static void Main(string[] args) { var sphere = new Sphere(new Vec3(-2.0f, -1.0f, -10.0f), 1, new Vec3(.1f, .1f, .1f), 0.1f, 0.8f); Ray r; r.Org = Vec3.Zero; r.Dir = new Vec3(0.3000566f, -0.3000566f, -0.9055009f); Console.WriteLine(Sphere.Intersect(sphere, r)); var c = new Vec3(-2.0f, -1.0f, -10.0f); Console.WriteLine(Vec3.Dot(Vec3.Zero - c, r.Dir)); }
private static Vec3 trace(Ray ray, Scene scene, int depth) { var nearest = Num.MaxValue; Sphere obj = null; // search the scene for nearest intersection foreach (var o in scene.Objects) { var distance = Num.MaxValue; if (Sphere.Intersect(o, ray, out distance)) { if (distance < nearest) { nearest = distance; obj = o; } } } if (obj == null) { return(Vec3.Zero); } var point_of_hit = ray.Org + (ray.Dir * nearest); var normal = Sphere.Normal(obj, point_of_hit); bool inside = false; if (Vec3.Dot(normal, ray.Dir) > 0) { inside = true; normal = -normal; } Vec3 color = Vec3.Zero; var reflection_ratio = obj.Reflection; foreach (var l in scene.Lights) { var light_direction = Vec3.Normalize(l.Position - point_of_hit); Ray r; #if BIT64 r.Org = point_of_hit + (normal * 1e-5); #else r.Org = point_of_hit + (normal * 1e-5f); #endif r.Dir = light_direction; // go through the scene check whether we're blocked from the lights bool blocked = false; foreach (var o in scene.Objects) { if (Sphere.Intersect(o, r)) { blocked = true; break; } } if (!blocked) { color += l.Color * MATH.Max(0, Vec3.Dot(normal, light_direction)) * obj.Color * (1.0f - reflection_ratio); } } var rayNormDot = Vec3.Dot(ray.Dir, normal); Num facing = MATH.Max(0, -rayNormDot); Num fresneleffect = reflection_ratio + ((1 - reflection_ratio) * MATH.Pow((1 - facing), 5)); // compute reflection if (depth < maxDepth && reflection_ratio > 0) { var reflection_direction = ray.Dir + (normal * 2 * rayNormDot * (-1)); Ray r; #if BIT64 r.Org = point_of_hit + (normal * 1e-5); #else r.Org = point_of_hit + (normal * 1e-5f); #endif r.Dir = reflection_direction; var reflection = trace(r, scene, depth + 1); color += reflection * fresneleffect; } // compute refraction if (depth < maxDepth && (obj.Transparency > 0)) { #if BIT64 Num ior = 1.5; #else Num ior = 1.5f; #endif var CE = Vec3.Dot(ray.Dir, normal) * (-1); ior = inside ? 1 / ior : ior; Num eta = 1 / ior; var GF = (ray.Dir + normal * CE) * eta; Num sin_t1_2 = 1 - (CE * CE); Num sin_t2_2 = sin_t1_2 * (eta * eta); if (sin_t2_2 < 1) { var GC = normal * MATH.Sqrt(1 - sin_t2_2); var refraction_direction = GF - GC; Ray r; #if BIT64 r.Org = point_of_hit - (normal * 1e-4); #else r.Org = point_of_hit - (normal * 1e-4f); #endif r.Dir = refraction_direction; var refraction = trace(r, scene, depth + 1); color += refraction * (1 - fresneleffect) * obj.Transparency; } } return(color); }