added sphere example

math/asymptote/sphere-sphere/Makefile

@@ -0,0 +1,35 @@
+SOURCE = sphere-sphere
+DELAY = 80
+DENSITY = 300
+WIDTH = 512
+
+make:
+	latexmk -pdf $(SOURCE).tex
+	make clean
+
+clean:
+	rm -rf  $(TARGET) *.class *.html *.log *.aux *.data *.gnuplot *.dvi *.ps *.pre *.fls *.fdb_latexmk *.asy sphere-sphere-1.tex
+
+gif:
+	pdfcrop $(SOURCE).pdf
+	convert -verbose -delay $(DELAY) -loop 0 -density $(DENSITY) $(SOURCE)-crop.pdf $(SOURCE).gif
+	make clean
+
+png:
+	make
+	make svg
+	inkscape $(SOURCE).svg -w $(WIDTH) --export-png=$(SOURCE).png
+
+transparentGif:
+	convert $(SOURCE).pdf -transparent white result.gif
+	make clean
+
+svg:
+	make
+	#inkscape $(SOURCE).pdf --export-plain-svg=$(SOURCE).svg
+	pdf2svg $(SOURCE).pdf $(SOURCE).svg
+	# Necessary, as pdf2svg does not always create valid svgs:
+	inkscape $(SOURCE).svg --export-plain-svg=$(SOURCE).svg
+	rsvg-convert -a -w $(WIDTH) -f svg $(SOURCE).svg -o $(SOURCE)2.svg
+	inkscape $(SOURCE)2.svg --export-plain-svg=$(SOURCE).svg
+	rm $(SOURCE)2.svg

math/asymptote/sphere-sphere/Readme.md

@@ -0,0 +1,9 @@
+This is an example from `pst-solides3d` documentation.
+
+Compiled example
+----------------
+![Example](sphere-sphere.png)
+
+Credits
+-------
+Thanks to [g.kov](http://tex.stackexchange.com/users/27243/g-kov) ([answer](http://tex.stackexchange.com/a/121900/5645))

math/asymptote/sphere-sphere/latexmkrc

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+sub asy {return system("asy '$_[0]'");}
+add_cus_dep("asy","eps",0,"asy");
+add_cus_dep("asy","pdf",0,"asy");
+add_cus_dep("asy","tex",0,"asy");

math/asymptote/sphere-sphere/sphere-sphere.tex

@@ -0,0 +1,53 @@
+\documentclass{article}
+\usepackage{lmodern}
+\usepackage[inline]{asymptote}
+\begin{document}
+\begin{figure}
+\begin{asy}
+settings.prc=false;
+settings.render=0;
+import graph3;
+
+currentprojection=orthographic(camera=(150,900,412),up=(-0.4,-0.7,1.4),target=(100,111,1),zoom=0.5);
+currentlight=nolight;
+size(300);size3(300);
+
+real r1=162;
+real r2=100;
+
+triple v1=(0,0,0);
+triple v2=(250,0,0);
+
+// from http://mathworld.wolfram.com/Sphere-SphereIntersection.html :
+real d=arclength(v1--v2); // distance between v1,v2
+real a=1/2/d*sqrt((2*d*r1)^2-(d^2-r2^2+r1^2)^2);
+
+triple P=(sqrt(r1^2-a^2),0,-a);
+
+triple fs1(pair t){
+  return v1+r1*(cos(t.x)*sin(t.y),sin(t.x)*sin(t.y),cos(t.y));
+}
+
+triple fs2(pair t){
+  return v2+r2*(cos(t.x)*sin(t.y),sin(t.x)*sin(t.y),cos(t.y));
+}
+
+surface s1=surface(fs1,(0,0),(2pi,pi),16,Spline);
+surface s2=surface(fs2,(0,0),(2pi,pi),16,Spline);
+
+draw(s1
+  ,darkgreen+opacity(0.2)
+  ,render(compression=Low,merge=true)
+);
+
+draw(s2
+  ,darkblue+opacity(0.2)
+  ,render(compression=Low,merge=true)
+);
+
+dot(v1); label("$V_1$",v1,-X+Z);
+dot(v2); label("$V_2$",v2,-X+Z);
+dot(P); label("$P$",P,-X-Z);
+\end{asy}
+\end{figure}
+\end{document}