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authorDavid Thompson <dthompson2@worcester.edu>2021-08-12 07:31:36 -0400
committerDavid Thompson <dthompson2@worcester.edu>2021-08-12 07:31:36 -0400
commit692eb45def187e2f2dbe7e40eacf27b2058c88bd (patch)
treef63749ccb9a43c2644a04a6bdab7137646e47b2e
parentb7350d996b5ef4942caf1e475bbd3a9d4c7bf5a9 (diff)
math: Rename 2pi to tau.
-rw-r--r--chickadee/graphics/path.scm10
-rw-r--r--chickadee/math.scm4
-rw-r--r--doc/api.texi2
3 files changed, 8 insertions, 8 deletions
diff --git a/chickadee/graphics/path.scm b/chickadee/graphics/path.scm
index 0d218fb..fb75efd 100644
--- a/chickadee/graphics/path.scm
+++ b/chickadee/graphics/path.scm
@@ -118,8 +118,8 @@
;; Curves" by Joe Cridge:
;; https://web.archive.org/web/20170829122313/https://www.joecridge.me/content/pdf/bezier-arcs.pdf
(define (adjust-angle angle)
- ;; Clamp within [0, 2pi] range.
- (let* ((clamped (mod angle 2pi))
+ ;; Clamp within [0, tau] range.
+ (let* ((clamped (mod angle tau))
(adjusted (atan (* (/ rx ry) (tan clamped)))))
;; Adjust angles to counter linear scaling.
(cond
@@ -129,11 +129,11 @@
(<= clamped (* pi 1.5)))
(+ adjusted pi))
(else
- (+ adjusted 2pi)))))
+ (+ adjusted tau)))))
(let* ((angle-start (adjust-angle angle-start))
(angle-end* (adjust-angle angle-end))
(angle-end (if (> angle-start angle-end*)
- (+ angle-end* 2pi)
+ (+ angle-end* tau)
angle-end*))
;; Don't bother making a curve for an angle smaller than
;; this.
@@ -416,7 +416,7 @@
(close-path))))
(define (regular-polygon center num-sides radius)
- (let ((theta-step (/ 2pi num-sides)))
+ (let ((theta-step (/ tau num-sides)))
(apply path
(let loop ((i 0))
(cond
diff --git a/chickadee/math.scm b/chickadee/math.scm
index c61b862..9286fe4 100644
--- a/chickadee/math.scm
+++ b/chickadee/math.scm
@@ -18,7 +18,7 @@
(define-module (chickadee math)
#:export (pi
pi/2
- 2pi
+ tau
cotan
clamp
min
@@ -30,7 +30,7 @@
(define pi 3.14159265358979323846)
(define pi/2 (/ pi 2.0))
-(define 2pi (* pi 2.0))
+(define tau 6.283185307179586) ;; AKA 2pi
(define-inlinable (cotan z)
"Return the cotangent of Z."
diff --git a/doc/api.texi b/doc/api.texi
index 96ac394..68cffef 100644
--- a/doc/api.texi
+++ b/doc/api.texi
@@ -581,7 +581,7 @@ approximation that is ``good enough.''
Half of @var{pi}.
@end defvar
-@defvar 2pi
+@defvar tau
Twice @var{pi}.
@end defvar