Add alt code, PDF + format/typo checks 2011/zucker

The alt code is based on the author's remarks - it sets binary mode on
stdout.

The PDF is about sphere tracing. Added it in case the link ever dies.

Format/typo check README.md file.

Updated .gitignore.

2011/zucker/.gitignore

@@ -1,6 +1,7 @@
 image.ppm
 hello.ppm
 image2.ppm
+ioccc2011.ppm
 zucker
 zucker.orig
 prog.orig

2011/zucker/Makefile

@@ -114,8 +114,8 @@ OBJ= ${PROG}.o
 DATA=
 TARGET= ${PROG}
 #
-ALT_OBJ=
+ALT_OBJ= ${PROG}.alt.o
-ALT_TARGET=
+ALT_TARGET= ${PROG}.alt
 
 
 #################
@@ -138,6 +138,9 @@ ${PROG}: ${PROG}.c
 alt: data ${ALT_TARGET}
 	@${TRUE}
 
+${PROG}.alt: ${PROG}.alt.c
+	${CC} ${CFLAGS} $< -o $@ ${LDFLAGS}
+
 # data files
 #
 data: ${DATA}

2011/zucker/README.md

@@ -4,6 +4,9 @@
 make
 ```
 
+There is an alternate version which should work for Windows which distinguishes
+binary mode from text mode. See [alternate code](#alternate-code) below.
+
 
 ## To use:
 
@@ -21,14 +24,29 @@ make
 
 Display the PPM image with your favorite image viewer.
 
-The author gave options for macOS but we note that you can just do:
+
+## Alternate code:
+
+This version uses the Windows functions `_setmode()` and `_fileno()` to set
+binary mode on `stdout` which the author noted would be necessary for systems
+that distinguish binary and text.
+
+
+### Alternate build:
 
 ```sh
-open image.ppm
+make alt
 ```
 
-which will open `Preview.app` which will let you look at the image no problem.
+
-No need to install additional software.
+### Alternate use:
+
+Use `zucker.alt` as you would `zucker` above.
+
+
+### Alternate try:
+
+Try `zucker.alt` instead of `zucker` above.
 
 
 ## Judges' remarks:
@@ -49,18 +67,40 @@ This program makes pretty pictures.  To see the default output, try
 running
 
 ```sh
-./zucker > image.ppm
+./zucker > ioccc2011.ppm
 ```
 
-On the author's 2.5 GHz MacBook Pro, this command takes approximately
+On the author's 2.5 GHz MacBook Pro, this command takes approximately 1 minute
-1 minute and 18 seconds to run -- your runtime may vary.  You will
+and 18 seconds to run -- your runtime may vary.  You will need an image viewer
-need an image viewer capable of displaying Netpbm images in order to
+capable of displaying [Netpbm images](https://en.wikipedia.org/wiki/Netpbm) in
-display the output. On the Mac, [Xee](http://wakaba.c3.cx/s/apps/xee)
+order to display the output. On the Mac, the system supplied `Preview.app` works
-works well; otherwise [ImageMagick](http://www.imagemagick.org/)
+well; otherwise [ImageMagick](http://www.imagemagick.org/) and/or
-and/or [GraphicsMagick](http://www.graphicsmagick.org/) are both
+[GraphicsMagick](http://www.graphicsmagick.org/) are both capable of displaying
-capable of displaying Netpbm files, and are available on multiple
+Netpbm files, and are available on multiple platforms.
-platforms. (Using Xee is particularly nice because it periodically
+
-reloads the image as it is rendered.)
+With macOS you can type at the command line:
+
+```sh
+open ioccc2021.ppm
+```
+
+and it will open image in the default application Preview.app.
+
+To use ImageMagick you might do something like:
+
+```sh
+convert ioccc2011.ppm ioccc2011.png
+```
+
+and then open `ioccc2011.png` in your viewer of choice.
+
+To use GraphicsMagick you might do something like:
+
+```sh
+gm convert ioccc2011.ppm ioccc2011.png
+```
+
+and then open `ioccc2011.png` in your viewer of choice.
 
 Aside from the default image, you may create your own by running the
 program as follows:
@@ -76,71 +116,75 @@ mode by appending `-preview` to the command line arguments, like so:
 ./zucker faster\! -preview > image.ppm
 ```
 
-If your platform distinguishes between binary and text streams, you
+If your platform distinguishes between binary and text streams, you may need to
-may need to insert some code to reopen standard output in binary mode
+insert some code to reopen standard output in binary mode at the start of
-at the start of `main`. An ASCII platform is assumed.
+`main()` (the provided [alternate version](#alternate-code) will set binary mode
+on `stdout` in Windows). An ASCII platform is assumed.
+
 
 #### Pedagogical value:
 
 This program is quite suitable for the inexperienced programmer, due
 to a number of considerations:
 
-  * It is fairly short: just 4 preprocessor directives followed by 29
+* It is fairly short: just 4 preprocessor directives followed by 29
-    lines of source.
+lines of source.
 
-  * It compiles cleanly as ANSI C under gcc 4.2.1 with very strict
+* It compiles cleanly as ANSI C under gcc 4.2.1 with very strict
-    compilation flags.
+compilation flags.
 
-  * It uses a very small subset of the keywords available in C, namely
+* It uses a very small subset of the keywords available in C, namely
-    `char`, `float`, `int`, `typedef`, `struct`, `for`, and `return`.
+`char`, `float`, `int`, `typedef`, `struct`, `for`, and `return`.
-    More difficult concepts such as `void`, `if`, `switch`, and
+More difficult concepts such as `void`, `if`, `switch`, and
-    `while` are eschewed for simplicity's sake.
+`while` are eschewed for simplicity's sake.
 
-  * It also uses a very small number of library functions: just `putchar`,
+* It also uses a very small number of library functions: just `putchar(3)`,
-    `cos`, `sin`, `atan2`, `sqrt`, and `pow`.
+`cos(3)`, `sin(3)`, `atan2(3)`, `sqrt(3)`, and `pow(3)`.
+
+* New programmers often prefer to use global variables when
+possible. Hence, *all* variables in this program (aside from
+function parameters) have global scope.
+
+* An important aspect of the computation is graphically illustrated
+by the source code itself: the geometric construction of a
+reflection ray at an object's surface, given the incoming
+direction and surface normal.
 
-  * New programmers often prefer to use global variables when
-    possible. Hence, *all* variables in this program (aside from
-    function parameters) have global scope.
 
-  * An important aspect of the computation is graphically illustrated
-    by the source code itself: the geometric construction of a
-    reflection ray at an object's surface, given the incoming
-    direction and surface normal.
-\
 #### Further details (contains spoilers):
 
-The program is not quite a traditional ray tracer, but a "sphere
+The program is not quite a traditional [ray
-tracer" which uses distance fields to encode proximity to objects in
+tracer](https://en.wikipedia.org/wiki/Ray_tracing_(graphics)), but a "[sphere
-the scene. Using sphere tracing to compute visibility instead of
+tracer](sphere-tracing.pdf)" which uses distance fields to encode proximity to
-analytic ray tracing provides two advantages: first, it greatly eases
+objects in the scene. Using sphere tracing to compute visibility instead of
-the computation of ray-torus intersection (which would otherwise
+analytic ray tracing provides two advantages: first, it greatly eases the
-require solving a quartic polynomial), and second, it makes it
+computation of [ray-torus](https://en.wikipedia.org/wiki/Toric_lens#Torus)
-possible to compute ambient occlusion (which is used to generate soft
+intersection (which would otherwise require solving a quartic polynomial), and
-shadows). Unlike many traditional ray tracers and sphere tracers, this
+second, it makes it possible to compute [ambient
-one uses iteration instead of recursion to compute the effect of
+occlusion](https://en.wikipedia.org/wiki/Ambient_occlusion) (which is used to
-reflections. This, unfortunately, resulted in the programmer going
+generate soft shadows). Unlike many traditional ray tracers and sphere tracers,
-insane; however, program size was reduced and readability
+this one uses iteration instead of recursion to compute the effect of
-hindered. Neither the plaintext for the program's default output nor
+reflections. This, unfortunately, resulted in the programmer going insane;
-for the Netpbm header appears in the program source, which hinders
+however, program size was reduced and readability hindered. Neither the
-readability as well. Also, unlike some previous IOCCC entries which
+plaintext for the program's default output nor for the Netpbm header appears in
-render ASCII text, this one uses a vector (as opposed to raster)
+the program source, which hinders readability as well. Also, unlike some
-font. Although the program does not generate uppercase letters, it
+previous IOCCC entries which render ASCII text, this one uses a vector (as
-handles them in a reasonable manner when they appear in the input.
+opposed to raster) font. Although the program does not generate uppercase
+letters, it handles them in a reasonable manner when they appear in the input.
 
 Even when the program is pretty-printed and preprocessor macros are
-expanded, it should be fairly resistant to analysis due to reckless
+translated, it should be fairly resistant to analysis due to reckless
-reuse of global variables, to the inherently opaque nature of the
+reuse of global variables, the inherently opaque nature of the
-math, and to its overall density. Global variables are used to store
+math, and its overall density. Global variables are used to store
 the results of intermediate computation. As a result, seemingly simple
 functions have important side effects. Although some of the global
 variables are simply constants, their use is overloaded. For instance,
-the variable `X` is used both as the number 40 and as the ASCII
+the variable `X` is used both as the number `40` and as the ASCII
 character `'('`.  Maintainability is hindered due to hardcoding
 several aspects of the program in multiple locations. As an example,
 it is impossible to modify either the image width or height without
 changing the source in at least three different places, including
-inside the large string literal.
+inside the large string literal `J`.
 
 Some of the functions are simple vector algebraic operations such as
 vector construction, dot product, and normalization. However, it was
@@ -153,26 +197,24 @@ get as much mileage as possible out of statements inside of loop
 declarations. Between `for` loops, the comma operator, and the ternary
 operator, it was possible to avoid `if` and `while` altogether.
 
-Bitwise and arithmetic operators are used instead of logical operators
+Bitwise and arithmetic operators are used instead of logical operators whenever
-whenever gcc doesn't warn about it. Conversely, integer
+gcc doesn't warn about it. Conversely, integer multiplication, division, and
-multiplication, division, and modulus are sometimes used in place of
+modulus are sometimes used in place of traditional bitwise operators just to
-traditional bitwise operators just to keep the reader on his or her
+keep the reader on his or her toes. Automatic casting between characters,
-toes. Automatic casting between characters, integers, and floats is
+integers, and floats is performed just about everywhere. Fascinatingly, this
-performed just about everywhere. Fascinatingly, this doesn't seem to
+doesn't seem to affect performance too badly. Sometimes when an explicit cast
-affect performance too badly. Sometimes when an explicit cast
+(i.e. from `float` to `int`) is needed, the program instead simply assigns to a
-(i.e. from float to int) is needed, the program instead simply assigns
+free variable of the desired type instead. Both the `array[index]` and
-to a free variable of the desired type instead. Both the `array[index]`
+`index[array]` notations are used interchangeably throughout the program.
-and `index[array]` notations are used interchangeably throughout the
-program.
 
-Two other programs were written to support development of this
+Two other programs were written to support development of this program. The
-program. The first used a randomized search algorithm to deduce the
+first used a randomized search algorithm to deduce the most compact encoding of
-most compact encoding of the vector font instructions into ASCII; the
+the vector font instructions into ASCII; the second used a modified form of the
-second used a modified form of the Knuth-Plass algorithm to layout the
+[Knuth-Plass](https://en.wikipedia.org/wiki/Line_wrap_and_word_wrap) algorithm
-final text on top of a hand-generated ASCII "stencil".  The programs
+to layout the final text on top of a hand-generated ASCII "stencil".  The
-were not submitted as entries for this year's IOCCC, not because they
+programs were not submitted as entries for this year's IOCCC, not because they
-lack obfuscation, but because neither is written in C (they are in C++
+lack obfuscation, but because neither is written in C (they are in C++ and
-and Python, respectively).
+Python, respectively).
 
 
 ## Copyright and CC BY-SA 4.0 License:

2011/zucker/zucker.alt.c

@@ -0,0 +1,35 @@
+#include <stdio.h>
+#include <math.h>
+#include <fcntl.h>
+#include <io.h>
+#define E return
+#define S for
+char*J="LJFFF%7544x^H^XXHZZXHZ]]2#( #@@DA#(.@@%(0CAaIqDCI$IDEH%P@T@qL%PEaIpBJCA\
+I%KBPBEP%CBPEaIqBAI%CAaIqBqDAI%U@PE%AAaIqBcDAI%ACaIaCqDCI%(aHCcIpBBH%E@aIqBAI%A\
+AaIqB%AAaIqBEH%AAPBaIqB%PCDHxL%H@hIcBBI%E@qJBH#C@@D%aIBI@D%E@QB2P#E@'C@qJBHqJBH\
+%C@qJBH%AAaIqBAI%C@cJ%"   "cJ"   "CH%C@qJ%aIqB1I%PCDI`I%BAaICH%KH+@'JH+@KP*@%S@\
+3P%H@ABhIaBBI%P@S@PC#",     *j   ,*e;typedef float x;x U(x a){E a<0?0:a>1?1:a; }
+typedef struct{x c,a,t;      }   y;y W={1,1,1},Z={0,0,0},B[99],P,C,M,N,K,p,s,d,h
+;y G(x t,x a,x c){K.c=t   ;      K.t=c; K.a=a;E K;}int T=-1,b=0,r,F=-111,(*m)(i\
+nt)=putchar,X=40,z=5,o,   a,     c,t=0   ,n,R;y A(y a,y b,x c){E G(a.c+b.c*c,a.a
++c*b.a,b.t*c+a.t);}x H=   .5,Y   =.66     ,I,l=0,q,w,u,i,g;x O(y a,y b){E q=a.t*
+b.t+b.c*a.c+a.a*b.a;}x Q(){E A(P,M,T       ),O(K,K)<I?C=M,I=q:0;}y V(y a){E A(Z,
+a,pow(O(a,a),-H));}x D(y p){S(I=X,P         =p,b=T; M=B[++b],p=B[M.c+=8.8-l*.45,
+++b],b<=r;Q())M=p.t?q =M_PI*H,w=atan2(   P.a-M.a,P.c-M.c)  /q,o=p.c-2,a=p.a+1,t=
+o+a,w=q*(w>t+H*a?o:    w>t?t:w<o-H*a?t   :w<o?o:w),A(      M,G(cos(w),sin(w),0),
+1):A(M,p,U(O(A(P,M,T)    ,p)/O(p,p)));   M=P;M.a=-         .9;o=P.c/8+8;o^=a=P.t
+/8+8; M=Q        ()?o&1    ?G(Y,0,0):W   :G(Y,Y,1);E       sqrt        (I)-.45;}
+int main(int L,char**k){_setmode(_fileno(stdin),_O_BINARY);S(e=L>1?1[z=0,k]:J ;*e   &&l<24 ;
+++e)S(o=a   =0,j   =J+9;(c=    *++j)&&   !(o&&c<    X&&(q=l+=w)   );o   ?o=*j++/
+32,b++[B]   =G(q   +=*j/8&3,*    j&7,0   ),B[r    =b++]=G((c/8&        3)*( o<2?
+T:1), (c&   7)+    1e-4,o>2),1:    (o    =(a    =(c-=X)<0?w=c+6   ,t=   a+1:c?(t
+?0:m(c),a        ):*++j)==((*e|32        )    ^z)&&1[j]-X));S(z   =3*(   L<3);++
+F<110;)S(L=-301;p=Z,++L<300;m(              p.c),m(p.a),m(p.t))S(c=T;++c<=z;)S(h
+=G(-4,4.6,29),d=V(A(A(A(Z,V(G(5,0         ,2)),L+L+c/2),V(G(2,-73,0)),F+F+c%2),G
+(30.75,-6,-75),20)),g=R=255-(n=z)*64;    R*n+R;g*=H){S(u=i=R=0;!R&&94>(u+=i=D(h=
+A(h,d,i)));R=i<.01);S(N=V(A(P,C,               T)),q=d.t*d.t,s=M,u=1;++i<6*R;u-=
+U(i/3-D(A(h,N,i/3)))/pow(                             2,i));s=R?i=pow(U(O(N,V(A(
+M=V(G(T,1,2)),d,T))))                                     ,X),p=A(p,W,g*i),u*=U(
+O(N,M))*H*Y+Y,g*=                                             n--?Y-Y*i:1-i,s:G(
+q,q,1); p=A(p,s                                                 ,g*u);h=A(h,N,.1
+);d=A(d,N,-2*O                                                     (d,N));}E 0;}

thanks-for-fixes.md

@@ -3268,6 +3268,17 @@ the author's comments (along with looking up the function for the right header
 file). To build try the alt rule of the Makefile.
 
 
+## [2011/zucker](2011/zucker/zucker.c) ([README.md](2011/zucker/README.md]))
+
+Cody added [alt code](2011/zucker/README.md#alternate-code) that should work on
+Windows, based on the author's remarks that if the system distinguishes binary
+and text then `stdout` needs to be set to binary mode.
+
+Cody also added the PDF file
+[sphere-tracing.pdf](2011/zucker/sphere-tracing.pdf) in case the link eventually
+dies.
+
+
 # <a name="2012"></a>2012