kayomarz

;; `(pathname "/foo/bar")` uses the trailing directory separator to decide if a
;; path refers to a file or directory

;; (pathname "/home/foo.bar" ) => #P"/home/foo.bar"

;; (pathname "/home/foo.bar/") => #P"/home/foo.bar/"

;; Instead, this function definition `pathname-as-dir` results in a pathname
;; which is a always a directory irrespective of the trailing slash contained in
;; the string argument.

kayomarz

;;; Start lisp, for example run sbcl.
;;; $ sbcl

;;; First uninstall all systems.
;;; ref: https://github.com/quicklisp/quicklisp-client/issues/147#issuecomment-1631778086

(mapc #'ql:uninstall (mapcar #'ql-dist:short-description (ql-dist:installed-systems t)))

;;; To be able to use slime, we install the slime helper
(ql:quickload "quicklisp-slime-helper")

kayomarz

;;; A Common Lisp port of the Möller–Trumbore ray-triangle intersection
;;; algorithm originally authored in C.

;;; Introduction
;;; ============

;;; The Möller–Trumbore ray-triangle intersection algorithm is credited to its
;;; inventors Tomas Möller and Ben Trumbore.

;;; The original C code was accessed from Möller Trumbore's article: `Practical