developer/Samples/NET 4.6/Samples for Parallel/Raytracer/Raytracer_CSharp/Sphere.cs

   1 //--------------------------------------------------------------------------
   2 //
   3 //  Copyright (c) Microsoft Corporation.  All rights reserved.
   4 //
   5 //  File: Sphere.cs
   6 //
   7 //--------------------------------------------------------------------------
   8
   9 using System;
  10
  11 namespace Microsoft.ParallelComputingPlatform.ParallelExtensions.Samples
  12 {
  13     class Sphere : SceneObject
  14     {
  15         public Vector Center;
  16         public double Radius;
  17
  18         public Sphere(Vector center, double radius, Surface surface) : base(surface) { Center = center; Radius = radius; }
  19
  20         public override ISect Intersect(Ray ray)
  21         {
  22             Vector eo = Vector.Minus(Center, ray.Start);
  23             double v = Vector.Dot(eo, ray.Dir);
  24             double dist;
  25             if (v < 0)
  26             {
  27                 dist = 0;
  28             }
  29             else
  30             {
  31                 double disc = Math.Pow(Radius, 2) - (Vector.Dot(eo, eo) - Math.Pow(v, 2));
  32                 dist = disc < 0 ? 0 : v - Math.Sqrt(disc);
  33             }
  34             if (dist == 0) return ISect.Null;
  35             return new ISect(this, ray, dist);
  36         }
  37
  38         public override Vector Normal(Vector pos)
  39         {
  40             return Vector.Norm(Vector.Minus(pos, Center));
  41         }
  42     }
  43 }