diff --git a/src/gl/data/gl_vertexbuffer.cpp b/src/gl/data/gl_vertexbuffer.cpp
index 3ea401dcd..b6d33dacd 100644
--- a/src/gl/data/gl_vertexbuffer.cpp
+++ b/src/gl/data/gl_vertexbuffer.cpp
@@ -90,6 +90,14 @@ FFlatVertexBuffer::FFlatVertexBuffer()
 	{
 		vbo_shadowdata.Reserve(BUFFER_SIZE);
 		map = &vbo_shadowdata[0];
+
+		FFlatVertex fill[20];
+		for (int i = 0; i < 20; i++)
+		{
+			fill[i].Set(0, 0, 0, 100001.f, i);
+		}
+		glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
+		glBufferData(GL_ARRAY_BUFFER, 20 * sizeof(FFlatVertex), fill, GL_STATIC_DRAW);
 	}
 	mIndex = mCurIndex = 0;
 }
@@ -109,15 +117,55 @@ FFlatVertexBuffer::~FFlatVertexBuffer()
 //
 //==========================================================================
 
+CVAR(Bool, gl_testbuffer, false, 0)
+
 void FFlatVertexBuffer::ImmRenderBuffer(unsigned int primtype, unsigned int offset, unsigned int count)
 {
-	glBegin(primtype);
-	for (unsigned int i = 0; i < count; i++)
+	if (!gl_testbuffer)	// todo: remove the immediate mode calls once the uniform array method has been tested.
 	{
-		glTexCoord2fv(&map[offset + i].u);
-		glVertex3fv(&map[offset + i].x);
+		glBegin(primtype);
+		for (unsigned int i = 0; i < count; i++)
+		{
+			glTexCoord2fv(&map[offset + i].u);
+			glVertex3fv(&map[offset + i].x);
+		}
+		glEnd();
+	}
+	else
+	{
+		if (count > 20)
+		{
+			int start = offset;
+			FFlatVertex ff = map[offset];
+			while (count > 20)
+			{
+
+				if (primtype == GL_TRIANGLE_FAN)
+				{
+					// split up the fan into multiple sub-fans
+					map[offset] = map[start];
+					glUniform1fv(GLRenderer->mShaderManager->GetActiveShader()->fakevb_index, 20 * 5, &map[offset].x);
+					glDrawArrays(primtype, 0, 20);
+					offset += 18;
+					count -= 18;
+				}
+				else
+				{
+					// we only have triangle fans of this size so don't bother with strips and triangles here.
+					break;
+				}
+			}
+			map[offset] = map[start];
+			glUniform1fv(GLRenderer->mShaderManager->GetActiveShader()->fakevb_index, count * 5, &map[offset].x);
+			glDrawArrays(primtype, 0, count);
+			map[offset] = ff;
+		}
+		else
+		{
+			glUniform1fv(GLRenderer->mShaderManager->GetActiveShader()->fakevb_index, count * 5, &map[offset].x);
+			glDrawArrays(primtype, 0, count);
+		}
 	}
-	glEnd();
 }
 
 //==========================================================================
@@ -324,7 +372,7 @@ void FFlatVertexBuffer::CreateVBO()
 
 void FFlatVertexBuffer::BindVBO()
 {
-	if (gl.flags & RFL_BUFFER_STORAGE)
+	//if (gl.flags & RFL_BUFFER_STORAGE)
 	{
 		glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
 		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
diff --git a/src/gl/shaders/gl_shader.cpp b/src/gl/shaders/gl_shader.cpp
index 76049eb1f..bd96c1ce2 100644
--- a/src/gl/shaders/gl_shader.cpp
+++ b/src/gl/shaders/gl_shader.cpp
@@ -90,6 +90,13 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 	if (gl.glslversion >= 3.3f) vp_comb = "#version 330 compatibility\n";	// I can't shut up the deprecation warnings in GLSL 1.3 so if available use a version with compatibility profile.
 	// todo when using shader storage buffers, add
 	// "#version 400 compatibility\n#extension GL_ARB_shader_storage_buffer_object : require\n" instead.
+
+	if (!(gl.flags & RFL_BUFFER_STORAGE))
+	{
+		// we only want the uniform array hack in the shader if we actually need it.
+		vp_comb << "#define UNIFORM_VB\n";
+	}
+
 	vp_comb << defines << i_data.GetString().GetChars();
 	FString fp_comb = vp_comb;
 
@@ -196,6 +203,7 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 
 	timer_index = glGetUniformLocation(hShader, "timer");
 	lights_index = glGetUniformLocation(hShader, "lights");
+	fakevb_index = glGetUniformLocation(hShader, "fakeVB");
 
 	glBindAttribLocation(hShader, VATTR_VERTEX2, "aVertex2");
 
diff --git a/src/gl/shaders/gl_shader.h b/src/gl/shaders/gl_shader.h
index d1518088d..b079e74c4 100644
--- a/src/gl/shaders/gl_shader.h
+++ b/src/gl/shaders/gl_shader.h
@@ -196,6 +196,9 @@ class FShader
 	
 	int timer_index;
 	int lights_index;
+public:
+	int fakevb_index;
+private:
 	int currentglowstate;
 	int currentfixedcolormap;
 
@@ -245,6 +248,10 @@ public:
 	FShader *BindEffect(int effect);
 	void SetActiveShader(FShader *sh);
 	void SetWarpSpeed(unsigned int eff, float speed);
+	FShader *GetActiveShader() const
+	{
+		return mActiveShader;
+	}
 
 	FShader *Get(unsigned int eff)
 	{
diff --git a/wadsrc/static/shaders/glsl/main.vp b/wadsrc/static/shaders/glsl/main.vp
index 3ec5990b2..81b0601c5 100644
--- a/wadsrc/static/shaders/glsl/main.vp
+++ b/wadsrc/static/shaders/glsl/main.vp
@@ -3,10 +3,34 @@ in vec4 aVertex2;
 out vec4 pixelpos;
 out vec2 glowdist;
 
+#ifdef UNIFORM_VB
+uniform float fakeVB[100];
+#endif
 
 void main()
 {
-	vec4 worldcoord = ModelMatrix * mix(gl_Vertex, aVertex2, uInterpolationFactor);
+
+#ifdef UNIFORM_VB
+	vec4 vert;
+	vec4 tc;
+	
+	if (gl_MultiTexCoord0.x >= 100000.0)
+	{
+		int fakeVI = int(gl_MultiTexCoord0.y)*5;
+		vert = gl_Vertex + vec4(fakeVB[fakeVI], fakeVB[fakeVI+1], fakeVB[fakeVI+2], 0.0);
+		tc = vec4(fakeVB[fakeVI+3], fakeVB[fakeVI+4], 0.0, 0.0);
+	}
+	else
+	{
+		vert = gl_Vertex;
+		tc = gl_MultiTexCoord0;
+	}
+#else
+	#define vert gl_Vertex
+	#define tc gl_MultiTexCoord0
+#endif
+	
+	vec4 worldcoord = ModelMatrix * mix(vert, aVertex2, uInterpolationFactor);
 	vec4 eyeCoordPos = ViewMatrix * worldcoord;
 
 	gl_FrontColor = gl_Color;
@@ -25,7 +49,7 @@ void main()
 		vec2 sst = vec2(r.x/m + 0.5,  r.y/m + 0.5);
 		gl_TexCoord[0].xy = sst;
 	#else
-		gl_TexCoord[0] = TextureMatrix * gl_MultiTexCoord0;
+		gl_TexCoord[0] = TextureMatrix * tc;
 	#endif
 	
 	gl_Position = ProjectionMatrix * eyeCoordPos;