Mercurial > projects > ldc
view demos/ray.cpp @ 1083:c1e9f612e2e2
Fix for dual operand form of fistp, also make reg ST(0) explicit and fix lindquists
previous code that allowed dual operand form of fstp but dissallowed the single
operand form accidently
author | Kelly Wilson <wilsonk cpsc.ucalgary.ca> |
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date | Tue, 10 Mar 2009 06:23:26 -0600 |
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; }