Analysis of the code shows that ''main'' calls ''ChessBoardTest'' which calls ''SaveImage''. Based on the profiling results above, the application spends the majority of its time in ''SaveImage''. Analyzing the code also shows that the rest of the methods listed above ('''CalculateLighting''', '''CalculateRefraction'SaveImage'', 'calls ''TraceRay''', '''CalculateMatte''', etcin a nested loop as follows:<code> <nowiki> for (size_t i=0; i < largePixelsWide; ++i) { ......  for (size_t j=0; j < largePixelsHigh; ++j) { ...... TraceRay() are called directly or indirectly from '''SaveImage'''; ...... } } </nowiki></code>