Move from github, collapse gltk and strictmath, add candle

[clnl] / src / main / clnl / nvm / topology.lisp

diff --git a/src/main/clnl/nvm/topology.lisp b/src/main/clnl/nvm/topology.lisp
new file mode 100644 (file)
index 0000000..d5fa64d
--- /dev/null
+++ b/src/main/clnl/nvm/topology.lisp
@@ -0,0 +1,20 @@
+(in-package #:clnl-nvm)
+
+(defun wrap (pos min max)
+ (cond
+  ((>= pos max) (+ min (mod (- pos max) (- max min))))
+  ((< pos min)
+   (let
+    ((res (- max (mod (- min pos) (- max min)))))
+    (if (< res max) res min))) ; If d is infinitesimal, may return max, which would be bad :(
+  (t pos)))
+
+(defgeneric wrap-x (topology x))
+(defgeneric wrap-y (topology y))
+
+; Torus implementations
+(defmethod wrap-x ((topology (eql :torus)) x)
+ (wrap x (- (min-pxcor) 0.5d0) (+ (max-pxcor) 0.5d0)))
+
+(defmethod wrap-y ((topology (eql :torus)) y)
+ (wrap y (- (min-pycor) 0.5d0) (+ (max-pycor) 0.5d0)))