關于遞回優化或轉迭代，有沒有大神能指導一下？

最近地圖專案中使用遞回取瓦片地圖，當地圖層級高且下一級沒有圖片時，遞回的效率變得相當慢，需要卡很久才能反應過來，考慮對代碼做優化，嘗試改成迭代，發現并沒有那么容易，有大神有這方面經驗的可以指導一下嗎？不勝感激！僅有的100分奉上，謝謝！！
以下是原始碼，為方便閱讀，省去了一些無關緊要的東西：
void CDrawImageDrawer::drawImages(int iHdc,double dLeft,double dTop,double dRight,double dBottom,int iZoom)
{
if(iZoom < 0)
    {
        return;
    }

    IImageSource* pImageSource = m_imageSourceMap[m_curImageSource];
    if(pImageSource->_bNeedCheckSource)
    {
        pImageSource->_bNeedCheckSource = false;
        checkImageSourceIsExsit();
    }

    if(!pImageSource->_bExsitImageSource) 
    {
        return;
    } 
   
    MapServerDiskImageSource* pMapServerDiskImageSource   =   0;

    IImageSource::IMAGESOURCE_TYPE imageType = pImageSource->getType();
    switch(imageType)
    {
    case IImageSource::IMAGESOURCE_TYPE_MapServerDisk:
        {
            pMapServerDiskImageSource  =   (MapServerDiskImageSource*)pImageSource;
            break;
        }
    }

    // 繪制
int minX = long2tilex(dLeft,iZoom);
int minY = lat2tiley(dTop,iZoom);
int maxX = long2tilex(dRight,iZoom);
int maxY = lat2tiley(dBottom,iZoom);

for(int i = minX;i <= maxX; ++i)
{
for(int j = minY;j <= maxY; ++j)
{
double dImageLeft    = tilex2long(i,iZoom);
double dImageTop     = tiley2lat(j,iZoom);
double dImageRight   = tilex2long(i+1,iZoom);
double dImageBottom  = tiley2lat(j+1,iZoom);

// 使用當前層圖片繪制
bool bIsValid = false;
                if(pMapServerDiskImageSource)
                {   
                    // 使用記憶體位圖來繪制
                    if(m_memoryImage[iZoom].isValid())
                    {
                        int iLDest = 0;
                        int iRDest = 0;
                        int iTDest = 0;
                        int iBDest = 0;
                        IGF_Display* pDisplay = m_pMain->GetDisplayPtr();
                        IGIS_SpatialReference* pSpatialReferenceBJ54 = m_pSpatialReferenceFactory->GetPredefinedSpatialReferenceByIndex(GIS_BJ54_SPATIALREFERENCE_INDEX);
                        pDisplay->WorldToClient((int)(dImageLeft*m_xyScale),(int)(dImageTop*m_xyScale),&iLDest,&iTDest,pSpatialReferenceBJ54);
                        pDisplay->WorldToClient((int)(dImageRight*m_xyScale),(int)(dImageBottom*m_xyScale),&iRDest,&iBDest,pSpatialReferenceBJ54);
                        pSpatialReferenceBJ54->Release();

                        bIsValid = m_memoryImage[iZoom].drawMemoryToScreen(iHdc,iZoom,i,j,iLDest,iTDest,iRDest,iBDest);
                    }

                    // 從檔案來繪制
                    if(!bIsValid)
                    {
                        //if(tileIsInRangeEx(i,j,iZoom) || pMapServerDiskImageSource->_levelRange.empty())
                        {
                            char imagePath[512] = {0};
                            sprintf_s(imagePath,"%s",pMapServerDiskImageSource->_imageDirectory.c_str());
                            bIsValid = drawImageFromFileEx(iHdc,imagePath,dImageLeft,dImageTop,dImageRight,dImageBottom,pMapServerDiskImageSource->_bImageEncrypt,pMapServerDiskImageSource->_dSaturation,iZoom,i,j);
                        }  
                    }           
                }

if(iZoom-1 < 0)
                {
                    continue;
                }

                // 使用上一層圖片繪制
if(!bIsValid)
{
                    /*if(iZoom == m_iRealZoom && 
                    m_memoryImage[iZoom-1].isValid())*/
                    if(m_memoryImage[iZoom-1].isValid())
{
                           /*----------- -----------  -----------
                            |   8     |  |     1   |  |    7    |
                            |     -------------------------     |
                            |     |   |  |         |  |   |     |
                            ------|----  -----------  ----|------
                                |                       |
                            ------|----               ----|------  ----------
                            |     |   | 記憶體位圖區域  |   |     |  |        |
                            |   3 |   |               |   | 4   |  |   9    |
                            |     |   |               |   |     |  |        |
                            ------|----               ----|------  ----------
                            ------|----  -----------  ----|------
                            |     -------------------------     |
                            |   6     |  |    2    |  |     5   |
                            |         |  |         |  |         |
                            -----------  -----------  -----------*/
// 使用上一層記憶體位圖來繪制
drawImageFromMemory(iHdc,dImageLeft,dImageTop,dImageRight,dImageBottom,iZoom - 1);

double dLeftEx = 0;
double dTopEx = 0;
double dRightEx = 0;
double dBottomEx = 0;
m_memoryImage[iZoom-1].getZXYValidRange(dLeftEx,dTopEx,dRightEx,dBottomEx);
bool bLTInRect = ptInRect(dImageLeft,dImageTop,dLeftEx,dTopEx,dRightEx,dBottomEx);
bool bRTInRect = ptInRect(dImageRight,dImageTop,dLeftEx,dTopEx,dRightEx,dBottomEx);
bool bLBInRect = ptInRect(dImageLeft,dImageBottom,dLeftEx,dTopEx,dRightEx,dBottomEx);
bool bRBInRect = ptInRect(dImageRight,dImageBottom,dLeftEx,dTopEx,dRightEx,dBottomEx);
//1. 左下角兩點和右下角兩點在
if(bLBInRect && bRBInRect  && !bLTInRect && !bRTInRect)
{
drawImages(iHdc,dImageLeft,dImageTop,dImageRight,m_dTop,(iZoom - 1));
}
//2. 左上角兩點和右上角兩點在
else if(bLTInRect && bRTInRect && !bLBInRect && !bRBInRect)
{
drawImages(iHdc,dImageLeft,m_dBottom,dImageRight,dImageBottom,(iZoom - 1));
}
// 。。。
}
else
{
drawImages(iHdc,dImageLeft,dImageTop,dImageRight,dImageBottom,(iZoom - 1));
}
}
}
}
}

uj5u.com熱心網友回復：

http://www.codeproject.com/Articles/418776/How-to-replace-recursive-functions-using-stack-and

轉載請註明出處，本文鏈接：https://www.uj5u.com/gongcheng/68649.html

標籤：圖形處理/算法

上一篇：如何使自己維護的lib/dll不再需要區分debug與release？

下一篇：C++簡單演算法求解