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, allowRotation);
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]);
}
//开始打图集
public int Build()
{
atlases = new List <Data>();
remainingRectIndices = new List <int>();
bool[] usedRect = new bool[sourceRects.Count];
int atlasWidth = this.atlasWidth >> alignShift;
int atlasHeight = this.atlasHeight >> alignShift;
//完整性检查，不能使用比实际最大图集大小更大的纹理构建
int align = (1 << alignShift) - 1;
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) + align) >> alignShift;
int minDim = (Math.Min(rs.width, rs.height) + align) >> alignShift;
//需要适配纹理尺寸
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);
}
}
//随着时间推移，减少
List <RectSize> rects = new List <RectSize>();
foreach (RectSize rs in sourceRects)
{
RectSize t = new RectSize();
t.width = (rs.width + align) >> alignShift;
t.height = (rs.height + align) >> alignShift;
rects.Add(t);
}
bool allUsed = false;
while (allUsed == false && atlases.Count < maxAllowedAtlasCount)
{
int numPasses = 1;
int thisCellW = atlasWidth, thisCellH = atlasHeight;
bool reverted = false;
while (numPasses > 0)
{
//复制一份，在必要时缩放纹理
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();
//考虑在第一次遍历之后，所有使用纹理占用> 0.5f减少一半，以保持PO2需求兴许会好点吧。。。
bool firstPassFull = numPasses == 1 && occupancy > 0.5f;
// 当占用率< 0.5时，恢复图集大小到减半
// 此时，大小恢复到先前的值，循环应该接受这个值作为最终值
if (firstPassFull ||
(numPasses > 1 && occupancy > 0.5f && allUsed) ||
reverted || !allowOptimizeSize)
{
List <Entry> atlasEntries = new List <Entry>();
foreach (var t in binPacker.GetMapped())
{
int matchedWidth = 0;
int matchedHeight = 0;
int matchedId = -1;
bool flipped = false;
for (int i = 0; i < sourceRects.Count; ++i)
{
int width = (sourceRects[i].width + align) >> alignShift;
int height = (sourceRects[i].height + align) >> alignShift;
if (!usedRect[i] && width == t.width && height == t.height)
{
matchedId = i;
matchedWidth = sourceRects[i].width;
matchedHeight = sourceRects[i].height;
break;
}
}
//若没有匹配的任何东西，开始寻找相同的矩形
if (matchedId == -1)
{
for (int i = 0; i < sourceRects.Count; ++i)
{
int width = (sourceRects[i].width + align) >> alignShift;
int height = (sourceRects[i].height + align) >> alignShift;
if (!usedRect[i] && width == t.height && height == t.width)
{
matchedId = i;
flipped = true;
matchedWidth = sourceRects[i].height;
matchedHeight = sourceRects[i].width;
break;
}
}
}
usedRect[matchedId] = true;
Entry newEntry = new Entry();
newEntry.flipped = flipped;
newEntry.x = t.x << alignShift;
newEntry.y = t.y << alignShift;
newEntry.w = matchedWidth;
newEntry.h = matchedHeight;
newEntry.index = matchedId;
atlasEntries.Add(newEntry);
}
Data currAtlas = new Data();
currAtlas.width = thisCellW << alignShift;
currAtlas.height = thisCellH << alignShift;
currAtlas.occupancy = binPacker.Occupancy();
currAtlas.entries = atlasEntries.ToArray();
atlases.Add(currAtlas);
rects = currRects;
break; // done
}
else
{
if (!allUsed)
{
if (forceSquare)
{
thisCellW *= 2;
thisCellH *= 2;
}
else
{
//只有在第一次缩小尺寸后才能尝试另一个尺寸
if (thisCellW < atlasWidth || thisCellH < atlasHeight)
{
//试图缩小比例，但纹理不适合，所以恢复以前的更改，并再次遍历数据，即使有些浪费
if (thisCellW < thisCellH)
{
thisCellW *= 2;
}
else
{
thisCellH *= 2;
}
}
}
reverted = true;
}
else
{
if (forceSquare)
{
thisCellH /= 2;
thisCellW /= 2;
}
else
{
//超过一半的纹理未被使用，按其中一个尺寸缩小
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);
}