47 lines
1.5 KiB
Rust
47 lines
1.5 KiB
Rust
// Copyright 2013-2014 The CGMath Developers. For a full listing of the authors,
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// refer to the AUTHORS file at the top-level directory of this distribution.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//! Bounding sphere
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use intersect::Intersect;
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use num::BaseFloat;
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use point::{Point, Point3};
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use ray::Ray3;
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use vector::Vector;
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use std::num::zero;
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#[deriving(Clone, PartialEq)]
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pub struct Sphere<S> {
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pub center: Point3<S>,
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pub radius: S,
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}
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impl<S: BaseFloat> Intersect<Option<Point3<S>>> for (Sphere<S>, Ray3<S>) {
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fn intersection(&self) -> Option<Point3<S>> {
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match *self {
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(ref s, ref r) => {
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let l = s.center.sub_p(&r.origin);
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let tca = l.dot(&r.direction);
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if tca < zero() { return None; }
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let d2 = l.dot(&l) - tca*tca;
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if d2 > s.radius*s.radius { return None; }
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let thc = (s.radius*s.radius - d2).sqrt();
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Some(r.origin.add_v(&r.direction.mul_s(tca - thc)))
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}
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}
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}
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}
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