From ab62c3937cc111ce1d61d76f0bdf396a4a5a9297 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andreas=20M=C3=BCller?= <andreas.mueller@othello.ch>
Date: Sat, 21 May 2022 20:36:01 +0200
Subject: add image code

---
 buch/papers/kugel/images/curvature.pov | 72 ++++++++++++++++++++++++++++++++--
 1 file changed, 69 insertions(+), 3 deletions(-)

(limited to 'buch/papers/kugel/images/curvature.pov')

diff --git a/buch/papers/kugel/images/curvature.pov b/buch/papers/kugel/images/curvature.pov
index 3535488..9dbaa86 100644
--- a/buch/papers/kugel/images/curvature.pov
+++ b/buch/papers/kugel/images/curvature.pov
@@ -11,17 +11,17 @@ global_settings {
 	assumed_gamma 1
 }
 
-#declare imagescale = 0.1;
+#declare imagescale = 0.09;
 
 camera {
-	location <40, 10, -20>
+	location <10, 10, -40>
 	look_at <0, 0, 0>
 	right 16/9 * x * imagescale
 	up y * imagescale
 }
 
 light_source {
-	<10, 10, -40> color White
+	<-10, 10, -40> color White
 	area_light <1,0,0> <0,0,1>, 10, 10
 	adaptive 1
 	jitter
@@ -70,3 +70,69 @@ arrow(<0,-1,0>, <0,1,0>, 0.01, White)
 arrow(<0,0,-2.1>, <0,0,2.1>, 0.01, White)
 
 #include "curvature.inc"
+
+#declare sigma = 1;
+#declare N0 = 0.5;
+#declare funktion = function(r) {
+	(exp(-r*r/(sigma*sigma)) / sigma
+	-
+	exp(-r*r/(2*sigma*sigma)) / (sqrt(2)*sigma)) / N0
+};
+#declare hypot = function(xx, yy) { sqrt(xx*xx+yy*yy) };
+
+#declare Funktion = function(x,y) { funktion(hypot(x+1,y)) - funktion(hypot(x-1,y)) };
+#macro punkt(xx,yy)
+	<xx, Funktion(xx, yy), yy>
+#end
+
+#declare griddiameter = 0.006;
+union {
+	#declare xmin = -3;
+	#declare xmax = 3;
+	#declare ymin = -2;
+	#declare ymax = 2;
+
+
+	#declare xstep = 0.2;
+	#declare ystep = 0.02;
+	#declare xx = xmin;
+	#while (xx < xmax + xstep/2)
+		#declare yy = ymin;
+		#declare P = punkt(xx, yy);
+		#while (yy < ymax - ystep/2)
+			#declare yy = yy + ystep;
+			#declare Q = punkt(xx, yy);
+			sphere { P, griddiameter }
+			cylinder { P, Q, griddiameter }
+			#declare P = Q;
+		#end
+		sphere { P, griddiameter }
+		#declare xx = xx + xstep;
+	#end
+
+	#declare xstep = 0.02;
+	#declare ystep = 0.2;
+	#declare yy = ymin;
+	#while (yy < ymax + ystep/2)
+		#declare xx = xmin;
+		#declare P = punkt(xx, yy);
+		#while (xx < xmax - xstep/2)
+			#declare xx = xx + xstep;
+			#declare Q = punkt(xx, yy);
+			sphere { P, griddiameter }
+			cylinder { P, Q, griddiameter }
+			#declare P = Q;
+		#end
+		sphere { P, griddiameter }
+		#declare yy = yy + ystep;
+	#end
+
+	pigment {
+		color rgb<0.8,0.8,0.8>
+	}
+	finish {
+		metallic
+		specular 0.8
+	}
+}
+
-- 
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