MaxRectsBinPack FindBestBinPacker(int width, int height, ref List <RectSize> currRects, ref bool allUsed)
        {
            List <MaxRectsBinPack>  binPackers       = new List <MaxRectsBinPack>();
            List <List <RectSize> > binPackerRects   = new List <List <RectSize> >();
            List <bool>             binPackerAllUsed = new List <bool>();

            //MaxRectsBinPack.FreeRectChoiceHeuristic[] heuristics = { MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestAreaFit,
            //                                                         MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestLongSideFit,
            //                                                         MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestShortSideFit,
            //                                                         MaxRectsBinPack.FreeRectChoiceHeuristic.RectBottomLeftRule,
            //                                                         MaxRectsBinPack.FreeRectChoiceHeuristic.RectContactPointRule };

            MaxRectsBinPack.FreeRectChoiceHeuristic[] heuristics = { MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestAreaFit,
                                                                     MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestLongSideFit,
                                                                     MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestShortSideFit,
                                                                     MaxRectsBinPack.FreeRectChoiceHeuristic.RectBottomLeftRule, };

            foreach (var heuristic in heuristics)
            {
                MaxRectsBinPack binPacker     = new MaxRectsBinPack(width, height);
                List <RectSize> activeRects   = new List <RectSize>(currRects);
                bool            activeAllUsed = binPacker.Insert(activeRects, heuristic);

                binPackers.Add(binPacker);
                binPackerRects.Add(activeRects);
                binPackerAllUsed.Add(activeAllUsed);
            }

            int leastWastedPixels = Int32.MaxValue;
            int leastWastedIndex  = -1;

            for (int i = 0; i < binPackers.Count; ++i)
            {
                int wastedPixels = binPackers[i].WastedBinArea();
                if (wastedPixels < leastWastedPixels)
                {
                    leastWastedPixels = wastedPixels;
                    leastWastedIndex  = i;
                    oversizeTextures  = true;
                }
            }

            currRects = binPackerRects[leastWastedIndex];
            allUsed   = binPackerAllUsed[leastWastedIndex];
            return(binPackers[leastWastedIndex]);
        }
        // Returns number of remaining rects
        public int Build()
        {
            // Initialize
            atlases = new List <AtlasData>();
            remainingRectIndices = new List <int>();
            bool[] usedRect = new bool[sourceRects.Count];

            // Sanity check, can't build with textures larger than the actual max atlas size
            int minSize = Math.Min(atlasWidth, atlasHeight);
            int maxSize = Math.Max(atlasWidth, atlasHeight);

            foreach (RectSize rs in sourceRects)
            {
                int maxDim = Math.Max(rs.width, rs.height);
                int minDim = Math.Min(rs.width, rs.height);

                // largest texture needs to fit in an atlas
                if (maxDim > maxSize || (maxDim <= maxSize && minDim > minSize))
                {
                    remainingRectIndices = new List <int>();
                    for (int i = 0; i < sourceRects.Count; ++i)
                    {
                        remainingRectIndices.Add(i);
                    }
                    return(remainingRectIndices.Count);
                }
            }

            // Start with all source rects, this list will get reduced over time
            List <RectSize> rects   = new List <RectSize>(sourceRects);
            bool            allUsed = false;

            while (allUsed == false && atlases.Count < maxAllowedAtlasCount)
            {
                int  numPasses = 1;
                int  thisCellW = atlasWidth, thisCellH = atlasHeight;
                bool reverted = false;

                while (numPasses > 0)
                {
                    // Create copy to make sure we can scale textures down when necessary
                    List <RectSize> currRects = new List <RectSize>(rects);

//					MaxRectsBinPack binPacker = new MaxRectsBinPack(thisCellW, thisCellH);
//					allUsed = binPacker.Insert(currRects, MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestAreaFit);
                    MaxRectsBinPack binPacker = FindBestBinPacker(thisCellW, thisCellH, ref currRects, ref allUsed);
                    float           occupancy = binPacker.Occupancy();

                    // Consider the atlas resolved when after the first pass, all textures are used, and the occupancy > 0.5f, scaling
                    // down by half to maintain PO2 requirements means this is as good as it gets
                    bool firstPassFull = numPasses == 1 && occupancy > 0.5f;

                    // Reverted copes with the case when halving the atlas size when occupancy < 0.5f, the textures don't fit in the
                    // atlas anymore. At this point, size is reverted to the previous value, and the loop should accept this as the final value
                    if (firstPassFull ||
                        (numPasses > 1 && occupancy > 0.5f && allUsed) ||
                        reverted)
                    {
                        List <AtlasEntry> atlasEntries = new List <AtlasEntry>();

                        foreach (var t in binPacker.GetMapped())
                        {
                            int  matchedId = -1;
                            bool flipped   = false;
                            for (int i = 0; i < sourceRects.Count; ++i)
                            {
                                if (!usedRect[i] && sourceRects[i].width == t.width && sourceRects[i].height == t.height)
                                {
                                    matchedId = i;
                                    break;
                                }
                            }

                            // Not matched anything yet, so look for the same rects rotated
                            if (matchedId == -1)
                            {
                                for (int i = 0; i < sourceRects.Count; ++i)
                                {
                                    if (!usedRect[i] && sourceRects[i].width == t.height && sourceRects[i].height == t.width)
                                    {
                                        matchedId = i;
                                        flipped   = true;
                                        break;
                                    }
                                }
                            }

                            // If this fails its a catastrophic error
                            usedRect[matchedId] = true;
                            AtlasEntry newEntry = new AtlasEntry();
                            newEntry.flipped = flipped;
                            newEntry.x       = t.x;
                            newEntry.y       = t.y;
                            newEntry.w       = t.width;
                            newEntry.h       = t.height;
                            newEntry.index   = matchedId;
                            atlasEntries.Add(newEntry);
                        }

                        AtlasData currAtlas = new AtlasData();
                        currAtlas.width     = thisCellW;
                        currAtlas.height    = thisCellH;
                        currAtlas.occupancy = binPacker.Occupancy();
                        currAtlas.entries   = atlasEntries.ToArray();

                        atlases.Add(currAtlas);

                        rects = currRects;
                        break;                         // done
                    }
                    else
                    {
                        if (!allUsed)
                        {
                            // Can only try another size when it already has been scaled down for the first time
                            if (thisCellW < atlasWidth && thisCellH < atlasHeight)
                            {
                                // Tried to scale down, but the texture doesn't fit, so revert previous change, and
                                // iterate over the data again forcing a pass even though there is wastage
                                if (thisCellW < thisCellH)
                                {
                                    thisCellW *= 2;
                                }
                                else
                                {
                                    thisCellH *= 2;
                                }
                            }


                            reverted = true;
                        }
                        else
                        {
                            // More than half the texture was unused, scale down by one of the dimensions
                            if (thisCellW < thisCellH)
                            {
                                thisCellH /= 2;
                            }
                            else
                            {
                                thisCellW /= 2;
                            }
                        }

                        numPasses++;
                    }
                }
            }

            remainingRectIndices = new List <int>();
            for (int i = 0; i < usedRect.Length; ++i)
            {
                if (!usedRect[i])
                {
                    remainingRectIndices.Add(i);
                }
            }

            return(remainingRectIndices.Count);
        }
        MaxRectsBinPack FindBestBinPacker(int width, int height, ref List<RectSize> currRects, ref bool allUsed)
        {
            List<MaxRectsBinPack> binPackers = new List<MaxRectsBinPack>();
            List<List<RectSize>> binPackerRects = new List<List<RectSize>>();
            List<bool> binPackerAllUsed = new List<bool>();

            //MaxRectsBinPack.FreeRectChoiceHeuristic[] heuristics = { MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestAreaFit,
            //                                                         MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestLongSideFit,
            //                                                         MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestShortSideFit,
            //                                                         MaxRectsBinPack.FreeRectChoiceHeuristic.RectBottomLeftRule,
            //                                                         MaxRectsBinPack.FreeRectChoiceHeuristic.RectContactPointRule };

            MaxRectsBinPack.FreeRectChoiceHeuristic[] heuristics = { MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestAreaFit,
                                                                     MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestLongSideFit,
                                                                     MaxRectsBinPack.FreeRectChoiceHeuristic.RectBestShortSideFit,
                                                                     MaxRectsBinPack.FreeRectChoiceHeuristic.RectBottomLeftRule,
                                                                      };

            foreach (var heuristic in heuristics)
            {
                MaxRectsBinPack binPacker = new MaxRectsBinPack(width, height);
                List<RectSize> activeRects = new List<RectSize>(currRects);
                bool activeAllUsed = binPacker.Insert(activeRects, heuristic);

                binPackers.Add(binPacker);
                binPackerRects.Add(activeRects);
                binPackerAllUsed.Add(activeAllUsed);
            }

            int leastWastedPixels = Int32.MaxValue;
            int leastWastedIndex = -1;
            for (int i = 0; i < binPackers.Count; ++i)
            {
                int wastedPixels = binPackers[i].WastedBinArea();
                if (wastedPixels < leastWastedPixels)
                {
                    leastWastedPixels = wastedPixels;
                    leastWastedIndex = i;
                    oversizeTextures = true;
                }
            }

            currRects = binPackerRects[leastWastedIndex];
            allUsed = binPackerAllUsed[leastWastedIndex];
            return binPackers[leastWastedIndex];
        }