1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
pub mod array;
pub mod ops;
pub mod query;
pub mod space;

// Foreign implementation modules. These are empty unless the corresponding
// geometry features are enabled.
mod cgmath;
mod mint;
mod nalgebra;

use arrayvec::ArrayVec;
use decorum::R64;
use num::{self, Num, NumCast, One, Zero};
use std::cmp::Ordering;

use crate::space::EuclideanSpace;

pub mod prelude {
    pub use crate::query::Intersection as _;
    pub use crate::Lattice as _;
}

pub type Position<T> = <T as AsPosition>::Position;

pub trait AsPosition {
    type Position: EuclideanSpace;

    fn as_position(&self) -> &Self::Position;

    fn as_position_mut(&mut self) -> &mut Self::Position;

    fn transform<F>(&mut self, mut f: F)
    where
        F: FnMut(&Self::Position) -> Self::Position,
    {
        *self.as_position_mut() = f(self.as_position());
    }

    fn map<F>(mut self, f: F) -> Self
    where
        Self: Sized,
        F: FnMut(&Self::Position) -> Self::Position,
    {
        self.transform(f);
        self
    }
}

impl<S> AsPosition for S
where
    S: EuclideanSpace,
{
    type Position = Self;

    fn as_position(&self) -> &Self::Position {
        self
    }

    fn as_position_mut(&mut self) -> &mut Self::Position {
        self
    }
}

pub trait Composite {
    type Item;
}

impl<T> Composite for (T, T) {
    type Item = T;
}

impl<T> Composite for (T, T, T) {
    type Item = T;
}

pub trait IntoItems: Composite {
    type Output: IntoIterator<Item = Self::Item>;

    fn into_items(self) -> Self::Output;
}

impl<T> IntoItems for (T, T) {
    type Output = ArrayVec<[T; 2]>;

    fn into_items(self) -> Self::Output {
        ArrayVec::from([self.0, self.1])
    }
}

impl<T> IntoItems for (T, T, T) {
    type Output = ArrayVec<[T; 3]>;

    fn into_items(self) -> Self::Output {
        ArrayVec::from([self.0, self.1, self.2])
    }
}

pub trait FromItems: Composite + Sized {
    fn from_items<I>(items: I) -> Option<Self>
    where
        I: IntoIterator<Item = Self::Item>;
}

impl<T> FromItems for (T, T) {
    fn from_items<I>(items: I) -> Option<Self>
    where
        I: IntoIterator<Item = Self::Item>,
    {
        let mut items = items.into_iter().take(2);
        match (items.next(), items.next()) {
            (Some(a), Some(b)) => Some((a, b)),
            _ => None,
        }
    }
}

impl<T> FromItems for (T, T, T) {
    fn from_items<I>(items: I) -> Option<Self>
    where
        I: IntoIterator<Item = Self::Item>,
    {
        let mut items = items.into_iter().take(3);
        match (items.next(), items.next(), items.next()) {
            (Some(a), Some(b), Some(c)) => Some((a, b, c)),
            _ => None,
        }
    }
}

pub trait Converged: Composite {
    fn converged(value: Self::Item) -> Self;
}

impl<T> Converged for (T, T)
where
    T: Clone,
{
    fn converged(value: Self::Item) -> Self {
        (value.clone(), value)
    }
}

impl<T> Converged for (T, T, T)
where
    T: Clone,
{
    fn converged(value: Self::Item) -> Self {
        (value.clone(), value.clone(), value)
    }
}

pub trait Lattice: PartialOrd + Sized {
    fn meet(&self, other: &Self) -> Self;

    fn join(&self, other: &Self) -> Self;

    fn meet_join(&self, other: &Self) -> (Self, Self) {
        (self.meet(other), self.join(other))
    }

    fn partial_min<'a>(&'a self, other: &'a Self) -> Option<&'a Self> {
        match self.partial_cmp(other) {
            Some(Ordering::Greater) => Some(other),
            Some(_) => Some(self),
            None => None,
        }
    }

    fn partial_max<'a>(&'a self, other: &'a Self) -> Option<&'a Self> {
        match self.partial_cmp(other) {
            Some(Ordering::Less) => Some(other),
            Some(_) => Some(self),
            None => None,
        }
    }

    fn partial_ordered_pair<'a>(&'a self, other: &'a Self) -> Option<(&'a Self, &'a Self)> {
        match self.partial_cmp(other) {
            Some(Ordering::Less) => Some((self, other)),
            Some(_) => Some((other, self)),
            None => None,
        }
    }

    fn partial_clamp<'a>(&'a self, min: &'a Self, max: &'a Self) -> Option<&'a Self> {
        let _ = (min, max);
        unimplemented!() // TODO:
    }
}

impl<T> Lattice for T
where
    T: Copy + PartialOrd + Sized,
{
    fn meet(&self, other: &Self) -> Self {
        if *self <= *other {
            *self
        }
        else {
            *other
        }
    }

    fn join(&self, other: &Self) -> Self {
        if *self >= *other {
            *self
        }
        else {
            *other
        }
    }
}

pub fn lerp<T>(a: T, b: T, f: R64) -> T
where
    T: Num + NumCast,
{
    let f = num::clamp(f, Zero::zero(), One::one());
    let af = <R64 as NumCast>::from(a).unwrap() * (R64::one() - f);
    let bf = <R64 as NumCast>::from(b).unwrap() * f;
    <T as NumCast>::from(af + bf).unwrap()
}

fn partial_min<T>(a: T, b: T) -> T
where
    T: Copy + Lattice,
{
    *a.partial_min(&b).unwrap()
}

fn partial_max<T>(a: T, b: T) -> T
where
    T: Copy + Lattice,
{
    *a.partial_max(&b).unwrap()
}