Hi All!
This is a revised version of the shader I posted here:
A shader for creating Perlin noise images
The new demo shows one way of creating several different images which will tile seamlessly. A possible application might be creating successive heightmaps for use in a never ending world. The tiling is achieved by making sure that the seed variables used for the edges of the images match those used by adjacent images. Some details of how this works in the demo are available in the two files "image layout.png" and "seed layout.txt" included in the zip file.
The shader takes a long time to compile (a few minutes on my laptop

) so I have used a compiled version of the shader (extension .obj instead of .fx) in the demo. I found it hard to use Dark Shader for this particular shader and compiled it using the DX9 SDK "fxc.exe" utility. You can use the .fx file if you prefer but you may experience a long wait while DBPro calls the DX9 shader compiler. The compiled version loads into DBPro very quickly in the demo

.
As in the earlier demo you can choose which octaves to use. You can also change some of the seeds used for the random number generatior in the shader. The shader uses 10 different pairs of seeds: 8 for the four corners and edges of the image , one for the random number generator itself (this allows a completely different set of images to be created), and one for the numbers generated in the interior of the image (together with the seeds used for the edges this allows the images to differ from each other within a set of 9 images).
Here's a screenshot of a sample of 9 images which tile seamlessly:
The demo creates 9 256x256 images arranged as a 3x3 grid. The shader is not limited to that size - I simply used it for ease of presentation. The images are only recalculated when their defining parameters are changed, i.e. seeds, octaves etc. The tiles are shown adjacent to each other by default. If you press <s> the demo inserts a i pixel width black border between them so you can see where the boundaries are. Turn this off by pressing <s> again.
You will need a PS3 capable GFX card. I've tested the demo using both DBPro U77 RC7 and Rudolpho's DBP DX9Ex version. Works fine with either.
As usual, any problems just ask.
EditI've just attached the correct version of the FX file to this post. It is functionally the same as the one in the zip file but is hopefully a bit more readable.