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[diderot] Annotation of /branches/pure-cfg/test/zslice-k1k2.diderot
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Annotation of /branches/pure-cfg/test/zslice-k1k2.diderot

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1 : glk 866
2 :     // quad-k1k2: demo of curvature calculation on quad patch dataset
3 : glk 884 // to process output:
4 :     // unu reshape -i mip.txt -s 3 200 200 | unu quantize -b 8 -o zslice-k1k2.png
5 :     //
6 : glk 866
7 :     int imgRes = 200;
8 :     int dataRes = 110;
9 :     vec3 orig = [0.0, 0.0, 10.0];
10 :     vec3 uVec = [1.0, 0.0, 0.0];
11 :     vec3 vVec = [0.0, 1.0, 0.0];
12 :     image(3)[] vol = load("../data/quad-patches-pad.nrrd");
13 :     field#2(3)[] F = vol ⊛ bspln3;
14 : glk 884 // HEY (want) some kind of error upon redeclaration
15 :     // of variables; was getting really confused by error messages
16 : glk 866 // associated with having used G both for green image (here)
17 :     // and geometry tensor (below)
18 :     image(2)[] imgR = load("../data/hue-0.nrrd"); field#0(2)[] RR = imgR ⊛ tent;
19 :     image(2)[] imgG = load("../data/hue-1.nrrd"); field#0(2)[] GG = imgG ⊛ tent;
20 :     image(2)[] imgB = load("../data/hue-2.nrrd"); field#0(2)[] BB = imgB ⊛ tent;
21 :     //image(2)[3] imgRGB = load("../data/hue.nhdr"); field#0(2)[3] RGB = imgRGB ⊛ tent;
22 :    
23 :     strand RayCast (int ui, int vi)
24 :     {
25 :     real uu = lerp(-0.5, real(dataRes)-0.5, -0.5, real(ui), real(imgRes)-0.5);
26 :     real vv = lerp(-0.5, real(dataRes)-0.5, -0.5, real(vi), real(imgRes)-0.5);
27 :     output vec3 rgb = [0.0,0.0,0.0];
28 :    
29 :     update
30 :     {
31 :     vec3 pos = orig + uu*uVec + vv*vVec;
32 :     if (inside (pos,F)) {
33 : glk 884 vec3 g = -∇F@pos;
34 :     // the "if (g[2] > 0.10)" test is specific to this dataset;
35 : glk 866 // it assesses if we're within one of the quadratic patches
36 : glk 884 if (g[2] > 0.10) {
37 : glk 866 vec3 n = normalize(g);
38 : jhr 898 tensor[3,3] H = -∇(∇F)@pos; // replace with -∇(∇F)@pos
39 : glk 866 tensor[3,3] P = identity[3] - n⊗n;
40 :     tensor[3,3] G = (P•H•P)/|g|;
41 :     real disc = max(0.0, sqrt(2.0*|G|^2 - trace(G)^2));
42 :     real k1 = (trace(G) + disc)/2.0;
43 :     real k2 = (trace(G) - disc)/2.0;
44 :     // correct curvature computation ends here
45 : glk 871 k1 = max(-0.99, min(0.99, 4.2*k1));
46 :     k2 = max(-0.99, min(0.99, 4.2*k2));
47 : glk 866 vec2 kk = [k1,k2];
48 :     rgb = [RR@kk,GG@kk,BB@kk] if inside(kk,RR)
49 :     else [0.0,0.0,0.0];
50 :     //rgb = RGB@kk if inside(kk,RGB) else [0.0,0.0,0.0];
51 :     }
52 :     }
53 :     stabilize;
54 :     }
55 :     }
56 :    
57 :     initially [ RayCast(ui, vi) | vi in 0..(imgRes-1), ui in 0..(imgRes-1) ];

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