Handle snake grow

1 files changed, 11 insertions, 0 deletions

diff --git a/server/game.lisp b/server/game.lisp
index 5658c5a..207b669 100644
--- a/server/game.lisp
+++ b/server/game.lisp
@@ -42,6 +42,17 @@
    (and (or (eq dir :left) (eq dir :right)) ; Goto left or right only if the snake is on the up or down direction
         (or (eq active-dir :up) (eq active-dir :down)))))
 
+;;; Grow snake of grow-size amount (snake is growing by the tail)
+(defun grow-snake (snake grow-size)
+  (let* ((old-size (first (array-dimensions snake)))
+         (new-size (+ old-size grow-size))
+         (tail (aref snake (- old-size 1)))
+         (new-tail (coerce (make-array grow-size :initial-element tail) 'list))
+         (new-snake (make-array new-size :initial-contents `(,@(coerce snake 'list) ,@new-tail))))
+    new-snake))
+         
+    
+
 (defmethod refresh ((g game) &key (dir nil dir-supplied-p))
   ;; First, update direction
   (with-slots ((active-dir dir)) g