1 files changed, 82 insertions, 0 deletions
diff --git a/2d/math.scm b/2d/math.scm
new file mode 100644
index 0000000..99db689
--- /dev/null
+++ b/2d/math.scm
@@ -0,0 +1,82 @@
+;;; guile-2d
+;;; Copyright (C) 2013 David Thompson <dthompson2@worcester.edu>
+;;;
+;;; Guile-2d is free software: you can redistribute it and/or modify it
+;;; under the terms of the GNU Lesser General Public License as
+;;; published by the Free Software Foundation, either version 3 of the
+;;; License, or (at your option) any later version.
+;;;
+;;; Guile-2d 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
+;;; Lesser General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Lesser General Public
+;;; License along with this program.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; Miscellaneous math procedures. Currently just trigonometry.
+;;
+;;; Code:
+
+(define-module (2d math)
+  #:export (pi
+            degrees->radians
+            radians->degress
+            sin-degrees
+            cos-degrees
+            tan-degrees
+            atan-degrees))
+
+;; Dave was editing this module on Pi Approximation Day.
+;;
+;;       3.141592653589793238462643383279
+;;     5028841971693993751058209749445923
+;;    07816406286208998628034825342117067
+;;    9821    48086         5132
+;;   823      06647        09384
+;;  46        09550        58223
+;;  17        25359        4081
+;;            2848         1117
+;;            4502         8410
+;;            2701         9385
+;;           21105        55964
+;;           46229        48954
+;;           9303         81964
+;;           4288         10975
+;;          66593         34461
+;;         284756         48233
+;;         78678          31652        71
+;;        2019091         456485       66
+;;       9234603           48610454326648
+;;      2133936            0726024914127
+;;      3724587             00660631558
+;;      817488               152092096
+;;
+(define pi 3.141592654)
+
+(define (degrees->radians angle)
+  "Converts angle in degrees to radians."
+  (* angle (/ pi 180)))
+
+(define (radians->degrees angle)
+  "Converts angle in radians to degrees."
+  (* angle (/ 180 pi)))
+
+(define (sin-degrees angle)
+  "Computes the sin of the angle expressed in degrees."
+  (sin (degrees->radians angle)))
+
+(define (cos-degrees angle)
+  "Computes the cosine of the angle expressed in degrees."
+  (cos (degrees->radians angle)))
+
+(define (tan-degrees angle)
+  "Computes the tangent of the angle expressed in degrees."
+  (tan (degrees->radians angle)))
+
+(define (atan-degrees y x)
+  "Computes the arctangent in degrees of the coordinates x and y."
+  (radians->degrees (atan y x)))