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use super::math::*;
///
/// A bounding box that aligns with the x, y and z axes.
///
#[derive(Debug, Copy, Clone)]
pub struct AxisAlignedBoundingBox {
min: Vec3,
max: Vec3,
}
impl AxisAlignedBoundingBox {
/// An empty bounding box.
pub const EMPTY: Self = Self {
min: Vec3::new(f32::INFINITY, f32::INFINITY, f32::INFINITY),
max: Vec3::new(f32::NEG_INFINITY, f32::NEG_INFINITY, f32::NEG_INFINITY),
};
/// An infinitely large bounding box.
pub const INFINITE: Self = Self {
min: Vec3::new(f32::NEG_INFINITY, f32::NEG_INFINITY, f32::NEG_INFINITY),
max: Vec3::new(f32::INFINITY, f32::INFINITY, f32::INFINITY),
};
///
/// Constructs a new bounding box and expands it such that all of the given positions are contained inside the bounding box.
///
pub fn new_with_positions(positions: &[Vec3]) -> Self {
let mut aabb = Self::EMPTY;
aabb.expand(positions);
aabb
}
///
/// Constructs a new bounding box and expands it such that all of the given positions transformed with the given transformation are contained inside the bounding box.
/// A position consisting of an x, y and z coordinate corresponds to three consecutive value in the positions array.
///
pub fn new_with_transformed_positions(positions: &[Vec3], transformation: Mat4) -> Self {
let mut aabb = Self::EMPTY;
aabb.expand_with_transformation(positions, transformation);
aabb
}
///
/// Returns true if the bounding box is empty (ie. constructed by [AxisAlignedBoundingBox::EMPTY]).
///
pub fn is_empty(&self) -> bool {
self.max.x == f32::NEG_INFINITY
}
///
/// Returns true if the bounding box is infinitely large (ie. constructed by [AxisAlignedBoundingBox::INFINITE]).
///
pub fn is_infinite(&self) -> bool {
self.max.x == f32::INFINITY
}
///
/// Get the minimum coordinate of the bounding box.
///
pub fn min(&self) -> Vec3 {
self.min
}
///
/// Get the maximum coordinate of the bounding box.
///
pub fn max(&self) -> Vec3 {
self.max
}
///
/// Get the center of the bounding box.
///
pub fn center(&self) -> Vec3 {
if self.is_infinite() {
Vec3::new(0.0, 0.0, 0.0)
} else {
0.5 * self.max + 0.5 * self.min
}
}
///
/// Get the size of the bounding box.
///
pub fn size(&self) -> Vec3 {
self.max - self.min
}
/// Expands the bounding box to be at least the given size, keeping the center the same.
pub fn ensure_size(&mut self, min_size: Vec3) {
if !self.is_empty() && !self.is_infinite() {
let size = self.size();
if size.x < min_size.x {
let diff = min_size.x - size.x;
self.min.x -= 0.5 * diff;
self.max.x += 0.5 * diff;
}
if size.y < min_size.y {
let diff = min_size.y - size.y;
self.min.y -= 0.5 * diff;
self.max.y += 0.5 * diff;
}
if size.z < min_size.z {
let diff = min_size.z - size.z;
self.min.z -= 0.5 * diff;
self.max.z += 0.5 * diff;
}
}
}
/// Returns the intersection between this and the other given bounding box.
/// Returns None if the bounding boxes doesn't overlap.
pub fn intersection(self, other: Self) -> Option<Self> {
let min_a = self.min();
let max_a = self.max();
let min_b = other.min();
let max_b = other.max();
if min_a.x >= max_b.x || min_a.y >= max_b.y || min_b.x >= max_a.x || min_b.y >= max_a.y {
return None;
}
let min = vec3(
min_a.x.max(min_b.x),
min_a.y.max(min_b.y),
min_a.z.max(min_b.z),
);
let max = vec3(
max_a.x.min(max_b.x),
max_a.y.min(max_b.y),
max_a.z.min(max_b.z),
);
Some(Self::new_with_positions(&[min, max]))
}
///
/// Expands the bounding box such that all of the given positions are contained inside the bounding box.
///
pub fn expand(&mut self, positions: &[Vec3]) {
for p in positions {
self.min.x = self.min.x.min(p.x);
self.min.y = self.min.y.min(p.y);
self.min.z = self.min.z.min(p.z);
self.max.x = self.max.x.max(p.x);
self.max.y = self.max.y.max(p.y);
self.max.z = self.max.z.max(p.z);
}
}
///
/// Expands the bounding box such that all of the given positions transformed with the given transformation are contained inside the bounding box.
///
pub fn expand_with_transformation(&mut self, positions: &[Vec3], transformation: Mat4) {
self.expand(
&positions
.iter()
.map(|p| (transformation * p.extend(1.0)).truncate())
.collect::<Vec<_>>(),
)
}
///
/// Expand the bounding box such that it also contains the given other bounding box.
///
pub fn expand_with_aabb(&mut self, other: AxisAlignedBoundingBox) {
if self.is_empty() {
*self = other;
} else if !other.is_empty() {
self.expand(&[other.min(), other.max()]);
}
}
///
/// Transforms the bounding box by the given transformation.
///
pub fn transform(&mut self, transformation: Mat4) {
if !self.is_empty() && !self.is_infinite() {
*self = Self::new_with_transformed_positions(
&[
self.min,
vec3(self.max.x, self.min.y, self.min.z),
vec3(self.min.x, self.max.y, self.min.z),
vec3(self.min.x, self.min.y, self.max.z),
vec3(self.min.x, self.max.y, self.max.z),
vec3(self.max.x, self.min.y, self.max.z),
vec3(self.max.x, self.max.y, self.min.z),
self.max,
],
transformation,
);
}
}
///
/// Returns the bounding box transformed by the given transformation.
///
pub fn transformed(mut self, transformation: Mat4) -> AxisAlignedBoundingBox {
self.transform(transformation);
self
}
/// Returns true if the given bounding box is fully inside this bounding box.
pub fn contains(&self, aabb: AxisAlignedBoundingBox) -> bool {
!self.is_empty()
&& !aabb.is_empty()
&& self.is_inside(aabb.min())
&& self.is_inside(aabb.max())
}
/// Returns true if the given position is inside this bounding box.
pub fn is_inside(&self, position: Vec3) -> bool {
self.min.x <= position.x
&& position.x <= self.max.x
&& self.min.y <= position.y
&& position.y <= self.max.y
&& self.min.z <= position.z
&& position.z <= self.max.z
}
///
/// The distance from position to the point in this bounding box that is closest to position.
///
pub fn distance(&self, position: Vec3) -> f32 {
let x = (self.min.x - position.x)
.max(position.x - self.max.x)
.max(0.0);
let y = (self.min.y - position.y)
.max(position.y - self.max.y)
.max(0.0);
let z = (self.min.z - position.z)
.max(position.z - self.max.z)
.max(0.0);
let d2 = x * x + y * y + z * z;
if d2 > 0.001 {
d2.sqrt()
} else {
d2
}
}
///
/// The distance from position to the point in this bounding box that is furthest away from position.
///
pub fn distance_max(&self, position: Vec3) -> f32 {
let x = (position.x - self.min.x)
.abs()
.max((self.max.x - position.x).abs());
let y = (position.y - self.min.y)
.abs()
.max((self.max.y - position.y).abs());
let z = (position.z - self.min.z)
.abs()
.max((self.max.z - position.z).abs());
let d2 = x * x + y * y + z * z;
if d2 > 0.001 {
d2.sqrt()
} else {
d2
}
}
}