Modules reorganization

[dungeon-master.git] / modules / dungeon-master / geom / point.scm

diff --git a/modules/dungeon-master/geom/point.scm b/modules/dungeon-master/geom/point.scm
new file mode 100644 (file)
index 0000000..72ca1bb
--- /dev/null
+++ b/modules/dungeon-master/geom/point.scm
@@ -0,0 +1,53 @@
+;;; Dungeon Master --- RPG Adventure Generator
+;;; Copyright © 2019 Javier Sancho <jsf@jsancho.org>
+;;;
+;;; Dungeon Master is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or
+;;; (at your option) any later version.
+;;;
+;;; Dungeon Master is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;;; General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with Dungeon Master. If not, see <http://www.gnu.org/licenses/>.
+
+
+(define-module (dungeon-master geom point)
+  #:use-module (srfi srfi-9)
+  #:export (make-point
+            point?
+            point-x
+            point-y
+           points-distance
+            sum-points
+            scale-point))
+
+(define-record-type <point>
+  (make-point x y)
+  point?
+  (x point-x)
+  (y point-y))
+
+(define (points-distance p1 p2)
+  (abs
+   (sqrt (+ (expt (- (point-x p1) (point-x p2)) 2)
+            (expt (- (point-y p1) (point-y p2)) 2)))))
+
+(define (sum-points . points-to-sum)
+  (let loop ((points points-to-sum)
+             (x 0)
+             (y 0))
+    (cond ((null? points)
+           (make-point x y))
+          (else
+           (loop (cdr points)
+                 (+ x (point-x (car points)))
+                 (+ y (point-y (car points))))))))
+
+(define (scale-point point scale)
+  (make-point
+   (* (point-x point) scale)
+   (* (point-y point) scale)))