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cchiw |
3281 |
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// set camera, image, and rendering parameters
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input vec3 camEye = [-1.5015, -3.6392, 5.27097];
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input vec3 camAt = [0, 0, 0]; // [-0.0455194, 0.0129536, -0.0035959];
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input vec3 camUp = [0.00940017, 0.298005, 0.954518];
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input real camNearAtRel = -1.9;
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input real camFarAtRel = 1.9;
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input real camFOV = 20;
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input int iresU = 600;
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input int iresV = 600;
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input real refStep = 0.1;
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input real rayStep = 0.06;
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input vec3 lightVsp = [-2, -3, -4];
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input real phongKa = 0.3;
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input real phongKd = 0.7;
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input real thickness = 0.1;
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input real isoval = 1800;
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field#4(3)[] V = bspln5 ⊛ image("canny.nrrd");
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field#3(3)[3] D = ∇V/|∇V|; // NOTISO (canny) NOTREF
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field#3(3)[] M = ∇V•∇V; // NOTISO (canny) NOTREF
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field#2(3)[] F = -∇M • D; // NOTISO (canny) NOTREF
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input real gmin = 1; // NOTISO (canny & ref)
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// field#1(3)[] S = ∇⊗∇M • D • D; // NOTISO
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// input real smax = -1;// NOTISO
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function real alpha(real v, real g) = clamp(0, 1, 1.2*(1 - |v|/(g*thickness)));
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field#0(1)[3] cmap = tent ⊛ image("isobow.nrrd");
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function vec3 color(vec3 x) = cmap(clamp(-3,1,V(x)));
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// (boilerplate) computation of camera and light info
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real camDist = |camAt - camEye|;
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real camNear = camNearAtRel + camDist;
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real camFar = camFarAtRel + camDist;
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vec3 camN = normalize(camAt - camEye); // away
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vec3 camU = normalize(camN × camUp); // right
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vec3 camV = camU × camN; // up
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real camVmax = tan(camFOV*π/360)*camDist;
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real camUmax = camVmax*iresU/iresV;
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vec3 light = transpose([camU,camV,camN])•normalize(lightVsp);
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strand raycast(int ui, int vi) {
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real rayU = lerp(-camUmax, camUmax, -0.5, ui, iresU-0.5);
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real rayV = lerp(camVmax, -camVmax, -0.5, vi, iresV-0.5);
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real rayN = camNear;
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vec3 rayVec = camN + (rayU*camU + rayV*camV)/camDist;
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real transp = 1;
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vec3 rgb = [0,0,0];
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output vec4 rgba = [0,0,0,0];
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update {
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vec3 x = camEye + rayN*rayVec;
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if (inside(x,V) && |∇V(x)| > gmin) { // NOTISO (canny & ref)
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real val = F(x); // (iso & canny) NOTREF
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vec3 grad = -∇F(x); // (iso & canny) NOTREF
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real a = alpha(val, |grad|);
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if (a > 0) { // we have some opacity
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a = 1 - pow(1-a, rayStep*|rayVec|/refStep);
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real depth = lerp(1.3, 0.6, camNear, rayN, camFar);
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real shade = max(0, normalize(grad)•light);
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rgb += transp*depth*a*(phongKa + phongKd*shade)*color(x);
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transp *= 1 - a;
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}
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}
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if (transp < 0.01) { // early ray termination
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transp = 0;
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stabilize;
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}
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if (rayN > camFar) {
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stabilize;
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}
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rayN = rayN + rayStep;
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}
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stabilize {
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real a = 1-transp;
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if (a > 0) rgba = [rgb[0]/a, rgb[1]/a, rgb[2]/a, a];
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}
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}
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initially [ raycast(ui, vi) | vi in 0..iresV-1, ui in 0..iresU-1 ];
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