cgmath/src-old/bounds/frustum.rs

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// Copyright 2013 The Lmath Developers. For a full listing of the authors,
// refer to the AUTHORS file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//! View frustum for visibility determination
use math::*;
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#[deriving(Clone, Eq)]
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pub struct Frustum<T> {
left: Plane3<T>,
right: Plane3<T>,
bottom: Plane3<T>,
top: Plane3<T>,
near: Plane3<T>,
far: Plane3<T>,
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}
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impl_dimensioned!(Frustum, Plane3<T>, 6)
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impl_approx!(Frustum {
left, right,
top, bottom,
near, far
})
#[deriving(Clone, Eq)]
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pub struct FrustumPoints<T> {
near_top_left: Point3<T>,
near_top_right: Point3<T>,
near_bottom_left: Point3<T>,
near_bottom_right: Point3<T>,
far_top_left: Point3<T>,
far_top_right: Point3<T>,
far_bottom_left: Point3<T>,
far_bottom_right: Point3<T>,
}
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impl_dimensioned!(FrustumPoints, Point3<T>, 8)
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impl_approx!(FrustumPoints {
near_top_left,
near_top_right,
near_bottom_left,
near_bottom_right,
far_top_left,
far_top_right,
far_bottom_left,
far_bottom_right
})
impl<T:Clone + Float> Frustum<T> {
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/// Constructs a frustum
pub fn from_planes(left: Plane3<T>, right: Plane3<T>,
bottom: Plane3<T>, top: Plane3<T>,
near: Plane3<T>, far: Plane3<T>) -> Frustum<T> {
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Frustum {
left: left,
right: right,
bottom: bottom,
top: top,
near: near,
far: far,
}
}
/// Extracts frustum planes from a projection matrix
pub fn from_matrix(mat: Mat4<T>) -> Frustum<T> {
Frustum {
left: Plane3::from_vec4(mat.r(3).add_v(&mat.r(0)).normalize()),
right: Plane3::from_vec4(mat.r(3).sub_v(&mat.r(0)).normalize()),
bottom: Plane3::from_vec4(mat.r(3).add_v(&mat.r(1)).normalize()),
top: Plane3::from_vec4(mat.r(3).sub_v(&mat.r(1)).normalize()),
near: Plane3::from_vec4(mat.r(3).add_v(&mat.r(2)).normalize()),
far: Plane3::from_vec4(mat.r(3).sub_v(&mat.r(2)).normalize()),
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}
}
}
impl<T:Clone + Float> Frustum<T> {
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/// Computes where the frustum planes intersect to form corners and returns
/// a struct containing the eight resulting position vectors.
pub fn to_points(&self) -> FrustumPoints<T> {
FrustumPoints {
near_top_left: self.near.intersection_3pl(&self.top, &self.left).unwrap(),
near_top_right: self.near.intersection_3pl(&self.top, &self.right).unwrap(),
near_bottom_left: self.near.intersection_3pl(&self.bottom, &self.left).unwrap(),
near_bottom_right: self.near.intersection_3pl(&self.bottom, &self.right).unwrap(),
far_top_left: self.far.intersection_3pl(&self.top, &self.left).unwrap(),
far_top_right: self.far.intersection_3pl(&self.top, &self.right).unwrap(),
far_bottom_left: self.far.intersection_3pl(&self.bottom, &self.left).unwrap(),
far_bottom_right: self.far.intersection_3pl(&self.bottom, &self.right).unwrap(),
}
}
}