Makefile, funcs.scad: helpful file

[reprap-play.git] / funcs.scad.cpp

diff --git a/funcs.scad.cpp b/funcs.scad.cpp
new file mode 100644 (file)
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