1 ;;; Gacela, a GNU Guile extension for fast games development
2 ;;; Copyright (C) 2009 by Javier Sancho Fernandez <jsf at jsancho dot org>
4 ;;; This program is free software: you can redistribute it and/or modify
5 ;;; it under the terms of the GNU General Public License as published by
6 ;;; the Free Software Foundation, either version 3 of the License, or
7 ;;; (at your option) any later version.
9 ;;; This program is distributed in the hope that it will be useful,
10 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
11 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 ;;; GNU General Public License for more details.
14 ;;; You should have received a copy of the GNU General Public License
15 ;;; along with this program. If not, see <http://www.gnu.org/licenses/>.
19 ;;; Additional modules
21 (use-modules (srfi srfi-1))
26 (define *pi* (* (asin 1) 2))
31 (define (degrees-to-radians angle)
32 (/ (* angle *pi*) 180))
34 (define (radians-to-degrees angle)
35 (/ (* angle 180) *pi*))
37 (define (distance-between-points p1 p2)
38 (define (add-power-of-two p1 p2)
42 (+ (expt (- (car p1) (car p2)) 2)
43 (add-power-of-two (cdr p1) (cdr p2))))))
45 (cond ((not (= (length p1) (length p2)))
48 (sqrt (add-power-of-two p1 p2)))))
53 (define (nearest-power-of-two n)
55 (cond ((> (* p 2) n) p)
56 (else (power (* p 2) n))))
59 (define-macro (pushnew elem list)
60 `(cond ((not (find (lambda (e) (eq? e ,elem)) ,list))
61 (set! ,list (cons ,elem ,list)))))
63 (define (assoc-multiple-set! alist . pairs)
64 (define (amset! alist pairs)
65 (cond ((< (length pairs) 2)
68 (assoc-set! alist (car pairs) (cadr pairs))
69 (amset! alist (cddr pairs)))))