I have noticed that if your window is abnormally wide or tall (in windowed mode), the bloom filter will get stretched accordingly. Is this a case of user error or is there no way to change the size of the bloom filter?
The bloom effect uses a fixed pattern to generate blur and the pattern is not affected by the screen resolution, so the having abnormally wide or tall window will stretch the effect. You can try an alternative version of bloom filter I have made: shaderFactory_Bloom. Here is the link: http://code.google.com/p/jmeaddons/downloads/list.