public TextOutput (
			TextVertexBuffer textBuffer,
			DrawElementsIndirectCommand[] drawCommands,
			SentanceBlockStorageBuffer storage)
		{
			TextBuffer = textBuffer;
			DrawCommands = drawCommands;
			Storage = storage;
			Stride = System.Runtime.InteropServices.Marshal.SizeOf (typeof(DrawElementsIndirectCommand));
		}
		void AddDrawCommand (IList<uint> indicesChunk, uint firstIndex, uint baseVertex, uint currentBlock)
		{
			var command = new DrawElementsIndirectCommand ();
			command.Count = (uint)indicesChunk.Count;
			command.InstanceCount = 1;
			command.FirstIndex = firstIndex;
			command.BaseVertex = baseVertex;
			// IMPORTANT - controls material index
			command.BaseInstance = currentBlock;
			mDrawCommands.Add (command);
		}