X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=funcs.scad.cpp;fp=funcs.scad.cpp;h=0d589ac9ecd3fe89a9201ed2c0a8da0a5dcb0a36;hb=3f431f5e5f72cc88127a70888575f9a18d2c871a;hp=0000000000000000000000000000000000000000;hpb=382b1f42ea067bfa5ea594bc2a971057b5105ad4;p=reprap-play.git

diff --git a/funcs.scad.cpp b/funcs.scad.cpp
new file mode 100644
index 0000000..0d589ac
--- /dev/null
+++ b/funcs.scad.cpp
@@ -0,0 +1,20 @@
+// -*- C -*-
+
+function dist(a,b) =
+#define dsq(i) (a[i]-b[i])*(a[i]-b[i])
+	       sqrt(dsq(0) + dsq(1));
+#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 alpha (atan2(a[1]-c[1],a[0]-c[0]))
+#define gamma (asin(r / d))
+#define beta  (alpha + 90 - gamma)
+              circle_point(c, r, beta);
+#undef d
+#undef alpha
+#undef gamma
+#undef beta