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annotate demos/ray.cpp @ 650:aa6a0b7968f7

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Added test case for bug #100 Removed dubious check for not emitting static private global in other modules without access. This should be handled properly somewhere else, it's causing unresolved global errors for stuff that should work (in MiniD)
author Tomas Lindquist Olsen <tomas.l.olsen@gmail.com>
date Sun, 05 Oct 2008 17:28:15 +0200
parents 90522b72128a
children
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1 #include <list>
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2 #include <iostream>
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3 #include <limits>
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4 #include <cmath>
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5 #include <cstdlib>
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6
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7 using namespace std;
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8
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9 numeric_limits<double> real;
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10 double delta = sqrt(real.epsilon()), infinity = real.infinity();
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11
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12 struct Vec {
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13 double x, y, z;
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14 Vec(double x2, double y2, double z2) : x(x2), y(y2), z(z2) {}
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15 };
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16 Vec operator+(const Vec &a, const Vec &b)
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17 { return Vec(a.x+b.x, a.y+b.y, a.z+b.z); }
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18 Vec operator-(const Vec &a, const Vec &b)
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19 { return Vec(a.x-b.x, a.y-b.y, a.z-b.z); }
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20 Vec operator*(double a, const Vec &b) { return Vec(a*b.x, a*b.y, a*b.z); }
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21 double dot(const Vec &a, const Vec &b) { return a.x*b.x + a.y*b.y + a.z*b.z; }
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22 Vec unitise(const Vec &a) { return (1 / sqrt(dot(a, a))) * a; }
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23
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24 typedef pair<double, Vec> Hit;
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25
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26 struct Ray {
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27 Vec orig, dir;
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28 Ray(const Vec &o, const Vec &d) : orig(o), dir(d) {}
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29 };
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30
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31 struct Scene {
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32 virtual ~Scene() {};
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33 virtual void intersect(Hit &, const Ray &) const = 0;
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34 };
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35
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36 struct Sphere : public Scene {
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37 Vec center;
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38 double radius;
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39
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40 Sphere(Vec c, double r) : center(c), radius(r) {}
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41 ~Sphere() {}
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42
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43 double ray_sphere(const Ray &ray) const {
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44 Vec v = center - ray.orig;
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45 double b = dot(v, ray.dir), disc = b*b - dot(v, v) + radius * radius;
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46 if (disc < 0) return infinity;
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47 double d = sqrt(disc), t2 = b + d;
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48 if (t2 < 0) return infinity;
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49 double t1 = b - d;
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50 return (t1 > 0 ? t1 : t2);
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51 }
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52
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53 void intersect(Hit &hit, const Ray &ray) const {
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54 double lambda = ray_sphere(ray);
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55 if (lambda >= hit.first) return;
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56 hit = Hit(lambda, unitise(ray.orig + lambda*ray.dir - center));
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57 }
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58 };
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59
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60 typedef list<Scene *> Scenes;
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61 struct Group : public Scene {
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62 Sphere bound;
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63 Scenes child;
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64
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65 Group(Sphere b, Scenes c) : bound(b), child(c) {}
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66 ~Group() {
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67 for (Scenes::const_iterator it=child.begin(); it!=child.end(); ++it)
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68 delete *it;
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69 }
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70
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71 void intersect(Hit &hit, const Ray &ray) const {
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72 double l = bound.ray_sphere(ray);
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73 if (l < hit.first)
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74 for (Scenes::const_iterator it=child.begin(); it!=child.end(); ++it)
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75 (*it)->intersect(hit, ray);
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76 }
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77 };
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78
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79 Hit intersect(const Ray &ray, const Scene &s) {
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80 Hit res = Hit(infinity, Vec(0, 0, 0));
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81 s.intersect(res, ray);
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82 return res;
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83 }
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84
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85 double ray_trace(const Vec &light, const Ray &ray, const Scene &s) {
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86 Hit hit = intersect(ray, s);
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87 if (hit.first == infinity) return 0;
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88 double g = dot(hit.second, light);
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89 if (g >= 0) return 0.;
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90 Vec p = ray.orig + hit.first*ray.dir + delta*hit.second;
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91 return (intersect(Ray(p, -1. * light), s).first < infinity ? 0 : -g);
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92 }
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93
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94 Scene *create(int level, const Vec &c, double r) {
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95 Scene *s = new Sphere(c, r);
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96 if (level == 1) return s;
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97 Scenes child;
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98 child.push_back(s);
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99 double rn = 3*r/sqrt(12.);
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100 for (int dz=-1; dz<=1; dz+=2)
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101 for (int dx=-1; dx<=1; dx+=2)
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102 child.push_back(create(level-1, c + rn*Vec(dx, 1, dz), r/2));
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103 return new Group(Sphere(c, 3*r), child);
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104 }
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105
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106 int main(int argc, char *argv[]) {
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107 int level = 6, n = 512, ss = 4;
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108 if (argc == 2) level = atoi(argv[1]);
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109 Vec light = unitise(Vec(-1, -3, 2));
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110 Scene *s(create(level, Vec(0, -1, 0), 1));
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111 cout << "P5\n" << n << " " << n << "\n255\n";
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112 for (int y=n-1; y>=0; --y)
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113 for (int x=0; x<n; ++x) {
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114 double g=0;
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115 for (int dx=0; dx<ss; ++dx)
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116 for (int dy=0; dy<ss; ++dy) {
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117 Vec dir(unitise(Vec(x+dx*1./ss-n/2., y+dy*1./ss-n/2., n)));
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118 g += ray_trace(light, Ray(Vec(0, 0, -4), dir), *s);
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119 }
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120 cout << char(int(.5 + 255. * g / (ss*ss)));
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121 }
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122 delete s;
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123 return 0;
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124 }