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chore,docs(math): rename 'cross_product' to 'perp_dot_product', add some documentation

This commit is contained in:
Alain Emilia Anna Zscheile 2025-01-05 01:01:20 +01:00 committed by mikolaj
parent b4fe7006b7
commit 344d892ae0
2 changed files with 12 additions and 10 deletions
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16
src/math/mod.rs
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@ -87,12 +87,12 @@ pub fn intersect_circle_segment(circle: &Circle, segment: &Line) -> Vec<Point> {
} }
pub fn between_vectors(p: Point, from: Point, to: Point) -> bool { pub fn between_vectors(p: Point, from: Point, to: Point) -> bool {
let cross = cross_product(from, to); let cross = perp_dot_product(from, to);
if cross > 0.0 { if cross > 0.0 {
cross_product(from, p) >= 0.0 && cross_product(p, to) >= 0.0 perp_dot_product(from, p) >= 0.0 && perp_dot_product(p, to) >= 0.0
} else if cross < 0.0 { } else if cross < 0.0 {
cross_product(from, p) >= 0.0 || cross_product(p, to) >= 0.0 perp_dot_product(from, p) >= 0.0 || perp_dot_product(p, to) >= 0.0
} else { } else {
false false
} }
@ -229,22 +229,24 @@ impl ops::MulAssign<f64> for NormalizedAngle {
pub fn angle_between(v1: Point, v2: Point) -> NormalizedAngle { pub fn angle_between(v1: Point, v2: Point) -> NormalizedAngle {
NormalizedAngle::atan2(geo::point! { NormalizedAngle::atan2(geo::point! {
x: dot_product(v1, v2), x: dot_product(v1, v2),
y: cross_product(v1, v2) y: perp_dot_product(v1, v2)
}) })
} }
pub fn seq_cross_product(start: Point, stop: Point, reference: Point) -> f64 { pub fn seq_perp_dot_product(start: Point, stop: Point, reference: Point) -> f64 {
let dx1 = stop.x() - start.x(); let dx1 = stop.x() - start.x();
let dy1 = stop.y() - start.y(); let dy1 = stop.y() - start.y();
let dx2 = reference.x() - stop.x(); let dx2 = reference.x() - stop.x();
let dy2 = reference.y() - stop.y(); let dy2 = reference.y() - stop.y();
cross_product((dx1, dy1).into(), (dx2, dy2).into()) perp_dot_product((dx1, dy1).into(), (dx2, dy2).into())
} }
pub fn dot_product(v1: Point, v2: Point) -> f64 { pub fn dot_product(v1: Point, v2: Point) -> f64 {
v1.x() * v2.x() + v1.y() * v2.y() v1.x() * v2.x() + v1.y() * v2.y()
} }
pub fn cross_product(v1: Point, v2: Point) -> f64 { /// This is often called [perp dot product](https://mathworld.wolfram.com/PerpDotProduct.html),
/// or "2D cross product".
pub fn perp_dot_product(v1: Point, v2: Point) -> f64 {
v1.x() * v2.y() - v1.y() * v2.x() v1.x() * v2.y() - v1.y() * v2.x()
} }

6
src/math/tangents.rs
View File

@ -7,7 +7,7 @@ use geo::{geometry::Point, point, Line};
use specctra_core::math::Circle; use specctra_core::math::Circle;
use thiserror::Error; use thiserror::Error;
use super::seq_cross_product; use super::seq_perp_dot_product;
#[derive(Error, Debug, Clone, Copy, PartialEq)] #[derive(Error, Debug, Clone, Copy, PartialEq)]
#[error("no tangents for {0:?} and {1:?}")] // TODO add real error message #[error("no tangents for {0:?} and {1:?}")] // TODO add real error message
@ -101,7 +101,7 @@ pub fn tangent_segments(
.filter_map(move |tangent_point_pair| { .filter_map(move |tangent_point_pair| {
if let Some(cw1) = cw1 { if let Some(cw1) = cw1 {
let cross1 = let cross1 =
seq_cross_product(tangent_point_pair.0, tangent_point_pair.1, circle1.pos); seq_perp_dot_product(tangent_point_pair.0, tangent_point_pair.1, circle1.pos);
if (cw1 && cross1 <= 0.0) || (!cw1 && cross1 >= 0.0) { if (cw1 && cross1 <= 0.0) || (!cw1 && cross1 >= 0.0) {
return None; return None;
@ -110,7 +110,7 @@ pub fn tangent_segments(
if let Some(cw2) = cw2 { if let Some(cw2) = cw2 {
let cross2 = let cross2 =
seq_cross_product(tangent_point_pair.0, tangent_point_pair.1, circle2.pos); seq_perp_dot_product(tangent_point_pair.0, tangent_point_pair.1, circle2.pos);
if (cw2 && cross2 >= 0.0) || (!cw2 && cross2 <= 0.0) { if (cw2 && cross2 >= 0.0) || (!cw2 && cross2 <= 0.0) {
return None; return None;