Re: [pygame] Perlin Noise Function

[Casey Duncan <casey@xxxxxxxxxxx>]

On Jul 30, 2008, at 12:08 PM, Knapp wrote:

> On Wed, Jul 30, 2008 at 8:00 PM, Casey Duncan <casey@xxxxxxxxxxx>  
> wrote:
>
> On Jul 30, 2008, at 11:08 AM, Knapp wrote:
> [..]
>
>
> One of the links I posted talked about the 3d+ Speed problems and  
> how to fix them. Have you see that yet?
>
> I had seen that before. The gradient optimization mentioned is  
> really only applicable to classic Perlin noise. The Perlin Improved  
> noise algorithm optimizes the gradients in a different way. The  
> gradients themselves in "improved noise" are no longer random,  
> though they are selected in a pseudo-random fashion, by hashing the  
> incoming coordinates. Basically. the moral equivalent of the  
> optimization is already present in "improved" noise.
>
> The scaling problem for higher dimensions is solved nicely by  
> simplex noise, which grows linearly in cost as you add dimensions,  
> rather than geometrically. However, simplex noise looks considerably  
> different, and so even a higher cost 4D Perlin noise function is  
> probably still desirable for applications not sensitive to that  
> cost. 4D noise is highly useful for real-time applications where you  
> desire to animate a 3D texture, and there, cost is typically  
> important.
>
> -Casey
>
> You can always take the easy way out. Four years from now your  
> computer will be so fast you will not care so much about this. :-)

Yeah, but by then I'll want fast 6D noise ;^) That said, I'm all for  
waiting for the problem to fix itself.

> Also when doing real-time 3d with movement, I use Blender, and they  
> let you map video to the surface. Thus you can precalculate the  
> image and just play it back. I guess there are some times when this  
> is not good enough, like when you want interaction.

In OpenGL, you can use a 3D texture for this. The shader noise code  
lets you generate these in real-time, which can come in handy when  
either they need to change in a non-deterministic way (e.g., in  
response to interaction) or you need to generate many different  
textures and animations but lack the talent or money of a dedicated  
art dept. (and you don't mind math migraines ;^).

-Casey