PRNG's :: pouët.net

PRNG's

category: code [glöplog]

The dithering happen because the position is always updated by moving left or right but also up or down:

Code:


int rnd = seed;
for(int j=0; j<8192; j++) { // 8192*16 string lenght
 rnd += rnd<<16 | rnd>>16;
 int d = rnd;
 for(int i=0; i<16; i++) { // plot 16 pixels
   xp += (d&2)-1;
   yp += (d&1)*2 -1;
   d >>= 2;
   plot(xp, yp);
 }
}

Here is another image I call "the genie" using plot(xp/2, yp/2)

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added on the 2011-09-03 18:04:42 by T21

Going down memory lane:

ACC = (ACC*3 + TopRightPixel - 0x1E) / 4 + rnd()&0xF + round;

This generate really cheap perlin noise.
rnd() is again : rnd += rnd<<16 | rnd>>16;

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added on the 2011-09-03 19:41:36 by T21

so your period is 2^32?
im having period of 2^16. but im using "independent" 8-bit registers in my calcs.
you're saving those images with crappy jpeg compression, jsyk. :P

added on the 2011-09-03 19:58:09 by rudi

Actually this is the random function I used in those test: So 2^64 ?

Code:


__inline __m128i Rnd() { // 8bytes
	rnd = _mm_add_epi64(rnd, _mm_shuffle_epi32(rnd, 0x1E));
	return rnd;
}

The fact that I use pure blue doesn't help ms paint default jpeg compression :)
A version shaded with : b = acc; g = acc *acc; r = acc*acc;
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added on the 2011-09-03 20:26:39 by T21

Quote:

it's a sailboat!

added on the 2011-09-04 22:13:35 by appas

simple glsl oneliner:

Quote:

float rand(vec2 co){
return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);
}

Also, Perlin and Simplex noise for GLSL.

added on the 2011-09-04 22:16:43 by appas

This is what I saw in the randomness:
Now, lets see your sailboat :)

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added on the 2011-09-05 05:09:57 by T21

That looks like a bust.

added on the 2011-09-05 05:27:15 by xernobyl

When I generated those random string I posted the result and called it "the genie" because I kind of saw a face in what looked like smoke rising from the bottom left corner.
The 'bust' is from erasing the 'smoke' around the face to make it obvious.
Here is the original random data with the face colorized blue.

But most seed result in a Scandinavian like coastline:)

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