Add angle-distance

Shirakumo · Feb 19, 2024 · b2b27ec · b2b27ec
1 parent 6d2e259
commit b2b27ec
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diff --git a/package.lisp b/package.lisp
@@ -1814,6 +1814,7 @@
    #:rad->deg
    #:db
    #:angle-midpoint
+   #:angle-distance
    #:clamp-angle
    #:lerp-angle
    #:symbol->c-name

diff --git a/toolkit.lisp b/toolkit.lisp
@@ -794,6 +794,10 @@
   (when (< PI (- b a)) (decf b F-2PI))
   (mod (/ (+ b a) 2) F-2PI))
 
+(defun angle-distance (a b)
+  (let ((da (mod (- b a) F-2PI)))
+    (- (mod (* 2 da) F-2PI) da)))
+
 (defun clamp-angle (min a max)
   (flet ((normalize-180 (a)
            (- (mod (+ a F-PI) F-2PI) F-PI)))