
# Objective - Implement common traits on primitives ## Solution - Derive PartialEq on types that were missing it. - Derive Copy on small types that were missing it. - Derive Serialize/Deserialize if the feature on bevy_math is enabled. - Add a lot of cursed stuff to the bevy_reflect `impls` module.
629 lines
20 KiB
Rust
629 lines
20 KiB
Rust
use super::{InvalidDirectionError, Primitive2d, WindingOrder};
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use crate::Vec2;
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/// A normalized vector pointing in a direction in 2D space
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#[derive(Clone, Copy, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct Direction2d(Vec2);
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impl Direction2d {
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/// A unit vector pointing along the positive X axis.
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pub const X: Self = Self(Vec2::X);
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/// A unit vector pointing along the positive Y axis.
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pub const Y: Self = Self(Vec2::Y);
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/// A unit vector pointing along the negative X axis.
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pub const NEG_X: Self = Self(Vec2::NEG_X);
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/// A unit vector pointing along the negative Y axis.
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pub const NEG_Y: Self = Self(Vec2::NEG_Y);
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/// Create a direction from a finite, nonzero [`Vec2`].
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///
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/// Returns [`Err(InvalidDirectionError)`](InvalidDirectionError) if the length
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/// of the given vector is zero (or very close to zero), infinite, or `NaN`.
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pub fn new(value: Vec2) -> Result<Self, InvalidDirectionError> {
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Self::new_and_length(value).map(|(dir, _)| dir)
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}
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/// Create a [`Direction2d`] from a [`Vec2`] that is already normalized.
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///
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/// # Warning
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///
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/// `value` must be normalized, i.e it's length must be `1.0`.
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pub fn new_unchecked(value: Vec2) -> Self {
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debug_assert!(value.is_normalized());
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Self(value)
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}
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/// Create a direction from a finite, nonzero [`Vec2`], also returning its original length.
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///
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/// Returns [`Err(InvalidDirectionError)`](InvalidDirectionError) if the length
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/// of the given vector is zero (or very close to zero), infinite, or `NaN`.
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pub fn new_and_length(value: Vec2) -> Result<(Self, f32), InvalidDirectionError> {
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let length = value.length();
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let direction = (length.is_finite() && length > 0.0).then_some(value / length);
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direction
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.map(|dir| (Self(dir), length))
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.ok_or(InvalidDirectionError::from_length(length))
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}
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/// Create a direction from its `x` and `y` components.
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///
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/// Returns [`Err(InvalidDirectionError)`](InvalidDirectionError) if the length
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/// of the vector formed by the components is zero (or very close to zero), infinite, or `NaN`.
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pub fn from_xy(x: f32, y: f32) -> Result<Self, InvalidDirectionError> {
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Self::new(Vec2::new(x, y))
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}
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}
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impl TryFrom<Vec2> for Direction2d {
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type Error = InvalidDirectionError;
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fn try_from(value: Vec2) -> Result<Self, Self::Error> {
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Self::new(value)
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}
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}
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impl std::ops::Deref for Direction2d {
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type Target = Vec2;
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fn deref(&self) -> &Self::Target {
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&self.0
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}
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}
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impl std::ops::Neg for Direction2d {
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type Output = Self;
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fn neg(self) -> Self::Output {
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Self(-self.0)
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}
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}
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/// A circle primitive
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#[derive(Clone, Copy, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct Circle {
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/// The radius of the circle
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pub radius: f32,
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}
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impl Primitive2d for Circle {}
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impl Circle {
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/// Create a new [`Circle`] from a `radius`
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#[inline(always)]
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pub const fn new(radius: f32) -> Self {
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Self { radius }
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}
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/// Finds the point on the circle that is closest to the given `point`.
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///
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/// If the point is outside the circle, the returned point will be on the perimeter of the circle.
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/// Otherwise, it will be inside the circle and returned as is.
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#[inline(always)]
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pub fn closest_point(&self, point: Vec2) -> Vec2 {
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let distance_squared = point.length_squared();
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if distance_squared <= self.radius.powi(2) {
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// The point is inside the circle.
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point
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} else {
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// The point is outside the circle.
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// Find the closest point on the perimeter of the circle.
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let dir_to_point = point / distance_squared.sqrt();
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self.radius * dir_to_point
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}
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}
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}
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/// An ellipse primitive
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#[derive(Clone, Copy, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct Ellipse {
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/// Half of the width and height of the ellipse.
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///
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/// This corresponds to the two perpendicular radii defining the ellipse.
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pub half_size: Vec2,
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}
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impl Primitive2d for Ellipse {}
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impl Ellipse {
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/// Create a new `Ellipse` from half of its width and height.
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///
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/// This corresponds to the two perpendicular radii defining the ellipse.
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#[inline]
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pub const fn new(half_width: f32, half_height: f32) -> Self {
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Self {
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half_size: Vec2::new(half_width, half_height),
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}
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}
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/// Create a new `Ellipse` from a given full size.
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///
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/// `size.x` is the diameter along the X axis, and `size.y` is the diameter along the Y axis.
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#[inline]
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pub fn from_size(size: Vec2) -> Self {
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Self {
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half_size: size / 2.0,
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}
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}
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/// Returns the length of the semi-major axis. This corresponds to the longest radius of the ellipse.
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#[inline]
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pub fn semi_major(self) -> f32 {
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self.half_size.max_element()
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}
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/// Returns the length of the semi-minor axis. This corresponds to the shortest radius of the ellipse.
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#[inline]
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pub fn semi_minor(self) -> f32 {
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self.half_size.min_element()
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}
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}
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/// An unbounded plane in 2D space. It forms a separating surface through the origin,
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/// stretching infinitely far
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#[derive(Clone, Copy, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct Plane2d {
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/// The normal of the plane. The plane will be placed perpendicular to this direction
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pub normal: Direction2d,
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}
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impl Primitive2d for Plane2d {}
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impl Plane2d {
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/// Create a new `Plane2d` from a normal
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///
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/// # Panics
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///
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/// Panics if the given `normal` is zero (or very close to zero), or non-finite.
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#[inline]
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pub fn new(normal: Vec2) -> Self {
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Self {
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normal: Direction2d::new(normal).expect("normal must be nonzero and finite"),
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}
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}
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}
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/// An infinite line along a direction in 2D space.
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///
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/// For a finite line: [`Segment2d`]
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#[derive(Clone, Copy, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct Line2d {
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/// The direction of the line. The line extends infinitely in both the given direction
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/// and its opposite direction
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pub direction: Direction2d,
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}
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impl Primitive2d for Line2d {}
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/// A segment of a line along a direction in 2D space.
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#[doc(alias = "LineSegment2d")]
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#[derive(Clone, Copy, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct Segment2d {
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/// The direction of the line segment
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pub direction: Direction2d,
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/// Half the length of the line segment. The segment extends by this amount in both
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/// the given direction and its opposite direction
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pub half_length: f32,
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}
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impl Primitive2d for Segment2d {}
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impl Segment2d {
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/// Create a line segment from a direction and full length of the segment
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pub fn new(direction: Direction2d, length: f32) -> Self {
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Self {
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direction,
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half_length: length / 2.,
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}
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}
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/// Get a line segment and translation from two points at each end of a line segment
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///
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/// Panics if point1 == point2
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pub fn from_points(point1: Vec2, point2: Vec2) -> (Self, Vec2) {
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let diff = point2 - point1;
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let length = diff.length();
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(
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// We are dividing by the length here, so the vector is normalized.
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Self::new(Direction2d::new_unchecked(diff / length), length),
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(point1 + point2) / 2.,
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)
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}
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/// Get the position of the first point on the line segment
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pub fn point1(&self) -> Vec2 {
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*self.direction * -self.half_length
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}
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/// Get the position of the second point on the line segment
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pub fn point2(&self) -> Vec2 {
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*self.direction * self.half_length
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}
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}
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/// A series of connected line segments in 2D space.
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///
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/// For a version without generics: [`BoxedPolyline2d`]
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#[derive(Clone, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct Polyline2d<const N: usize> {
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/// The vertices of the polyline
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#[cfg_attr(feature = "serialize", serde(with = "super::serde::array"))]
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pub vertices: [Vec2; N],
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}
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impl<const N: usize> Primitive2d for Polyline2d<N> {}
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impl<const N: usize> FromIterator<Vec2> for Polyline2d<N> {
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fn from_iter<I: IntoIterator<Item = Vec2>>(iter: I) -> Self {
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let mut vertices: [Vec2; N] = [Vec2::ZERO; N];
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for (index, i) in iter.into_iter().take(N).enumerate() {
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vertices[index] = i;
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}
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Self { vertices }
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}
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}
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impl<const N: usize> Polyline2d<N> {
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/// Create a new `Polyline2d` from its vertices
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pub fn new(vertices: impl IntoIterator<Item = Vec2>) -> Self {
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Self::from_iter(vertices)
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}
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}
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/// A series of connected line segments in 2D space, allocated on the heap
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/// in a `Box<[Vec2]>`.
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///
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/// For a version without alloc: [`Polyline2d`]
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#[derive(Clone, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct BoxedPolyline2d {
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/// The vertices of the polyline
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pub vertices: Box<[Vec2]>,
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}
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impl Primitive2d for BoxedPolyline2d {}
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impl FromIterator<Vec2> for BoxedPolyline2d {
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fn from_iter<I: IntoIterator<Item = Vec2>>(iter: I) -> Self {
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let vertices: Vec<Vec2> = iter.into_iter().collect();
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Self {
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vertices: vertices.into_boxed_slice(),
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}
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}
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}
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impl BoxedPolyline2d {
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/// Create a new `BoxedPolyline2d` from its vertices
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pub fn new(vertices: impl IntoIterator<Item = Vec2>) -> Self {
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Self::from_iter(vertices)
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}
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}
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/// A triangle in 2D space
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#[derive(Clone, Copy, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct Triangle2d {
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/// The vertices of the triangle
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pub vertices: [Vec2; 3],
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}
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impl Primitive2d for Triangle2d {}
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impl Triangle2d {
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/// Create a new `Triangle2d` from points `a`, `b`, and `c`
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pub fn new(a: Vec2, b: Vec2, c: Vec2) -> Self {
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Self {
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vertices: [a, b, c],
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}
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}
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/// Get the [`WindingOrder`] of the triangle
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#[doc(alias = "orientation")]
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pub fn winding_order(&self) -> WindingOrder {
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let [a, b, c] = self.vertices;
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let area = (b - a).perp_dot(c - a);
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if area > f32::EPSILON {
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WindingOrder::CounterClockwise
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} else if area < -f32::EPSILON {
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WindingOrder::Clockwise
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} else {
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WindingOrder::Invalid
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}
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}
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/// Compute the circle passing through all three vertices of the triangle.
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/// The vector in the returned tuple is the circumcenter.
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pub fn circumcircle(&self) -> (Circle, Vec2) {
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// We treat the triangle as translated so that vertex A is at the origin. This simplifies calculations.
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//
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// A = (0, 0)
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// *
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// / \
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// / \
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// / \
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// / \
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// / U \
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// / \
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// *-------------*
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// B C
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let a = self.vertices[0];
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let (b, c) = (self.vertices[1] - a, self.vertices[2] - a);
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let b_length_sq = b.length_squared();
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let c_length_sq = c.length_squared();
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// Reference: https://en.wikipedia.org/wiki/Circumcircle#Cartesian_coordinates_2
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let inv_d = (2.0 * (b.x * c.y - b.y * c.x)).recip();
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let ux = inv_d * (c.y * b_length_sq - b.y * c_length_sq);
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let uy = inv_d * (b.x * c_length_sq - c.x * b_length_sq);
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let u = Vec2::new(ux, uy);
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// Compute true circumcenter and circumradius, adding the tip coordinate so that
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// A is translated back to its actual coordinate.
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let center = u + a;
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let radius = u.length();
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(Circle { radius }, center)
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}
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/// Reverse the [`WindingOrder`] of the triangle
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/// by swapping the second and third vertices
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pub fn reverse(&mut self) {
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self.vertices.swap(1, 2);
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}
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}
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/// A rectangle primitive
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#[doc(alias = "Quad")]
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#[derive(Clone, Copy, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct Rectangle {
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/// Half of the width and height of the rectangle
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pub half_size: Vec2,
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}
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impl Rectangle {
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/// Create a rectangle from a full width and height
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pub fn new(width: f32, height: f32) -> Self {
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Self::from_size(Vec2::new(width, height))
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}
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/// Create a rectangle from a given full size
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pub fn from_size(size: Vec2) -> Self {
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Self {
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half_size: size / 2.,
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}
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}
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/// Finds the point on the rectangle that is closest to the given `point`.
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///
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/// If the point is outside the rectangle, the returned point will be on the perimeter of the rectangle.
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/// Otherwise, it will be inside the rectangle and returned as is.
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#[inline(always)]
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pub fn closest_point(&self, point: Vec2) -> Vec2 {
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// Clamp point coordinates to the rectangle
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point.clamp(-self.half_size, self.half_size)
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}
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}
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/// A polygon with N vertices.
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///
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/// For a version without generics: [`BoxedPolygon`]
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#[derive(Clone, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct Polygon<const N: usize> {
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/// The vertices of the `Polygon`
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#[cfg_attr(feature = "serialize", serde(with = "super::serde::array"))]
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pub vertices: [Vec2; N],
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}
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impl<const N: usize> Primitive2d for Polygon<N> {}
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impl<const N: usize> FromIterator<Vec2> for Polygon<N> {
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fn from_iter<I: IntoIterator<Item = Vec2>>(iter: I) -> Self {
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let mut vertices: [Vec2; N] = [Vec2::ZERO; N];
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for (index, i) in iter.into_iter().take(N).enumerate() {
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vertices[index] = i;
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}
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Self { vertices }
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}
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}
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impl<const N: usize> Polygon<N> {
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/// Create a new `Polygon` from its vertices
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pub fn new(vertices: impl IntoIterator<Item = Vec2>) -> Self {
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Self::from_iter(vertices)
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}
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}
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/// A polygon with a variable number of vertices, allocated on the heap
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/// in a `Box<[Vec2]>`.
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///
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/// For a version without alloc: [`Polygon`]
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#[derive(Clone, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct BoxedPolygon {
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/// The vertices of the `BoxedPolygon`
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pub vertices: Box<[Vec2]>,
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}
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impl Primitive2d for BoxedPolygon {}
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impl FromIterator<Vec2> for BoxedPolygon {
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fn from_iter<I: IntoIterator<Item = Vec2>>(iter: I) -> Self {
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let vertices: Vec<Vec2> = iter.into_iter().collect();
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Self {
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vertices: vertices.into_boxed_slice(),
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}
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}
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}
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impl BoxedPolygon {
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/// Create a new `BoxedPolygon` from its vertices
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pub fn new(vertices: impl IntoIterator<Item = Vec2>) -> Self {
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Self::from_iter(vertices)
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}
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}
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/// A polygon where all vertices lie on a circle, equally far apart.
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#[derive(Clone, Copy, Debug, PartialEq)]
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#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
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pub struct RegularPolygon {
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/// The circumcircle on which all vertices lie
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pub circumcircle: Circle,
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/// The number of sides
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pub sides: usize,
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}
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impl Primitive2d for RegularPolygon {}
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impl RegularPolygon {
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/// Create a new `RegularPolygon`
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/// from the radius of the circumcircle and number of sides
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///
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/// # Panics
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///
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/// Panics if `circumcircle_radius` is non-positive
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pub fn new(circumcircle_radius: f32, sides: usize) -> Self {
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assert!(circumcircle_radius > 0.0);
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Self {
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circumcircle: Circle {
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radius: circumcircle_radius,
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},
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sides,
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}
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}
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/// Returns an iterator over the vertices of the regular polygon,
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/// rotated counterclockwise by the given angle in radians.
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///
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/// With a rotation of 0, a vertex will be placed at the top `(0.0, circumradius)`.
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|
pub fn vertices(self, rotation: f32) -> impl IntoIterator<Item = Vec2> {
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|
// Add pi/2 so that the polygon has a vertex at the top (sin is 1.0 and cos is 0.0)
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|
let start_angle = rotation + std::f32::consts::FRAC_PI_2;
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|
let step = std::f32::consts::TAU / self.sides as f32;
|
|
|
|
(0..self.sides).map(move |i| {
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|
let theta = start_angle + i as f32 * step;
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|
let (sin, cos) = theta.sin_cos();
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|
Vec2::new(cos, sin) * self.circumcircle.radius
|
|
})
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
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|
mod tests {
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|
use super::*;
|
|
|
|
#[test]
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|
fn direction_creation() {
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|
assert_eq!(Direction2d::new(Vec2::X * 12.5), Ok(Direction2d::X));
|
|
assert_eq!(
|
|
Direction2d::new(Vec2::new(0.0, 0.0)),
|
|
Err(InvalidDirectionError::Zero)
|
|
);
|
|
assert_eq!(
|
|
Direction2d::new(Vec2::new(f32::INFINITY, 0.0)),
|
|
Err(InvalidDirectionError::Infinite)
|
|
);
|
|
assert_eq!(
|
|
Direction2d::new(Vec2::new(f32::NEG_INFINITY, 0.0)),
|
|
Err(InvalidDirectionError::Infinite)
|
|
);
|
|
assert_eq!(
|
|
Direction2d::new(Vec2::new(f32::NAN, 0.0)),
|
|
Err(InvalidDirectionError::NaN)
|
|
);
|
|
assert_eq!(
|
|
Direction2d::new_and_length(Vec2::X * 6.5),
|
|
Ok((Direction2d::X, 6.5))
|
|
);
|
|
}
|
|
|
|
#[test]
|
|
fn triangle_winding_order() {
|
|
let mut cw_triangle = Triangle2d::new(
|
|
Vec2::new(0.0, 2.0),
|
|
Vec2::new(-0.5, -1.2),
|
|
Vec2::new(-1.0, -1.0),
|
|
);
|
|
assert_eq!(cw_triangle.winding_order(), WindingOrder::Clockwise);
|
|
|
|
let ccw_triangle = Triangle2d::new(
|
|
Vec2::new(0.0, 2.0),
|
|
Vec2::new(-1.0, -1.0),
|
|
Vec2::new(-0.5, -1.2),
|
|
);
|
|
assert_eq!(ccw_triangle.winding_order(), WindingOrder::CounterClockwise);
|
|
|
|
// The clockwise triangle should be the same as the counterclockwise
|
|
// triangle when reversed
|
|
cw_triangle.reverse();
|
|
assert_eq!(cw_triangle, ccw_triangle);
|
|
|
|
let invalid_triangle = Triangle2d::new(
|
|
Vec2::new(0.0, 2.0),
|
|
Vec2::new(0.0, -1.0),
|
|
Vec2::new(0.0, -1.2),
|
|
);
|
|
assert_eq!(invalid_triangle.winding_order(), WindingOrder::Invalid);
|
|
}
|
|
|
|
#[test]
|
|
fn triangle_circumcenter() {
|
|
let triangle = Triangle2d::new(
|
|
Vec2::new(10.0, 2.0),
|
|
Vec2::new(-5.0, -3.0),
|
|
Vec2::new(2.0, -1.0),
|
|
);
|
|
let (Circle { radius }, circumcenter) = triangle.circumcircle();
|
|
|
|
// Calculated with external calculator
|
|
assert_eq!(radius, 98.34887);
|
|
assert_eq!(circumcenter, Vec2::new(-28.5, 92.5));
|
|
}
|
|
|
|
#[test]
|
|
fn regular_polygon_vertices() {
|
|
let polygon = RegularPolygon::new(1.0, 4);
|
|
|
|
// Regular polygons have a vertex at the top by default
|
|
let mut vertices = polygon.vertices(0.0).into_iter();
|
|
assert!((vertices.next().unwrap() - Vec2::Y).length() < 1e-7);
|
|
|
|
// Rotate by 45 degrees, forming an axis-aligned square
|
|
let mut rotated_vertices = polygon.vertices(std::f32::consts::FRAC_PI_4).into_iter();
|
|
|
|
// Distance from the origin to the middle of a side, derived using Pythagorean theorem
|
|
let side_sistance = std::f32::consts::FRAC_1_SQRT_2;
|
|
assert!(
|
|
(rotated_vertices.next().unwrap() - Vec2::new(-side_sistance, side_sistance)).length()
|
|
< 1e-7,
|
|
);
|
|
}
|
|
|
|
#[test]
|
|
fn rectangle_closest_point() {
|
|
let rectangle = Rectangle::new(2.0, 2.0);
|
|
assert_eq!(rectangle.closest_point(Vec2::X * 10.0), Vec2::X);
|
|
assert_eq!(rectangle.closest_point(Vec2::NEG_ONE * 10.0), Vec2::NEG_ONE);
|
|
assert_eq!(
|
|
rectangle.closest_point(Vec2::new(0.25, 0.1)),
|
|
Vec2::new(0.25, 0.1)
|
|
);
|
|
}
|
|
|
|
#[test]
|
|
fn circle_closest_point() {
|
|
let circle = Circle { radius: 1.0 };
|
|
assert_eq!(circle.closest_point(Vec2::X * 10.0), Vec2::X);
|
|
assert_eq!(
|
|
circle.closest_point(Vec2::NEG_ONE * 10.0),
|
|
Vec2::NEG_ONE.normalize()
|
|
);
|
|
assert_eq!(
|
|
circle.closest_point(Vec2::new(0.25, 0.1)),
|
|
Vec2::new(0.25, 0.1)
|
|
);
|
|
}
|
|
}
|