Use a better packing algorithm for the texture atlases

- The old algorithm is something I threw together that produced decent, but not spectacular results since it had a tendency to waste space by forcing everything onto "shelves". The new packer is the Skyline-MinWaste-WasteMap-BestFirstFit algorithm described by Jukka Jylanki in his paper *A Thousand Ways to Pack the Bin - A Practical Approach to Two-Dimensional Rectangle Bin Packing*, which can currently be read at http://clb.demon.fi/files/RectangleBinPack.pdf This is minus the optimization to rotate rectangles to make better fits.
2024-11-10 14:51:46 +00:00 · 2016-01-08 22:07:16 -06:00 · 2016-01-08 22:07:16 -06:00 · bf31d66d31
commit bf31d66d31
parent f330a81909
9 changed files with 1378 additions and 251 deletions
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@ -995,6 +995,8 @@ add_executable( zdoom WIN32 MACOSX_BUNDLE
 	wi_stuff.cpp
 	zstrformat.cpp
 	zstring.cpp
+	GuillotineBinPack.cpp
+	SkylineBinPack.cpp
 	g_doom/a_doommisc.cpp
 	g_heretic/a_hereticmisc.cpp
 	g_hexen/a_hexenmisc.cpp
--- a/src/GuillotineBinPack.cpp
+++ b/src/GuillotineBinPack.cpp
@ -0,0 +1,633 @@
+/** @file GuillotineBinPack.cpp
+	@author Jukka Jylänki
+
+	@brief Implements different bin packer algorithms that use the GUILLOTINE data structure.
+
+	This work is released to Public Domain, do whatever you want with it.
+*/
+
+#include <cassert>
+
+#include "GuillotineBinPack.h"
+
+using namespace std;
+
+GuillotineBinPack::GuillotineBinPack()
+:binWidth(0),
+binHeight(0)
+{
+}
+
+GuillotineBinPack::GuillotineBinPack(int width, int height)
+{
+	Init(width, height);
+}
+
+void GuillotineBinPack::Init(int width, int height)
+{
+	binWidth = width;
+	binHeight = height;
+
+#ifdef _DEBUG
+	disjointRects.Clear();
+#endif
+
+	// Clear any memory of previously packed rectangles.
+	usedRectangles.Clear();
+
+	// We start with a single big free rectangle that spans the whole bin.
+	Rect n;
+	n.x = 0;
+	n.y = 0;
+	n.width = width;
+	n.height = height;
+
+	freeRectangles.Clear();
+	freeRectangles.Push(n);
+}
+
+void GuillotineBinPack::Insert(TArray<RectSize> &rects, TArray<Rect> &dst, bool merge, 
+	FreeRectChoiceHeuristic rectChoice, GuillotineSplitHeuristic splitMethod)
+{
+	dst.Clear();
+
+	// Remember variables about the best packing choice we have made so far during the iteration process.
+	int bestFreeRect = 0;
+	int bestRect = 0;
+	bool bestFlipped = false;
+
+	// Pack rectangles one at a time until we have cleared the rects array of all rectangles.
+	// rects will get destroyed in the process.
+	while(rects.Size() > 0)
+	{
+		// Stores the penalty score of the best rectangle placement - bigger=worse, smaller=better.
+		int bestScore = INT_MAX;
+
+		for(unsigned i = 0; i < freeRectangles.Size(); ++i)
+		{
+			for(unsigned j = 0; j < rects.Size(); ++j)
+			{
+				// If this rectangle is a perfect match, we pick it instantly.
+				if (rects[j].width == freeRectangles[i].width && rects[j].height == freeRectangles[i].height)
+				{
+					bestFreeRect = i;
+					bestRect = j;
+					bestFlipped = false;
+					bestScore = INT_MIN;
+					i = freeRectangles.Size(); // Force a jump out of the outer loop as well - we got an instant fit.
+					break;
+				}
+				// If flipping this rectangle is a perfect match, pick that then.
+				else if (rects[j].height == freeRectangles[i].width && rects[j].width == freeRectangles[i].height)
+				{
+					bestFreeRect = i;
+					bestRect = j;
+					bestFlipped = true;
+					bestScore = INT_MIN;
+					i = freeRectangles.Size(); // Force a jump out of the outer loop as well - we got an instant fit.
+					break;
+				}
+				// Try if we can fit the rectangle upright.
+				else if (rects[j].width <= freeRectangles[i].width && rects[j].height <= freeRectangles[i].height)
+				{
+					int score = ScoreByHeuristic(rects[j].width, rects[j].height, freeRectangles[i], rectChoice);
+					if (score < bestScore)
+					{
+						bestFreeRect = i;
+						bestRect = j;
+						bestFlipped = false;
+						bestScore = score;
+					}
+				}
+				// If not, then perhaps flipping sideways will make it fit?
+				else if (rects[j].height <= freeRectangles[i].width && rects[j].width <= freeRectangles[i].height)
+				{
+					int score = ScoreByHeuristic(rects[j].height, rects[j].width, freeRectangles[i], rectChoice);
+					if (score < bestScore)
+					{
+						bestFreeRect = i;
+						bestRect = j;
+						bestFlipped = true;
+						bestScore = score;
+					}
+				}
+			}
+		}
+
+		// If we didn't manage to find any rectangle to pack, abort.
+		if (bestScore == INT_MAX)
+			return;
+
+		// Otherwise, we're good to go and do the actual packing.
+		Rect newNode;
+		newNode.x = freeRectangles[bestFreeRect].x;
+		newNode.y = freeRectangles[bestFreeRect].y;
+		newNode.width = rects[bestRect].width;
+		newNode.height = rects[bestRect].height;
+
+		if (bestFlipped)
+			std::swap(newNode.width, newNode.height);
+
+		// Remove the free space we lost in the bin.
+		SplitFreeRectByHeuristic(freeRectangles[bestFreeRect], newNode, splitMethod);
+		freeRectangles.Delete(bestFreeRect);
+
+		// Remove the rectangle we just packed from the input list.
+		rects.Delete(bestRect);
+
+		// Perform a Rectangle Merge step if desired.
+		if (merge)
+			MergeFreeList();
+
+		// Remember the new used rectangle.
+		usedRectangles.Push(newNode);
+
+		// Check that we're really producing correct packings here.
+		assert(disjointRects.Add(newNode) == true);
+	}
+}
+
+/// @return True if r fits inside freeRect (possibly rotated).
+bool Fits(const RectSize &r, const Rect &freeRect)
+{
+	return (r.width <= freeRect.width && r.height <= freeRect.height) ||
+		(r.height <= freeRect.width && r.width <= freeRect.height);
+}
+
+/// @return True if r fits perfectly inside freeRect, i.e. the leftover area is 0.
+bool FitsPerfectly(const RectSize &r, const Rect &freeRect)
+{
+	return (r.width == freeRect.width && r.height == freeRect.height) ||
+		(r.height == freeRect.width && r.width == freeRect.height);
+}
+
+/*
+// A helper function for GUILLOTINE-MAXFITTING. Counts how many rectangles fit into the given rectangle
+// after it has been split.
+void CountNumFitting(const Rect &freeRect, int width, int height, const TArray<RectSize> &rects, 
+	int usedRectIndex, bool splitHorizontal, int &score1, int &score2)
+{
+	const int w = freeRect.width - width;
+	const int h = freeRect.height - height;
+
+	Rect bottom;
+	bottom.x = freeRect.x;
+	bottom.y = freeRect.y + height;
+	bottom.height = h;
+
+	Rect right;
+	right.x = freeRect.x + width;
+	right.y = freeRect.y;
+	right.width = w;
+
+	if (splitHorizontal)
+	{
+		bottom.width = freeRect.width;
+		right.height = height;
+	}
+	else // Split vertically
+	{
+		bottom.width = width;
+		right.height = freeRect.height;
+	}
+
+	int fitBottom = 0;
+	int fitRight = 0;
+	for(size_t i = 0; i < rects.size(); ++i)
+		if (i != usedRectIndex)
+		{
+			if (FitsPerfectly(rects[i], bottom))
+				fitBottom |= 0x10000000;
+			if (FitsPerfectly(rects[i], right))
+				fitRight |= 0x10000000;
+
+			if (Fits(rects[i], bottom))
+				++fitBottom;
+			if (Fits(rects[i], right))
+				++fitRight;
+		}
+
+	score1 = min(fitBottom, fitRight);
+	score2 = max(fitBottom, fitRight);
+}
+*/
+/*
+// Implements GUILLOTINE-MAXFITTING, an experimental heuristic that's really cool but didn't quite work in practice.
+void GuillotineBinPack::InsertMaxFitting(TArray<RectSize> &rects, TArray<Rect> &dst, bool merge, 
+	FreeRectChoiceHeuristic rectChoice, GuillotineSplitHeuristic splitMethod)
+{
+	dst.clear();
+	int bestRect = 0;
+	bool bestFlipped = false;
+	bool bestSplitHorizontal = false;
+
+	// Pick rectangles one at a time and pack the one that leaves the most choices still open.
+	while(rects.size() > 0 && freeRectangles.size() > 0)
+	{
+		int bestScore1 = -1;
+		int bestScore2 = -1;
+
+		///\todo Different sort predicates.
+		clb::sort::QuickSort(&freeRectangles[0], freeRectangles.size(), CompareRectShortSide);
+
+		Rect &freeRect = freeRectangles[0];
+
+		for(size_t j = 0; j < rects.size(); ++j)
+		{
+			int score1;
+			int score2;
+
+			if (rects[j].width == freeRect.width && rects[j].height == freeRect.height)
+			{
+				bestRect = j;
+				bestFlipped = false;
+				bestScore1 = bestScore2 = std::numeric_limits<int>::max();
+				break;
+			}
+			else if (rects[j].width <= freeRect.width && rects[j].height <= freeRect.height)
+			{
+				CountNumFitting(freeRect, rects[j].width, rects[j].height, rects, j, false, score1, score2);
+
+				if (score1 > bestScore1 || (score1 == bestScore1 && score2 > bestScore2))
+				{
+					bestRect = j;
+					bestScore1 = score1;
+					bestScore2 = score2;
+					bestFlipped = false;
+					bestSplitHorizontal = false;
+				}
+
+				CountNumFitting(freeRect, rects[j].width, rects[j].height, rects, j, true, score1, score2);
+
+				if (score1 > bestScore1 || (score1 == bestScore1 && score2 > bestScore2))
+				{
+					bestRect = j;
+					bestScore1 = score1;
+					bestScore2 = score2;
+					bestFlipped = false;
+					bestSplitHorizontal = true;
+				}
+			}
+
+			if (rects[j].height == freeRect.width && rects[j].width == freeRect.height)
+			{
+				bestRect = j;
+				bestFlipped = true;
+				bestScore1 = bestScore2 = std::numeric_limits<int>::max();
+				break;
+			}
+			else if (rects[j].height <= freeRect.width && rects[j].width <= freeRect.height)
+			{
+				CountNumFitting(freeRect, rects[j].height, rects[j].width, rects, j, false, score1, score2);
+
+				if (score1 > bestScore1 || (score1 == bestScore1 && score2 > bestScore2))
+				{
+					bestRect = j;
+					bestScore1 = score1;
+					bestScore2 = score2;
+					bestFlipped = true;
+					bestSplitHorizontal = false;
+				}
+
+				CountNumFitting(freeRect, rects[j].height, rects[j].width, rects, j, true, score1, score2);
+
+				if (score1 > bestScore1 || (score1 == bestScore1 && score2 > bestScore2))
+				{
+					bestRect = j;
+					bestScore1 = score1;
+					bestScore2 = score2;
+					bestFlipped = true;
+					bestSplitHorizontal = true;
+				}
+			}
+		}
+
+		if (bestScore1 >= 0)
+		{
+			Rect newNode;
+			newNode.x = freeRect.x;
+			newNode.y = freeRect.y;
+			newNode.width = rects[bestRect].width;
+			newNode.height = rects[bestRect].height;
+			if (bestFlipped)
+				std::swap(newNode.width, newNode.height);
+
+			assert(disjointRects.Disjoint(newNode));
+			SplitFreeRectAlongAxis(freeRect, newNode, bestSplitHorizontal);
+
+			rects.erase(rects.begin() + bestRect);
+
+			if (merge)
+				MergeFreeList();
+
+			usedRectangles.push_back(newNode);
+#ifdef _DEBUG
+			disjointRects.Add(newNode);
+#endif
+		}
+
+		freeRectangles.erase(freeRectangles.begin());
+	}
+}
+*/
+
+Rect GuillotineBinPack::Insert(int width, int height, bool merge, FreeRectChoiceHeuristic rectChoice, 
+	GuillotineSplitHeuristic splitMethod)
+{
+	// Find where to put the new rectangle.
+	int freeNodeIndex = 0;
+	Rect newRect = FindPositionForNewNode(width, height, rectChoice, &freeNodeIndex);
+
+	// Abort if we didn't have enough space in the bin.
+	if (newRect.height == 0)
+		return newRect;
+
+	// Remove the space that was just consumed by the new rectangle.
+	SplitFreeRectByHeuristic(freeRectangles[freeNodeIndex], newRect, splitMethod);
+	freeRectangles.Delete(freeNodeIndex);
+
+	// Perform a Rectangle Merge step if desired.
+	if (merge)
+		MergeFreeList();
+
+	// Remember the new used rectangle.
+	usedRectangles.Push(newRect);
+
+	// Check that we're really producing correct packings here.
+	assert(disjointRects.Add(newRect) == true);
+
+	return newRect;
+}
+
+/// Computes the ratio of used surface area to the total bin area.
+float GuillotineBinPack::Occupancy() const
+{
+	///\todo The occupancy rate could be cached/tracked incrementally instead
+	///      of looping through the list of packed rectangles here.
+	unsigned long usedSurfaceArea = 0;
+	for(unsigned i = 0; i < usedRectangles.Size(); ++i)
+		usedSurfaceArea += usedRectangles[i].width * usedRectangles[i].height;
+
+	return (float)usedSurfaceArea / (binWidth * binHeight);
+}
+
+/// Returns the heuristic score value for placing a rectangle of size width*height into freeRect. Does not try to rotate.
+int GuillotineBinPack::ScoreByHeuristic(int width, int height, const Rect &freeRect, FreeRectChoiceHeuristic rectChoice)
+{
+	switch(rectChoice)
+	{
+	case RectBestAreaFit: return ScoreBestAreaFit(width, height, freeRect);
+	case RectBestShortSideFit: return ScoreBestShortSideFit(width, height, freeRect);
+	case RectBestLongSideFit: return ScoreBestLongSideFit(width, height, freeRect);
+	case RectWorstAreaFit: return ScoreWorstAreaFit(width, height, freeRect);
+	case RectWorstShortSideFit: return ScoreWorstShortSideFit(width, height, freeRect);
+	case RectWorstLongSideFit: return ScoreWorstLongSideFit(width, height, freeRect);
+	default: assert(false); return INT_MAX;
+	}
+}
+
+int GuillotineBinPack::ScoreBestAreaFit(int width, int height, const Rect &freeRect)
+{
+	return freeRect.width * freeRect.height - width * height;
+}
+
+int GuillotineBinPack::ScoreBestShortSideFit(int width, int height, const Rect &freeRect)
+{
+	int leftoverHoriz = abs(freeRect.width - width);
+	int leftoverVert = abs(freeRect.height - height);
+	int leftover = min(leftoverHoriz, leftoverVert);
+	return leftover;
+}
+
+int GuillotineBinPack::ScoreBestLongSideFit(int width, int height, const Rect &freeRect)
+{
+	int leftoverHoriz = abs(freeRect.width - width);
+	int leftoverVert = abs(freeRect.height - height);
+	int leftover = max(leftoverHoriz, leftoverVert);
+	return leftover;
+}
+
+int GuillotineBinPack::ScoreWorstAreaFit(int width, int height, const Rect &freeRect)
+{
+	return -ScoreBestAreaFit(width, height, freeRect);
+}
+
+int GuillotineBinPack::ScoreWorstShortSideFit(int width, int height, const Rect &freeRect)
+{
+	return -ScoreBestShortSideFit(width, height, freeRect);
+}
+
+int GuillotineBinPack::ScoreWorstLongSideFit(int width, int height, const Rect &freeRect)
+{
+	return -ScoreBestLongSideFit(width, height, freeRect);
+}
+
+Rect GuillotineBinPack::FindPositionForNewNode(int width, int height, FreeRectChoiceHeuristic rectChoice, int *nodeIndex)
+{
+	Rect bestNode;
+	memset(&bestNode, 0, sizeof(Rect));
+
+	int bestScore = INT_MAX;
+
+	/// Try each free rectangle to find the best one for placement.
+	for(unsigned i = 0; i < freeRectangles.Size(); ++i)
+	{
+		// If this is a perfect fit upright, choose it immediately.
+		if (width == freeRectangles[i].width && height == freeRectangles[i].height)
+		{
+			bestNode.x = freeRectangles[i].x;
+			bestNode.y = freeRectangles[i].y;
+			bestNode.width = width;
+			bestNode.height = height;
+			bestScore = INT_MIN;
+			*nodeIndex = i;
+			assert(disjointRects.Disjoint(bestNode));
+			break;
+		}
+		// If this is a perfect fit sideways, choose it.
+/*		else if (height == freeRectangles[i].width && width == freeRectangles[i].height)
+		{
+			bestNode.x = freeRectangles[i].x;
+			bestNode.y = freeRectangles[i].y;
+			bestNode.width = height;
+			bestNode.height = width;
+			bestScore = INT_MIN;
+			*nodeIndex = i;
+			assert(disjointRects.Disjoint(bestNode));
+			break;
+		}
+*/		// Does the rectangle fit upright?
+		else if (width <= freeRectangles[i].width && height <= freeRectangles[i].height)
+		{
+			int score = ScoreByHeuristic(width, height, freeRectangles[i], rectChoice);
+
+			if (score < bestScore)
+			{
+				bestNode.x = freeRectangles[i].x;
+				bestNode.y = freeRectangles[i].y;
+				bestNode.width = width;
+				bestNode.height = height;
+				bestScore = score;
+				*nodeIndex = i;
+				assert(disjointRects.Disjoint(bestNode));
+			}
+		}
+		// Does the rectangle fit sideways?
+/*		else if (height <= freeRectangles[i].width && width <= freeRectangles[i].height)
+		{
+			int score = ScoreByHeuristic(height, width, freeRectangles[i], rectChoice);
+
+			if (score < bestScore)
+			{
+				bestNode.x = freeRectangles[i].x;
+				bestNode.y = freeRectangles[i].y;
+				bestNode.width = height;
+				bestNode.height = width;
+				bestScore = score;
+				*nodeIndex = i;
+				assert(disjointRects.Disjoint(bestNode));
+			}
+		}
+*/	}
+	return bestNode;
+}
+
+void GuillotineBinPack::SplitFreeRectByHeuristic(const Rect &freeRect, const Rect &placedRect, GuillotineSplitHeuristic method)
+{
+	// Compute the lengths of the leftover area.
+	const int w = freeRect.width - placedRect.width;
+	const int h = freeRect.height - placedRect.height;
+
+	// Placing placedRect into freeRect results in an L-shaped free area, which must be split into
+	// two disjoint rectangles. This can be achieved with by splitting the L-shape using a single line.
+	// We have two choices: horizontal or vertical.	
+
+	// Use the given heuristic to decide which choice to make.
+
+	bool splitHorizontal;
+	switch(method)
+	{
+	case SplitShorterLeftoverAxis:
+		// Split along the shorter leftover axis.
+		splitHorizontal = (w <= h);
+		break;
+	case SplitLongerLeftoverAxis:
+		// Split along the longer leftover axis.
+		splitHorizontal = (w > h);
+		break;
+	case SplitMinimizeArea:
+		// Maximize the larger area == minimize the smaller area.
+		// Tries to make the single bigger rectangle.
+		splitHorizontal = (placedRect.width * h > w * placedRect.height);
+		break;
+	case SplitMaximizeArea:
+		// Maximize the smaller area == minimize the larger area.
+		// Tries to make the rectangles more even-sized.
+		splitHorizontal = (placedRect.width * h <= w * placedRect.height);
+		break;
+	case SplitShorterAxis:
+		// Split along the shorter total axis.
+		splitHorizontal = (freeRect.width <= freeRect.height);
+		break;
+	case SplitLongerAxis:
+		// Split along the longer total axis.
+		splitHorizontal = (freeRect.width > freeRect.height);
+		break;
+	default:
+		splitHorizontal = true;
+		assert(false);
+	}
+
+	// Perform the actual split.
+	SplitFreeRectAlongAxis(freeRect, placedRect, splitHorizontal);
+}
+
+/// This function will add the two generated rectangles into the freeRectangles array. The caller is expected to
+/// remove the original rectangle from the freeRectangles array after that.
+void GuillotineBinPack::SplitFreeRectAlongAxis(const Rect &freeRect, const Rect &placedRect, bool splitHorizontal)
+{
+	// Form the two new rectangles.
+	Rect bottom;
+	bottom.x = freeRect.x;
+	bottom.y = freeRect.y + placedRect.height;
+	bottom.height = freeRect.height - placedRect.height;
+
+	Rect right;
+	right.x = freeRect.x + placedRect.width;
+	right.y = freeRect.y;
+	right.width = freeRect.width - placedRect.width;
+
+	if (splitHorizontal)
+	{
+		bottom.width = freeRect.width;
+		right.height = placedRect.height;
+	}
+	else // Split vertically
+	{
+		bottom.width = placedRect.width;
+		right.height = freeRect.height;
+	}
+
+	// Add the new rectangles into the free rectangle pool if they weren't degenerate.
+	if (bottom.width > 0 && bottom.height > 0)
+		freeRectangles.Push(bottom);
+	if (right.width > 0 && right.height > 0)
+		freeRectangles.Push(right);
+
+	assert(disjointRects.Disjoint(bottom));
+	assert(disjointRects.Disjoint(right));
+}
+
+void GuillotineBinPack::MergeFreeList()
+{
+#ifdef _DEBUG
+	DisjointRectCollection test;
+	for(unsigned i = 0; i < freeRectangles.Size(); ++i)
+		assert(test.Add(freeRectangles[i]) == true);
+#endif
+
+	// Do a Theta(n^2) loop to see if any pair of free rectangles could me merged into one.
+	// Note that we miss any opportunities to merge three rectangles into one. (should call this function again to detect that)
+	for(unsigned i = 0; i < freeRectangles.Size(); ++i)
+		for(unsigned j = i+1; j < freeRectangles.Size(); ++j)
+		{
+			if (freeRectangles[i].width == freeRectangles[j].width && freeRectangles[i].x == freeRectangles[j].x)
+			{
+				if (freeRectangles[i].y == freeRectangles[j].y + freeRectangles[j].height)
+				{
+					freeRectangles[i].y -= freeRectangles[j].height;
+					freeRectangles[i].height += freeRectangles[j].height;
+					freeRectangles.Delete(j);
+					--j;
+				}
+				else if (freeRectangles[i].y + freeRectangles[i].height == freeRectangles[j].y)
+				{
+					freeRectangles[i].height += freeRectangles[j].height;
+					freeRectangles.Delete(j);
+					--j;
+				}
+			}
+			else if (freeRectangles[i].height == freeRectangles[j].height && freeRectangles[i].y == freeRectangles[j].y)
+			{
+				if (freeRectangles[i].x == freeRectangles[j].x + freeRectangles[j].width)
+				{
+					freeRectangles[i].x -= freeRectangles[j].width;
+					freeRectangles[i].width += freeRectangles[j].width;
+					freeRectangles.Delete(j);
+					--j;
+				}
+				else if (freeRectangles[i].x + freeRectangles[i].width == freeRectangles[j].x)
+				{
+					freeRectangles[i].width += freeRectangles[j].width;
+					freeRectangles.Delete(j);
+					--j;
+				}
+			}
+		}
+
+#ifdef _DEBUG
+	test.Clear();
+	for(unsigned i = 0; i < freeRectangles.Size(); ++i)
+		assert(test.Add(freeRectangles[i]) == true);
+#endif
+}
--- a/src/GuillotineBinPack.h
+++ b/src/GuillotineBinPack.h
@ -0,0 +1,135 @@
+/** @file GuillotineBinPack.h
+	@author Jukka Jylänki
+
+	@brief Implements different bin packer algorithms that use the GUILLOTINE data structure.
+
+	This work is released to Public Domain, do whatever you want with it.
+*/
+#pragma once
+
+#include "tarray.h"
+
+#include "Rect.h"
+
+/** GuillotineBinPack implements different variants of bin packer algorithms that use the GUILLOTINE data structure
+	to keep track of the free space of the bin where rectangles may be placed. */
+class GuillotineBinPack
+{
+public:
+	/// The initial bin size will be (0,0). Call Init to set the bin size.
+	GuillotineBinPack();
+
+	/// Initializes a new bin of the given size.
+	GuillotineBinPack(int width, int height);
+
+	/// (Re)initializes the packer to an empty bin of width x height units. Call whenever
+	/// you need to restart with a new bin.
+	void Init(int width, int height);
+
+	/// Specifies the different choice heuristics that can be used when deciding which of the free subrectangles
+	/// to place the to-be-packed rectangle into.
+	enum FreeRectChoiceHeuristic
+	{
+		RectBestAreaFit, ///< -BAF
+		RectBestShortSideFit, ///< -BSSF
+		RectBestLongSideFit, ///< -BLSF
+		RectWorstAreaFit, ///< -WAF
+		RectWorstShortSideFit, ///< -WSSF
+		RectWorstLongSideFit ///< -WLSF
+	};
+
+	/// Specifies the different choice heuristics that can be used when the packer needs to decide whether to
+	/// subdivide the remaining free space in horizontal or vertical direction.
+	enum GuillotineSplitHeuristic
+	{
+		SplitShorterLeftoverAxis, ///< -SLAS
+		SplitLongerLeftoverAxis, ///< -LLAS
+		SplitMinimizeArea, ///< -MINAS, Try to make a single big rectangle at the expense of making the other small.
+		SplitMaximizeArea, ///< -MAXAS, Try to make both remaining rectangles as even-sized as possible.
+		SplitShorterAxis, ///< -SAS
+		SplitLongerAxis ///< -LAS
+	};
+
+	/// Inserts a single rectangle into the bin. The packer might rotate the rectangle, in which case the returned
+	/// struct will have the width and height values swapped.
+	/// @param merge If true, performs free Rectangle Merge procedure after packing the new rectangle. This procedure
+	///		tries to defragment the list of disjoint free rectangles to improve packing performance, but also takes up 
+	///		some extra time.
+	/// @param rectChoice The free rectangle choice heuristic rule to use.
+	/// @param splitMethod The free rectangle split heuristic rule to use.
+	Rect Insert(int width, int height, bool merge, FreeRectChoiceHeuristic rectChoice, GuillotineSplitHeuristic splitMethod);
+
+	/// Inserts a list of rectangles into the bin.
+	/// @param rects The list of rectangles to add. This list will be destroyed in the packing process.
+	/// @param dst The outputted list of rectangles. Note that the indices will not correspond to the input indices.
+	/// @param merge If true, performs Rectangle Merge operations during the packing process.
+	/// @param rectChoice The free rectangle choice heuristic rule to use.
+	/// @param splitMethod The free rectangle split heuristic rule to use.
+	void Insert(TArray<RectSize> &rects, TArray<Rect> &dst, bool merge, 
+		FreeRectChoiceHeuristic rectChoice, GuillotineSplitHeuristic splitMethod);
+
+// Implements GUILLOTINE-MAXFITTING, an experimental heuristic that's really cool but didn't quite work in practice.
+//	void InsertMaxFitting(TArray<RectSize> &rects, TArray<Rect> &dst, bool merge, 
+//		FreeRectChoiceHeuristic rectChoice, GuillotineSplitHeuristic splitMethod);
+
+	/// Computes the ratio of used/total surface area. 0.00 means no space is yet used, 1.00 means the whole bin is used.
+	float Occupancy() const;
+
+	/// Returns the internal list of disjoint rectangles that track the free area of the bin. You may alter this vector
+	/// any way desired, as long as the end result still is a list of disjoint rectangles.
+	TArray<Rect> &GetFreeRectangles() { return freeRectangles; }
+
+	/// Returns the list of packed rectangles. You may alter this vector at will, for example, you can move a Rect from
+	/// this list to the Free Rectangles list to free up space on-the-fly, but notice that this causes fragmentation.
+	TArray<Rect> &GetUsedRectangles() { return usedRectangles; }
+
+	/// Performs a Rectangle Merge operation. This procedure looks for adjacent free rectangles and merges them if they
+	/// can be represented with a single rectangle. Takes up Theta(|freeRectangles|^2) time.
+	void MergeFreeList();
+
+#ifdef _DEBUG
+	void DelDisjoint(const Rect &r) { disjointRects.Del(r); }
+#endif
+
+private:
+	int binWidth;
+	int binHeight;
+
+	/// Stores a list of all the rectangles that we have packed so far. This is used only to compute the Occupancy ratio,
+	/// so if you want to have the packer consume less memory, this can be removed.
+	TArray<Rect> usedRectangles;
+
+	/// Stores a list of rectangles that represents the free area of the bin. This rectangles in this list are disjoint.
+	TArray<Rect> freeRectangles;
+
+#ifdef _DEBUG
+	/// Used to track that the packer produces proper packings.
+	DisjointRectCollection disjointRects;
+#endif
+
+	/// Goes through the list of free rectangles and finds the best one to place a rectangle of given size into.
+	/// Running time is Theta(|freeRectangles|).
+	/// @param nodeIndex [out] The index of the free rectangle in the freeRectangles array into which the new
+	///		rect was placed.
+	/// @return A Rect structure that represents the placement of the new rect into the best free rectangle.
+	Rect FindPositionForNewNode(int width, int height, FreeRectChoiceHeuristic rectChoice, int *nodeIndex);
+
+	static int ScoreByHeuristic(int width, int height, const Rect &freeRect, FreeRectChoiceHeuristic rectChoice);
+	// The following functions compute (penalty) score values if a rect of the given size was placed into the 
+	// given free rectangle. In these score values, smaller is better.
+
+	static int ScoreBestAreaFit(int width, int height, const Rect &freeRect);
+	static int ScoreBestShortSideFit(int width, int height, const Rect &freeRect);
+	static int ScoreBestLongSideFit(int width, int height, const Rect &freeRect);
+
+	static int ScoreWorstAreaFit(int width, int height, const Rect &freeRect);
+	static int ScoreWorstShortSideFit(int width, int height, const Rect &freeRect);
+	static int ScoreWorstLongSideFit(int width, int height, const Rect &freeRect);
+
+	/// Splits the given L-shaped free rectangle into two new free rectangles after placedRect has been placed into it.
+	/// Determines the split axis by using the given heuristic.
+	void SplitFreeRectByHeuristic(const Rect &freeRect, const Rect &placedRect, GuillotineSplitHeuristic method);
+
+	/// Splits the given L-shaped free rectangle into two new free rectangles along the given fixed split axis.
+	void SplitFreeRectAlongAxis(const Rect &freeRect, const Rect &placedRect, bool splitHorizontal);
+};
--- a/src/Rect.h
+++ b/src/Rect.h
@ -0,0 +1,94 @@
+/** @file Rect.h
+	@author Jukka Jylänki
+
+	This work is released to Public Domain, do whatever you want with it.
+*/
+#pragma once
+
+#include <vector>
+
+struct RectSize
+{
+	int width;
+	int height;
+};
+
+struct Rect
+{
+	int x;
+	int y;
+	int width;
+	int height;
+};
+
+/// Performs a lexicographic compare on (rect short side, rect long side).
+/// @return -1 if the smaller side of a is shorter than the smaller side of b, 1 if the other way around.
+///   If they are equal, the larger side length is used as a tie-breaker.
+///   If the rectangles are of same size, returns 0.
+int CompareRectShortSide(const Rect &a, const Rect &b);
+
+/// Performs a lexicographic compare on (x, y, width, height).
+int NodeSortCmp(const Rect &a, const Rect &b);
+
+/// Returns true if a is contained in b.
+bool IsContainedIn(const Rect &a, const Rect &b);
+
+#ifdef _DEBUG
+class DisjointRectCollection
+{
+public:
+	TArray<Rect> rects;
+
+	bool Add(const Rect &r)
+	{
+		// Degenerate rectangles are ignored.
+		if (r.width == 0 || r.height == 0)
+			return true;
+
+		if (!Disjoint(r))
+			return false;
+		rects.Push(r);
+		return true;
+	}
+
+	bool Del(const Rect &r)
+	{
+		for(unsigned i = 0; i < rects.Size(); ++i)
+		{
+			if(r.x == rects[i].x && r.y == rects[i].y && r.width == rects[i].width && r.height == rects[i].height)
+			{
+				rects.Delete(i);
+				return true;
+			}
+		}
+		return false;
+	}
+
+	void Clear()
+	{
+		rects.Clear();
+	}
+
+	bool Disjoint(const Rect &r) const
+	{
+		// Degenerate rectangles are ignored.
+		if (r.width == 0 || r.height == 0)
+			return true;
+
+		for(unsigned i = 0; i < rects.Size(); ++i)
+			if (!Disjoint(rects[i], r))
+				return false;
+		return true;
+	}
+
+	static bool Disjoint(const Rect &a, const Rect &b)
+	{
+		if (a.x + a.width <= b.x ||
+			b.x + b.width <= a.x ||
+			a.y + a.height <= b.y ||
+			b.y + b.height <= a.y)
+			return true;
+		return false;
+	}
+};
+#endif
--- a/src/SkylineBinPack.cpp
+++ b/src/SkylineBinPack.cpp
@ -0,0 +1,329 @@
+/** @file SkylineBinPack.cpp
+	@author Jukka Jylänki
+
+	@brief Implements different bin packer algorithms that use the SKYLINE data structure.
+
+	This work is released to Public Domain, do whatever you want with it.
+*/
+
+#include <cassert>
+
+#include "SkylineBinPack.h"
+
+using namespace std;
+
+SkylineBinPack::SkylineBinPack()
+:binWidth(0),
+binHeight(0)
+{
+}
+
+SkylineBinPack::SkylineBinPack(int width, int height, bool useWasteMap)
+{
+	Init(width, height, useWasteMap);
+}
+
+void SkylineBinPack::Init(int width, int height, bool useWasteMap_)
+{
+	binWidth = width;
+	binHeight = height;
+
+	useWasteMap = useWasteMap_;
+
+#ifdef _DEBUG
+	disjointRects.Clear();
+#endif
+
+	usedSurfaceArea = 0;
+	skyLine.Clear();
+	SkylineNode node;
+	node.x = 0;
+	node.y = 0;
+	node.width = binWidth;
+	skyLine.Push(node);
+
+	if (useWasteMap)
+	{
+		wasteMap.Init(width, height);
+		wasteMap.GetFreeRectangles().Clear();
+	}
+}
+
+void SkylineBinPack::Insert(TArray<RectSize> &rects, TArray<Rect> &dst)
+{
+	dst.Clear();
+
+	while(rects.Size() > 0)
+	{
+		Rect bestNode;
+		int bestScore1 = INT_MAX;
+		int bestScore2 = INT_MAX;
+		int bestSkylineIndex = -1;
+		int bestRectIndex = -1;
+		for(unsigned i = 0; i < rects.Size(); ++i)
+		{
+			Rect newNode;
+			int score1;
+			int score2;
+			int index;
+			newNode = FindPositionForNewNodeMinWaste(rects[i].width, rects[i].height, score2, score1, index);
+			assert(disjointRects.Disjoint(newNode));
+			if (newNode.height != 0)
+			{
+				if (score1 < bestScore1 || (score1 == bestScore1 && score2 < bestScore2))
+				{
+					bestNode = newNode;
+					bestScore1 = score1;
+					bestScore2 = score2;
+					bestSkylineIndex = index;
+					bestRectIndex = i;
+				}
+			}
+		}
+
+		if (bestRectIndex == -1)
+			return;
+
+		// Perform the actual packing.
+		assert(disjointRects.Disjoint(bestNode));
+#ifdef _DEBUG
+		disjointRects.Add(bestNode);
+#endif
+		AddSkylineLevel(bestSkylineIndex, bestNode);
+		usedSurfaceArea += rects[bestRectIndex].width * rects[bestRectIndex].height;
+		rects.Delete(bestRectIndex);
+		dst.Push(bestNode);
+	}
+}
+
+Rect SkylineBinPack::Insert(int width, int height)
+{
+	// First try to pack this rectangle into the waste map, if it fits.
+	Rect node = wasteMap.Insert(width, height, true, GuillotineBinPack::RectBestShortSideFit, 
+		GuillotineBinPack::SplitMaximizeArea);
+	assert(disjointRects.Disjoint(node));
+
+	if (node.height != 0)
+	{
+		Rect newNode;
+		newNode.x = node.x;
+		newNode.y = node.y;
+		newNode.width = node.width;
+		newNode.height = node.height;
+		usedSurfaceArea += width * height;
+		assert(disjointRects.Disjoint(newNode));
+#ifdef _DEBUG
+		disjointRects.Add(newNode);
+#endif
+		return newNode;
+	}
+	
+	return InsertMinWaste(width, height);
+}
+
+bool SkylineBinPack::RectangleFits(int skylineNodeIndex, int width, int height, int &y) const
+{
+	int x = skyLine[skylineNodeIndex].x;
+	if (x + width > binWidth)
+		return false;
+	int widthLeft = width;
+	int i = skylineNodeIndex;
+	y = skyLine[skylineNodeIndex].y;
+	while(widthLeft > 0)
+	{
+		y = max(y, skyLine[i].y);
+		if (y + height > binHeight)
+			return false;
+		widthLeft -= skyLine[i].width;
+		++i;
+		assert(i < (int)skyLine.Size() || widthLeft <= 0);
+	}
+	return true;
+}
+
+int SkylineBinPack::ComputeWastedArea(int skylineNodeIndex, int width, int height, int y) const
+{
+	int wastedArea = 0;
+	const int rectLeft = skyLine[skylineNodeIndex].x;
+	const int rectRight = rectLeft + width;
+	for(; skylineNodeIndex < (int)skyLine.Size() && skyLine[skylineNodeIndex].x < rectRight; ++skylineNodeIndex)
+	{
+		if (skyLine[skylineNodeIndex].x >= rectRight || skyLine[skylineNodeIndex].x + skyLine[skylineNodeIndex].width <= rectLeft)
+			break;
+
+		int leftSide = skyLine[skylineNodeIndex].x;
+		int rightSide = min(rectRight, leftSide + skyLine[skylineNodeIndex].width);
+		assert(y >= skyLine[skylineNodeIndex].y);
+		wastedArea += (rightSide - leftSide) * (y - skyLine[skylineNodeIndex].y);
+	}
+	return wastedArea;
+}
+
+bool SkylineBinPack::RectangleFits(int skylineNodeIndex, int width, int height, int &y, int &wastedArea) const
+{
+	bool fits = RectangleFits(skylineNodeIndex, width, height, y);
+	if (fits)
+		wastedArea = ComputeWastedArea(skylineNodeIndex, width, height, y);
+	
+	return fits;
+}
+
+void SkylineBinPack::AddWasteMapArea(int skylineNodeIndex, int width, int height, int y)
+{
+	int wastedArea = 0;
+	const int rectLeft = skyLine[skylineNodeIndex].x;
+	const int rectRight = rectLeft + width;
+	for(; skylineNodeIndex < (int)skyLine.Size() && skyLine[skylineNodeIndex].x < rectRight; ++skylineNodeIndex)
+	{
+		if (skyLine[skylineNodeIndex].x >= rectRight || skyLine[skylineNodeIndex].x + skyLine[skylineNodeIndex].width <= rectLeft)
+			break;
+
+		int leftSide = skyLine[skylineNodeIndex].x;
+		int rightSide = min(rectRight, leftSide + skyLine[skylineNodeIndex].width);
+		assert(y >= skyLine[skylineNodeIndex].y);
+
+		Rect waste;
+		waste.x = leftSide;
+		waste.y = skyLine[skylineNodeIndex].y;
+		waste.width = rightSide - leftSide;
+		waste.height = y - skyLine[skylineNodeIndex].y;
+
+		assert(disjointRects.Disjoint(waste));
+		wasteMap.GetFreeRectangles().Push(waste);
+	}
+}
+
+void SkylineBinPack::AddWaste(const Rect &waste)
+{
+	wasteMap.GetFreeRectangles().Push(waste);
+#ifdef _DEBUG
+	disjointRects.Del(waste);
+	wasteMap.DelDisjoint(waste);
+#endif
+}
+
+void SkylineBinPack::AddSkylineLevel(int skylineNodeIndex, const Rect &rect)
+{
+	// First track all wasted areas and mark them into the waste map if we're using one.
+	if (useWasteMap)
+		AddWasteMapArea(skylineNodeIndex, rect.width, rect.height, rect.y);
+
+	SkylineNode newNode;
+	newNode.x = rect.x;
+	newNode.y = rect.y + rect.height;
+	newNode.width = rect.width;
+	skyLine.Insert(skylineNodeIndex, newNode);
+
+	assert(newNode.x + newNode.width <= binWidth);
+	assert(newNode.y <= binHeight);
+
+	for(unsigned i = skylineNodeIndex+1; i < skyLine.Size(); ++i)
+	{
+		assert(skyLine[i-1].x <= skyLine[i].x);
+
+		if (skyLine[i].x < skyLine[i-1].x + skyLine[i-1].width)
+		{
+			int shrink = skyLine[i-1].x + skyLine[i-1].width - skyLine[i].x;
+
+			skyLine[i].x += shrink;
+			skyLine[i].width -= shrink;
+
+			if (skyLine[i].width <= 0)
+			{
+				skyLine.Delete(i);
+				--i;
+			}
+			else
+				break;
+		}
+		else
+			break;
+	}
+	MergeSkylines();
+}
+
+void SkylineBinPack::MergeSkylines()
+{
+	for(unsigned i = 0; i < skyLine.Size()-1; ++i)
+		if (skyLine[i].y == skyLine[i+1].y)
+		{
+			skyLine[i].width += skyLine[i+1].width;
+			skyLine.Delete(i+1);
+			--i;
+		}
+}
+
+Rect SkylineBinPack::InsertMinWaste(int width, int height)
+{
+	int bestHeight;
+	int bestWastedArea;
+	int bestIndex;
+	Rect newNode = FindPositionForNewNodeMinWaste(width, height, bestHeight, bestWastedArea, bestIndex);
+
+	if (bestIndex != -1)
+	{
+		assert(disjointRects.Disjoint(newNode));
+		// Perform the actual packing.
+		AddSkylineLevel(bestIndex, newNode);
+
+		usedSurfaceArea += width * height;
+#ifdef _DEBUG
+		disjointRects.Add(newNode);
+#endif
+	}
+	else
+		memset(&newNode, 0, sizeof(newNode));
+
+	return newNode;
+}
+
+Rect SkylineBinPack::FindPositionForNewNodeMinWaste(int width, int height, int &bestHeight, int &bestWastedArea, int &bestIndex) const
+{
+	bestHeight = INT_MAX;
+	bestWastedArea = INT_MAX;
+	bestIndex = -1;
+	Rect newNode;
+	memset(&newNode, 0, sizeof(newNode));
+	for(unsigned i = 0; i < skyLine.Size(); ++i)
+	{
+		int y;
+		int wastedArea;
+
+		if (RectangleFits(i, width, height, y, wastedArea))
+		{
+			if (wastedArea < bestWastedArea || (wastedArea == bestWastedArea && y + height < bestHeight))
+			{
+				bestHeight = y + height;
+				bestWastedArea = wastedArea;
+				bestIndex = i;
+				newNode.x = skyLine[i].x;
+				newNode.y = y;
+				newNode.width = width;
+				newNode.height = height;
+				assert(disjointRects.Disjoint(newNode));
+			}
+		}
+/*		if (RectangleFits(i, height, width, y, wastedArea))
+		{
+			if (wastedArea < bestWastedArea || (wastedArea == bestWastedArea && y + width < bestHeight))
+			{
+				bestHeight = y + width;
+				bestWastedArea = wastedArea;
+				bestIndex = i;
+				newNode.x = skyLine[i].x;
+				newNode.y = y;
+				newNode.width = height;
+				newNode.height = width;
+				assert(disjointRects.Disjoint(newNode));
+			}
+		}*/
+	}
+
+	return newNode;
+}
+
+/// Computes the ratio of used surface area.
+float SkylineBinPack::Occupancy() const
+{
+	return (float)usedSurfaceArea / (binWidth * binHeight);
+}
--- a/src/SkylineBinPack.h
+++ b/src/SkylineBinPack.h
@ -0,0 +1,88 @@
+/** @file SkylineBinPack.h
+	@author Jukka Jylänki
+
+	@brief Implements different bin packer algorithms that use the SKYLINE data structure.
+
+	This work is released to Public Domain, do whatever you want with it.
+*/
+#pragma once
+
+#include "tarray.h"
+
+#include "Rect.h"
+#include "GuillotineBinPack.h"
+
+/** Implements bin packing algorithms that use the SKYLINE data structure to store the bin contents. Uses
+	GuillotineBinPack as the waste map. */
+class SkylineBinPack
+{
+public:
+	/// Instantiates a bin of size (0,0). Call Init to create a new bin.
+	SkylineBinPack();
+
+	/// Instantiates a bin of the given size.
+	SkylineBinPack(int binWidth, int binHeight, bool useWasteMap);
+
+	/// (Re)initializes the packer to an empty bin of width x height units. Call whenever
+	/// you need to restart with a new bin.
+	void Init(int binWidth, int binHeight, bool useWasteMap);
+
+	/// Inserts the given list of rectangles in an offline/batch mode, possibly rotated.
+	/// @param rects The list of rectangles to insert. This vector will be destroyed in the process.
+	/// @param dst [out] This list will contain the packed rectangles. The indices will not correspond to that of rects.
+	/// @param method The rectangle placement rule to use when packing.
+	void Insert(TArray<RectSize> &rects, TArray<Rect> &dst);
+
+	/// Inserts a single rectangle into the bin, possibly rotated.
+	Rect Insert(int width, int height);
+
+	/// Adds a rectangle to the waste list. It must have been previously returned by
+	/// Insert or the results are undefined.
+	void AddWaste(const Rect &rect);
+
+	/// Computes the ratio of used surface area to the total bin area.
+	float Occupancy() const;
+
+private:
+	int binWidth;
+	int binHeight;
+
+#ifdef _DEBUG
+	DisjointRectCollection disjointRects;
+#endif
+
+	/// Represents a single level (a horizontal line) of the skyline/horizon/envelope.
+	struct SkylineNode
+	{
+		/// The starting x-coordinate (leftmost).
+		int x;
+
+		/// The y-coordinate of the skyline level line.
+		int y;
+
+		/// The line width. The ending coordinate (inclusive) will be x+width-1.
+		int width;
+	};
+
+	TArray<SkylineNode> skyLine;
+
+	unsigned long usedSurfaceArea;
+
+	/// If true, we use the GuillotineBinPack structure to recover wasted areas into a waste map.
+	bool useWasteMap;
+	GuillotineBinPack wasteMap;
+
+	Rect InsertMinWaste(int width, int height);
+	Rect FindPositionForNewNodeMinWaste(int width, int height, int &bestHeight, int &bestWastedArea, int &bestIndex) const;
+
+	bool RectangleFits(int skylineNodeIndex, int width, int height, int &y) const;
+	bool RectangleFits(int skylineNodeIndex, int width, int height, int &y, int &wastedArea) const;
+	int ComputeWastedArea(int skylineNodeIndex, int width, int height, int y) const;
+
+	void AddWasteMapArea(int skylineNodeIndex, int width, int height, int y);
+
+	void AddSkylineLevel(int skylineNodeIndex, const Rect &rect);
+
+	/// Merges all skyline nodes that are at the same level.
+	void MergeSkylines();
+};
--- a/src/win32/fb_d3d9.cpp
+++ b/src/win32/fb_d3d9.cpp
@ -72,6 +72,7 @@
 #include "v_palette.h"
 #include "w_wad.h"
 #include "r_data/colormaps.h"
+#include "SkylineBinPack.h"

 // MACROS ------------------------------------------------------------------

@ -92,7 +93,7 @@ struct D3DFB::PackedTexture
 {
 	D3DFB::Atlas *Owner;

-	PackedTexture *Next, **Prev;
+	PackedTexture **Prev, *Next;

 	// Pixels this image covers
 	RECT Area;
@ -109,18 +110,14 @@ struct D3DFB::Atlas
 	Atlas(D3DFB *fb, int width, int height, D3DFORMAT format);
 	~Atlas();

-	PackedTexture *GetBestFit(int width, int height, int &area);
-	void AllocateImage(PackedTexture *box, int width, int height);
-	PackedTexture *AllocateBox();
-	void AddEmptyBox(int left, int top, int right, int bottom);
+	PackedTexture *AllocateImage(const Rect &rect, bool padded);
 	void FreeBox(PackedTexture *box);

+	SkylineBinPack Packer;
 	Atlas *Next;
 	IDirect3DTexture9 *Tex;
 	D3DFORMAT Format;
 	PackedTexture *UsedList;	// Boxes that contain images
-	PackedTexture *EmptyList;	// Boxes that contain empty space
-	PackedTexture *FreeList;	// Boxes that are just waiting to be used
 	int Width, Height;
 	bool OneUse;
 };
@ -1871,7 +1868,8 @@ void D3DFB::DrawPackedTextures(int packnum)
 			continue;
 		}

-		AddColorOnlyQuad(x-1, y-1-LBOffsetI, 258, 258, D3DCOLOR_XRGB(255,255,0));
+		AddColorOnlyRect(x-1, y-1-LBOffsetI, 258, 258, D3DCOLOR_XRGB(255,255,0));
+		AddColorOnlyQuad(x, y-LBOffsetI, 256, 256, D3DCOLOR_ARGB(180,0,0,0));

 		CheckQuadBatch();

@ -1881,12 +1879,12 @@ void D3DFB::DrawPackedTextures(int packnum)
 		quad->Group1 = 0;
 		if (pack->Format == D3DFMT_L8/* && !tex->IsGray*/)
 		{
-			quad->Flags = BQF_WrapUV | BQF_GamePalette | BQF_DisableAlphaTest;
+			quad->Flags = BQF_WrapUV | BQF_GamePalette/* | BQF_DisableAlphaTest*/;
 			quad->ShaderNum = BQS_PalTex;
 		}
 		else
 		{
-			quad->Flags = BQF_WrapUV | BQF_DisableAlphaTest;
+			quad->Flags = BQF_WrapUV/* | BQF_DisableAlphaTest*/;
 			quad->ShaderNum = BQS_Plain;
 		}
 		quad->Palette = NULL;
@ -1946,16 +1944,6 @@ void D3DFB::DrawPackedTextures(int packnum)
 		VertexPos += 4;
 		IndexPos += 6;

-		// Draw entries in the empty list.
-		PackedTexture *box;
-		int emptynum;
-		for (box = pack->EmptyList, emptynum = 0; box != NULL; box = box->Next, emptynum++)
-		{
-			AddColorOnlyQuad(x + box->Area.left, y + box->Area.top - LBOffsetI,
-				box->Area.right - box->Area.left, box->Area.bottom - box->Area.top,
-				empty_colors[emptynum & 7]);
-		}
-
 		x += 256 + 8;
 		if (x > Width - 256)
 		{
@ -1981,54 +1969,43 @@ void D3DFB::DrawPackedTextures(int packnum)

 D3DFB::PackedTexture *D3DFB::AllocPackedTexture(int w, int h, bool wrapping, D3DFORMAT format)
 {
-	Atlas *bestpack;
-	PackedTexture *bestbox;
-	int area;
+	Atlas *pack;
+	Rect box;
+	bool padded;

 	// check for 254 to account for padding
 	if (w > 254 || h > 254 || wrapping)
 	{ // Create a new texture atlas.
-		bestpack = new Atlas(this, w, h, format);
-		bestpack->OneUse = true;
-		bestbox = bestpack->GetBestFit(w, h, area);
-		bestbox->Padded = false;
+		pack = new Atlas(this, w, h, format);
+		pack->OneUse = true;
+		box = pack->Packer.Insert(w, h);
+		padded = false;
 	}
 	else
 	{ // Try to find space in an existing texture atlas.
 		w += 2; // Add padding
 		h += 2;
-		int bestarea = INT_MAX;
-		int bestareaever = w * h;
-		bestpack = NULL;
-		bestbox = NULL;
-		for (Atlas *pack = Atlases; pack != NULL; pack = pack->Next)
+		for (pack = Atlases; pack != NULL; pack = pack->Next)
 		{
+			// Use the first atlas it fits in.
 			if (pack->Format == format)
 			{
-				PackedTexture *box = pack->GetBestFit(w, h, area);
-				if (area == bestareaever)
-				{ // An exact fit! Use it!
-					bestpack = pack;
-					bestbox = box;
-					break;
-				}
-				if (area < bestarea)
+				box = pack->Packer.Insert(w, h);
+				if (box.width != 0)
 				{
-					bestarea = area;
-					bestpack = pack;
-					bestbox = box;
+					break;
 				}
 			}
 		}
-		if (bestpack == NULL)
+		if (pack == NULL)
 		{ // Create a new texture atlas.
-			bestpack = new Atlas(this, 256, 256, format);
-			bestbox = bestpack->GetBestFit(w, h, bestarea);
+			pack = new Atlas(this, 256, 256, format);
+			box = pack->Packer.Insert(w, h);
 		}
-		bestbox->Padded = true;
+		padded = true;
 	}
-	bestpack->AllocateImage(bestbox, w, h);
-	return bestbox;
+	assert(box.width != 0 && box.height != 0);
+	return pack->AllocateImage(box, padded);
 }

 //==========================================================================
@ -2038,18 +2015,23 @@ D3DFB::PackedTexture *D3DFB::AllocPackedTexture(int w, int h, bool wrapping, D3D
 //==========================================================================

 D3DFB::Atlas::Atlas(D3DFB *fb, int w, int h, D3DFORMAT format)
+	: Packer(w, h, true)
 {
 	Tex = NULL;
 	Format = format;
 	UsedList = NULL;
-	EmptyList = NULL;
-	FreeList = NULL;
 	OneUse = false;
 	Width = 0;
 	Height = 0;
+	Next = NULL;

-	Next = fb->Atlases;
-	fb->Atlases = this;
+	// Attach to the end of the atlas list
+	Atlas **prev = &fb->Atlases;
+	while (*prev != NULL)
+	{
+		prev = &((*prev)->Next);
+	}
+	*prev = this;

 #if 1
 	if (FAILED(fb->D3DDevice->CreateTexture(w, h, 1, 0, format, D3DPOOL_MANAGED, &Tex, NULL)))
@ -2066,9 +2048,6 @@ D3DFB::Atlas::Atlas(D3DFB *fb, int w, int h, D3DFORMAT format)
 	}
 	Width = w;
 	Height = h;
-
-	// The whole texture is initially empty.
-	AddEmptyBox(0, 0, w, h);
 }

 //==========================================================================
@ -2087,53 +2066,6 @@ D3DFB::Atlas::~Atlas()
 		next = box->Next;
 		delete box;
 	}
-	for (box = EmptyList; box != NULL; box = next)
-	{
-		next = box->Next;
-		delete box;
-	}
-	for (box = FreeList; box != NULL; box = next)
-	{
-		next = box->Next;
-		delete box;
-	}
-}
-
-//==========================================================================
-//
-// Atlas :: GetBestFit
-//
-// Returns the empty box that provides the best fit for the requested
-// dimensions, or NULL if none of them are large enough.
-//
-//==========================================================================
-
-D3DFB::PackedTexture *D3DFB::Atlas::GetBestFit(int w, int h, int &area)
-{
-	PackedTexture *box;
-	int smallestarea = INT_MAX;
-	PackedTexture *smallestbox = NULL;
-
-	for (box = EmptyList; box != NULL; box = box->Next)
-	{
-		int boxw = box->Area.right - box->Area.left;
-		int boxh = box->Area.bottom - box->Area.top;
-		if (boxw >= w && boxh >= h)
-		{
-			int boxarea = boxw * boxh;
-			if (boxarea < smallestarea)
-			{
-				smallestarea = boxarea;
-				smallestbox = box;
-				if (boxw == w && boxh == h)
-				{ // An exact fit! Use it!
-					break;
-				}
-			}
-		}
-	}
-	area = smallestarea;
-	return smallestbox;
 }

 //==========================================================================
@ -2148,24 +2080,22 @@ D3DFB::PackedTexture *D3DFB::Atlas::GetBestFit(int w, int h, int &area)
 //
 //==========================================================================

-void D3DFB::Atlas::AllocateImage(D3DFB::PackedTexture *box, int w, int h)
+D3DFB::PackedTexture *D3DFB::Atlas::AllocateImage(const Rect &rect, bool padded)
 {
-	RECT start = box->Area;
+	PackedTexture *box = new PackedTexture;

-	box->Area.right = box->Area.left + w;
-	box->Area.bottom = box->Area.top + h;
+	box->Owner = this;
+	box->Area.left = rect.x;
+	box->Area.top = rect.y;
+	box->Area.right = rect.x + rect.width;
+	box->Area.bottom = rect.y + rect.height;

-	box->Left = float(box->Area.left + box->Padded) / Width;
-	box->Right = float(box->Area.right - box->Padded) / Width;
-	box->Top = float(box->Area.top + box->Padded) / Height;
-	box->Bottom = float(box->Area.bottom - box->Padded) / Height;
+	box->Left = float(box->Area.left + padded) / Width;
+	box->Right = float(box->Area.right - padded) / Width;
+	box->Top = float(box->Area.top + padded) / Height;
+	box->Bottom = float(box->Area.bottom - padded) / Height;

-	// Remove it from the empty list.
-	*(box->Prev) = box->Next;
-	if (box->Next != NULL)
-	{
-		box->Next->Prev = box->Prev;
-	}
+	box->Padded = padded;

 	// Add it to the used list.
 	box->Next = UsedList;
@ -2176,96 +2106,6 @@ void D3DFB::Atlas::AllocateImage(D3DFB::PackedTexture *box, int w, int h)
 	UsedList = box;
 	box->Prev = &UsedList;

-	// If we didn't use the whole box, split the remainder into the empty list.
-	if (box->Area.bottom + 7 < start.bottom && box->Area.right + 7 < start.right)
-	{
-		// Split like this:
-		//   +---+------+
-		//   |###|      |
-		//   +---+------+
-		//   |          |
-		//   |          |
-		//   +----------+
-		if (box->Area.bottom < start.bottom)
-		{
-			AddEmptyBox(start.left, box->Area.bottom, start.right, start.bottom);
-		}
-		if (box->Area.right < start.right)
-		{
-			AddEmptyBox(box->Area.right, start.top, start.right, box->Area.bottom);
-		}
-	}
-	else
-	{
-		// Split like this:
-		//   +---+------+
-		//   |###|      |
-		//   +---+      |
-		//   |   |      |
-		//   |   |      |
-		//   +---+------+
-		if (box->Area.bottom < start.bottom)
-		{
-			AddEmptyBox(start.left, box->Area.bottom, box->Area.right, start.bottom);
-		}
-		if (box->Area.right < start.right)
-		{
-			AddEmptyBox(box->Area.right, start.top, start.right, start.bottom);
-		}
-	}
-}
-
-//==========================================================================
-//
-// Atlas :: AddEmptyBox
-//
-// Adds a box with the specified dimensions to the empty list.
-//
-//==========================================================================
-
-void D3DFB::Atlas::AddEmptyBox(int left, int top, int right, int bottom)
-{
-	PackedTexture *box = AllocateBox();
-	box->Area.left = left;
-	box->Area.top = top;
-	box->Area.right = right;
-	box->Area.bottom = bottom;
-	box->Next = EmptyList;
-	if (box->Next != NULL)
-	{
-		box->Next->Prev = &box->Next;
-	}
-	box->Prev = &EmptyList;
-	EmptyList = box;
-}
-
-//==========================================================================
-//
-// Atlas :: AllocateBox
-//
-// Returns a new PackedTexture box, either by retrieving one off the free
-// list or by creating a new one. The box is not linked into a list.
-//
-//==========================================================================
-
-D3DFB::PackedTexture *D3DFB::Atlas::AllocateBox()
-{
-	PackedTexture *box;
-
-	if (FreeList != NULL)
-	{
-		box = FreeList;
-		FreeList = box->Next;
-		if (box->Next != NULL)
-		{
-			box->Next->Prev = &FreeList;
-		}
-	}
-	else
-	{
-		box = new PackedTexture;
-		box->Owner = this;
-	}
 	return box;
 }

@ -2273,10 +2113,9 @@ D3DFB::PackedTexture *D3DFB::Atlas::AllocateBox()
 //
 // Atlas :: FreeBox
 //
-// Removes a box from its current list and adds it to the empty list,
-// updating EmptyArea. If there are no boxes left in the used list, then
-// the empty list is replaced with a single box, so the texture can be
-// subdivided again.
+// Removes a box from the used list and deletes it. Space is returned to the
+// waste list. Once all boxes for this atlas are freed, the entire bin
+// packer is reinitialized for maximum efficiency.
 //
 //==========================================================================

@ -2287,47 +2126,16 @@ void D3DFB::Atlas::FreeBox(D3DFB::PackedTexture *box)
 	{
 		box->Next->Prev = box->Prev;
 	}
-	box->Next = EmptyList;
-	box->Prev = &EmptyList;
-	if (EmptyList != NULL)
-	{
-		EmptyList->Prev = &box->Next;
-	}
-	EmptyList = box;
+	Rect waste;
+	waste.x = box->Area.left;
+	waste.y = box->Area.top;
+	waste.width = box->Area.right - box->Area.left;
+	waste.height = box->Area.bottom - box->Area.top;
+	box->Owner->Packer.AddWaste(waste);
+	delete box;
 	if (UsedList == NULL)
-	{ // No more space in use! Move all but this into the free list.
-		if (box->Next != NULL)
-		{
-			D3DFB::PackedTexture *lastbox;
-
-			// Find the last box in the free list.
-			lastbox = FreeList;
-			if (lastbox != NULL)
-			{
-				while (lastbox->Next != NULL)
-				{
-					lastbox = lastbox->Next;
-				}
-			}
-			// Chain the empty list to the end of the free list.
-			if (lastbox != NULL)
-			{
-				lastbox->Next = box->Next;
-				box->Next->Prev = &lastbox->Next;
-			}
-			else
-			{
-				FreeList = box->Next;
-				box->Next->Prev = &FreeList;
-			}
-			box->Next = NULL;
-		}
-		// Now this is the only box in the empty list, so it should
-		// contain the whole texture.
-		box->Area.left = 0;
-		box->Area.top = 0;
-		box->Area.right = Width;
-		box->Area.bottom = Height;
+	{
+		Packer.Init(Width, Height, true);
 	}
 }

@ -2412,6 +2220,7 @@ bool D3DTex::CheckWrapping(bool wrapping)

 bool D3DTex::Create(D3DFB *fb, bool wrapping)
 {
+	assert(Box == NULL);
 	if (Box != NULL)
 	{
 		Box->Owner->FreeBox(Box);
@ -3441,6 +3250,22 @@ void D3DFB::AddColorOnlyQuad(int left, int top, int width, int height, D3DCOLOR
 	IndexPos += 6;
 }

+//==========================================================================
+//
+// D3DFB :: AddColorOnlyRect
+//
+// Like AddColorOnlyQuad, except it's hollow.
+//
+//==========================================================================
+
+void D3DFB::AddColorOnlyRect(int left, int top, int width, int height, D3DCOLOR color)
+{
+	AddColorOnlyQuad(left, top, width - 1, 1, color);					// top
+	AddColorOnlyQuad(left + width - 1, top, 1, height - 1, color);		// right
+	AddColorOnlyQuad(left + 1, top + height - 1, width - 1, 1, color);	// bottom
+	AddColorOnlyQuad(left, top + 1, 1, height - 1, color);				// left
+}
+
 //==========================================================================
 //
 // D3DFB :: CheckQuadBatch
--- a/src/win32/win32iface.h
+++ b/src/win32/win32iface.h
@ -375,6 +375,7 @@ private:
 	static void SetColorOverlay(DWORD color, float alpha, D3DCOLOR &color0, D3DCOLOR &color1);
 	void DoWindowedGamma();
 	void AddColorOnlyQuad(int left, int top, int width, int height, D3DCOLOR color);
+	void AddColorOnlyRect(int left, int top, int width, int height, D3DCOLOR color);
 	void CheckQuadBatch(int numtris=2, int numverts=4);
 	void BeginQuadBatch();
 	void EndQuadBatch();
--- a/zdoom.vcproj
+++ b/zdoom.vcproj
@ -666,6 +666,10 @@
 				RelativePath=".\src\gitinfo.cpp"
 				>
 			</File>
+			<File
+				RelativePath=".\src\GuillotineBinPack.cpp"
+				>
+			</File>
 			<File
 				RelativePath=".\src\hu_scores.cpp"
 				>
@ -1026,6 +1030,10 @@
 				RelativePath=".\src\skins.cpp"
 				>
 			</File>
+			<File
+				RelativePath=".\src\SkylineBinPack.cpp"
+				>
+			</File>
 			<File
 				RelativePath=".\src\st_stuff.cpp"
 				>
@ -1311,6 +1319,10 @@
 				RelativePath=".\src\gstrings.h"
 				>
 			</File>
+			<File
+				RelativePath=".\src\GuillotineBinPack.h"
+				>
+			</File>
 			<File
 				RelativePath=".\src\hu_stuff.h"
 				>
@ -1491,6 +1503,10 @@
 				RelativePath=".\src\po_man.h"
 				>
 			</File>
+			<File
+				RelativePath=".\src\Rect.h"
+				>
+			</File>
 			<File
 				RelativePath=".\src\s_playlist.h"
 				>
@ -1515,6 +1531,10 @@
 				RelativePath=".\src\skins.h"
 				>
 			</File>
+			<File
+				RelativePath=".\src\SkylineBinPack.h"
+				>
+			</File>
 			<File
 				RelativePath=".\src\st_start.h"
 				>