Replaced 2pi with tau, the proposed 'new' circle constant

git-svn-id: https://forth-ev.de/repos/bigforth@2502 3b8d8251-53f3-0310-8f3b-fd1cb8370982

3d-turtle.fs

@@ -169,8 +169,8 @@ IS dummy-canvas
 [THEN]
 
 1e f>fs Constant #1.
-pi f2* FConstant 2pi
-2pi 1/f FConstant 1/2pi
+pi f2* FConstant tau
+tau 1/f FConstant 1/tau
 
 \ : .matrix ( addr -- )
 \   &12 sfloats bounds
@@ -488,7 +488,7 @@ class;
 
     : phi>xy ( f -- f1 f2 )
       rot-mode sf@ f* fsincos 1e f- 1e f+ ;
-    : degrees ( f -- )  1/2pi f* rot-mode ! ;
+    : degrees ( f -- )  1/tau f* rot-mode ! ;
 
     : left ( f -- )       phi>xy  trans-2,0 trans-3,0 do-turn ;
     : down ( f -- )       phi>xy  trans-1,0 trans-3,0 do-turn ;
@@ -695,10 +695,10 @@ class;
     : >texture  ( addr f -- )
       IS do-texture y-text sf! 0e z-off sf! ;
     : xy-texture    ['] do-xy-text    1e    >texture ;
-    : zphi-texture  ['] do-zphi-text  1/2pi >texture ;
-    : zphi2-texture ['] do-zphi2-text 1/2pi >texture ;
+    : zphi-texture  ['] do-zphi-text  1/tau >texture ;
+    : zphi2-texture ['] do-zphi2-text 1/tau >texture ;
     : zp-texture    ['] do-zp-text    1e    >texture ;
-    : rphi-texture  ['] do-rphi-text  1/2pi >texture ;
+    : rphi-texture  ['] do-rphi-text  1/tau >texture ;
     : no-texture    ['] noop          1e    >texture ;
 
 \ texture loading (ppm)                                31jan99py
@@ -1117,7 +1117,7 @@ class;
       LOOP  f2* forward
       drop end-path ;
     : cylinder ( r1 r2 d n -- ) { f: r1 f: r2 f: d }
-      2pi dup fm/ set-dphi
+      tau dup fm/ set-dphi
       dup start-path
       r1 .01e f* 0e dup segment  \ ugly workaround
       r1 0e dup segment

dragon-shoot.fs

@@ -30,10 +30,10 @@ Create .sky   .3e sf, .6e sf, .8e sf, 1e  sf,
   IF  .text  ELSE  drop  THEN ;
 
 Variable tail-time
-: time' ( -- 0..2pi )
+: time' ( -- 0..tau )
   tail-time @ [ #24 #60 #30 * * ] Literal um* drop
   0 d>f [ !$2'-8 pi f* ] FLiteral f* ;
-: time-pos ( -- 0..2pi )
+: time-pos ( -- 0..tau )
   tail-time @ [ #24 #60 #5 * * ] Literal um* drop
   0 d>f [ !$2'-8 pi f* ] FLiteral f* ;
 : tail-wag ( n -- f )
@@ -46,7 +46,7 @@ Variable tail-time
         ro set-r
         ri .1e set-rp  dphi sf@ phi sf@ f+ phi sf!
         1 DO  ri set-r  LOOP
-        2pi phi sf! ro set-r
+        tau phi sf! ro set-r
         0e phi sf! } ;
   F : tail-compensate ( n -- f )  0e
       0 DO  I 2+ tail-wag f+ [ 1.1e 1/f ] Fliteral f*  LOOP

dragon.fs

@@ -30,7 +30,7 @@ Create .sky   .3e sf, .6e sf, .8e sf, 1e  sf,
   IF  .text  ELSE  drop  THEN ;
 
 Variable tail-time
-: time' ( -- 0..2pi )
+: time' ( -- 0..tau )
   tail-time @ [ #24 #60 #30 * * ] Literal um* drop
   0 d>f [ !$2'-8 pi f* ] FLiteral f* ;
 : tail-wag ( n -- f )
@@ -43,7 +43,7 @@ Variable tail-time
         ro set-r
         ri .1e set-rp  dphi sf@ phi sf@ f+ phi sf!
         1 DO  ri set-r  LOOP
-        2pi phi sf! ro set-r
+        tau phi sf! ro set-r
         0e phi sf! } ;
   F : tail-compensate ( n -- f )  0e
       0 DO  I 2+ tail-wag f+ [ 1.1e 1/f ] Fliteral f*  LOOP

sincos.fs

@@ -39,9 +39,9 @@ base @ hex
 
 base !
 
-$6487F Constant 2pi
-2pi 1 + 4 / Constant pi/2
-2pi 3 + 8 / Constant pi/4
+$6487F Constant tau
+tau 1 + 4 / Constant pi/2
+tau 3 + 8 / Constant pi/4
  $B505 Constant sqrt.5
 
 | : (sini ( n -- sin[n] ) 2* sintab + w@ ;

tree.fs

@@ -23,7 +23,7 @@ Create .green .5e sf, .8e sf, .4e  sf, 1e  sf,
              dup .03e fm* dup .1e fm* 6 segment
              over 1 ?DO
                 #1000 random rd-val <
-                IF  2pi I I' fm*/ { f: di |
+                IF  tau I I' fm*/ { f: di |
                     >turtle
                        di roll-left pi 5 fm/ right di roll-right
                        2dup 1- (tree

xmas-tree.fs

@@ -100,7 +100,7 @@ forward tree-branch
              [ pi 0.2e f* ] Fliteral roll-left
              dup 1 2e color-cylinder
              over 0 ?DO
-                 2pi I I' fm*/ to di
+                 tau I I' fm*/ to di
                  >turtle
                      di roll-left pi 3 fm/ right
                      pi f2/ roll-right