Index: source/renderer/VertexBuffer.h
===================================================================
--- source/renderer/VertexBuffer.h
+++ source/renderer/VertexBuffer.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2015 Wildfire Games.
+/* Copyright (C) 2020 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -102,7 +102,11 @@
 	static void Unbind();
 
 	/// Make the vertex data available for the next call to Bind()
-	void PrepareForRendering(VBChunk* chunk) { chunk->m_Needed = true; }
+	void PrepareForRendering(VBChunk* chunk)
+	{
+		chunk->m_Needed = true;
+		m_HasNeededChunks = true;
+	}
 
 	/// Update vertex data for given chunk. Transfers the provided data to the actual OpenGL vertex buffer.
 	void UpdateChunkVertices(VBChunk* chunk, void* data);
@@ -158,6 +162,7 @@
 	GLenum m_Usage;
 	/// Buffer target (GL_ARRAY_BUFFER, GL_ELEMENT_ARRAY_BUFFER)
 	GLenum m_Target;
+	bool m_HasNeededChunks;
 };
 
 #endif
Index: source/renderer/VertexBuffer.cpp
===================================================================
--- source/renderer/VertexBuffer.cpp
+++ source/renderer/VertexBuffer.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2016 Wildfire Games.
+/* Copyright (C) 2020 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -35,7 +35,7 @@
 #define MAX_VB_SIZE_BYTES		(4*1024*1024)
 
 CVertexBuffer::CVertexBuffer(size_t vertexSize, GLenum usage, GLenum target)
-	: m_VertexSize(vertexSize), m_Handle(0), m_SysMem(0), m_Usage(usage), m_Target(target)
+	: m_VertexSize(vertexSize), m_Handle(0), m_SysMem(0), m_Usage(usage), m_Target(target), m_HasNeededChunks(false)
 {
 	size_t size = MAX_VB_SIZE_BYTES;
 
@@ -168,26 +168,18 @@
 
 	// Coalesce with any free-list items that are adjacent to this chunk;
 	// merge the found chunk with the new one, and remove the old one
-	// from the list, and repeat until no more are found
-	bool coalesced;
-	do
+	// from the list
+	for (Iter iter = m_FreeList.begin(); iter != m_FreeList.end(); ++iter)
 	{
-		coalesced = false;
-		for (Iter iter = m_FreeList.begin(); iter != m_FreeList.end(); ++iter)
+		if ((*iter)->m_Index == chunk->m_Index + chunk->m_Count
+		 || (*iter)->m_Index + (*iter)->m_Count == chunk->m_Index)
 		{
-			if ((*iter)->m_Index == chunk->m_Index + chunk->m_Count
-			 || (*iter)->m_Index + (*iter)->m_Count == chunk->m_Index)
-			{
-				chunk->m_Index = std::min(chunk->m_Index, (*iter)->m_Index);
-				chunk->m_Count += (*iter)->m_Count;
-				delete *iter;
-				m_FreeList.erase(iter);
-				coalesced = true;
-				break;
-			}
+			chunk->m_Index = std::min(chunk->m_Index, (*iter)->m_Index);
+			chunk->m_Count += (*iter)->m_Count;
+			delete *iter;
+			iter = std::prev(m_FreeList.erase(iter));
 		}
 	}
-	while (coalesced);
 
 	m_FreeList.push_front(chunk);
 }
@@ -232,8 +224,12 @@
 
 	pglBindBufferARB(m_Target, m_Handle);
 
+
 	if (UseStreaming(m_Usage))
 	{
+		if (!m_HasNeededChunks)
+                        return static_cast<u8*>(0);
+
 		// If any chunks are out of sync with the current VBO, and are
 		// needed for rendering this frame, we'll need to re-upload the VBO
 		bool needUpload = false;
@@ -294,15 +290,20 @@
 			for (VBChunk* const& chunk : m_AllocList)
 			{
 				if (chunk->m_Needed)
+				{
 					chunk->m_Dirty = false;
+					chunk->m_Needed = false;
+				}
 				else
 					chunk->m_Dirty = true;
 			}
 		}
+		else
+			// Reset the flags for the next phase.
+			for (VBChunk* const& chunk : m_AllocList)
+				chunk->m_Needed = false;
 
-		// Reset the flags for the next phase
-		for (VBChunk* const& chunk : m_AllocList)
-			chunk->m_Needed = false;
+		m_HasNeededChunks = false;
 	}
 
 	return (u8*)0;