Mercurial > projects > ldc
view demos/ray.cpp @ 1112:829ac3f30103
Updating revisions.pl.in:
- Change the way the LLVM SVN revision is detected, using `svn info` instead
of `svnversion`. This speeds it up significantly on my machine (especially
when the LLVM SVN checkout isn't in disk cache).
- Add "last changed date" to SVN checkouts too, not just unpacked tarballs
- No longer rely on SVN revision to detect release vs trunk checkouts, treat
release checkout the same as unpacked release tarball. (Except for date
determination, which uses SVN date instead of filesystem date)
author | Frits van Bommel <fvbommel wxs.nl> |
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date | Fri, 13 Mar 2009 16:18:01 +0100 |
parents | 90522b72128a |
children |
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#include <list> #include <iostream> #include <limits> #include <cmath> #include <cstdlib> using namespace std; numeric_limits<double> real; double delta = sqrt(real.epsilon()), infinity = real.infinity(); struct Vec { double x, y, z; Vec(double x2, double y2, double z2) : x(x2), y(y2), z(z2) {} }; Vec operator+(const Vec &a, const Vec &b) { return Vec(a.x+b.x, a.y+b.y, a.z+b.z); } Vec operator-(const Vec &a, const Vec &b) { return Vec(a.x-b.x, a.y-b.y, a.z-b.z); } Vec operator*(double a, const Vec &b) { return Vec(a*b.x, a*b.y, a*b.z); } double dot(const Vec &a, const Vec &b) { return a.x*b.x + a.y*b.y + a.z*b.z; } Vec unitise(const Vec &a) { return (1 / sqrt(dot(a, a))) * a; } typedef pair<double, Vec> Hit; struct Ray { Vec orig, dir; Ray(const Vec &o, const Vec &d) : orig(o), dir(d) {} }; struct Scene { virtual ~Scene() {}; virtual void intersect(Hit &, const Ray &) const = 0; }; struct Sphere : public Scene { Vec center; double radius; Sphere(Vec c, double r) : center(c), radius(r) {} ~Sphere() {} double ray_sphere(const Ray &ray) const { Vec v = center - ray.orig; double b = dot(v, ray.dir), disc = b*b - dot(v, v) + radius * radius; if (disc < 0) return infinity; double d = sqrt(disc), t2 = b + d; if (t2 < 0) return infinity; double t1 = b - d; return (t1 > 0 ? t1 : t2); } void intersect(Hit &hit, const Ray &ray) const { double lambda = ray_sphere(ray); if (lambda >= hit.first) return; hit = Hit(lambda, unitise(ray.orig + lambda*ray.dir - center)); } }; typedef list<Scene *> Scenes; struct Group : public Scene { Sphere bound; Scenes child; Group(Sphere b, Scenes c) : bound(b), child(c) {} ~Group() { for (Scenes::const_iterator it=child.begin(); it!=child.end(); ++it) delete *it; } void intersect(Hit &hit, const Ray &ray) const { double l = bound.ray_sphere(ray); if (l < hit.first) for (Scenes::const_iterator it=child.begin(); it!=child.end(); ++it) (*it)->intersect(hit, ray); } }; Hit intersect(const Ray &ray, const Scene &s) { Hit res = Hit(infinity, Vec(0, 0, 0)); s.intersect(res, ray); return res; } double ray_trace(const Vec &light, const Ray &ray, const Scene &s) { Hit hit = intersect(ray, s); if (hit.first == infinity) return 0; double g = dot(hit.second, light); if (g >= 0) return 0.; Vec p = ray.orig + hit.first*ray.dir + delta*hit.second; return (intersect(Ray(p, -1. * light), s).first < infinity ? 0 : -g); } Scene *create(int level, const Vec &c, double r) { Scene *s = new Sphere(c, r); if (level == 1) return s; Scenes child; child.push_back(s); double rn = 3*r/sqrt(12.); for (int dz=-1; dz<=1; dz+=2) for (int dx=-1; dx<=1; dx+=2) child.push_back(create(level-1, c + rn*Vec(dx, 1, dz), r/2)); return new Group(Sphere(c, 3*r), child); } int main(int argc, char *argv[]) { int level = 6, n = 512, ss = 4; if (argc == 2) level = atoi(argv[1]); Vec light = unitise(Vec(-1, -3, 2)); Scene *s(create(level, Vec(0, -1, 0), 1)); cout << "P5\n" << n << " " << n << "\n255\n"; for (int y=n-1; y>=0; --y) for (int x=0; x<n; ++x) { double g=0; for (int dx=0; dx<ss; ++dx) for (int dy=0; dy<ss; ++dy) { Vec dir(unitise(Vec(x+dx*1./ss-n/2., y+dy*1./ss-n/2., n))); g += ray_trace(light, Ray(Vec(0, 0, -4), dir), *s); } cout << char(int(.5 + 255. * g / (ss*ss))); } delete s; return 0; }