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[QuadrupleA]

I'm trying to write a shader to do some trippy, psychedlic backgrounds - I have a warped photo of myself that I generated a while ago that has a similar pattern to what I want:



Problem is, it was done 3+ years ago and I have no idea how I did it. Pretty sure it was a shader, using a "mirror" UV addressing mode, but I don't know how to reproduce that "increasing repetitions going inward" type of thing. I want that kind of tesselated / fractal look. I've tried some polar coordinate system experiments, but not what I want so far (I get spiraling effects).

Assuming I'm drawing a fullscreen quad with UV coordinates from 0,0 to 1,1, and a single sampled texture to repeat (perhaps with mirrored sampling enabled) does anyone have any clues what the hell I did?

I was a lot less experienced with shaders than I am now, so I suspect it was something simple I stumbled on (a mapping to a different standard coordinate system perhaps). Not even sure I knew shaders, perhaps it was just some builtin fixed-function mode.

[Geti]

Probably something along the lines of this http://www.iquilezles.org/www/articles/deform/deform.htm I think - Staple of old demos

If not, you'll probably be able to recreate it using that anyway.

[eigenbom]

Reminds me a little of Escher's print gallery..

[QuadrupleA]

Probably something along the lines of this http://www.iquilezles.org/www/articles/deform/deform.htm I think - Staple of old demos

If not, you'll probably be able to recreate it using that anyway.

Cool! This one did it:

float u = cosf( a )/d;
float v = sinf( a )/d;

Thanks for the tip.

[Geti]

No worries, glad I was able to help.