Annotation of /examples/vr-demo/vr-lite-cam.diderot

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Revision 2058 - (view) (download)

1 :	jhr	2058	// vr-lite-cam
2 :			//
3 :			// simple volume renderer, now with a single directional light,
4 :			// Phong shading, and the new camera.
5 :			//
6 :
7 :			// image parameters
8 :			input int imgResU = 480;
9 :			input int imgResV = 345;
10 :			input real rayStep = 0.1;
11 :
12 :			// camera controls
13 :			input vec3 camEye = [127.331, -1322.05, 272.53];
14 :			input vec3 camAt = [63.0, 82.6536, 98.0];
15 :			input vec3 camUp = [0.9987, 0.0459166, -0.0221267];
16 :			input real camNear = -78.0;
17 :			input real camFar = 78.0;
18 :			input real camFOV = 5.0;
19 :
20 :			/* we control the opacity by its center value and the +/- keys */
21 :			input real valOpacMid = 550.0; // 550 for skin, 1300.0 for bone
22 :			real valOpacMin = valOpacMid - 150.0;
23 :			real valOpacMax = valOpacMid + 150.0;
24 :
25 :			real camDist = |camAt - camEye|;
26 :			real camVspNear = camDist + camNear;
27 :			real camVspFar = camDist + camFar;
28 :			vec3 camN = normalize(camAt - camEye);
29 :			vec3 camU = normalize(camN × camUp);
30 :			vec3 camV = camN × camU;
31 :			real camVmax = tan(camFOV*π/360.0)*camDist;
32 :			real camUmax = camVmax*real(imgResU)/real(imgResV);
33 :
34 :			vec3 lightVspDir = [0.9, -1.0, -2.5];
35 :			vec3 lightDir = normalize(lightVspDir[0]*camU + lightVspDir[1]*camV + lightVspDir[2]*camN);
36 :			//vec3 lightRGB = [1.0, 1.0, 1.0];
37 :
38 :			real phongKa = 0.05;
39 :			real phongKd = 0.65;
40 :			real phongKs = 0.45;
41 :			real phongSp = 50.0;
42 :
43 :			field#2(3)[] F = bspln3 ⊛ image("data/vfrhand-nohip.nhdr");
44 :
45 :			strand RayCast (int ui, int vi)
46 :			{
47 :			real rayU = lerp(-camUmax, camUmax, -0.5, real(ui), real(imgResU)-0.5);
48 :			real rayV = lerp(-camVmax, camVmax, -0.5, real(vi), real(imgResV)-0.5);
49 :			vec3 rayVec = (camDist*camN + rayU*camU + rayV*camV)/camDist;
50 :			vec3 toEye = normalize(-rayVec);
51 :
52 :			real rayN = camVspNear;
53 :			// ########## BEGIN per-ray initialization
54 :			real rayTransp = 1.0;
55 :			// vec3 rayRGB = [0.0, 0.0, 0.0];
56 :			real rayGrey = 0.0;
57 :			output vec4 outRGBA = [0.0, 0.0, 0.0, 0.0];
58 :			// ########## END per-ray initialization
59 :
60 :			update
61 :			{
62 :			vec3 rayPos = camEye + rayN*rayVec;
63 :			if (inside (rayPos,F)) {
64 :			// ########## BEGIN per-sample code
65 :			real val = F(rayPos);
66 :			if (val > valOpacMin) { // we have some opacity
67 :			vec3 grad = ∇F(rayPos);
68 :			vec3 norm = normalize(-∇F(rayPos));
69 :			real alpha = min(1.0, lerp(0.0, 1.0, valOpacMin, val, valOpacMax));
70 :			real ld = max(0.0, norm • lightDir);
71 :			real hd = max(0.0, norm • normalize(lightDir + toEye));
72 :			real pnt = phongKa
73 :			+ phongKd * ld
74 :			+ phongKs * hd^phongSp;
75 :			rayGrey += rayTransp*alpha*pnt;
76 :			rayTransp = rayTransp*(1.0 - alpha);
77 :			}
78 :			// ########## END per-sample code
79 :			}
80 :			if (rayTransp < 0.01) { // early ray termination
81 :			rayTransp = 0.0;
82 :			stabilize;
83 :			}
84 :			if (rayN > camVspFar) {
85 :			stabilize;
86 :			}
87 :			rayN += rayStep;
88 :			}
89 :
90 :			stabilize {
91 :			outRGBA = [rayGrey, rayGrey, rayGrey, 1.0-rayTransp];
92 :			}
93 :
94 :			}
95 :
96 :			initially [ RayCast(ui, vi) | vi in 0..(imgResV-1), ui in 0..(imgResU-1) ];

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