASTMATH_SOURCES
 	gl/shaders/gl_presentshader.cpp
 	gl/shaders/gl_bloomshader.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 97abc0d82..fdda99130 100644
--- a/src/gl/compatibility/gl_20.cpp
+++ b/src/gl/compatibility/gl_20.cpp
@@ -66,42 +66,39 @@
 
 void gl_PatchMenu()
 {
-	if (gl.legacyMode)
+	// 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;
-
-		// todo: remove more unsupported stuff like postprocessing options.
 	}
+
+	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.
 }
 
 
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 047153554..77ee5cd79 100644
--- a/src/gl/renderer/gl_postprocess.cpp
+++ b/src/gl/renderer/gl_postprocess.cpp
@@ -71,6 +71,7 @@
 #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"
@@ -284,6 +285,38 @@ 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
diff --git a/src/gl/renderer/gl_renderbuffers.cpp b/src/gl/renderer/gl_renderbuffers.cpp
index f8b5dfcdd..35be00abc 100644
--- a/src/gl/renderer/gl_renderbuffers.cpp
+++ b/src/gl/renderer/gl_renderbuffers.cpp
@@ -55,7 +55,14 @@
 #include "doomerrors.h"
 
 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();
+	}
+}
 
 //==========================================================================
 //
diff --git a/src/gl/renderer/gl_renderer.cpp b/src/gl/renderer/gl_renderer.cpp
index 20126ba77..6cd38390f 100644
--- a/src/gl/renderer/gl_renderer.cpp
+++ b/src/gl/renderer/gl_renderer.cpp
@@ -67,6 +67,7 @@
 #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"
@@ -97,21 +98,30 @@ 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();
@@ -124,6 +134,7 @@ 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();
@@ -184,6 +195,7 @@ 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 4b663680f..120f6a449 100644
--- a/src/gl/renderer/gl_renderer.h
+++ b/src/gl/renderer/gl_renderer.h
@@ -23,6 +23,7 @@ class FBloomExtractShader;
 class FBloomCombineShader;
 class FBlurShader;
 class FTonemapShader;
+class FColormapShader;
 class FLensShader;
 class FPresentShader;
 class F2DDrawer;
@@ -93,6 +94,7 @@ public:
 	FBloomCombineShader *mBloomCombineShader;
 	FBlurShader *mBlurShader;
 	FTonemapShader *mTonemapShader;
+	FColormapShader *mColormapShader;
 	FHardwareTexture *mTonemapPalette;
 	FLensShader *mLensShader;
 	FPresentShader *mPresentShader;
@@ -166,6 +168,7 @@ public:
 	void EndDrawScene(sector_t * viewsector);
 	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 caf276d37..c3cc905e5 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);
 
@@ -220,15 +221,24 @@ 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)
 		{
diff --git a/src/gl/scene/gl_scene.cpp b/src/gl/scene/gl_scene.cpp
index 7d634054a..ab3fe744d 100644
--- a/src/gl/scene/gl_scene.cpp
+++ b/src/gl/scene/gl_scene.cpp
@@ -635,9 +635,9 @@ 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();
 	}
@@ -676,16 +676,19 @@ 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.legacyMode)
+	if (FGLRenderBuffers::IsEnabled())
 	{
-		gl_RenderState.SetFixedColormap(cm);
-		gl_RenderState.DrawColormapOverlay();
-		gl_RenderState.SetFixedColormap(CM_DEFAULT);
+		DrawBlend(viewsector);
 	}
 
 	// Restore standard rendering state
@@ -851,7 +854,9 @@ sector_t * FGLRenderer::RenderViewpoint (AActor * camera, GL_IRECT * bounds, flo
 			mBuffers->BlitSceneToTexture();
 			BloomScene();
 			TonemapScene();
+			ColormapScene();
 			LensDistortScene();
+			DrawBlend(viewsector);	// This should be done after postprocessing, not before.
 		}
 		mDrawingScene2D = false;
 		eye->TearDown();
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/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);
+}
+

From 4e8027612ff40ec71d1717171dddb3dc253cb16c Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Thu, 1 Sep 2016 17:38:17 +0200
Subject: [PATCH 8/8] - restored 2 lines of code that somehow got lost before
 the last commit.

---
 src/gl/scene/gl_scene.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/gl/scene/gl_scene.cpp b/src/gl/scene/gl_scene.cpp
index ab3fe744d..c1f022ab0 100644
--- a/src/gl/scene/gl_scene.cpp
+++ b/src/gl/scene/gl_scene.cpp
@@ -641,6 +641,8 @@ void FGLRenderer::DrawBlend(sector_t * viewsector)
 		gl_RenderState.SetColor(blend[0], blend[1], blend[2], blend[3]);
 		gl_FillScreen();
 	}
+	gl_RenderState.ResetColor();
+	gl_RenderState.EnableTexture(true);
 }