Doomsday Engine

Build 1528 fails when compiling with Qt 4.7, because QMap::firstKey() is not availble.

This loop could be written in a way that doesn't modify newSprites:

            int lastFrame = -1;
            while(!newSprites.isEmpty())
            {
                int frame = newSprites.firstKey();
                // Insert dummy sprites to fill any gaps in the frame set.
                for(int i = lastFrame + 1; i < frame; ++i)
                {
                    group.sprites << new Sprite;
                }

                group.sprites << newSprites.take(frame);
                lastFrame = frame;
            }

One could simply for()/foreach() over newSprites, accessing the map iterator's key() and value().

Even if one would want to modify newSprites, there's QMutableMapIterator that doesn't require firstKey().