Add find-arc and find-circle for eventual vision

src/crypts-and-corpses.lisp

@@ -279,6 +279,35 @@
       ((eq :not-found (gethash right mobiles :not-found)) right)
       ((eq :not-found (gethash down mobiles :not-found)) down))))
 
+(defun find-arc (x y x0 y0 map)
+  (labels ((calc-location-map (x y) (calc-location x y map)))
+    (let ((coords (list (list (+ x x0) (+ y y0))
+                        (list (+ y x0) (+ x y0))
+                        (list (- x0 x) (+ y y0))
+                        (list (- x0 y) (+ x y0))
+                        (list (- x0 x) (- y0 y))
+                        (list (- x0 y) (- y0 x))
+                        (list (+ x x0) (- y0 y))
+                        (list (+ y x0) (- y0 x)))))
+      (loop for i in coords collect (apply #'calc-location-map i)))))
+
+
+
+(defun find-circle (location radius map)
+  (multiple-value-bind (x0 y0) (calc-coord location map)
+    (let ((cur-radius radius)
+          (y 0)
+          (decision-over-2 (- 1 radius)))
+      (loop while (<= y cur-radius)
+            as coords = (find-arc cur-radius y x0 y0 map) do
+              (incf y)
+              (if (<= decision-over-2 0)
+                  (incf decision-over-2 (1+ (* 2 y)))
+                  (progn
+                    (decf cur-radius)
+                    (incf decision-over-2 (1+ (* 2 (- y cur-radius))))))
+            collect coords))))
+
 (defun fill-map-from-crawler (dungeon map player)
   (with-slots ((width crawler:width) (height crawler:height)) dungeon
     (dotimes (x width)