3 function vecdiff2d(a,b) = [b[0]-a[0], b[1]-a[1]];
4 function vecdiff(a,b) = [b[0]-a[0], b[1]-a[1], b[2]-a[2]];
6 #define dsq(i) (a[i]-b[i])*(a[i]-b[i])
7 function dist2d(a,b) = sqrt(dsq(0) + dsq(1));
8 function dist(a,b) = sqrt(dsq(0) + dsq(1) + dsq(2));
11 function circle_point(c, r, alpha) = [ c[0] + r * cos(alpha),
12 c[1] + r * sin(alpha) ];
14 #define d (dist2d(a,c))
15 #define alpha (atan2(a[1]-c[1],a[0]-c[0]))
16 #define gamma (asin(r / d))
17 #define beta (alpha + 90 - gamma)
19 function tangent_intersect_beta(c,r,a) =
22 function tangent_intersect_b(c,r,a) =
23 circle_point(c, r, beta);
29 function tangents_intersect_beta(cbig,rbig,csmall,rsmall) =
30 tangent_intersect_beta(cbig,rbig-rsmall,csmall);
32 function reflect_in_y(p) = [-p[0], p[1]];
34 function angle_map_range(in,base) =
35 in < base ? in + 360 :
36 in >= base + 360 ? in - 360 :