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use glam::{BVec2, IVec2, Vec2};
use crate::GridPoint;
use super::GridShape;
pub struct GridLine {
start: IVec2,
end: IVec2,
}
impl GridLine {
pub fn new(start: impl GridPoint, end: impl GridPoint) -> Self {
GridLine {
start: start.as_ivec2(),
end: end.as_ivec2(),
}
}
}
impl GridShape for GridLine {
type Iterator = LineIter;
fn iter(&self) -> Self::Iterator {
LineIter::new(self)
}
}
pub struct LineIter {
dist: i32,
step: i32,
start: IVec2,
end: IVec2,
}
impl LineIter {
fn new(line: &GridLine) -> Self {
LineIter {
start: line.start,
end: line.end,
step: 0,
dist: diag_distance(line.start, line.end),
}
}
}
impl Iterator for LineIter {
type Item = IVec2;
fn next(&mut self) -> Option<Self::Item> {
if self.step > self.dist {
return None;
}
let t = self.step as f32 / self.dist as f32;
self.step += 1;
Some(lerp_pos(self.start, self.end, t))
}
}
#[inline]
fn lerp(start: f32, end: f32, t: f32) -> f32 {
start + (t * (end - start))
}
#[inline]
fn lerp_pos(p1: IVec2, p2: IVec2, t: f32) -> IVec2 {
let p1 = p1.as_vec2();
let p2 = p2.as_vec2();
let x = lerp(p1.x, p2.x, t);
let y = lerp(p1.y, p2.y, t);
Vec2::new(x, y).round().as_ivec2()
}
#[inline]
fn diag_distance(p1: IVec2, p2: IVec2) -> i32 {
let d = p2 - p1;
i32::max(d.x.abs(), d.y.abs())
}
pub struct GridLineOrthogonal {
start: IVec2,
end: IVec2,
}
impl GridLineOrthogonal {
pub fn new(start: impl GridPoint, end: impl GridPoint) -> Self {
Self {
start: start.as_ivec2(),
end: end.as_ivec2(),
}
}
}
impl GridShape for GridLineOrthogonal {
type Iterator = LineOrthogonalIter;
fn iter(&self) -> Self::Iterator {
LineOrthogonalIter::new(self)
}
}
pub struct LineOrthogonalIter {
nxy: Vec2,
i: Vec2,
sign: Vec2,
curr: Vec2,
start: IVec2,
yielded_start: bool,
}
impl LineOrthogonalIter {
pub fn new(line: &GridLineOrthogonal) -> LineOrthogonalIter {
let start = line.start.as_vec2();
let dxy = line.end.as_vec2() - start;
let nxy = dxy.abs();
let sign = dxy.signum();
LineOrthogonalIter {
i: Vec2::ZERO,
nxy,
sign,
curr: start,
start: line.start,
yielded_start: false,
}
}
}
impl Iterator for LineOrthogonalIter {
type Item = IVec2;
fn next(&mut self) -> Option<Self::Item> {
if self.i.cmpge(self.nxy).any() {
return None;
}
if !self.yielded_start {
self.yielded_start = true;
return Some(self.start);
}
let cmp = (self.i + 0.5) / self.nxy;
let cmp = if cmp.x < cmp.y {
BVec2::new(true, false)
} else {
BVec2::new(false, true)
};
let cd = Vec2::select(cmp, self.sign, Vec2::ZERO);
let id = Vec2::select(cmp, Vec2::ONE, Vec2::ZERO);
self.curr += cd;
self.i += id;
Some(self.curr.as_ivec2())
}
}
#[cfg(test)]
mod tests {
use crate::util::Canvas;
use super::*;
#[test]
fn iter_orthogonal() {
let line = GridLine::new([9, 4], [0, 0]);
let mut canvas = Canvas::new([10, 5]);
for p in line.iter() {
canvas.put(p, '*');
}
canvas.print();
}
}
