// -*- C -*-
-function dist(a,b) =
+function vecdiff2d(a,b) = [b[0]-a[0], b[1]-a[1]];
+function vecdiff(a,b) = [b[0]-a[0], b[1]-a[1], b[2]-a[2]];
+
#define dsq(i) (a[i]-b[i])*(a[i]-b[i])
- sqrt(dsq(0) + dsq(1));
+function dist2d(a,b) = sqrt(dsq(0) + dsq(1));
+function dist(a,b) = sqrt(dsq(0) + dsq(1) + dsq(2));
#undef dsq
function circle_point(c, r, alpha) = [ c[0] + r * cos(alpha),
c[1] + r * sin(alpha) ];
-function tangent_intersect(a,c,r) =
-#define d (dist(a,c))
+#define d (dist2d(a,c))
#define alpha (atan2(a[1]-c[1],a[0]-c[0]))
#define gamma (asin(r / d))
#define beta (alpha + 90 - gamma)
+
+function tangent_intersect_beta(c,r,a) =
+ beta;
+
+function tangent_intersect_b(c,r,a) =
circle_point(c, r, beta);
#undef d
#undef alpha
#undef gamma
#undef beta
+
+function tangents_intersect_beta(cbig,rbig,csmall,rsmall) =
+ tangent_intersect_beta(cbig,rbig-rsmall,csmall);
+
+function reflect_in_y(p) = [-p[0], p[1]];
+
+function angle_map_range(in,base) =
+ in < base ? in + 360 :
+ in >= base + 360 ? in - 360 :
+ in;