Light Function Material 'Banding' on some surfaces

[TJ_MkII]

I have created a light function material which creates a dynamic caustic water effect, see the effect on the rocks below. The idea is it will cast caustic water reflections on nearby surfaces, something I observed when I was recently walking the dog, and light was being cast on the nearby trees in cool patterns

[shot]http://i239.photobucket.com/albums/ff29/thejamsh/FUnction.jpg[/shot]

However you can see that on the wall, the material is banding and stretching. I'm using a pointlight moveable to cast the light function.

The UDN says you can use a 'Texture Cube' to avoid this banding, but is there anyway to use a texture cube with a material as a light function? Or is there a better way to achieve this? Thanks in advance

[JessieG]

Have you tried adding that effect to the material for those objects instead? You could use a vertex color to paint the water reflection selectively onto the meshes instead of trying it with lights.

[James Ordner]

I assume your are using a texture2d? If you are, the best way is just to use a texturecube texture instead, as that gives you all three axis instead of just one axis, which casts a non-stretched pattern in all directions.

Edit:
Like Jessie said, if you can lay out the UVs correctly to achieve the effect in the material instead of with a light, it would be much less problematic and much easier to control with vertex paint. Not to mention the performance gains.

[TJ_MkII]

I assume your are using a texture2d? If you are, the best way is just to use a texturecube texture instead, as that gives you all three axis instead of just one axis, which casts a non-stretched pattern in all directions.

Edit:
Like Jessie said, if you can lay out the UVs correctly to achieve the effect in the material instead of with a light, it would be much less problematic and much easier to control with vertex paint. Not to mention the performance gains.

No, I'm using a material. I managed to avoid the banding slightly by rotating the light a little, which makes the banding a little less apparent. Any tutorials around for the vertex painting tips?

[ambershee]

James is correct, you're seeing what you're seeing because you are using a flat texture for your caustic pattern, when in reality you would want to be using a cube map in the material, or at least an alternative projection technique. Unless your light source is dynamic, I would also recommend painting it on using your materials - there should be a fair few vertex painting tutorials out there and it's not hard to set up or use; there are some basic bits of documentation on the UDN too.

[JessieG]

Yeah we mean using the materials of the objects that receive the pattern on them, not the light function material.

This is one of the main resources I used to learn how it works:

http://http://www.chrisalbeluhn.com/..._Tutorial.html

[TJ_MkII]

Right I can see how it works now, so effectively I would add my light function material to the rock material, then effectively use vertex colours to mask it out on a per-instance basis?

Are the performance differences really that noticeable?

[ambershee]

The difference in performance between using a dynamic light with a material function, and staticly painting it using vertex colours will be very significant.