Mercurial > projects > ldc
view demos/ray.cpp @ 948:780530d1cad3
Revert templates to old behavior.
While emitting a template instantiation only once is good for compile times
and binary sizes, it doesn't work with linkonce linkage as inlined function
bodies could be discarded. Since we don't want to inhibit inlining, templates
are reverted to the previous behavior, where an instantiation is emitted for
each module using it.
In the future, a custom inlining pass may allow us to switch back to
common/weak linkage and reenable smart template instance emission.
author | Christian Kamm <kamm incasoftware de> |
---|---|
date | Sun, 08 Feb 2009 21:44:46 +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; }