Annotation of /trunk/doc/report/vr-lite.tex

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1 :	jhr	335	\begin{lstlisting}[mathescape=true]
2 :			input string dataFile; // name of dataset
3 :			input real stepSz = 0.1; // size of steps
4 :			input vec3 eye; // location of eye point
5 :			input vec3 orig; // location of pixel (0,0)
6 :			input vec3 cVec; // vector between pixels horizontally
7 :			input vec3 rVec; // vector between pixels vertically
8 :			input real valOpacMin; // highest value with opacity 0.0
9 :			input real valOpacMax; // lowest value with opacity 1.0
10 :
11 :			image(3)[] img = load (dataFile);
12 :			field#1(3)[] F = convolve (bspln3, img);
13 :
14 :			actor RayCast (int row, int col)
15 :			{
16 :			vec3 pos = orig + real(row)*rVec + real(col)*cVec;
17 :			vec3 dir = (pos - eye)/|pos - eye|;
18 :			real t = 0.0;
19 :			real transp = 1.0;
20 :			real gray = 0.0;
21 :			output vec4 rgba = [0.0, 0.0, 0.0, 0.0];
22 :
23 :			update {
24 :			pos = pos + stepSz*dir;
25 :			if (inside (pos,F)) {
26 :			real val = F@pos;
27 :			vec3 grad = ($\nabla$ F)@pos;
28 :			vec3 norm = -grad/|grad|;
29 :			if (val > valOpacMin) { // we have some opacity
30 :			real opac = 0.0; // dummy initialization
31 :			if (val > valOpacMax) opac = 1.0;
32 :			else opac = (val - valOpacMin)/(valOpacMax - valOpacMin);
33 :			gray = gray + transp*opac*max(0.0, dot(-dir,norm));
34 :			transp = transp*(1.0 - opac);
35 :			}
36 :			}
37 :			if (transp < 0.01) { // early ray termination
38 :			transp = 0.0;
39 :			stabilize;
40 :			}
41 :			else if (t > 40.0) {
42 :			stabilize;
43 :			}
44 :			t = t + stepSz;
45 :			}
46 :
47 :			stabilize {
48 :			rgba = [gray, gray, gray, 1.0-transp];
49 :			}
50 :			}
51 :
52 :			initially [ RayCast(r, c) | r in 0..199, c in 0..199 ];
53 :			\end{lstlisting}%

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