Alife Digest Number 043

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Alife Digest

 · 11 months ago

 
ALIFE LIST: Artificial Life Research List Number 43  Sunday, October 14th 1990 
  
             ARTIFICIAL LIFE RESEARCH ELECTRONIC MAILING LIST 
    Maintained by the Indiana University Artificial Life Research Group 

Contents: 
  
                        Plant generator program available 

---------------------------------------------------------------------- 
  
Date: Fri, 12 Oct 90 19:24:26 -0400 
From: Jonathan Leech <leech@cs.unc.edu> 
Subject: Plant generator program available 

    The following README file describes the first release of a program 
to generate plant and fractal models, based on the "Algorithmic Beauty 
of Plants" book discussed previously in comp.graphics and this mailing 
list.  The code is available by anonymous ftp in: 

    dopey.cs.unc.edu[128.109.136.82]:~ftp/pub/lsys.tar.Z 
    iuvax.cs.indiana.edu[129.79.254.192]: 
                 ~ftp/pub/alife/software/unix/Lsys/lsys.tar.Z 

    Dopey has a flaky net connection, so I recommend trying iuvax 
first. 

============================================================================= 
	    RELEASE NOTES FOR LSYS - October 12, 1990 

    INTRODUCTION 

    This is an early release of lsys, a program to generate complex 
models using L-Systems.  Only graphics/C++ hackers should be using 
this code at present.  The program was inspired by the Springer-Verlag 
text _The Virtual Laboratory: The Algorithmic Beauty of Plants_, by P. 
Prusinkiewicz and A.  Lindenmayer, and maintains as much compatibility 
with their input format as I could manage. 

    Documentation for the program is found in lsys.l in [nt]roff form 
(process with the -man macros), and in lsys.cat in lineprinter form. 
The book will be needed to make use of the program, as many semantic 
issues are not documented in the (rather terse) man page. 

    PORTING 

    The code has been compiled and tested using AT&T C++ 2.0 on 
DECstation 3100s and Sun C++ 2.0 on Sun-4s.  It should port easily to 
AT&T C++ running on other platforms, possibly by simply recompiling. 
However, the parser is written in yacc and the generated y.tab.c 
compiled with C++.  Since the output of yacc is usually K&R-style C, 
some knowledge of yacc internals is needed to provide prototypes. 
Fortunately, this can be accomplished by working with the source 
produced by yacc and the error messages (if any) from compiling it. 

    Some versions of malloc() allow more efficient allocation of small 
blocks by the call mallopt(M_MXFAST, maxblocksize).  If M_MXFAST is 
defined by the <malloc.h> header file, lsys will attempt to use it. 
It may be necessary to link an additional library to obtain this 
version of malloc; for example, on DECstations running Ultrix, the 
-lmalloc library must be used.	The make variable LIBS may be set to 
specify this library, either by editing the Makefile (preferred) or by 
command-line options to make, e.g. 

    % make		    # SunOS 
    % make LIBS=-lmalloc    # Ultrix 

    lsys uses C++ 2.0 features such as pure virtual member functions, 
static initialization of scalars with functions, const member 
functions, and the iostream library, which means it will be tedious to 
port back to earlier versions of C++.  Anyone wishing to port the code 
to the GNU tools should contact me by email first, so the work doesn't 
end up being done several times. 

    NEW OUTPUT FORMATS 

    Currently, PostScript and a 'generic' output format may be 
generated.  It should be straightforward to add new output formats for 
ray-tracers and such by subclassing class DBGenerator, an abstract 
output class.  See README.OUTPUT, DBGenerator.[ch], and 
GenericGenerator.[ch].	Please send any output generators for 
widely-used formats (e.g.  NFF) to me for inclusion in the 
distribution. 

    EXAMPLES 

    Examples drawn from the text are provided in the subdirectory 
'Examples' (see README.EXAMPLES), and may be examined to gain 
familiarity with the input format.  With few exceptions (see BUGS in 
the man page), these produce images and databases very close to those 
in the book. 

    BUGS 

    Please contact me via email with bug reports (accompanied by 
L-systems causing them), interesting L-systems for inclusion in the 
release, enhancements, and suggestions. 

    Jon Leech (leech@cs.unc.edu) 
    __@/ 

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