/* * The MIT License * * Copyright 2023 akava. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package ptjava; class Sphere extends TransformedShape { public Vector Center; public double Radius; Material Material; Box Box; static final double EPS = 1e-9; Sphere(Vector center, double radius, Material material, Box box) { Center = center; Radius = radius; Material = material; Box = box; } static Sphere NewSphere(Vector center, double radius, Material material) { Vector min = new Vector(center.getX() - radius, center.getY() - radius, center.getZ() - radius); Vector max = new Vector(center.getX() + radius, center.getY() + radius, center.getZ() + radius); Box box = new Box(min, max); return new Sphere(center, radius, material, box); } @Override public Box BoundingBox() { return Box; } @Override public Hit Intersect(Ray r) { Vector to = r.Origin.Sub(Center); double b = to.Dot(r.Direction); double c = to.Dot(to) - Radius * Radius; double d = b * b - c; if (d > 0) { d = Math.sqrt(d); double t1 = -b - d; if (t1 > EPS) { return new Hit(this, t1, null); } double t2 = -b + d; if (t2 > EPS) { return new Hit(this, t2, null); } } return Hit.NoHit; } @Override public Vector UV(Vector p) { p = p.Sub(Center); double u = Math.atan2(p.getZ(), p.getX()); double v = Math.atan2(p.getY(), Math.sqrt(p.getX() * p.getX() + p.getZ() * p.getZ())); u = 1 - (u + Math.PI) / (2 * Math.PI); v = (v + Math.PI / 2) / Math.PI; return new Vector(u, v, 0); } @Override public void Compile() { } @Override public Material MaterialAt(Vector p) { return Material; } @Override public Vector NormalAt(Vector p) { return p.Sub(Center).Normalize(); } }