/* (C)2013 Claudio Rocchini, CC-BY 3.0 */
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <vector>

const double PI = 3.1415926535897932384626433832795;

class edge {
public:
	double l,t,a,x,y;
	edge() {}
	edge( double nl, double nt, double na, double nx, double ny ) :
		l(nl),t(nt),a(na),x(nx),y(ny) {}
};

int main() {
	const double SX = 800;  const double SY = 800;
	const double a = PI/11; const double r = 0.75; const double minl = 10;
	
	std::vector<edge> st;
	st.push_back( edge(200,25,-PI/2,SX/2,SY-10) );
	
	FILE * fo = fopen("fractal_canopy.svg","w");
	fprintf(fo,
		"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n"
		"<svg xmlns:svg=\"http://www.w3.org/2000/svg\" xmlns=\"http://www.w3.org/2000/svg\"\n"
		"version=\"1.0\" width=\"%g\" height=\"%g\" id=\"fractal_canopy\">\n"
		,SX,SY
	);
	
	double lastt = -1.0;
	for(size_t i=0;i<st.size();++i) {
		double nx = st[i].x+st[i].l*cos(st[i].a);
		double ny = st[i].y+st[i].l*sin(st[i].a);
	
		if(lastt!=st[i].t) {
			if(lastt!=-1.0) fprintf(fo,"</g>\n");
			lastt = st[i].t;
			fprintf(fo,"<g style=\"stroke:#000000;stroke-width:%g;fill:none\">\n"
				,lastt);
		}
		fprintf(fo,"<line x1=\"%6.2f\" y1=\"%6.2f\" x2=\"%6.2f\" y2=\"%6.2f\"/>\n"
			,st[i].x,st[i].y,nx,ny);
		if(st[i].l<=minl) continue;
		st.push_back( edge(st[i].l*r,st[i].t*r,st[i].a+a,nx,ny) );
		st.push_back( edge(st[i].l*r,st[i].t*r,st[i].a-a,nx,ny) );
	}
	fprintf(fo,"</g>\n");
	fprintf(fo,"</svg>\n");
	fclose(fo);
	return 0;
}