diff --git a/src/gl/data/gl_vertexbuffer.cpp b/src/gl/data/gl_vertexbuffer.cpp
index c5703a8ef..a0f9aa849 100644
--- a/src/gl/data/gl_vertexbuffer.cpp
+++ b/src/gl/data/gl_vertexbuffer.cpp
@@ -296,6 +296,7 @@ void FFlatVertexBuffer::CreateVBO()
 	{
 		CreateFlatVBO();
 		memcpy(map, &vbo_shadowdata[0], vbo_shadowdata.Size() * sizeof(FFlatVertex));
+		mIndex = vbo_shadowdata.Size();
 	}
 	else if (sectors)
 	{
diff --git a/src/gl/data/gl_vertexbuffer.h b/src/gl/data/gl_vertexbuffer.h
index 2755b6494..24fe5b4d5 100644
--- a/src/gl/data/gl_vertexbuffer.h
+++ b/src/gl/data/gl_vertexbuffer.h
@@ -35,6 +35,7 @@ class FFlatVertexBuffer : public FVertexBuffer
 {
 	FFlatVertex *map;
 	unsigned int mIndex;
+	unsigned int mCurIndex;
 
 	void CheckPlanes(sector_t *sector);
 
@@ -49,6 +50,23 @@ public:
 	void BindVBO();
 	void CheckUpdate(sector_t *sector);
 
+	FFlatVertex *GetBuffer()
+	{
+		return &map[mCurIndex];
+	}
+	unsigned int GetCount(FFlatVertex *newptr, unsigned int *poffset)
+	{
+		unsigned int newofs = unsigned int(newptr - map);
+		unsigned int diff = newofs - mCurIndex;
+		*poffset = mCurIndex;
+		mCurIndex = newofs;
+		return diff;
+	}
+	void Reset()
+	{
+		mCurIndex = mIndex;
+	}
+
 private:
 	int CreateSubsectorVertices(subsector_t *sub, const secplane_t &plane, int floor);
 	int CreateSectorVertices(sector_t *sec, const secplane_t &plane, int floor);
diff --git a/src/gl/scene/gl_flats.cpp b/src/gl/scene/gl_flats.cpp
index 7ff3d7110..c32011998 100644
--- a/src/gl/scene/gl_flats.cpp
+++ b/src/gl/scene/gl_flats.cpp
@@ -238,21 +238,72 @@ bool GLFlat::SetupSubsectorLights(bool lightsapplied, subsector_t * sub)
 
 void GLFlat::DrawSubsector(subsector_t * sub)
 {
-	glBegin(GL_TRIANGLE_FAN);
-
-	for(unsigned int k=0; k<sub->numlines; k++)
+	if (!gl_usevbo)
 	{
-		vertex_t *vt = sub->firstline[k].v1;
-		glTexCoord2f(vt->fx/64.f, -vt->fy/64.f);
-		float zc = plane.plane.ZatPoint(vt->fx, vt->fy) + dz;
-		glVertex3f(vt->fx, zc, vt->fy);
+		glBegin(GL_TRIANGLE_FAN);
+
+		if (plane.plane.a | plane.plane.b)
+		{
+			for (unsigned int k = 0; k < sub->numlines; k++)
+			{
+				vertex_t *vt = sub->firstline[k].v1;
+				glTexCoord2f(vt->fx / 64.f, -vt->fy / 64.f);
+				float zc = plane.plane.ZatPoint(vt->fx, vt->fy) + dz;
+				glVertex3f(vt->fx, zc, vt->fy);
+			}
+		}
+		else
+		{
+			float zc = FIXED2FLOAT(plane.plane.Zat0()) + dz;
+			for (unsigned int k = 0; k < sub->numlines; k++)
+			{
+				vertex_t *vt = sub->firstline[k].v1;
+				glTexCoord2f(vt->fx / 64.f, -vt->fy / 64.f);
+				glVertex3f(vt->fx, zc, vt->fy);
+			}
+		}
+		glEnd();
+	}
+	else
+	{
+		FFlatVertex *ptr = GLRenderer->mVBO->GetBuffer();
+		if (plane.plane.a | plane.plane.b)
+		{
+			for (unsigned int k = 0; k < sub->numlines; k++)
+			{
+				vertex_t *vt = sub->firstline[k].v1;
+				ptr->x = vt->fx;
+				ptr->y = vt->fy;
+				ptr->z = plane.plane.ZatPoint(vt->fx, vt->fy) + dz;
+				ptr->u = vt->fx / 64.f;
+				ptr->v = -vt->fy / 64.f;
+				ptr++;
+			}
+		}
+		else
+		{
+			float zc = FIXED2FLOAT(plane.plane.Zat0()) + dz;
+			for (unsigned int k = 0; k < sub->numlines; k++)
+			{
+				vertex_t *vt = sub->firstline[k].v1;
+				ptr->x = vt->fx;
+				ptr->y = vt->fy;
+				ptr->z = zc;
+				ptr->u = vt->fx / 64.f;
+				ptr->v = -vt->fy / 64.f;
+				ptr++;
+			}
+		}
+		unsigned int offset;
+		unsigned int count = GLRenderer->mVBO->GetCount(ptr, &offset);
+		glDrawArrays(GL_TRIANGLE_FAN, offset, count);
 	}
-	glEnd();
 
 	flatvertices += sub->numlines;
 	flatprimitives++;
 }
 
+
 //==========================================================================
 //
 //
@@ -292,7 +343,6 @@ void GLFlat::DrawSubsectors(int pass, bool istrans)
 		}
 		else
 		{
-			//glColor3f( .5f,1.f,.5f); // these are for testing the VBO stuff.
 			// Draw the subsectors belonging to this sector
 			for (int i=0; i<sector->subsectorcount; i++)
 			{
diff --git a/src/gl/scene/gl_scene.cpp b/src/gl/scene/gl_scene.cpp
index 47f990796..1aa3c2b3f 100644
--- a/src/gl/scene/gl_scene.cpp
+++ b/src/gl/scene/gl_scene.cpp
@@ -931,6 +931,7 @@ void FGLRenderer::RenderView (player_t* player)
 	}
 
 	gl_RenderState.SetVertexBuffer(mVBO);
+	GLRenderer->mVBO->Reset();
 
 	// reset statistics counters
 	ResetProfilingData();
@@ -991,6 +992,8 @@ void FGLRenderer::WriteSavePic (player_t *player, FILE *file, int width, int hei
 	bounds.height=height;
 	glFlush();
 	SetFixedColormap(player);
+	gl_RenderState.SetVertexBuffer(mVBO);
+	GLRenderer->mVBO->Reset();
 
 	// 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_vertex.cpp b/src/gl/scene/gl_vertex.cpp
index 3aff28d1f..03f7df520 100644
--- a/src/gl/scene/gl_vertex.cpp
+++ b/src/gl/scene/gl_vertex.cpp
@@ -45,6 +45,7 @@
 #include "gl/renderer/gl_renderer.h"
 #include "gl/renderer/gl_lightdata.h"
 #include "gl/data/gl_data.h"
+#include "gl/data/gl_vertexbuffer.h"
 #include "gl/dynlights/gl_glow.h"
 #include "gl/scene/gl_drawinfo.h"
 #include "gl/scene/gl_portal.h"
@@ -88,6 +89,37 @@ void GLWall::SplitUpperEdge(texcoord * tcs)
 	vertexcount += sidedef->numsegs-1;
 }
 
+void GLWall::SplitUpperEdge(texcoord * tcs, FFlatVertex *&ptr)
+{
+	if (seg == NULL || seg->sidedef == NULL || (seg->sidedef->Flags & WALLF_POLYOBJ) || seg->sidedef->numsegs == 1) return;
+
+	side_t *sidedef = seg->sidedef;
+	float polyw = glseg.fracright - glseg.fracleft;
+	float facu = (tcs[2].u - tcs[1].u) / polyw;
+	float facv = (tcs[2].v - tcs[1].v) / polyw;
+	float fact = (ztop[1] - ztop[0]) / polyw;
+	float facc = (zceil[1] - zceil[0]) / polyw;
+	float facf = (zfloor[1] - zfloor[0]) / polyw;
+
+	for (int i = 0; i < sidedef->numsegs - 1; i++)
+	{
+		seg_t *cseg = sidedef->segs[i];
+		float sidefrac = cseg->sidefrac;
+		if (sidefrac <= glseg.fracleft) continue;
+		if (sidefrac >= glseg.fracright) return;
+
+		float fracfac = sidefrac - glseg.fracleft;
+
+		ptr->x = cseg->v2->fx;
+		ptr->y = cseg->v2->fy;
+		ptr->z = ztop[0] + fact * fracfac;
+		ptr->u = tcs[1].u + facu * fracfac;
+		ptr->v = tcs[1].v + facv * fracfac;
+		ptr++;
+	}
+	vertexcount += sidedef->numsegs - 1;
+}
+
 //==========================================================================
 //
 // Split upper edge of wall
@@ -121,6 +153,37 @@ void GLWall::SplitLowerEdge(texcoord * tcs)
 	vertexcount += sidedef->numsegs-1;
 }
 
+void GLWall::SplitLowerEdge(texcoord * tcs, FFlatVertex *&ptr)
+{
+	if (seg == NULL || seg->sidedef == NULL || (seg->sidedef->Flags & WALLF_POLYOBJ) || seg->sidedef->numsegs == 1) return;
+
+	side_t *sidedef = seg->sidedef;
+	float polyw = glseg.fracright - glseg.fracleft;
+	float facu = (tcs[3].u - tcs[0].u) / polyw;
+	float facv = (tcs[3].v - tcs[0].v) / polyw;
+	float facb = (zbottom[1] - zbottom[0]) / polyw;
+	float facc = (zceil[1] - zceil[0]) / polyw;
+	float facf = (zfloor[1] - zfloor[0]) / polyw;
+
+	for (int i = sidedef->numsegs - 2; i >= 0; i--)
+	{
+		seg_t *cseg = sidedef->segs[i];
+		float sidefrac = cseg->sidefrac;
+		if (sidefrac >= glseg.fracright) continue;
+		if (sidefrac <= glseg.fracleft) return;
+
+		float fracfac = sidefrac - glseg.fracleft;
+
+		ptr->x = cseg->v2->fx;
+		ptr->y = cseg->v2->fy;
+		ptr->z = zbottom[0] + facb * fracfac;
+		ptr->u = tcs[0].u + facu * fracfac;
+		ptr->v = tcs[0].v + facv * fracfac;
+		ptr++;
+	}
+	vertexcount += sidedef->numsegs - 1;
+}
+
 //==========================================================================
 //
 // Split left edge of wall
@@ -153,6 +216,35 @@ void GLWall::SplitLeftEdge(texcoord * tcs)
 	}
 }
 
+void GLWall::SplitLeftEdge(texcoord * tcs, FFlatVertex *&ptr)
+{
+	if (vertexes[0] == NULL) return;
+
+	vertex_t * vi = vertexes[0];
+
+	if (vi->numheights)
+	{
+		int i = 0;
+
+		float polyh1 = ztop[0] - zbottom[0];
+		float factv1 = polyh1 ? (tcs[1].v - tcs[0].v) / polyh1 : 0;
+		float factu1 = polyh1 ? (tcs[1].u - tcs[0].u) / polyh1 : 0;
+
+		while (i<vi->numheights && vi->heightlist[i] <= zbottom[0]) i++;
+		while (i<vi->numheights && vi->heightlist[i] < ztop[0])
+		{
+			ptr->x = glseg.x1;
+			ptr->y = glseg.y1;
+			ptr->z = vi->heightlist[i];
+			ptr->u = factu1*(vi->heightlist[i] - ztop[0]) + tcs[1].u;
+			ptr->v = factv1*(vi->heightlist[i] - ztop[0]) + tcs[1].v;
+			ptr++;
+			i++;
+		}
+		vertexcount += i;
+	}
+}
+
 //==========================================================================
 //
 // Split right edge of wall
@@ -185,3 +277,32 @@ void GLWall::SplitRightEdge(texcoord * tcs)
 	}
 }
 
+void GLWall::SplitRightEdge(texcoord * tcs, FFlatVertex *&ptr)
+{
+	if (vertexes[1] == NULL) return;
+
+	vertex_t * vi = vertexes[1];
+
+	if (vi->numheights)
+	{
+		int i = vi->numheights - 1;
+
+		float polyh2 = ztop[1] - zbottom[1];
+		float factv2 = polyh2 ? (tcs[2].v - tcs[3].v) / polyh2 : 0;
+		float factu2 = polyh2 ? (tcs[2].u - tcs[3].u) / polyh2 : 0;
+
+		while (i>0 && vi->heightlist[i] >= ztop[1]) i--;
+		while (i>0 && vi->heightlist[i] > zbottom[1])
+		{
+			ptr->x = glseg.x2;
+			ptr->y = glseg.y2;
+			ptr->z = vi->heightlist[i];
+			ptr->u = factu2*(vi->heightlist[i] - ztop[1]) + tcs[2].u;
+			ptr->v = factv2*(vi->heightlist[i] - ztop[1]) + tcs[2].v;
+			ptr++;
+			i--;
+		}
+		vertexcount += i;
+	}
+}
+
diff --git a/src/gl/scene/gl_wall.h b/src/gl/scene/gl_wall.h
index e53513167..207b7bdbf 100644
--- a/src/gl/scene/gl_wall.h
+++ b/src/gl/scene/gl_wall.h
@@ -20,6 +20,7 @@ struct GLDrawList;
 struct GLSkyInfo;
 struct FTexCoordInfo;
 struct FPortal;
+struct FFlatVertex;
 
 
 enum WallTypes
@@ -215,6 +216,11 @@ private:
 	void SplitUpperEdge(texcoord * tcs);
 	void SplitLowerEdge(texcoord * tcs);
 
+	void SplitLeftEdge(texcoord * tcs, FFlatVertex *&ptr);
+	void SplitRightEdge(texcoord * tcs, FFlatVertex *&ptr);
+	void SplitUpperEdge(texcoord * tcs, FFlatVertex *&ptr);
+	void SplitLowerEdge(texcoord * tcs, FFlatVertex *&ptr);
+
 public:
 
 	void Process(seg_t *seg, sector_t *frontsector, sector_t *backsector);
diff --git a/src/gl/scene/gl_walls_draw.cpp b/src/gl/scene/gl_walls_draw.cpp
index d7edc6ef7..63e5086a7 100644
--- a/src/gl/scene/gl_walls_draw.cpp
+++ b/src/gl/scene/gl_walls_draw.cpp
@@ -48,7 +48,9 @@
 #include "gl/system/gl_cvars.h"
 #include "gl/renderer/gl_lightdata.h"
 #include "gl/renderer/gl_renderstate.h"
+#include "gl/renderer/gl_renderer.h"
 #include "gl/data/gl_data.h"
+#include "gl/data/gl_vertexbuffer.h"
 #include "gl/dynlights/gl_dynlight.h"
 #include "gl/dynlights/gl_glow.h"
 #include "gl/scene/gl_drawinfo.h"
@@ -248,38 +250,80 @@ void GLWall::RenderWall(int textured, float * color2, ADynamicLight * light)
 
 	// the rest of the code is identical for textured rendering and lights
 
-	glBegin(GL_TRIANGLE_FAN);
 
-	// lower left corner
-	if (textured&1) glTexCoord2f(tcs[0].u,tcs[0].v);
-	glVertex3f(glseg.x1,zbottom[0],glseg.y1);
+	if (!gl_usevbo)
+	{
+		glBegin(GL_TRIANGLE_FAN);
 
-	if (split && glseg.fracleft==0) SplitLeftEdge(tcs);
+		// lower left corner
+		if (textured & 1) glTexCoord2f(tcs[0].u, tcs[0].v);
+		glVertex3f(glseg.x1, zbottom[0], glseg.y1);
 
-	// upper left corner
-	if (textured&1) glTexCoord2f(tcs[1].u,tcs[1].v);
-	glVertex3f(glseg.x1,ztop[0],glseg.y1);
+		if (split && glseg.fracleft == 0) SplitLeftEdge(tcs);
 
-	if (split && !(flags & GLWF_NOSPLITUPPER)) SplitUpperEdge(tcs);
+		// upper left corner
+		if (textured & 1) glTexCoord2f(tcs[1].u, tcs[1].v);
+		glVertex3f(glseg.x1, ztop[0], glseg.y1);
 
-	// color for right side
-	if (color2) glColor4fv(color2);
+		if (split && !(flags & GLWF_NOSPLITUPPER)) SplitUpperEdge(tcs);
 
-	// upper right corner
-	if (textured&1) glTexCoord2f(tcs[2].u,tcs[2].v);
-	glVertex3f(glseg.x2,ztop[1],glseg.y2);
+		// color for right side
+		if (color2) glColor4fv(color2);
 
-	if (split && glseg.fracright==1) SplitRightEdge(tcs);
+		// upper right corner
+		if (textured & 1) glTexCoord2f(tcs[2].u, tcs[2].v);
+		glVertex3f(glseg.x2, ztop[1], glseg.y2);
 
-	// lower right corner
-	if (textured&1) glTexCoord2f(tcs[3].u,tcs[3].v); 
-	glVertex3f(glseg.x2,zbottom[1],glseg.y2);
+		if (split && glseg.fracright == 1) SplitRightEdge(tcs);
 
-	if (split && !(flags & GLWF_NOSPLITLOWER)) SplitLowerEdge(tcs);
+		// lower right corner
+		if (textured & 1) glTexCoord2f(tcs[3].u, tcs[3].v);
+		glVertex3f(glseg.x2, zbottom[1], glseg.y2);
 
-	glEnd();
+		if (split && !(flags & GLWF_NOSPLITLOWER)) SplitLowerEdge(tcs);
+
+		glEnd();
+
+		vertexcount += 4;
+	}
+	else
+	{
+		FFlatVertex *ptr = GLRenderer->mVBO->GetBuffer();
+
+		ptr->x = glseg.x1;
+		ptr->y = glseg.y1;
+		ptr->z = zbottom[0];
+		ptr->u = tcs[0].u;
+		ptr->v = tcs[0].v;
+		ptr++;
+		if (split && glseg.fracleft == 0) SplitLeftEdge(tcs, ptr);
+		ptr->x = glseg.x1;
+		ptr->y = glseg.y1;
+		ptr->z = ztop[0];
+		ptr->u = tcs[1].u;
+		ptr->v = tcs[1].v;
+		ptr++;
+		if (split && !(flags & GLWF_NOSPLITUPPER)) SplitUpperEdge(tcs, ptr);
+		ptr->x = glseg.x2;
+		ptr->y = glseg.y2;
+		ptr->z = ztop[1];
+		ptr->u = tcs[2].u;
+		ptr->v = tcs[2].v;
+		ptr++;
+		if (split && glseg.fracright == 1) SplitRightEdge(tcs, ptr);
+		ptr->x = glseg.x2;
+		ptr->y = glseg.y2;
+		ptr->z = zbottom[1];
+		ptr->u = tcs[3].u;
+		ptr->v = tcs[3].v;
+		ptr++;
+		if (split && !(flags & GLWF_NOSPLITLOWER)) SplitLowerEdge(tcs, ptr);
+		unsigned int offset;
+		unsigned int count = GLRenderer->mVBO->GetCount(ptr, &offset);
+		glDrawArrays(GL_TRIANGLE_FAN, offset, count);
+		vertexcount += 4;
+	}
 
-	vertexcount+=4;
 
 }