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@a1k0n
Created October 22, 2015 01:02
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Expanded version of the code featured in http://www.a1k0n.net/2011/06/26/obfuscated-c-yahoo-logo.html
#include <math.h>
#include <stdio.h>
#include <unistd.h>
// Each character encodes an angle of a plane we are checking
const char plane_angles[] = "O:85!fI,wfO8!yZfO8!f*hXK3&fO;:O;#hP;\"i[";
// and these encode an offset from the origin s.t. (x, y) dot (cos(a), sin(a)) < offset
const char plane_offsets[] = "<[\\]O=IKNAL;KNRbF8EbGEROQ@BSXXtG!#t3!^";
// this table encodes the offsets within the above tables of each polygon
const char polygon_offsets[] = "8<AFJPTX";
int main() {
float scale = 0, velocity = 0;
for(int frame = 0; frame < 40; frame++) {
if (frame != 0) {
// after the first frame, bring the cursor up 25 lines
puts("\x1b[25A");
}
// scale is controlled by a simple underdamped spring system -- velocity is
// proportional to displacement, with a damping factor (velocity/4)
scale += velocity;
velocity += (1 - scale) / 10 - velocity / 4;
// j loops over rows of the image
for(int j = 0; j < 72; j += 3) {
// and i loops over columns
for(int i = 0; i < 73; i++) {
float x = scale * (i - 27); // x coordinate in object, controlled by scale and i
// now we make three vertical samples of our object and put them in the
// low bits of our accumulator c
int c = 0;
for(int n = 2; n >= 0; n--) {
float y = scale * (j+n-36); // y coordinate in object
int plane_idx = 0;
int inside_ellipse = (136*x*x+84*y*y<92033);
c ^= inside_ellipse << n;
// this single loop runs over all polygons and all planes within each
// polygon. it really should be two loops, but this enables us to
// break out early without a goto, and this hews closer to the
// original obfuscated code.
for (int polygon = 0; polygon < 8;) {
// plane_end_idx is the last plane in our polygon
int plane_end_idx = polygon_offsets[polygon] - 50;
float angle = (plane_angles[plane_idx]-79)/14.64;
float plane_offset = plane_offsets[plane_idx++] / 1.16 - 68;
if (plane_offset > x*cos(angle) + y*sin(angle)) {
// we are outside the polygon
// advance to end of polygon and compute end of the next one
plane_idx = plane_end_idx;
polygon++;
} else if (plane_idx == plane_end_idx) {
// we are inside all planes of our polygon, so toggle our pixel
// and early-out
c ^= 1<<n;
break;
}
}
}
// finally, c indexes into a predefined list of characters based on the
// presence of the object in the three positions
putchar(" ''\".$u$"[c]);
}
putchar('\n');
}
usleep(50000);
}
}
@wafflespeanut
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This is awesome! :)

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