Jim Susinno 2003
README for citygen - JHU masters project
v1.0.2 Jan 7 2003

All code by Jim Susinno except Triangulation Code by Atul Narkhede and Dinesh Manocha
in src/tri.


___Required files:___
newcity.gram
empty.city
heightmap3.obj


___Reading the output format, .city___
The output file named "generated.city" by default is an ASCII file with many lines of data.
Each line is distinguished by a space-delimited token at the beginning.
Line types include:
 dir [semicolon-delimited path string]		a path listing for model files
 obj [string]					a filename of an obj model to load
 i [int] [16 float transformationmatrix]	an instance of a particular obj file
 poly [9 floats][3 optional floats if quad]	a polygon to draw in space(streets)
 hmap [string filename] [float size scale]	an obj file to load as a heightmap

A poly line consists of either 9 floats for a triangle(xyz1, xyz2, xyz3) or 12 floats in the case
of a quadrilateral polygon(xyz1 xyz2 xyz3 xyz4).  The middle y component of each float triple
is the height value along the up axis.  Such is the convention throughout citygen.
The hmap line includes an extra float after the filename indicating the factor by which the heightmap
model should be scaled to match with the placement of the buildings.  This factor was introduced to 
simplify the process of "scaling up" a city and placing more, comparatively smaller buildings in
relatively larger lots.  In order to get the obj file to be the proper size, simply scale each vertex
by the scale factor.



___Model Conversion___
Also included is the simple app obj2jat, which requires model.cpp/h/o.
This program simplifies the conversion of obj files to ply by saving them
in a straightforward intermediate format.
usage: obj2jat [infile] -o [outfile]
       obj2jat infile.obj infile.obj infile.obj infile.obj...



___Triangulation Notes:___
Home Page: http://www.cs.unc.edu/~dm/CODE/GEM/chapter.html
  - located in src/tri.
This source code is part of a Graphics Gem called "Fast Polygon Triangulation
based on Seidel's Algorithm." It is an incremental randomized algorithm that in
practice works in linear time to take a polygon having n vertices and decompse 
this into n-2 triangles. The code also deals with simple polygons that contain holes. 






___Instructions:___
1. plot polygons of city layout			[mouse clicks]
2. triangulate					[t key]
3. populate winged edge list			[p key]
35. initialize layout structure			[i key]
4. merge potential rectangular quads(optional)	[m key]
5. grow layout(repeat until completion)		[g,G key]
6. export to .city file				[s key]




Changelog:
v1.0.2: functions added for new output format
	LayoutGenerator::
	int saveLayoutToFile(char*);
	void writePolysToFilePointer(FILE*);
	void writePolysToFilePointerRecurse(FILE*,LayoutNode_t*);
	City::
	void writeCityInfoToFilePointer(FILE*);
	consisting of city info followed by a listing of each polygonal zone to be drawn
	and the name of the heightmap file and its size scale.
	Updated README.


v1.0.1: Makefile cleanup, added obj2jat, created doc/ folder, README.
	Cleaned up main in plotter.cpp.  Added usage instructions, more to come.
	Introduced default values for arguments not given on cmd line for launching
	app through windows.

v1.0.0: masters degree, initial release