-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Take the geometry calculations and put them in a seperate module and replace CollisionBox with a more generic Polygon data structure.
- Loading branch information
1 parent
884dfdb
commit bab3dcb
Showing
6 changed files
with
210 additions
and
206 deletions.
There are no files selected for viewing
Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.
Oops, something went wrong.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,136 @@ | ||
| // SPDX-License-Identifier: GPL-3.0-or-later | ||
| // Copyright (C) 2023-2024 Daniel Thompson | ||
|
|
||
| use bevy::{math::vec2, prelude::*}; | ||
| use smallvec::SmallVec; | ||
|
|
||
| fn same_side(p1: Vec2, p2: Vec2, line: (Vec2, Vec2)) -> bool { | ||
| let p1 = Vec3::from((p1, 0.0)); | ||
| let p2 = Vec3::from((p2, 0.0)); | ||
| let line = (Vec3::from((line.0, 0.0)), Vec3::from((line.1, 0.0))); | ||
|
|
||
| let cp1 = (line.1 - line.0).cross(p1 - line.0); | ||
| let cp2 = (line.1 - line.0).cross(p2 - line.0); | ||
|
|
||
| cp1.dot(cp2) >= 0.0 | ||
| } | ||
|
|
||
| /// Calculate the length of a line between two points. | ||
| /// | ||
| /// This is is a simple application of the Pythagorean theorem. | ||
| fn length_of_line(line: (Vec2, Vec2)) -> f32 { | ||
| ((line.1.x - line.0.x).powi(2) + (line.1.y - line.0.y).powi(2)).sqrt() | ||
| } | ||
|
|
||
| /// Calculate the area of a triangle defined by three points. | ||
| fn area_of_triangle(triangle: (Vec2, Vec2, Vec2)) -> f32 { | ||
| (((triangle.0.x - triangle.2.x) * (triangle.1.y - triangle.0.y)) | ||
| - ((triangle.0.x - triangle.1.x) * (triangle.2.y - triangle.0.y))) | ||
| .abs() | ||
| / 2.0 | ||
| } | ||
|
|
||
| /// Calculate the shortest distance from the point to a line. | ||
| fn distance_to_line(pt: Vec2, line: (Vec2, Vec2)) -> f32 { | ||
| 2.0 * area_of_triangle((pt, line.0, line.1)) / length_of_line(line) | ||
| } | ||
|
|
||
| pub fn reflect_against_line(v: Vec2, line: (Vec2, Vec2)) -> Vec2 { | ||
| let normal = (line.1 - line.0).perp().normalize(); | ||
|
|
||
| v - ((2.0 * v.dot(normal)) * normal) | ||
| } | ||
|
|
||
| #[derive(Clone, Debug)] | ||
| pub struct Polygon { | ||
| pub shape: SmallVec<[Vec2; 8]>, | ||
| } | ||
|
|
||
| impl FromIterator<Vec2> for Polygon { | ||
| fn from_iter<I: IntoIterator<Item = Vec2>>(iter: I) -> Self { | ||
| Self { | ||
| shape: SmallVec::from_iter(iter), | ||
| } | ||
| } | ||
| } | ||
|
|
||
| impl Polygon { | ||
| pub fn from_diagonal(sz: &Vec2) -> Self { | ||
| let w = sz.x * 0.5; | ||
| let h = sz.y * 0.5; | ||
|
|
||
| // c is used to round the corners of the box, choosing | ||
| // 2.5 is a little arbitrary but it gives a good "feel" | ||
| // for most artwork... and you could handle special cases | ||
| // by creating the box by hand. | ||
| let c = w.min(h) / 2.5; | ||
|
|
||
| [ | ||
| vec2(c - w, h), | ||
| vec2(w - c, h), | ||
| vec2(w, h - c), | ||
| vec2(w, c - h), | ||
| vec2(w - c, -h), | ||
| vec2(c - w, -h), | ||
| vec2(-w, c - h), | ||
| vec2(-w, h - c), | ||
| ] | ||
| .into_iter() | ||
| .collect() | ||
| } | ||
|
|
||
| pub fn contains_point(&self, pt: Vec2) -> bool { | ||
| let shape = self.shape.as_slice(); | ||
| let n = shape.len(); | ||
| shape | ||
| .windows(3) | ||
| .chain(std::iter::once( | ||
| [shape[n - 2], shape[n - 1], shape[0]].as_slice(), | ||
| )) | ||
| .chain(std::iter::once( | ||
| [shape[n - 1], shape[0], shape[1]].as_slice(), | ||
| )) | ||
| .all(|x| same_side(pt, x[0], (x[1], x[2]))) | ||
| } | ||
|
|
||
| pub fn closest_edge_to_point(&self, pt: Vec2) -> (Vec2, Vec2) { | ||
| let shape = self.shape.as_slice(); | ||
| let n = shape.len(); | ||
| shape | ||
| .windows(2) | ||
| .chain(std::iter::once([shape[n - 1], shape[0]].as_slice())) | ||
| .map(|line| (line[0], line[1])) | ||
| .min_by(|a, b| { | ||
| distance_to_line(pt, *a) | ||
| .partial_cmp(&distance_to_line(pt, *b)) | ||
| .expect("Floating point numbers must be comparable") | ||
| }) | ||
| .expect("Shape must not be empty") | ||
| } | ||
|
|
||
| pub fn draw(&self, gizmos: &mut Gizmos) { | ||
| let shape = self.shape.as_slice(); | ||
| let n = shape.len(); | ||
| for w in shape.windows(2) { | ||
| gizmos.line_2d(w[0], w[1], Color::BLUE); | ||
| } | ||
| gizmos.line_2d(shape[n - 1], shape[0], Color::BLUE); | ||
| } | ||
|
|
||
| /// Test whether two rectangles are touching. | ||
| pub fn is_touching(&self, other: &Polygon) -> bool { | ||
| other.shape.iter().any(|pt| self.contains_point(*pt)) | ||
| || self.shape.iter().any(|pt| other.contains_point(*pt)) | ||
| } | ||
|
|
||
| pub fn transform(&self, tf: &Transform) -> Self { | ||
| self.shape | ||
| .iter() | ||
| .map(|v2| { | ||
| let v3 = Vec3::from((*v2, 0.0)); | ||
| let pt = tf.transform_point(v3); | ||
| vec2(pt.x, pt.y) | ||
| }) | ||
| .collect() | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.