qzdoom-gpl/src/GuillotineBinPack.cpp

643 lines
19 KiB
C++

/** @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 <limits.h>
#include "templates.h"
#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.
#ifdef _DEBUG
assert(disjointRects.Add(newNode) == true);
#endif
}
}
/// @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.
#ifdef _DEBUG
assert(disjointRects.Add(newRect) == true);
#endif
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;
#ifdef _DEBUG
assert(disjointRects.Disjoint(bestNode));
#endif
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;
#ifdef _DEBUG
assert(disjointRects.Disjoint(bestNode));
#endif
}
}
// 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);
#ifdef _DEBUG
assert(disjointRects.Disjoint(bottom));
assert(disjointRects.Disjoint(right));
#endif
}
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
}