diff --git a/src/gl/data/gl_vertexbuffer.cpp b/src/gl/data/gl_vertexbuffer.cpp
index 223fb67f87..a0865c435e 100644
--- a/src/gl/data/gl_vertexbuffer.cpp
+++ b/src/gl/data/gl_vertexbuffer.cpp
@@ -57,12 +57,10 @@
 //
 //==========================================================================
 
-FVertexBuffer::FVertexBuffer()
+FVertexBuffer::FVertexBuffer(bool wantbuffer)
 {
-	vao_id = vbo_id = 0;
-	glGenBuffers(1, &vbo_id);
-	glGenVertexArrays(1, &vao_id);
-
+	vbo_id = 0;
+	if (wantbuffer) glGenBuffers(1, &vbo_id);
 }
 	
 FVertexBuffer::~FVertexBuffer()
@@ -71,15 +69,6 @@ FVertexBuffer::~FVertexBuffer()
 	{
 		glDeleteBuffers(1, &vbo_id);
 	}
-	if (vao_id != 0)
-	{
-		glDeleteVertexArrays(1, &vao_id);
-	}
-}
-
-void FVertexBuffer::BindVBO()
-{
-	glBindVertexArray(vao_id);
 }
 
 //==========================================================================
@@ -89,7 +78,7 @@ void FVertexBuffer::BindVBO()
 //==========================================================================
 
 FFlatVertexBuffer::FFlatVertexBuffer()
-: FVertexBuffer()
+: FVertexBuffer(!!(gl.flags & RFL_BUFFER_STORAGE))
 {
 	if (gl.flags & RFL_BUFFER_STORAGE)
 	{
@@ -97,17 +86,10 @@ FFlatVertexBuffer::FFlatVertexBuffer()
 		glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
 		glBufferStorage(GL_ARRAY_BUFFER, bytesize, NULL, GL_MAP_WRITE_BIT | GL_MAP_PERSISTENT_BIT | GL_MAP_COHERENT_BIT);
 		map = (FFlatVertex*)glMapBufferRange(GL_ARRAY_BUFFER, 0, bytesize, GL_MAP_WRITE_BIT | GL_MAP_PERSISTENT_BIT | GL_MAP_COHERENT_BIT);
-
-		glBindVertexArray(vao_id);
-		glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
-		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);
-		glBindVertexArray(0);
 	}
 	else
 	{
+		// The fallback path uses immediate mode rendering and does not set up an actual vertex buffer
 		vbo_shadowdata.Reserve(BUFFER_SIZE);
 		map = &vbo_shadowdata[0];
 	}
@@ -124,6 +106,26 @@ FFlatVertexBuffer::~FFlatVertexBuffer()
 	}
 }
 
+
+void FFlatVertexBuffer::BindVBO()
+{
+	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
+	if (vbo_id != 0)	// set this up only if there is an actual buffer.
+	{
+		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);
+	}
+	else
+	{
+		glDisableVertexAttribArray(VATTR_VERTEX);
+		glDisableVertexAttribArray(VATTR_TEXCOORD);
+	}
+	glDisableVertexAttribArray(VATTR_COLOR);
+	glDisableVertexAttribArray(VATTR_VERTEX2);
+}
+
 //==========================================================================
 //
 // immediate mode fallback for drivers without GL_ARB_buffer_storage
@@ -138,7 +140,7 @@ void FFlatVertexBuffer::ImmRenderBuffer(unsigned int primtype, unsigned int offs
 	// this will only get called if we can't acquire a persistently mapped buffer.
 #ifndef CORE_PROFILE
 	glBegin(primtype);
-	if (gl.compatibility > CMPT_GL2)
+	if (gl.glslversion > 0)
 	{
 		for (unsigned int i = 0; i < count; i++)
 		{
diff --git a/src/gl/data/gl_vertexbuffer.h b/src/gl/data/gl_vertexbuffer.h
index 12b536f105..c56cadcbac 100644
--- a/src/gl/data/gl_vertexbuffer.h
+++ b/src/gl/data/gl_vertexbuffer.h
@@ -15,12 +15,11 @@ class FVertexBuffer
 {
 protected:
 	unsigned int vbo_id;
-	unsigned int vao_id;
 
 public:
-	FVertexBuffer();
+	FVertexBuffer(bool wantbuffer = true);
 	virtual ~FVertexBuffer();
-	void BindVBO();
+	virtual void BindVBO() = 0;
 };
 
 struct FFlatVertex
@@ -37,6 +36,7 @@ struct FFlatVertex
 		u = uu;
 		v = vv;
 	}
+	void BindVBO();
 };
 
 #define VTO ((FFlatVertex*)NULL)
@@ -62,6 +62,8 @@ public:
 	FFlatVertexBuffer();
 	~FFlatVertexBuffer();
 
+	void BindVBO();
+
 	void CreateVBO();
 	void CheckUpdate(sector_t *sector);
 
@@ -165,6 +167,7 @@ public:
 	FSkyVertexBuffer();
 	virtual ~FSkyVertexBuffer();
 	void RenderDome(FMaterial *tex, int mode);
+	void BindVBO();
 
 };
 
@@ -208,6 +211,7 @@ public:
 	void UnlockIndexBuffer();
 
 	unsigned int SetupFrame(unsigned int frame1, unsigned int frame2);
+	void BindVBO();
 };
 
 #define VMO ((FModelVertex*)NULL)
diff --git a/src/gl/models/gl_models.cpp b/src/gl/models/gl_models.cpp
index 6050ac24d4..abf3efcd5b 100644
--- a/src/gl/models/gl_models.cpp
+++ b/src/gl/models/gl_models.cpp
@@ -117,20 +117,27 @@ void gl_FlushModels()
 
 FModelVertexBuffer::FModelVertexBuffer(bool needindex)
 {
-	glBindVertexArray(vao_id);
-
 	ibo_id = 0;
 	if (needindex)
 	{
 		glGenBuffers(1, &ibo_id);
-		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo_id);
 	}
+}
 
+//===========================================================================
+//
+//
+//
+//===========================================================================
+
+void FModelVertexBuffer::BindVBO()
+{
+	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo_id);
 	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
 	glEnableVertexAttribArray(VATTR_VERTEX);
 	glEnableVertexAttribArray(VATTR_TEXCOORD);
 	glEnableVertexAttribArray(VATTR_VERTEX2);
-	glBindVertexArray(0);
+	glDisableVertexAttribArray(VATTR_COLOR);
 }
 
 //===========================================================================
diff --git a/src/gl/renderer/gl_renderer.cpp b/src/gl/renderer/gl_renderer.cpp
index 3e198b1a04..cca2e9b2bc 100644
--- a/src/gl/renderer/gl_renderer.cpp
+++ b/src/gl/renderer/gl_renderer.cpp
@@ -103,6 +103,14 @@ void gl_FlushModels();
 
 void FGLRenderer::Initialize()
 {
+	// Only needed for the core profile, because someone decided it was a good idea to remove the default VAO.
+	if (gl.version >= 4.0)
+	{
+		glGenVertexArrays(1, &mVAOID);
+		glBindVertexArray(mVAOID);
+	}
+	else mVAOID = 0;
+
 	glpart2 = FTexture::CreateTexture(Wads.GetNumForFullName("glstuff/glpart2.png"), FTexture::TEX_MiscPatch);
 	glpart = FTexture::CreateTexture(Wads.GetNumForFullName("glstuff/glpart.png"), FTexture::TEX_MiscPatch);
 	mirrortexture = FTexture::CreateTexture(Wads.GetNumForFullName("glstuff/mirror.png"), FTexture::TEX_MiscPatch);
@@ -113,6 +121,7 @@ void FGLRenderer::Initialize()
 	else mLights = NULL;
 	gl_RenderState.SetVertexBuffer(mVBO);
 	mFBID = 0;
+
 	SetupLevel();
 	mShaderManager = new FShaderManager;
 	mSamplerManager = new FSamplerManager;
@@ -133,6 +142,12 @@ FGLRenderer::~FGLRenderer()
 	if (glpart) delete glpart;
 	if (mirrortexture) delete mirrortexture;
 	if (mFBID != 0) glDeleteFramebuffers(1, &mFBID);
+	if (mVAOID != 0)
+	{
+		glBindVertexArray(0);
+		glDeleteVertexArrays(1, &mVAOID);
+	}
+
 }
 
 //===========================================================================
diff --git a/src/gl/renderer/gl_renderer.h b/src/gl/renderer/gl_renderer.h
index a2f4c7d349..f266bcd370 100644
--- a/src/gl/renderer/gl_renderer.h
+++ b/src/gl/renderer/gl_renderer.h
@@ -69,6 +69,7 @@ public:
 	FSamplerManager *mSamplerManager;
 	int gl_spriteindex;
 	unsigned int mFBID;
+	unsigned int mVAOID;
 
 	FTexture *glpart2;
 	FTexture *glpart;
diff --git a/src/gl/renderer/gl_renderstate.cpp b/src/gl/renderer/gl_renderstate.cpp
index 892e384e76..1398191e12 100644
--- a/src/gl/renderer/gl_renderstate.cpp
+++ b/src/gl/renderer/gl_renderstate.cpp
@@ -279,7 +279,7 @@ void FRenderState::Apply()
 		else mVertexBuffer->BindVBO();
 		mCurrentVertexBuffer = mVertexBuffer;
 	}
-	if (gl.compatibility > CMPT_GL2) 
+	if (gl.glslversion > 0) 
 	{
 		ApplyShader();
 	}
diff --git a/src/gl/scene/gl_skydome.cpp b/src/gl/scene/gl_skydome.cpp
index 69968ddf7f..ae78b0291a 100644
--- a/src/gl/scene/gl_skydome.cpp
+++ b/src/gl/scene/gl_skydome.cpp
@@ -78,8 +78,14 @@ extern int skyfog;
 FSkyVertexBuffer::FSkyVertexBuffer()
 {
 	CreateDome();
+}
 
-	glBindVertexArray(vao_id);
+FSkyVertexBuffer::~FSkyVertexBuffer()
+{
+}
+
+void FSkyVertexBuffer::BindVBO()
+{
 	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
 	glVertexAttribPointer(VATTR_VERTEX, 3, GL_FLOAT, false, sizeof(FSkyVertex), &VSO->x);
 	glVertexAttribPointer(VATTR_TEXCOORD, 2, GL_FLOAT, false, sizeof(FSkyVertex), &VSO->u);
@@ -87,12 +93,7 @@ FSkyVertexBuffer::FSkyVertexBuffer()
 	glEnableVertexAttribArray(VATTR_VERTEX);
 	glEnableVertexAttribArray(VATTR_TEXCOORD);
 	glEnableVertexAttribArray(VATTR_COLOR);
-	glBindVertexArray(0);
-
-}
-
-FSkyVertexBuffer::~FSkyVertexBuffer()
-{
+	glDisableVertexAttribArray(VATTR_VERTEX2);
 }
 
 //-----------------------------------------------------------------------------
diff --git a/src/gl/shaders/gl_shader.cpp b/src/gl/shaders/gl_shader.cpp
index 4a82251d0e..af6accdb57 100644
--- a/src/gl/shaders/gl_shader.cpp
+++ b/src/gl/shaders/gl_shader.cpp
@@ -129,7 +129,7 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 
 	if (gl.lightmethod == LM_SOFTWARE)
 	{
-		if (gl.compatibility >= CMPT_GL3)
+		if (gl.glslversion >= 1.3)
 		{
 			vp_comb = "#version 130\n";
 		}
@@ -201,7 +201,7 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 		}
 	}
 
-	if (gl.compatibility < CMPT_GL3)
+	if (gl.glslversion < 1.3)
 	{
 		PatchVertShader(vp_comb);
 		PatchFragShader(fp_comb);
@@ -439,7 +439,7 @@ static const FEffectShader effectshaders[]=
 
 FShaderManager::FShaderManager()
 {
-	if (gl.compatibility > CMPT_GL2) CompileShaders();
+	if (gl.glslversion > 0) CompileShaders();
 }
 
 //==========================================================================
@@ -450,7 +450,7 @@ FShaderManager::FShaderManager()
 
 FShaderManager::~FShaderManager()
 {
-	if (gl.compatibility > CMPT_GL2) Clean();
+	if (gl.glslversion > 0) Clean();
 }
 
 //==========================================================================
@@ -592,7 +592,7 @@ EXTERN_CVAR(Int, gl_fuzztype)
 
 void FShaderManager::ApplyMatrices(VSMatrix *proj, VSMatrix *view)
 {
-	if (gl.compatibility == CMPT_GL2)
+	if (gl.glslversion == 0)
 	{
 		glMatrixMode(GL_PROJECTION);
 		glLoadMatrixf(proj->get());
diff --git a/src/gl/system/gl_interface.cpp b/src/gl/system/gl_interface.cpp
index d2b69ad0a5..12e879a239 100644
--- a/src/gl/system/gl_interface.cpp
+++ b/src/gl/system/gl_interface.cpp
@@ -158,25 +158,24 @@ void gl_LoadExtensions()
 	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"))
+	if (Args->CheckParm("-noshader") || gl.glslversion < 1.2f)
 	{
-		gl.version = 2.1f;
-		gl.compatibility = CMPT_GL2;	// force the low end path
+		gl.version = 2.11f;
+		gl.glslversion = 0;
 	}
 	else if (gl.version < 3.0f)
 	{
-		if (CheckExtension("GL_NV_GPU_shader4") || CheckExtension("GL_EXT_GPU_shader4")) gl.compatibility = CMPT_GL2_SHADER;	// for pre-3.0 drivers that support capable hardware. Needed for Apple.
-		else gl.compatibility = CMPT_GL2;
+		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.glslversion = 0;
 	}
 	else if (gl.version < 4.f)
 	{
 		if (strstr(gl.vendorstring, "ATI Tech")) 
 		{
-			gl.version = 2.1f;
-			gl.compatibility = CMPT_GL2_SHADER;	// most of these drivers are irreperably broken with GLSL 1.3 and higher.
+			gl.version = 2.11f;
+			gl.glslversion = 1.21f;
 			gl.lightmethod = LM_SOFTWARE;		// do not use uniform buffers with the fallback shader, it may cause problems.
 		}
-		else gl.compatibility = CMPT_GL3;
 	}
 	else
 	{
@@ -194,13 +193,11 @@ void gl_LoadExtensions()
 				}
 			}
 			gl.flags |= RFL_BUFFER_STORAGE;
-			gl.compatibility = CMPT_GL4;
 			gl.lightmethod = LM_DIRECT;
 		}
 		else
 		{
 			gl.version = 3.3f;
-			gl.compatibility = CMPT_GL3;
 		}
 	}
 
diff --git a/src/gl/system/gl_interface.h b/src/gl/system/gl_interface.h
index 5248c2f8b1..433c2327ce 100644
--- a/src/gl/system/gl_interface.h
+++ b/src/gl/system/gl_interface.h
@@ -48,7 +48,6 @@ struct RenderContext
 	unsigned int maxuniformblock;
 	unsigned int uniformblockalignment;
 	int lightmethod;
-	int compatibility;
 	float version;
 	float glslversion;
 	int max_texturesize;
diff --git a/src/gl/textures/gl_hqresize.cpp b/src/gl/textures/gl_hqresize.cpp
index 993e9f138b..785f3c6e94 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.compatibility == CMPT_GL2 && inputTexture->bWarped)
+	if (gl.glslversion == 0 && inputTexture->bWarped)
 		return inputBuffer;
 
 	// already scaled?