[kaka/rust-sdl-test.git] / src / geometry.rs

use std::ops::{Add, AddAssign, Sub, SubAssign, Mul, MulAssign, Div, DivAssign, Neg};

////////// POINT ///////////////////////////////////////////////////////////////

#[macro_export]
macro_rules! point {
    ( $x:expr, $y:expr ) => {
        Point { x: $x, y: $y }
    };
}

#[derive(Debug, Default, Copy, Clone, PartialEq)]
pub struct Point<T> {
    pub x: T,
    pub y: T,
}

impl Point<f64> {
    pub fn length(&self) -> f64 {
        ((self.x * self.x) + (self.y * self.y)).sqrt()
    }

    pub fn normalized(&self) -> Self {
	let l = self.length();
	Self {
	    x: self.x / l,
	    y: self.y / l,
	}
    }

    pub fn to_angle(&self) -> Angle {
	self.y.atan2(self.x).radians()
    }

    pub fn to_i32(self) -> Point<i32> {
	Point {
	    x: self.x as i32,
	    y: self.y as i32,
	}
    }

    pub fn cross_product(&self, p: Self) -> f64 {
        return self.x * p.y - self.y * p.x;
    }
}

macro_rules! impl_point_op {
    ($op:tt, $trait:ident($fn:ident), $trait_assign:ident($fn_assign:ident), $rhs:ident = $Rhs:ty => $x:expr, $y:expr) => {
        impl<T: $trait<Output = T>> $trait<$Rhs> for Point<T> {
            type Output = Self;

            fn $fn(self, $rhs: $Rhs) -> Self {
                Self {
                    x: self.x $op $x,
                    y: self.y $op $y,
                }
            }
        }

        impl<T: $trait<Output = T> + Copy> $trait_assign<$Rhs> for Point<T> {
            fn $fn_assign(&mut self, $rhs: $Rhs) {
                *self = Self {
                    x: self.x $op $x,
                    y: self.y $op $y,
                }
            }
        }
    }
}

impl_point_op!(+, Add(add), AddAssign(add_assign), rhs = Point<T> => rhs.x, rhs.y);
impl_point_op!(-, Sub(sub), SubAssign(sub_assign), rhs = Point<T> => rhs.x, rhs.y);
impl_point_op!(*, Mul(mul), MulAssign(mul_assign), rhs = Point<T> => rhs.x, rhs.y);
impl_point_op!(/, Div(div), DivAssign(div_assign), rhs = Point<T> => rhs.x, rhs.y);
impl_point_op!(+, Add(add), AddAssign(add_assign), rhs = (T, T) => rhs.0, rhs.1);
impl_point_op!(-, Sub(sub), SubAssign(sub_assign), rhs = (T, T) => rhs.0, rhs.1);
impl_point_op!(*, Mul(mul), MulAssign(mul_assign), rhs = (T, T) => rhs.0, rhs.1);
impl_point_op!(/, Div(div), DivAssign(div_assign), rhs = (T, T) => rhs.0, rhs.1);
impl_point_op!(*, Mul(mul), MulAssign(mul_assign), rhs = Dimension<T> => rhs.width, rhs.height);
impl_point_op!(/, Div(div), DivAssign(div_assign), rhs = Dimension<T> => rhs.width, rhs.height);

////////// multiply point with scalar //////////////////////////////////////////
impl<T: Mul<Output = T> + Copy> Mul<T> for Point<T> {
    type Output = Self;

    fn mul(self, rhs: T) -> Self {
	Self {
	    x: self.x * rhs,
	    y: self.y * rhs,
	}
    }
}

impl<T: Mul<Output = T> + Copy> MulAssign<T> for Point<T> {
    fn mul_assign(&mut self, rhs: T) {
	*self = Self {
	    x: self.x * rhs,
	    y: self.y * rhs,
	}
    }
}

////////// divide point with scalar ////////////////////////////////////////////
impl<T: Div<Output = T> + Copy> Div<T> for Point<T> {
    type Output = Self;

    fn div(self, rhs: T) -> Self {
	Self {
	    x: self.x / rhs,
	    y: self.y / rhs,
	}
    }
}

impl<T: Div<Output = T> + Copy> DivAssign<T> for Point<T> {
    fn div_assign(&mut self, rhs: T) {
	*self = Self {
	    x: self.x / rhs,
	    y: self.y / rhs,
	}
    }
}

impl<T: Neg<Output = T>> Neg for Point<T> {
    type Output = Self;

    fn neg(self) -> Self {
	Self {
	    x: -self.x,
	    y: -self.y,
	}
    }
}

impl<T> From<(T, T)> for Point<T> {
    fn from(item: (T, T)) -> Self {
        Point {
            x: item.0,
            y: item.1,
        }
    }
}

impl<T> From<Point<T>> for (T, T) {
    fn from(item: Point<T>) -> Self {
        (item.x, item.y)
    }
}

impl From<Angle> for Point<f64> {
    fn from(item: Angle) -> Self {
	Point {
	    x: item.0.cos(),
	    y: item.0.sin(),
	}
    }
}

////////// ANGLE ///////////////////////////////////////////////////////////////

#[derive(Debug, Default, Clone, Copy)]
pub struct Angle(pub f64);

pub trait ToAngle {
    fn radians(self) -> Angle;
    fn degrees(self) -> Angle;
}

macro_rules! impl_angle {
    ($($type:ty),*) => {
	$(
	    impl ToAngle for $type {
		fn radians(self) -> Angle {
		    Angle(self as f64)
		}

		fn degrees(self) -> Angle {
		    Angle((self as f64).to_radians())
		}
	    }

	    impl Mul<$type> for Angle {
		type Output = Self;

		fn mul(self, rhs: $type) -> Self {
		    Angle(self.0 * (rhs as f64))
		}
	    }

	    impl MulAssign<$type> for Angle {
		fn mul_assign(&mut self, rhs: $type) {
		    self.0 *= rhs as f64;
		}
	    }

	    impl Div<$type> for Angle {
		type Output = Self;

		fn div(self, rhs: $type) -> Self {
		    Angle(self.0 / (rhs as f64))
		}
	    }

	    impl DivAssign<$type> for Angle {
		fn div_assign(&mut self, rhs: $type) {
		    self.0 /= rhs as f64;
		}
	    }
	)*
    }
}

impl_angle!(f32, f64, i8, i16, i32, i64, isize, u8, u16, u32, u64, usize);

impl Angle {
    pub fn to_radians(self) -> f64 {
	self.0
    }

    pub fn to_degrees(self) -> f64 {
	self.0.to_degrees()
    }

    /// Returns the reflection of the incident when mirrored along this angle.
    pub fn mirror(&self, incidence: Angle) -> Angle {
	Angle((std::f64::consts::PI + self.0 * 2.0 - incidence.0) % std::f64::consts::TAU)
    }
}

impl PartialEq for Angle {
    fn eq(&self, rhs: &Angle) -> bool {
	self.0 % std::f64::consts::TAU == rhs.0 % std::f64::consts::TAU
    }
}

// addition and subtraction of angles

impl Add<Angle> for Angle {
    type Output = Self;

    fn add(self, rhs: Angle) -> Self {
	Angle(self.0 + rhs.0)
    }
}

impl AddAssign<Angle> for Angle {
    fn add_assign(&mut self, rhs: Angle) {
	self.0 += rhs.0;
    }
}

impl Sub<Angle> for Angle {
    type Output = Self;

    fn sub(self, rhs: Angle) -> Self {
	Angle(self.0 - rhs.0)
    }
}

impl SubAssign<Angle> for Angle {
    fn sub_assign(&mut self, rhs: Angle) {
	self.0 -= rhs.0;
    }
}

////////// INTERSECTION ////////////////////////////////////////////////////////

#[derive(Debug)]
pub enum Intersection {
    Point(Point<f64>),
    //Line(Point<f64>, Point<f64>), // TODO: overlapping collinear
    None,
}

impl Intersection {
    pub fn lines(p1: Point<f64>, p2: Point<f64>, p3: Point<f64>, p4: Point<f64>) -> Intersection {
	let s1 = p2 - p1;
	let s2 = p4 - p3;

	let denomimator = -s2.x * s1.y + s1.x * s2.y;
	if denomimator != 0.0 {
	    let s = (-s1.y * (p1.x - p3.x) + s1.x * (p1.y - p3.y)) / denomimator;
	    let t = ( s2.x * (p1.y - p3.y) - s2.y * (p1.x - p3.x)) / denomimator;

	    if (0.0..=1.0).contains(&s) && (0.0..=1.0).contains(&t) {
		return Intersection::Point(p1 + (s1 * t))
	    }
	}

	Intersection::None
    }
}

////////// DIMENSION ///////////////////////////////////////////////////////////

#[macro_export]
macro_rules! dimen {
    ( $w:expr, $h:expr ) => {
        Dimension { width: $w, height: $h }
    };
}

#[derive(Debug, Default, Copy, Clone, PartialEq)]
pub struct Dimension<T> {
    pub width: T,
    pub height: T,
}

impl<T: Mul<Output = T> + Copy> Dimension<T> {
    #[allow(dead_code)]
    pub fn area(&self) -> T {
        self.width * self.height
    }
}

impl<T> From<(T, T)> for Dimension<T> {
    fn from(item: (T, T)) -> Self {
        Dimension {
            width: item.0,
            height: item.1,
        }
    }
}

impl<T> From<Dimension<T>> for (T, T) {
    fn from(item: Dimension<T>) -> Self {
        (item.width, item.height)
    }
}

////////////////////////////////////////////////////////////////////////////////

#[allow(dead_code)]
pub fn supercover_line_int(p1: Point<isize>, p2: Point<isize>) -> Vec<Point<isize>> {
    let d = p2 - p1;
    let n = point!(d.x.abs(), d.y.abs());
    let step = point!(d.x.signum(), d.y.signum());

    let mut p = p1;
    let mut points = vec!(point!(p.x as isize, p.y as isize));
    let mut i = point!(0, 0);
    while i.x < n.x || i.y < n.y {
        let decision = (1 + 2 * i.x) * n.y - (1 + 2 * i.y) * n.x;
        if decision == 0 { // next step is diagonal
            p.x += step.x;
            p.y += step.y;
            i.x += 1;
            i.y += 1;
        } else if decision < 0 { // next step is horizontal
            p.x += step.x;
	    i.x += 1;
        } else { // next step is vertical
            p.y += step.y;
            i.y += 1;
        }
        points.push(point!(p.x as isize, p.y as isize));
    }

    points
}

/// Calculates all points a line crosses, unlike Bresenham's line algorithm.
/// There might be room for a lot of improvement here.
pub fn supercover_line(mut p1: Point<f64>, mut p2: Point<f64>) -> Vec<Point<isize>> {
    let mut delta = p2 - p1;
    if (delta.x.abs() > delta.y.abs() && delta.x.is_sign_negative()) || (delta.x.abs() <= delta.y.abs() && delta.y.is_sign_negative()) {
	std::mem::swap(&mut p1, &mut p2);
	delta = -delta;
    }

    let mut last = point!(p1.x as isize, p1.y as isize);
    let mut coords: Vec<Point<isize>> = vec!();
    coords.push(last);

    if delta.x.abs() > delta.y.abs() {
	let k = delta.y / delta.x;
	let m = p1.y as f64 - p1.x as f64 * k;
	for x in (p1.x as isize + 1)..=(p2.x as isize) {
	    let y = (k * x as f64 + m).floor();
	    let next = point!(x as isize - 1, y as isize);
	    if next != last {
		coords.push(next);
	    }
	    let next = point!(x as isize, y as isize);
	    coords.push(next);
	    last = next;
	}
    } else {
	let k = delta.x / delta.y;
	let m = p1.x as f64 - p1.y as f64 * k;
	for y in (p1.y as isize + 1)..=(p2.y as isize) {
	    let x = (k * y as f64 + m).floor();
	    let next = point!(x as isize, y as isize - 1);
	    if next != last {
		coords.push(next);
	    }
	    let next = point!(x as isize, y as isize);
	    coords.push(next);
	    last = next;
	}
    }

    let next = point!(p2.x as isize, p2.y as isize);
    if next != last {
	coords.push(next);
    }

    coords
}

////////// TESTS ///////////////////////////////////////////////////////////////

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn immutable_copy_of_point() {
        let a = point!(0, 0);
        let mut b = a; // Copy
        assert_eq!(a, b); // PartialEq
        b.x = 1;
        assert_ne!(a, b); // PartialEq
    }

    #[test]
    fn add_points() {
        let mut a = point!(1, 0);
        assert_eq!(a + point!(2, 2), point!(3, 2)); // Add
        a += point!(2, 2); // AddAssign
        assert_eq!(a, point!(3, 2));
        assert_eq!(point!(1, 0) + (2, 3), point!(3, 3));
    }

    #[test]
    fn sub_points() {
        let mut a = point!(1, 0);
        assert_eq!(a - point!(2, 2), point!(-1, -2));
        a -= point!(2, 2);
        assert_eq!(a, point!(-1, -2));
        assert_eq!(point!(1, 0) - (2, 3), point!(-1, -3));
    }

    #[test]
    fn mul_points() {
        let mut a = point!(1, 2);
        assert_eq!(a * 2, point!(2, 4));
        assert_eq!(a * point!(2, 3), point!(2, 6));
        a *= 2;
        assert_eq!(a, point!(2, 4));
        a *= point!(3, 1);
        assert_eq!(a, point!(6, 4));
        assert_eq!(point!(1, 0) * (2, 3), point!(2, 0));
    }

    #[test]
    fn div_points() {
        let mut a = point!(4, 8);
        assert_eq!(a / 2, point!(2, 4));
        assert_eq!(a / point!(2, 4), point!(2, 2));
        a /= 2;
        assert_eq!(a, point!(2, 4));
        a /= point!(2, 4);
        assert_eq!(a, point!(1, 1));
        assert_eq!(point!(6, 3) / (2, 3), point!(3, 1));
    }

    #[test]
    fn neg_point() {
        assert_eq!(point!(1, 1), -point!(-1, -1));
    }

    #[test]
    fn angles() {
	assert_eq!(0.radians(), 0.degrees());
	assert_eq!(0.degrees(), 360.degrees());
	assert_eq!(180.degrees(), std::f64::consts::PI.radians());
	assert_eq!(std::f64::consts::PI.radians().to_degrees(), 180.0);
	assert!((Point::from(90.degrees()) - point!(0.0, 1.0)).length() < 0.001);
	assert!((Point::from(std::f64::consts::FRAC_PI_2.radians()) - point!(0.0, 1.0)).length() < 0.001);
    }

    #[test]
    fn area_for_dimension_of_multipliable_type() {
        let r: Dimension<_> = (30, 20).into(); // the Into trait uses the From trait
        assert_eq!(r.area(), 30 * 20);
        // let a = Dimension::from(("a".to_string(), "b".to_string())).area(); // this doesn't work, because area() is not implemented for String
    }

    #[test]
    fn intersection_of_lines() {
        let p1 = point!(0.0, 0.0);
        let p2 = point!(2.0, 2.0);
        let p3 = point!(0.0, 2.0);
        let p4 = point!(2.0, 0.0);
	let r = Intersection::lines(p1, p2, p3, p4);
	if let Intersection::Point(p) = r {
            assert_eq!(p, point!(1.0, 1.0));
	} else {
	    panic!();
	}
    }

    #[test]
    fn some_coordinates_on_line() {
	// horizontally up
	let coords = supercover_line(point!(0.0, 0.0), point!(3.3, 2.2));
	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(1, 0), point!(1, 1), point!(2, 1), point!(2, 2), point!(3, 2)]);

	// horizontally down
	let coords = supercover_line(point!(0.0, 5.0), point!(3.3, 2.2));
	assert_eq!(coords.as_slice(), &[point!(0, 5), point!(0, 4), point!(1, 4), point!(1, 3), point!(2, 3), point!(2, 2), point!(3, 2)]);

	// vertically right
	let coords = supercover_line(point!(0.0, 0.0), point!(2.2, 3.3));
	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(0, 1), point!(1, 1), point!(1, 2), point!(2, 2), point!(2, 3)]);

	// vertically left
	let coords = supercover_line(point!(5.0, 0.0), point!(3.0, 3.0));
	assert_eq!(coords.as_slice(), &[point!(5, 0), point!(4, 0), point!(4, 1), point!(3, 1), point!(3, 2), point!(3, 3)]);

	// negative
	let coords = supercover_line(point!(0.0, 0.0), point!(-3.0, -2.0));
	assert_eq!(coords.as_slice(), &[point!(-3, -2), point!(-2, -2), point!(-2, -1), point!(-1, -1), point!(-1, 0), point!(0, 0)]);

	// 
	let coords = supercover_line(point!(0.0, 0.0), point!(2.3, 1.1));
	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(1, 0), point!(2, 0), point!(2, 1)]);
    }
}
Commit	Line	Data
2836f506	1	use std::ops::{Add, AddAssign, Sub, SubAssign, Mul, MulAssign, Div, DivAssign, Neg};
296187ca	2
60058b91 TW	3	////////// POINT ///////////////////////////////////////////////////////////////
60058b91 TW	4
787dbfb4	5	#[macro_export]
296187ca	6	macro_rules! point {
6ba7aef1	7	( $x:expr, $y:expr ) => {
e570927a	8	Point { x: $x, y: $y }
6ba7aef1	9	};
296187ca TW	10	}
296187ca TW	11
b0566120	12	#[derive(Debug, Default, Copy, Clone, PartialEq)]
e570927a	13	pub struct Point<T> {
296187ca TW	14	pub x: T,
	15	pub y: T,
	16	}
	17
e570927a	18	impl Point<f64> {
eca25591	19	pub fn length(&self) -> f64 {
296187ca TW	20	((self.x * self.x) + (self.y * self.y)).sqrt()
296187ca TW	21	}
bf7b5671	22
93fc5734	23	pub fn normalized(&self) -> Self {
eca25591 TW	24	let l = self.length();
	25	Self {
	26	x: self.x / l,
	27	y: self.y / l,
	28	}
	29	}
	30
40742678 TW	31	pub fn to_angle(&self) -> Angle {
40742678 TW	32	self.y.atan2(self.x).radians()
eca25591 TW	33	}
eca25591 TW	34
e570927a TW	35	pub fn to_i32(self) -> Point<i32> {
e570927a TW	36	Point {
bf7b5671 TW	37	x: self.x as i32,
	38	y: self.y as i32,
	39	}
	40	}
b1075e66 TW	41
	42	pub fn cross_product(&self, p: Self) -> f64 {
	43	return self.x * p.y - self.y * p.x;
	44	}
296187ca TW	45	}
296187ca TW	46
0d75b79e	47	macro_rules! impl_point_op {
6cd86b94	48	($op:tt, $trait:ident($fn:ident), $trait_assign:ident($fn_assign:ident), $rhs:ident = $Rhs:ty => $x:expr, $y:expr) => {
e570927a	49	impl<T: $trait<Output = T>> $trait<$Rhs> for Point<T> {
6cd86b94 TW	50	type Output = Self;
	51
	52	fn $fn(self, $rhs: $Rhs) -> Self {
	53	Self {
	54	x: self.x $op $x,
	55	y: self.y $op $y,
	56	}
	57	}
2836f506	58	}
2836f506	59
e570927a	60	impl<T: $trait<Output = T> + Copy> $trait_assign<$Rhs> for Point<T> {
6cd86b94 TW	61	fn $fn_assign(&mut self, $rhs: $Rhs) {
	62	*self = Self {
	63	x: self.x $op $x,
	64	y: self.y $op $y,
	65	}
	66	}
2836f506 TW	67	}
	68	}
	69	}
	70
0d75b79e TW	71	impl_point_op!(+, Add(add), AddAssign(add_assign), rhs = Point<T> => rhs.x, rhs.y);
	72	impl_point_op!(-, Sub(sub), SubAssign(sub_assign), rhs = Point<T> => rhs.x, rhs.y);
	73	impl_point_op!(*, Mul(mul), MulAssign(mul_assign), rhs = Point<T> => rhs.x, rhs.y);
	74	impl_point_op!(/, Div(div), DivAssign(div_assign), rhs = Point<T> => rhs.x, rhs.y);
	75	impl_point_op!(+, Add(add), AddAssign(add_assign), rhs = (T, T) => rhs.0, rhs.1);
	76	impl_point_op!(-, Sub(sub), SubAssign(sub_assign), rhs = (T, T) => rhs.0, rhs.1);
	77	impl_point_op!(*, Mul(mul), MulAssign(mul_assign), rhs = (T, T) => rhs.0, rhs.1);
	78	impl_point_op!(/, Div(div), DivAssign(div_assign), rhs = (T, T) => rhs.0, rhs.1);
	79	impl_point_op!(*, Mul(mul), MulAssign(mul_assign), rhs = Dimension<T> => rhs.width, rhs.height);
	80	impl_point_op!(/, Div(div), DivAssign(div_assign), rhs = Dimension<T> => rhs.width, rhs.height);
2836f506 TW	81
2836f506 TW	82	////////// multiply point with scalar //////////////////////////////////////////
e570927a	83	impl<T: Mul<Output = T> + Copy> Mul<T> for Point<T> {
2836f506 TW	84	type Output = Self;
	85
	86	fn mul(self, rhs: T) -> Self {
	87	Self {
	88	x: self.x * rhs,
	89	y: self.y * rhs,
	90	}
	91	}
	92	}
	93
e570927a	94	impl<T: Mul<Output = T> + Copy> MulAssign<T> for Point<T> {
2836f506 TW	95	fn mul_assign(&mut self, rhs: T) {
	96	*self = Self {
	97	x: self.x * rhs,
	98	y: self.y * rhs,
	99	}
	100	}
	101	}
	102
2836f506	103	////////// divide point with scalar ////////////////////////////////////////////
e570927a	104	impl<T: Div<Output = T> + Copy> Div<T> for Point<T> {
2836f506 TW	105	type Output = Self;
	106
	107	fn div(self, rhs: T) -> Self {
	108	Self {
	109	x: self.x / rhs,
	110	y: self.y / rhs,
	111	}
	112	}
	113	}
	114
e570927a	115	impl<T: Div<Output = T> + Copy> DivAssign<T> for Point<T> {
2836f506 TW	116	fn div_assign(&mut self, rhs: T) {
	117	*self = Self {
	118	x: self.x / rhs,
	119	y: self.y / rhs,
	120	}
	121	}
	122	}
	123
e570927a	124	impl<T: Neg<Output = T>> Neg for Point<T> {
2836f506 TW	125	type Output = Self;
	126
	127	fn neg(self) -> Self {
	128	Self {
	129	x: -self.x,
	130	y: -self.y,
	131	}
296187ca TW	132	}
	133	}
	134
e570927a	135	impl<T> From<(T, T)> for Point<T> {
b0566120	136	fn from(item: (T, T)) -> Self {
e570927a	137	Point {
b0566120 TW	138	x: item.0,
	139	y: item.1,
	140	}
	141	}
	142	}
	143
e570927a TW	144	impl<T> From<Point<T>> for (T, T) {
e570927a TW	145	fn from(item: Point<T>) -> Self {
bf7b5671 TW	146	(item.x, item.y)
	147	}
	148	}
	149
40742678 TW	150	impl From<Angle> for Point<f64> {
	151	fn from(item: Angle) -> Self {
	152	Point {
	153	x: item.0.cos(),
	154	y: item.0.sin(),
	155	}
e58a1769 TW	156	}
	157	}
	158
40742678	159	////////// ANGLE ///////////////////////////////////////////////////////////////
e58a1769	160
a9eacb2b	161	#[derive(Debug, Default, Clone, Copy)]
40742678	162	pub struct Angle(pub f64);
e58a1769	163
40742678 TW	164	pub trait ToAngle {
	165	fn radians(self) -> Angle;
	166	fn degrees(self) -> Angle;
	167	}
	168
	169	macro_rules! impl_angle {
	170	($($type:ty),*) => {
	171	$(
	172	impl ToAngle for $type {
	173	fn radians(self) -> Angle {
	174	Angle(self as f64)
	175	}
	176
	177	fn degrees(self) -> Angle {
	178	Angle((self as f64).to_radians())
	179	}
	180	}
	181
	182	impl Mul<$type> for Angle {
	183	type Output = Self;
	184
	185	fn mul(self, rhs: $type) -> Self {
	186	Angle(self.0 * (rhs as f64))
	187	}
	188	}
	189
	190	impl MulAssign<$type> for Angle {
	191	fn mul_assign(&mut self, rhs: $type) {
	192	self.0 *= rhs as f64;
	193	}
	194	}
	195
	196	impl Div<$type> for Angle {
	197	type Output = Self;
	198
	199	fn div(self, rhs: $type) -> Self {
	200	Angle(self.0 / (rhs as f64))
	201	}
	202	}
	203
	204	impl DivAssign<$type> for Angle {
	205	fn div_assign(&mut self, rhs: $type) {
	206	self.0 /= rhs as f64;
	207	}
	208	}
	209	)*
e58a1769 TW	210	}
	211	}
	212
40742678 TW	213	impl_angle!(f32, f64, i8, i16, i32, i64, isize, u8, u16, u32, u64, usize);
	214
	215	impl Angle {
	216	pub fn to_radians(self) -> f64 {
	217	self.0
	218	}
	219
	220	pub fn to_degrees(self) -> f64 {
	221	self.0.to_degrees()
e58a1769	222	}
8065e264 TW	223
8065e264 TW	224	/// Returns the reflection of the incident when mirrored along this angle.
40742678 TW	225	pub fn mirror(&self, incidence: Angle) -> Angle {
	226	Angle((std::f64::consts::PI + self.0 * 2.0 - incidence.0) % std::f64::consts::TAU)
	227	}
	228	}
	229
a9eacb2b TW	230	impl PartialEq for Angle {
	231	fn eq(&self, rhs: &Angle) -> bool {
	232	self.0 % std::f64::consts::TAU == rhs.0 % std::f64::consts::TAU
	233	}
	234	}
40742678 TW	235
	236	// addition and subtraction of angles
	237
	238	impl Add<Angle> for Angle {
	239	type Output = Self;
	240
	241	fn add(self, rhs: Angle) -> Self {
	242	Angle(self.0 + rhs.0)
	243	}
	244	}
	245
	246	impl AddAssign<Angle> for Angle {
	247	fn add_assign(&mut self, rhs: Angle) {
	248	self.0 += rhs.0;
	249	}
	250	}
	251
	252	impl Sub<Angle> for Angle {
	253	type Output = Self;
	254
	255	fn sub(self, rhs: Angle) -> Self {
	256	Angle(self.0 - rhs.0)
	257	}
	258	}
	259
	260	impl SubAssign<Angle> for Angle {
	261	fn sub_assign(&mut self, rhs: Angle) {
	262	self.0 -= rhs.0;
8065e264	263	}
e58a1769 TW	264	}
e58a1769 TW	265
60058b91 TW	266	////////// INTERSECTION ////////////////////////////////////////////////////////
	267
	268	#[derive(Debug)]
	269	pub enum Intersection {
	270	Point(Point<f64>),
	271	//Line(Point<f64>, Point<f64>), // TODO: overlapping collinear
	272	None,
	273	}
	274
	275	impl Intersection {
	276	pub fn lines(p1: Point<f64>, p2: Point<f64>, p3: Point<f64>, p4: Point<f64>) -> Intersection {
	277	let s1 = p2 - p1;
	278	let s2 = p4 - p3;
	279
	280	let denomimator = -s2.x * s1.y + s1.x * s2.y;
	281	if denomimator != 0.0 {
	282	let s = (-s1.y * (p1.x - p3.x) + s1.x * (p1.y - p3.y)) / denomimator;
	283	let t = ( s2.x * (p1.y - p3.y) - s2.y * (p1.x - p3.x)) / denomimator;
	284
0c56b1f7	285	if (0.0..=1.0).contains(&s) && (0.0..=1.0).contains(&t) {
60058b91 TW	286	return Intersection::Point(p1 + (s1 * t))
	287	}
	288	}
	289
	290	Intersection::None
	291	}
	292	}
	293
	294	////////// DIMENSION ///////////////////////////////////////////////////////////
	295
0b5024d1	296	#[macro_export]
1f42d724 TW	297	macro_rules! dimen {
	298	( $w:expr, $h:expr ) => {
	299	Dimension { width: $w, height: $h }
0b5024d1 TW	300	};
	301	}
	302
8012f86b	303	#[derive(Debug, Default, Copy, Clone, PartialEq)]
1f42d724	304	pub struct Dimension<T> {
6edafdc0 TW	305	pub width: T,
	306	pub height: T,
	307	}
	308
1f42d724	309	impl<T: Mul<Output = T> + Copy> Dimension<T> {
6edafdc0 TW	310	#[allow(dead_code)]
6edafdc0 TW	311	pub fn area(&self) -> T {
6ba7aef1	312	self.width * self.height
6edafdc0 TW	313	}
	314	}
	315
1f42d724	316	impl<T> From<(T, T)> for Dimension<T> {
6edafdc0	317	fn from(item: (T, T)) -> Self {
1f42d724	318	Dimension {
6ba7aef1 TW	319	width: item.0,
	320	height: item.1,
	321	}
6edafdc0 TW	322	}
	323	}
	324
8012f86b TW	325	impl<T> From<Dimension<T>> for (T, T) {
	326	fn from(item: Dimension<T>) -> Self {
	327	(item.width, item.height)
	328	}
	329	}
	330
	331	////////////////////////////////////////////////////////////////////////////////
	332
	333	#[allow(dead_code)]
	334	pub fn supercover_line_int(p1: Point<isize>, p2: Point<isize>) -> Vec<Point<isize>> {
	335	let d = p2 - p1;
	336	let n = point!(d.x.abs(), d.y.abs());
bb3eb700	337	let step = point!(d.x.signum(), d.y.signum());
8012f86b	338
0c56b1f7	339	let mut p = p1;
8012f86b TW	340	let mut points = vec!(point!(p.x as isize, p.y as isize));
	341	let mut i = point!(0, 0);
	342	while i.x < n.x \|\| i.y < n.y {
	343	let decision = (1 + 2 * i.x) * n.y - (1 + 2 * i.y) * n.x;
	344	if decision == 0 { // next step is diagonal
	345	p.x += step.x;
	346	p.y += step.y;
	347	i.x += 1;
	348	i.y += 1;
	349	} else if decision < 0 { // next step is horizontal
	350	p.x += step.x;
	351	i.x += 1;
	352	} else { // next step is vertical
	353	p.y += step.y;
	354	i.y += 1;
	355	}
	356	points.push(point!(p.x as isize, p.y as isize));
	357	}
	358
	359	points
	360	}
	361
	362	/// Calculates all points a line crosses, unlike Bresenham's line algorithm.
	363	/// There might be room for a lot of improvement here.
	364	pub fn supercover_line(mut p1: Point<f64>, mut p2: Point<f64>) -> Vec<Point<isize>> {
	365	let mut delta = p2 - p1;
	366	if (delta.x.abs() > delta.y.abs() && delta.x.is_sign_negative()) \|\| (delta.x.abs() <= delta.y.abs() && delta.y.is_sign_negative()) {
	367	std::mem::swap(&mut p1, &mut p2);
	368	delta = -delta;
	369	}
	370
	371	let mut last = point!(p1.x as isize, p1.y as isize);
	372	let mut coords: Vec<Point<isize>> = vec!();
	373	coords.push(last);
	374
	375	if delta.x.abs() > delta.y.abs() {
	376	let k = delta.y / delta.x;
	377	let m = p1.y as f64 - p1.x as f64 * k;
	378	for x in (p1.x as isize + 1)..=(p2.x as isize) {
	379	let y = (k * x as f64 + m).floor();
	380	let next = point!(x as isize - 1, y as isize);
	381	if next != last {
	382	coords.push(next);
	383	}
	384	let next = point!(x as isize, y as isize);
	385	coords.push(next);
	386	last = next;
	387	}
	388	} else {
	389	let k = delta.x / delta.y;
	390	let m = p1.x as f64 - p1.y as f64 * k;
	391	for y in (p1.y as isize + 1)..=(p2.y as isize) {
	392	let x = (k * y as f64 + m).floor();
	393	let next = point!(x as isize, y as isize - 1);
	394	if next != last {
	395	coords.push(next);
	396	}
	397	let next = point!(x as isize, y as isize);
	398	coords.push(next);
	399	last = next;
	400	}
	401	}
	402
	403	let next = point!(p2.x as isize, p2.y as isize);
404	if next != last {
405	coords.push(next);
406	}
407
408	coords
409	}
410
60058b91	411	////////// TESTS ///////////////////////////////////////////////////////////////
249d43ea	412
296187ca TW	413	#[cfg(test)]
	414	mod tests {
	415	use super::*;
	416
	417	#[test]
	418	fn immutable_copy_of_point() {
	419	let a = point!(0, 0);
	420	let mut b = a; // Copy
	421	assert_eq!(a, b); // PartialEq
	422	b.x = 1;
	423	assert_ne!(a, b); // PartialEq
	424	}
	425
	426	#[test]
	427	fn add_points() {
	428	let mut a = point!(1, 0);
	429	assert_eq!(a + point!(2, 2), point!(3, 2)); // Add
	430	a += point!(2, 2); // AddAssign
	431	assert_eq!(a, point!(3, 2));
2836f506 TW	432	assert_eq!(point!(1, 0) + (2, 3), point!(3, 3));
	433	}
	434
	435	#[test]
	436	fn sub_points() {
	437	let mut a = point!(1, 0);
	438	assert_eq!(a - point!(2, 2), point!(-1, -2));
	439	a -= point!(2, 2);
	440	assert_eq!(a, point!(-1, -2));
6cd86b94	441	assert_eq!(point!(1, 0) - (2, 3), point!(-1, -3));
2836f506 TW	442	}
	443
	444	#[test]
	445	fn mul_points() {
	446	let mut a = point!(1, 2);
	447	assert_eq!(a * 2, point!(2, 4));
	448	assert_eq!(a * point!(2, 3), point!(2, 6));
	449	a *= 2;
	450	assert_eq!(a, point!(2, 4));
	451	a *= point!(3, 1);
	452	assert_eq!(a, point!(6, 4));
6cd86b94	453	assert_eq!(point!(1, 0) * (2, 3), point!(2, 0));
2836f506 TW	454	}
	455
	456	#[test]
	457	fn div_points() {
	458	let mut a = point!(4, 8);
	459	assert_eq!(a / 2, point!(2, 4));
	460	assert_eq!(a / point!(2, 4), point!(2, 2));
	461	a /= 2;
	462	assert_eq!(a, point!(2, 4));
	463	a /= point!(2, 4);
	464	assert_eq!(a, point!(1, 1));
6cd86b94	465	assert_eq!(point!(6, 3) / (2, 3), point!(3, 1));
2836f506 TW	466	}
	467
	468	#[test]
	469	fn neg_point() {
	470	assert_eq!(point!(1, 1), -point!(-1, -1));
296187ca	471	}
6edafdc0 TW	472
6edafdc0 TW	473	#[test]
e58a1769	474	fn angles() {
40742678	475	assert_eq!(0.radians(), 0.degrees());
a9eacb2b	476	assert_eq!(0.degrees(), 360.degrees());
40742678 TW	477	assert_eq!(180.degrees(), std::f64::consts::PI.radians());
	478	assert_eq!(std::f64::consts::PI.radians().to_degrees(), 180.0);
	479	assert!((Point::from(90.degrees()) - point!(0.0, 1.0)).length() < 0.001);
	480	assert!((Point::from(std::f64::consts::FRAC_PI_2.radians()) - point!(0.0, 1.0)).length() < 0.001);
e58a1769 TW	481	}
	482
	483	#[test]
1f42d724 TW	484	fn area_for_dimension_of_multipliable_type() {
1f42d724 TW	485	let r: Dimension<_> = (30, 20).into(); // the Into trait uses the From trait
6ba7aef1	486	assert_eq!(r.area(), 30 * 20);
1f42d724	487	// let a = Dimension::from(("a".to_string(), "b".to_string())).area(); // this doesn't work, because area() is not implemented for String
6edafdc0	488	}
60058b91 TW	489
	490	#[test]
	491	fn intersection_of_lines() {
	492	let p1 = point!(0.0, 0.0);
	493	let p2 = point!(2.0, 2.0);
	494	let p3 = point!(0.0, 2.0);
	495	let p4 = point!(2.0, 0.0);
	496	let r = Intersection::lines(p1, p2, p3, p4);
	497	if let Intersection::Point(p) = r {
	498	assert_eq!(p, point!(1.0, 1.0));
	499	} else {
	500	panic!();
	501	}
	502	}
8012f86b TW	503
	504	#[test]
	505	fn some_coordinates_on_line() {
	506	// horizontally up
	507	let coords = supercover_line(point!(0.0, 0.0), point!(3.3, 2.2));
	508	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(1, 0), point!(1, 1), point!(2, 1), point!(2, 2), point!(3, 2)]);
	509
	510	// horizontally down
	511	let coords = supercover_line(point!(0.0, 5.0), point!(3.3, 2.2));
	512	assert_eq!(coords.as_slice(), &[point!(0, 5), point!(0, 4), point!(1, 4), point!(1, 3), point!(2, 3), point!(2, 2), point!(3, 2)]);
	513
	514	// vertically right
	515	let coords = supercover_line(point!(0.0, 0.0), point!(2.2, 3.3));
	516	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(0, 1), point!(1, 1), point!(1, 2), point!(2, 2), point!(2, 3)]);
	517
	518	// vertically left
	519	let coords = supercover_line(point!(5.0, 0.0), point!(3.0, 3.0));
	520	assert_eq!(coords.as_slice(), &[point!(5, 0), point!(4, 0), point!(4, 1), point!(3, 1), point!(3, 2), point!(3, 3)]);
	521
	522	// negative
	523	let coords = supercover_line(point!(0.0, 0.0), point!(-3.0, -2.0));
	524	assert_eq!(coords.as_slice(), &[point!(-3, -2), point!(-2, -2), point!(-2, -1), point!(-1, -1), point!(-1, 0), point!(0, 0)]);
	525
	526	//
	527	let coords = supercover_line(point!(0.0, 0.0), point!(2.3, 1.1));
	528	assert_eq!(coords.as_slice(), &[point!(0, 0), point!(1, 0), point!(2, 0), point!(2, 1)]);
	529	}
296187ca	530	}