public static void Bump(ITexture<double> d, DifferentialGeometry dgGeom, DifferentialGeometry dgShading, ref DifferentialGeometry dgBump) { DifferentialGeometry dgEval = new DifferentialGeometry (dgShading); double du = 0.5 * (Math.Abs (dgShading.dudx) + Math.Abs (dgShading.dudy)); if (du == 0.0) du = 0.01; dgEval.p = dgShading.p + du * dgShading.dpdu; dgEval.u = dgShading.u + du; dgEval.n = (new Normal(dgShading.dpdu % dgShading.dpdv) + du * dgShading.dndu).Normalized; double uDisplace = d.Evaluate (dgEval); double dv = 0.5 * (Math.Abs (dgShading.dvdx) + Math.Abs (dgShading.dvdy)); if (dv == 0.0) dv = 0.01; dgEval.p = dgShading.p + dv * dgShading.dpdv; dgEval.u = dgShading.u; dgEval.v = dgShading.v + dv; dgEval.n = (new Normal(dgShading.dpdu % dgShading.dpdv) + dv * dgShading.dndv).Normalized; double vDisplace = d.Evaluate (dgEval); double displace = d.Evaluate (dgShading); dgBump = new DifferentialGeometry (dgShading); dgBump.dpdu = dgShading.dpdu + (uDisplace - displace) / du * new Vector (dgShading.n) + displace * new Vector (dgShading.dndu); dgBump.dpdv = dgShading.dpdv + (vDisplace - displace) / dv * new Vector (dgShading.n) + displace * new Vector (dgShading.dndv); dgBump.n = new Normal((dgBump.dpdu % dgBump.dpdv).Normalized); if (dgShading.Shape.ReverseOrientation ^ dgShading.Shape.TransformSwapsHandedness) dgBump.n *= -1.0; dgBump.n = Util.FaceForward (dgBump.n, dgGeom.n); }
/// <summary> /// /// </summary> /// <param name="d"></param> /// <param name="dgGeom"></param> /// <param name="dgShading"></param> /// <param name="dgBump"></param> public static DifferentialGeometry Bump (ITexture<double> d, DifferentialGeometry dgGeom, DifferentialGeometry dgShading) { var dgBump = new DifferentialGeometry (); var dgEval = new DifferentialGeometry (dgShading); var du = .5 * (Math.Abs (dgShading.dudx) + Math.Abs (dgShading.dudy)); if (du == 0.0) du = .01; dgEval.p = dgShading.p + du * dgShading.dpdu; dgEval.u = dgShading.u + du; dgEval.nn = null;// TODO var uDisplace = d.Evaluate (dgEval); var dv = .5 * (Math.Abs (dgShading.dvdx) + Math.Abs (dgShading.dvdy)); // var vDisplace = d.Evaluate (dgEval); var displace = d.Evaluate (dgShading); dgBump = new DifferentialGeometry (dgShading); dgBump.dpdu = dgShading.dpdu + (uDisplace - displace) / du * new Vector (dgShading.nn) + displace * new Vector (dgShading.dndu); dgBump.dpdv = dgShading.dpdv + (vDisplace - displace) / dv * new Vector (dgShading.nn) + displace * new Vector (dgShading.dndv); if (dgShading.Shape.ReverseOrientation ^ dgShading.Shape.TransformSwapsHandedness) dgBump.nn *= -1.0; dgBump.nn = Util.FaceForward (dgBump.nn, dgGeom.nn); return dgBump; }