From 48b9f83db917d2ea9db6a6533b79421d404ee4ee Mon Sep 17 00:00:00 2001 From: Cody Boone Ferguson <53008573+xexyl@users.noreply.github.com> Date: Sun, 26 Nov 2023 06:03:26 -0800 Subject: [PATCH] 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 + 2011/zucker/Makefile | 7 +- 2011/zucker/README.md | 194 ++++++++++++++++++++++++--------------- 2011/zucker/zucker.alt.c | 35 +++++++ thanks-for-fixes.md | 11 +++ 5 files changed, 170 insertions(+), 78 deletions(-) create mode 100644 2011/zucker/zucker.alt.c diff --git a/2011/zucker/.gitignore b/2011/zucker/.gitignore index b11ce3dcc..a5001eaaf 100644 --- a/2011/zucker/.gitignore +++ b/2011/zucker/.gitignore @@ -1,6 +1,7 @@ image.ppm hello.ppm image2.ppm +ioccc2011.ppm zucker zucker.orig prog.orig diff --git a/2011/zucker/Makefile b/2011/zucker/Makefile index df5bb4562..abae3cc76 100644 --- a/2011/zucker/Makefile +++ b/2011/zucker/Makefile @@ -114,8 +114,8 @@ OBJ= ${PROG}.o DATA= TARGET= ${PROG} # -ALT_OBJ= -ALT_TARGET= +ALT_OBJ= ${PROG}.alt.o +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} diff --git a/2011/zucker/README.md b/2011/zucker/README.md index 8dea09c54..90abcea68 100644 --- a/2011/zucker/README.md +++ b/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 -1 minute and 18 seconds to run -- your runtime may vary. You will -need an image viewer capable of displaying Netpbm images in order to -display the output. On the Mac, [Xee](http://wakaba.c3.cx/s/apps/xee) -works well; otherwise [ImageMagick](http://www.imagemagick.org/) -and/or [GraphicsMagick](http://www.graphicsmagick.org/) are both -capable of displaying Netpbm files, and are available on multiple -platforms. (Using Xee is particularly nice because it periodically -reloads the image as it is rendered.) +On the author's 2.5 GHz MacBook Pro, this command takes approximately 1 minute +and 18 seconds to run -- your runtime may vary. You will need an image viewer +capable of displaying [Netpbm images](https://en.wikipedia.org/wiki/Netpbm) in +order to display the output. On the Mac, the system supplied `Preview.app` works +well; otherwise [ImageMagick](http://www.imagemagick.org/) and/or +[GraphicsMagick](http://www.graphicsmagick.org/) are both capable of displaying +Netpbm files, and are available on multiple platforms. + +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 -may need to insert some code to reopen standard output in binary mode -at the start of `main`. An ASCII platform is assumed. +If your platform distinguishes between binary and text streams, you may need to +insert some code to reopen standard output in binary mode at the start of +`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 - lines of source. +* It is fairly short: just 4 preprocessor directives followed by 29 +lines of source. - * It compiles cleanly as ANSI C under gcc 4.2.1 with very strict - compilation flags. +* It compiles cleanly as ANSI C under gcc 4.2.1 with very strict +compilation flags. - * It uses a very small subset of the keywords available in C, namely - `char`, `float`, `int`, `typedef`, `struct`, `for`, and `return`. - More difficult concepts such as `void`, `if`, `switch`, and - `while` are eschewed for simplicity's sake. +* It uses a very small subset of the keywords available in C, namely +`char`, `float`, `int`, `typedef`, `struct`, `for`, and `return`. +More difficult concepts such as `void`, `if`, `switch`, and +`while` are eschewed for simplicity's sake. - * It also uses a very small number of library functions: just `putchar`, - `cos`, `sin`, `atan2`, `sqrt`, and `pow`. +* It also uses a very small number of library functions: just `putchar(3)`, +`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 -tracer" which uses distance fields to encode proximity to objects in -the scene. Using sphere tracing to compute visibility instead of -analytic ray tracing provides two advantages: first, it greatly eases -the computation of ray-torus intersection (which would otherwise -require solving a quartic polynomial), and second, it makes it -possible to compute ambient occlusion (which is used to generate soft -shadows). Unlike many traditional ray tracers and sphere tracers, this -one uses iteration instead of recursion to compute the effect of -reflections. This, unfortunately, resulted in the programmer going -insane; however, program size was reduced and readability -hindered. Neither the plaintext for the program's default output nor -for the Netpbm header appears in the program source, which hinders -readability as well. Also, unlike some previous IOCCC entries which -render ASCII text, this one uses a vector (as 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. +The program is not quite a traditional [ray +tracer](https://en.wikipedia.org/wiki/Ray_tracing_(graphics)), but a "[sphere +tracer](sphere-tracing.pdf)" which uses distance fields to encode proximity to +objects in the scene. Using sphere tracing to compute visibility instead of +analytic ray tracing provides two advantages: first, it greatly eases the +computation of [ray-torus](https://en.wikipedia.org/wiki/Toric_lens#Torus) +intersection (which would otherwise require solving a quartic polynomial), and +second, it makes it possible to compute [ambient +occlusion](https://en.wikipedia.org/wiki/Ambient_occlusion) (which is used to +generate soft shadows). Unlike many traditional ray tracers and sphere tracers, +this one uses iteration instead of recursion to compute the effect of +reflections. This, unfortunately, resulted in the programmer going insane; +however, program size was reduced and readability hindered. Neither the +plaintext for the program's default output nor for the Netpbm header appears in +the program source, which hinders readability as well. Also, unlike some +previous IOCCC entries which render ASCII text, this one uses a vector (as +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 -reuse of global variables, to the inherently opaque nature of the -math, and to its overall density. Global variables are used to store +translated, it should be fairly resistant to analysis due to reckless +reuse of global variables, the inherently opaque nature of the +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 -whenever gcc doesn't warn about it. Conversely, integer -multiplication, division, and modulus are sometimes used in place of -traditional bitwise operators just to keep the reader on his or her -toes. Automatic casting between characters, integers, and floats is -performed just about everywhere. Fascinatingly, this doesn't seem to -affect performance too badly. Sometimes when an explicit cast -(i.e. from float to int) is needed, the program instead simply assigns -to a free variable of the desired type instead. Both the `array[index]` -and `index[array]` notations are used interchangeably throughout the -program. +Bitwise and arithmetic operators are used instead of logical operators whenever +gcc doesn't warn about it. Conversely, integer multiplication, division, and +modulus are sometimes used in place of traditional bitwise operators just to +keep the reader on his or her toes. Automatic casting between characters, +integers, and floats is performed just about everywhere. Fascinatingly, this +doesn't seem to affect performance too badly. Sometimes when an explicit cast +(i.e. from `float` to `int`) is needed, the program instead simply assigns to a +free variable of the desired type instead. Both the `array[index]` and +`index[array]` notations are used interchangeably throughout the program. -Two other programs were written to support development of this -program. The first used a randomized search algorithm to deduce the -most compact encoding of the vector font instructions into ASCII; the -second used a modified form of the Knuth-Plass algorithm to layout the -final text on top of a hand-generated ASCII "stencil". The 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++ -and Python, respectively). +Two other programs were written to support development of this program. The +first used a randomized search algorithm to deduce the most compact encoding of +the vector font instructions into ASCII; the second used a modified form of the +[Knuth-Plass](https://en.wikipedia.org/wiki/Line_wrap_and_word_wrap) algorithm +to layout the final text on top of a hand-generated ASCII "stencil". The +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++ and +Python, respectively). ## Copyright and CC BY-SA 4.0 License: diff --git a/2011/zucker/zucker.alt.c b/2011/zucker/zucker.alt.c new file mode 100644 index 000000000..b7d868e63 --- /dev/null +++ b/2011/zucker/zucker.alt.c @@ -0,0 +1,35 @@ +#include +#include +#include +#include +#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)t+H*a?o: w>t?t:w1?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;} diff --git a/thanks-for-fixes.md b/thanks-for-fixes.md index 9b3dc5e95..57246b1fd 100644 --- a/thanks-for-fixes.md +++ b/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. + + # 2012