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Add ellipse changes no angle

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Signed-off-by: Mark Tolmacs <mark@lazycat.hu>
This commit is contained in:
Mark Tolmacs 2024-09-27 11:34:02 +02:00
parent d9ea7190ec
commit 7b4e989d65
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12 changed files with 97 additions and 357 deletions
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85
packages/math/ellipse.ts
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@ -1,12 +1,5 @@
import { radians } from "./angle";
import { line } from "./line";
import {
point,
pointDistance,
pointFromVector,
pointRotateRads,
} from "./point";
import type { Ellipse, GenericPoint, Segment, Radians } from "./types";
import { point, pointDistance, pointFromVector } from "./point";
import type { Ellipse, GenericPoint, Segment } from "./types";
import { PRECISION } from "./utils";
import {
vector,
@ -27,13 +20,11 @@ import {
*/
export function ellipse<Point extends GenericPoint>(
center: Point,
angle: Radians,
halfWidth: number,
halfHeight: number,
): Ellipse<Point> {
return {
center,
angle,
halfWidth,
halfHeight,
} as Ellipse<Point>;
@ -50,22 +41,11 @@ export const ellipseIncludesPoint = <Point extends GenericPoint>(
p: Point,
ellipse: Ellipse<Point>,
) => {
const { center, angle, halfWidth, halfHeight } = ellipse;
const translatedPoint = vectorAdd(
vectorFromPoint(p),
vectorScale(vectorFromPoint(center), -1),
);
const [rotatedPointX, rotatedPointY] = pointRotateRads(
pointFromVector(translatedPoint),
point(0, 0),
radians(-angle),
);
const { center, halfWidth, halfHeight } = ellipse;
const normalizedX = (p[0] - center[0]) / halfWidth;
const normalizedY = (p[1] - center[1]) / halfHeight;
return (
(rotatedPointX / halfWidth) * (rotatedPointX / halfWidth) +
(rotatedPointY / halfHeight) * (rotatedPointY / halfHeight) <=
1
);
return normalizedX * normalizedX + normalizedY * normalizedY <= 1;
};
/**
@ -97,21 +77,16 @@ export const ellipseDistanceFromPoint = <Point extends GenericPoint>(
p: Point,
ellipse: Ellipse<Point>,
): number => {
const { angle, halfWidth, halfHeight, center } = ellipse;
const { halfWidth, halfHeight, center } = ellipse;
const a = halfWidth;
const b = halfHeight;
const translatedPoint = vectorAdd(
vectorFromPoint(p),
vectorScale(vectorFromPoint(center), -1),
);
const [rotatedPointX, rotatedPointY] = pointRotateRads(
pointFromVector(translatedPoint),
point(0, 0),
radians(-angle),
);
const px = Math.abs(rotatedPointX);
const py = Math.abs(rotatedPointY);
const px = Math.abs(translatedPoint[0]);
const py = Math.abs(translatedPoint[1]);
let tx = 0.707;
let ty = 0.707;
@ -140,11 +115,11 @@ export const ellipseDistanceFromPoint = <Point extends GenericPoint>(
}
const [minX, minY] = [
a * tx * Math.sign(rotatedPointX),
b * ty * Math.sign(rotatedPointY),
a * tx * Math.sign(translatedPoint[0]),
b * ty * Math.sign(translatedPoint[1]),
];
return pointDistance(point(rotatedPointX, rotatedPointY), point(minX, minY));
return pointDistance(pointFromVector(translatedPoint), point(minX, minY));
};
/**
@ -153,19 +128,13 @@ export const ellipseDistanceFromPoint = <Point extends GenericPoint>(
*/
export function ellipseSegmentInterceptPoints<Point extends GenericPoint>(
e: Readonly<Ellipse<Point>>,
l: Readonly<Segment<Point>>,
s: Readonly<Segment<Point>>,
): Point[] {
const rx = e.halfWidth;
const ry = e.halfHeight;
const nonRotatedLine = line(
pointRotateRads(l[0], e.center, radians(-e.angle)),
pointRotateRads(l[1], e.center, radians(-e.angle)),
);
const dir = vectorFromPoint(nonRotatedLine[1], nonRotatedLine[0]);
const diff = vector(
nonRotatedLine[0][0] - e.center[0],
nonRotatedLine[0][1] - e.center[1],
);
const dir = vectorFromPoint(s[1], s[0]);
const diff = vector(s[0][0] - e.center[0], s[0][1] - e.center[1]);
const mDir = vector(dir[0] / (rx * rx), dir[1] / (ry * ry));
const mDiff = vector(diff[0] / (rx * rx), diff[1] / (ry * ry));
@ -183,10 +152,8 @@ export function ellipseSegmentInterceptPoints<Point extends GenericPoint>(
if (0 <= t_a && t_a <= 1) {
intersections.push(
point(
nonRotatedLine[0][0] +
(nonRotatedLine[1][0] - nonRotatedLine[0][0]) * t_a,
nonRotatedLine[0][1] +
(nonRotatedLine[1][1] - nonRotatedLine[0][1]) * t_a,
s[0][0] + (s[1][0] - s[0][0]) * t_a,
s[0][1] + (s[1][1] - s[0][1]) * t_a,
),
);
}
@ -194,10 +161,8 @@ export function ellipseSegmentInterceptPoints<Point extends GenericPoint>(
if (0 <= t_b && t_b <= 1) {
intersections.push(
point(
nonRotatedLine[0][0] +
(nonRotatedLine[1][0] - nonRotatedLine[0][0]) * t_b,
nonRotatedLine[0][1] +
(nonRotatedLine[1][1] - nonRotatedLine[0][1]) * t_b,
s[0][0] + (s[1][0] - s[0][0]) * t_b,
s[0][1] + (s[1][1] - s[0][1]) * t_b,
),
);
}
@ -206,16 +171,12 @@ export function ellipseSegmentInterceptPoints<Point extends GenericPoint>(
if (0 <= t && t <= 1) {
intersections.push(
point(
nonRotatedLine[0][0] +
(nonRotatedLine[1][0] - nonRotatedLine[0][0]) * t,
nonRotatedLine[0][1] +
(nonRotatedLine[1][1] - nonRotatedLine[0][1]) * t,
s[0][0] + (s[1][0] - s[0][0]) * t,
s[0][1] + (s[1][1] - s[0][1]) * t,
),
);
}
}
return intersections.map((point) =>
pointRotateRads(point, e.center, e.angle),
);
return intersections;
}