Don't store direction as a VEC2

Author: svercl

snake.lisp

@@ -40,21 +40,14 @@
 ;; TODO(bsvercl): Don't allow Left<->Right Up<->Down
 (defun change-direction (snake direction)
   "Modify DIRECTION of SNAKE with NEW-DIRECTION."
-  (let ((new-direction (case direction
-                         (:up (gamekit:vec2 0 1))
-                         (:down (gamekit:vec2 0 -1))
-                         (:left (gamekit:vec2 -1 0))
-                         (:right (gamekit:vec2 1 0))
-                         ;; We don't know that this is supposed to be.
-                         (t (gamekit:vec2)))))
-    (setf (direction-of snake) new-direction)))
+  (setf (direction-of snake) direction))
 
 (defun advance (snake ate-food-p)
   "Moves the SNAKE according to it's DIRECTION."
   (with-slots (segments direction) snake
     (let* ((position (snake-position snake))
            ;; The position of the next head.
-           (new-head (gamekit:add position direction))
+           (new-head (gamekit:add position (direction-vec direction)))
            ;; If we ate the food we do not chop off the end of the SEGMENTS.
            (which-segments (if ate-food-p segments (butlast segments)))
            (new-segments (push new-head which-segments)))

state.lisp

@@ -60,7 +60,8 @@
         (funcall end-callback)))))
 
 (defmethod draw ((this game-state))
-  ;; TODO(bsvercl): Drop into CL-BODGE to speed this up.
+  ;; TODO(bsvercl): Drop into CL-BODGE to speed this up,
+  ;; or just remove this completely?
   (loop for x from 0 below +segments-across-width+
         do (loop for y from 0 below +segments-across-height+
                  do (draw-segment (gamekit:vec2 x y)

util.lisp

@@ -23,3 +23,12 @@
                      size size
                      :fill-paint fill-paint
                      :stroke-paint stroke-paint))
+
+(defun direction-vec (direction)
+  (case direction
+    (:up (gamekit:vec2 0 1))
+    (:down (gamekit:vec2 0 -1))
+    (:left (gamekit:vec2 -1 0))
+    (:right (gamekit:vec2 1 0))
+    ;; We don't know that this is supposed to be.
+    (t (gamekit:vec2))))