diff --git a/src/gl/data/gl_vertexbuffer.h b/src/gl/data/gl_vertexbuffer.h
index c56cadcbac..b88cc6ca16 100644
--- a/src/gl/data/gl_vertexbuffer.h
+++ b/src/gl/data/gl_vertexbuffer.h
@@ -197,11 +197,12 @@ struct FModelVertex
 class FModelVertexBuffer : public FVertexBuffer
 {
 	int mIndexFrame[2];
-	unsigned int ibo_id;
+	FModelVertex *vbo_ptr;
+	uint32_t ibo_id;
 
 public:
 
-	FModelVertexBuffer(bool needindex);
+	FModelVertexBuffer(bool needindex, bool singleframe);
 	~FModelVertexBuffer();
 
 	FModelVertex *LockVertexBuffer(unsigned int size);
@@ -210,7 +211,7 @@ public:
 	unsigned int *LockIndexBuffer(unsigned int size);
 	void UnlockIndexBuffer();
 
-	unsigned int SetupFrame(unsigned int frame1, unsigned int frame2);
+	unsigned int SetupFrame(unsigned int frame1, unsigned int frame2, unsigned int size);
 	void BindVBO();
 };
 
diff --git a/src/gl/models/gl_models.cpp b/src/gl/models/gl_models.cpp
index dc937ea408..6b586706a6 100644
--- a/src/gl/models/gl_models.cpp
+++ b/src/gl/models/gl_models.cpp
@@ -111,16 +111,22 @@ void gl_FlushModels()
 
 //===========================================================================
 //
+// Uses a hardware buffer if either single frame (i.e. no interpolation needed)
+// or shading is available (interpolation is done by the vertex shader)
 //
+// If interpolation has to be done on the CPU side this will fall back
+// to CPU-side arrays.
 //
 //===========================================================================
 
-FModelVertexBuffer::FModelVertexBuffer(bool needindex)
+FModelVertexBuffer::FModelVertexBuffer(bool needindex, bool singleframe)
+	: FVertexBuffer(singleframe || gl.glslversion > 0)
 {
+	vbo_ptr = nullptr;
 	ibo_id = 0;
 	if (needindex)
 	{
-		glGenBuffers(1, &ibo_id);
+		glGenBuffers(1, &ibo_id);	// The index buffer can always be a real buffer.
 	}
 }
 
@@ -161,6 +167,10 @@ FModelVertexBuffer::~FModelVertexBuffer()
 	{
 		glDeleteBuffers(1, &ibo_id);
 	}
+	if (vbo_ptr != nullptr)
+	{
+		delete[] vbo_ptr;
+	}
 }
 
 //===========================================================================
@@ -171,9 +181,19 @@ FModelVertexBuffer::~FModelVertexBuffer()
 
 FModelVertex *FModelVertexBuffer::LockVertexBuffer(unsigned int size)
 {
-	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
-	glBufferData(GL_ARRAY_BUFFER, size * sizeof(FModelVertex), NULL, GL_STATIC_DRAW);
-	return (FModelVertex*)glMapBufferRange(GL_ARRAY_BUFFER, 0, size * sizeof(FModelVertex), GL_MAP_WRITE_BIT|GL_MAP_INVALIDATE_BUFFER_BIT);
+	if (vbo_id > 0)
+	{
+		glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
+		glBufferData(GL_ARRAY_BUFFER, size * sizeof(FModelVertex), nullptr, GL_STATIC_DRAW);
+		return (FModelVertex*)glMapBufferRange(GL_ARRAY_BUFFER, 0, size * sizeof(FModelVertex), GL_MAP_WRITE_BIT | GL_MAP_INVALIDATE_BUFFER_BIT);
+	}
+	else
+	{
+		if (vbo_ptr != nullptr) delete[] vbo_ptr;
+		vbo_ptr = new FModelVertex[size];
+		memset(vbo_ptr, 0, size * sizeof(FModelVertex));
+		return vbo_ptr;
+	}
 }
 
 //===========================================================================
@@ -184,8 +204,11 @@ FModelVertex *FModelVertexBuffer::LockVertexBuffer(unsigned int size)
 
 void FModelVertexBuffer::UnlockVertexBuffer()
 {
-	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
-	glUnmapBuffer(GL_ARRAY_BUFFER); 
+	if (vbo_id > 0)
+	{
+		glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
+		glUnmapBuffer(GL_ARRAY_BUFFER);
+	}
 }
 
 //===========================================================================
@@ -204,7 +227,7 @@ unsigned int *FModelVertexBuffer::LockIndexBuffer(unsigned int size)
 	}
 	else
 	{
-		return NULL;
+		return nullptr;
 	}
 }
 
@@ -216,8 +239,11 @@ unsigned int *FModelVertexBuffer::LockIndexBuffer(unsigned int size)
 
 void FModelVertexBuffer::UnlockIndexBuffer()
 {
-	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo_id);
-	glUnmapBuffer(GL_ELEMENT_ARRAY_BUFFER); 
+	if (ibo_id > 0)
+	{
+		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo_id);
+		glUnmapBuffer(GL_ELEMENT_ARRAY_BUFFER);
+	}
 }
 
 
@@ -227,21 +253,44 @@ void FModelVertexBuffer::UnlockIndexBuffer()
 // This must be called after gl_RenderState.Apply!
 //
 //===========================================================================
+static TArray<FModelVertex> iBuffer;
 
-unsigned int FModelVertexBuffer::SetupFrame(unsigned int frame1, unsigned int frame2)
+unsigned int FModelVertexBuffer::SetupFrame(unsigned int frame1, unsigned int frame2, unsigned int size)
 {
 	glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
-	if (gl.glslversion > 0)
+	if (vbo_id > 0)
 	{
-		glVertexAttribPointer(VATTR_VERTEX, 3, GL_FLOAT, false, sizeof(FModelVertex), &VMO[frame1].x);
-		glVertexAttribPointer(VATTR_TEXCOORD, 2, GL_FLOAT, false, sizeof(FModelVertex), &VMO[frame1].u);
-		glVertexAttribPointer(VATTR_VERTEX2, 3, GL_FLOAT, false, sizeof(FModelVertex), &VMO[frame2].x);
+		if (gl.glslversion > 0)
+		{
+			glVertexAttribPointer(VATTR_VERTEX, 3, GL_FLOAT, false, sizeof(FModelVertex), &VMO[frame1].x);
+			glVertexAttribPointer(VATTR_TEXCOORD, 2, GL_FLOAT, false, sizeof(FModelVertex), &VMO[frame1].u);
+			glVertexAttribPointer(VATTR_VERTEX2, 3, GL_FLOAT, false, sizeof(FModelVertex), &VMO[frame2].x);
+		}
+		else
+		{
+			// only used for single frame models so there is no vertex2 here, which has no use without a shader.
+			glVertexPointer(3, GL_FLOAT, sizeof(FModelVertex), &VMO[frame1].x);
+			glTexCoordPointer(2, GL_FLOAT, sizeof(FModelVertex), &VMO[frame1].u);
+		}
+	}
+	else if (frame1 == frame2 || size == 0 || gl_RenderState.GetInterpolationFactor() == 0.f)
+	{
+		glVertexPointer(3, GL_FLOAT, sizeof(FModelVertex), &vbo_ptr[frame1].x);
+		glTexCoordPointer(2, GL_FLOAT, sizeof(FModelVertex), &vbo_ptr[frame1].u);
 	}
 	else
 	{
-		// only used for single frame models so there is no vertex2 here, which has no use without a shader.
-		glVertexPointer(3, GL_FLOAT, sizeof(FModelVertex), &VMO[frame1].x);
-		glTexCoordPointer(2, GL_FLOAT, sizeof(FModelVertex), &VMO[frame1].u);
+		// must interpolate
+		iBuffer.Resize(size);
+		glVertexPointer(3, GL_FLOAT, sizeof(FModelVertex), &iBuffer[0].x);
+		glTexCoordPointer(2, GL_FLOAT, sizeof(FModelVertex), &vbo_ptr[frame1].u);
+		float frac = gl_RenderState.GetInterpolationFactor();
+		for (unsigned i = 0; i < size; i++)
+		{
+			iBuffer[i].x = vbo_ptr[frame1].x * (1.f - frac) + vbo_ptr[frame2].x * frac;
+			iBuffer[i].y = vbo_ptr[frame1].y * (1.f - frac) + vbo_ptr[frame2].y * frac;
+			iBuffer[i].z = vbo_ptr[frame1].z * (1.f - frac) + vbo_ptr[frame2].z * frac;
+		}
 	}
 	return frame1;
 }
@@ -254,7 +303,7 @@ unsigned int FModelVertexBuffer::SetupFrame(unsigned int frame1, unsigned int fr
 
 FModel::~FModel()
 {
-	if (mVBuf != NULL) delete mVBuf;
+	if (mVBuf != nullptr) delete mVBuf;
 }
 
 
@@ -266,8 +315,8 @@ static int * SpriteModelHash;
 
 static void DeleteModelHash()
 {
-	if (SpriteModelHash != NULL) delete [] SpriteModelHash;
-	SpriteModelHash = NULL;
+	if (SpriteModelHash != nullptr) delete [] SpriteModelHash;
+	SpriteModelHash = nullptr;
 }
 
 //===========================================================================
@@ -283,7 +332,7 @@ static int FindGFXFile(FString & fn)
 	int slash = fn.LastIndexOf('/');
 	if (dot > slash) fn.Truncate(dot);
 
-	static const char * extensions[] = { ".png", ".jpg", ".tga", ".pcx", NULL };
+	static const char * extensions[] = { ".png", ".jpg", ".tga", ".pcx", nullptr };
 
 	for (const char ** extp=extensions; *extp; extp++)
 	{
@@ -313,7 +362,7 @@ FTexture * LoadSkin(const char * path, const char * fn)
 	}
 	else 
 	{
-		return NULL;
+		return nullptr;
 	}
 }
 
@@ -346,7 +395,7 @@ static int ModelFrameHash(FSpriteModelFrame * smf)
 
 static FModel * FindModel(const char * path, const char * modelfile)
 {
-	FModel * model = NULL;
+	FModel * model = nullptr;
 	FString fullname;
 
 	fullname.Format("%s%s", path, modelfile);
@@ -355,7 +404,7 @@ static FModel * FindModel(const char * path, const char * modelfile)
 	if (lump<0)
 	{
 		Printf("FindModel: '%s' not found\n", fullname.GetChars());
-		return NULL;
+		return nullptr;
 	}
 
 	for(int i = 0; i< (int)Models.Size(); i++)
@@ -380,26 +429,26 @@ static FModel * FindModel(const char * path, const char * modelfile)
 		model = new FMD3Model;
 	}
 
-	if (model != NULL)
+	if (model != nullptr)
 	{
 		if (!model->Load(path, lump, buffer, len))
 		{
 			delete model;
-			return NULL;
+			return nullptr;
 		}
 	}
 	else
 	{
 		// try loading as a voxel
 		FVoxel *voxel = R_LoadKVX(lump);
-		if (voxel != NULL)
+		if (voxel != nullptr)
 		{
 			model = new FVoxelModel(voxel, true);
 		}
 		else
 		{
 			Printf("LoadModel: Unknown model format in '%s'\n", fullname.GetChars());
-			return NULL;
+			return nullptr;
 		}
 	}
 	// The vertex buffer cannot be initialized here because this gets called before OpenGL is initialized
@@ -486,7 +535,7 @@ void gl_InitModels()
 				smf.xscale=smf.yscale=smf.zscale=1.f;
 
 				smf.type = PClass::FindClass(sc.String);
-				if (!smf.type || smf.type->Defaults == NULL) 
+				if (!smf.type || smf.type->Defaults == nullptr) 
 				{
 					sc.ScriptError("MODELDEF: Unknown actor type '%s'\n", sc.String);
 				}
@@ -631,12 +680,12 @@ void gl_InitModels()
 						FixPathSeperator(sc.String);
 						if (sc.Compare(""))
 						{
-							smf.skins[index]=NULL;
+							smf.skins[index]=nullptr;
 						}
 						else
 						{
 							smf.skins[index]=LoadSkin(path.GetChars(), sc.String);
-							if (smf.skins[index] == NULL)
+							if (smf.skins[index] == nullptr)
 							{
 								Printf("Skin '%s' not found in '%s'\n",
 									sc.String, smf.type->TypeName.GetChars());
@@ -678,7 +727,7 @@ void gl_InitModels()
 						if (isframe)
 						{
 							sc.MustGetString();
-							if (smf.models[index]!=NULL) 
+							if (smf.models[index]!=nullptr) 
 							{
 								smf.modelframes[index] = smf.models[index]->FindFrame(sc.String);
 								if (smf.modelframes[index]==-1) sc.ScriptError("Unknown frame '%s' in %s", sc.String, smf.type->TypeName.GetChars());
@@ -765,7 +814,7 @@ FSpriteModelFrame * gl_FindModelFrame(const PClass * ti, int sprite, int frame,
 		if (frame < sprdef->numframes)
 		{
 			spriteframe_t *sprframe = &SpriteFrames[sprdef->spriteframes + frame];
-			if (sprframe->Voxel != NULL)
+			if (sprframe->Voxel != nullptr)
 			{
 				int index = sprframe->Voxel->VoxeldefIndex;
 				if (dropped && sprframe->Voxel->DroppedSpin !=sprframe->Voxel->PlacedSpin) index++;
@@ -773,7 +822,7 @@ FSpriteModelFrame * gl_FindModelFrame(const PClass * ti, int sprite, int frame,
 			}
 		}
 	}
-	return NULL;
+	return nullptr;
 }
 
 
@@ -792,7 +841,7 @@ void gl_RenderFrameModels( const FSpriteModelFrame *smf,
 {
 	// [BB] Frame interpolation: Find the FSpriteModelFrame smfNext which follows after smf in the animation
 	// and the scalar value inter ( element of [0,1) ), both necessary to determine the interpolated frame.
-	FSpriteModelFrame * smfNext = NULL;
+	FSpriteModelFrame * smfNext = nullptr;
 	double inter = 0.;
 	if( gl_interpolate_model_frames && !(smf->flags & MDL_NOINTERPOLATION) )
 	{
@@ -841,7 +890,7 @@ void gl_RenderFrameModels( const FSpriteModelFrame *smf,
 	{
 		FModel * mdl = smf->models[i];
 
-		if (mdl!=NULL)
+		if (mdl!=nullptr)
 		{
 			mdl->BuildVertexBuffer();
 			gl_RenderState.SetVertexBuffer(mdl->mVBuf);
@@ -949,12 +998,12 @@ void gl_RenderModel(GLSprite * spr)
 	gl_RenderState.mModelMatrix.rotate(-smf->rolloffset, 1, 0, 0);
 
 	// consider the pixel stretching. For non-voxels this must be factored out here
-	float stretch = (smf->models[0] != NULL ? smf->models[0]->getAspectFactor() : 1.f) / glset.pixelstretch;
+	float stretch = (smf->models[0] != nullptr ? smf->models[0]->getAspectFactor() : 1.f) / glset.pixelstretch;
 	gl_RenderState.mModelMatrix.scale(1, stretch, 1);
 
 
 	gl_RenderState.EnableModelMatrix(true);
-	gl_RenderFrameModels( smf, spr->actor->state, spr->actor->tics, spr->actor->GetClass(), NULL, translation );
+	gl_RenderFrameModels( smf, spr->actor->state, spr->actor->tics, spr->actor->GetClass(), nullptr, translation );
 	gl_RenderState.EnableModelMatrix(false);
 
 	glDepthFunc(GL_LESS);
@@ -975,7 +1024,7 @@ void gl_RenderHUDModel(pspdef_t *psp, float ofsX, float ofsY)
 	FSpriteModelFrame *smf = gl_FindModelFrame(playermo->player->ReadyWeapon->GetClass(), psp->state->sprite, psp->state->GetFrame(), false);
 
 	// [BB] No model found for this sprite, so we can't render anything.
-	if ( smf == NULL )
+	if ( smf == nullptr )
 		return;
 
 	glDepthFunc(GL_LEQUAL);
@@ -1012,7 +1061,7 @@ void gl_RenderHUDModel(pspdef_t *psp, float ofsX, float ofsY)
 	gl_RenderState.mViewMatrix.rotate(-smf->rolloffset, 1, 0, 0);
 	gl_RenderState.ApplyMatrices();
 
-	gl_RenderFrameModels( smf, psp->state, psp->tics, playermo->player->ReadyWeapon->GetClass(), NULL, 0 );
+	gl_RenderFrameModels( smf, psp->state, psp->tics, playermo->player->ReadyWeapon->GetClass(), nullptr, 0 );
 
 	glDepthFunc(GL_LESS);
 	if (!( playermo->RenderStyle == LegacyRenderStyles[STYLE_Normal] ))
@@ -1027,11 +1076,11 @@ void gl_RenderHUDModel(pspdef_t *psp, float ofsX, float ofsY)
 
 bool gl_IsHUDModelForPlayerAvailable (player_t * player)
 {
-	if ( (player == NULL) || (player->ReadyWeapon == NULL) || (player->psprites[0].state == NULL) )
+	if ( (player == nullptr) || (player->ReadyWeapon == nullptr) || (player->psprites[0].state == nullptr) )
 		return false;
 
 	FState* state = player->psprites[0].state;
 	FSpriteModelFrame *smf = gl_FindModelFrame(player->ReadyWeapon->GetClass(), state->sprite, state->GetFrame(), false);
-	return ( smf != NULL );
+	return ( smf != nullptr );
 }
 
diff --git a/src/gl/models/gl_models_md2.cpp b/src/gl/models/gl_models_md2.cpp
index 7a27e12dc0..b0713ce443 100644
--- a/src/gl/models/gl_models_md2.cpp
+++ b/src/gl/models/gl_models_md2.cpp
@@ -304,7 +304,7 @@ void FDMDModel::BuildVertexBuffer()
 		int VertexBufferSize = info.numFrames * lodInfo[0].numTriangles * 3;
 		unsigned int vindex = 0;
 
-		mVBuf = new FModelVertexBuffer(false);
+		mVBuf = new FModelVertexBuffer(false, info.numFrames == 1);
 		FModelVertex *vertptr = mVBuf->LockVertexBuffer(VertexBufferSize);
 
 		for (int i = 0; i < info.numFrames; i++)
@@ -375,7 +375,7 @@ void FDMDModel::RenderFrame(FTexture * skin, int frameno, int frameno2, double i
 	gl_RenderState.SetInterpolationFactor((float)inter);
 
 	gl_RenderState.Apply();
-	mVBuf->SetupFrame(frames[frameno].vindex, frames[frameno2].vindex);
+	mVBuf->SetupFrame(frames[frameno].vindex, frames[frameno2].vindex, lodInfo[0].numTriangles * 3);
 	glDrawArrays(GL_TRIANGLES, 0, lodInfo[0].numTriangles * 3);
 	gl_RenderState.SetInterpolationFactor(0.f);
 }
diff --git a/src/gl/models/gl_models_md3.cpp b/src/gl/models/gl_models_md3.cpp
index 024f8ac817..1a49d9691d 100644
--- a/src/gl/models/gl_models_md3.cpp
+++ b/src/gl/models/gl_models_md3.cpp
@@ -186,7 +186,7 @@ bool FMD3Model::Load(const char * path, int lumpnum, const char * buffer, int le
 			// [BB] According to the MD3 spec, Name is supposed to include the full path.
 			s->skins[i] = LoadSkin("", shader[i].Name);
 			// [BB] Fall back and check if Name is relative.
-			if (s->skins[i] == NULL)
+			if (s->skins[i] == nullptr)
 				s->skins[i] = LoadSkin(path, shader[i].Name);
 		}
 	}
@@ -255,7 +255,7 @@ void FMD3Model::LoadGeometry()
 
 void FMD3Model::BuildVertexBuffer()
 {
-	if (mVBuf == NULL)
+	if (mVBuf == nullptr)
 	{
 		LoadGeometry();
 
@@ -269,11 +269,11 @@ void FMD3Model::BuildVertexBuffer()
 			ibufsize += 3 * surf->numTriangles;
 		}
 
-		mVBuf = new FModelVertexBuffer(true);
+		mVBuf = new FModelVertexBuffer(true, numFrames == 1);
 		FModelVertex *vertptr = mVBuf->LockVertexBuffer(vbufsize);
 		unsigned int *indxptr = mVBuf->LockIndexBuffer(ibufsize);
 
-		assert(vertptr != NULL && indxptr != NULL);
+		assert(vertptr != nullptr && indxptr != nullptr);
 
 		unsigned int vindex = 0, iindex = 0;
 
@@ -354,7 +354,7 @@ void FMD3Model::RenderFrame(FTexture * skin, int frameno, int frameno2, double i
 		gl_RenderState.SetMaterial(tex, CLAMP_NONE, translation, -1, false);
 
 		gl_RenderState.Apply();
-		mVBuf->SetupFrame(surf->vindex + frameno * surf->numVertices, surf->vindex + frameno2 * surf->numVertices);
+		mVBuf->SetupFrame(surf->vindex + frameno * surf->numVertices, surf->vindex + frameno2 * surf->numVertices, surf->numVertices);
 		glDrawElements(GL_TRIANGLES, surf->numTriangles * 3, GL_UNSIGNED_INT, (void*)(intptr_t)(surf->iindex * sizeof(unsigned int)));
 	}
 	gl_RenderState.SetInterpolationFactor(0.f);
@@ -370,6 +370,6 @@ FMD3Model::~FMD3Model()
 {
 	if (frames) delete [] frames;
 	if (surfaces) delete [] surfaces;
-	frames = NULL;
-	surfaces = NULL;
+	frames = nullptr;
+	surfaces = nullptr;
 }
diff --git a/src/gl/models/gl_voxels.cpp b/src/gl/models/gl_voxels.cpp
index 3a34117b9e..2fdb8e1625 100644
--- a/src/gl/models/gl_voxels.cpp
+++ b/src/gl/models/gl_voxels.cpp
@@ -378,7 +378,7 @@ void FVoxelModel::BuildVertexBuffer()
 	{
 		Initialize();
 
-		mVBuf = new FModelVertexBuffer(true);
+		mVBuf = new FModelVertexBuffer(true, true);
 		FModelVertex *vertptr = mVBuf->LockVertexBuffer(mVertices.Size());
 		unsigned int *indxptr = mVBuf->LockIndexBuffer(mIndices.Size());
 
@@ -443,7 +443,7 @@ void FVoxelModel::RenderFrame(FTexture * skin, int frame, int frame2, double int
 	gl_RenderState.SetMaterial(tex, CLAMP_NOFILTER, translation, -1, false);
 
 	gl_RenderState.Apply();
-	mVBuf->SetupFrame(0, 0);
+	mVBuf->SetupFrame(0, 0, 0);
 	glDrawElements(GL_TRIANGLES, mNumIndices, GL_UNSIGNED_INT, (void*)(intptr_t)0);
 }
 
diff --git a/src/gl/renderer/gl_renderstate.h b/src/gl/renderer/gl_renderstate.h
index cebbb95704..0172488eb1 100644
--- a/src/gl/renderer/gl_renderstate.h
+++ b/src/gl/renderer/gl_renderstate.h
@@ -439,6 +439,11 @@ public:
 		mInterpolationFactor = fac;
 	}
 
+	float GetInterpolationFactor()
+	{
+		return mInterpolationFactor;
+	}
+
 	// Backwards compatibility crap follows
 	void ApplyFixedFunction();
 	void DrawColormapOverlay();