@stringsync/vexml/dist/esm/spatial/collision.js

MusicXML to Vexflow

import { Circle } from './circle';
import { Rect } from './rect';
/** Represents a collision between two shapes. */
export class Collision {
    /** Creates a CollisionSubject for fluent APIs. */
    static is(shape) {
        return new CollisionSubject(shape);
    }
}
/**
 * A collision calculator that enables fluent APIs.
 *
 * This is done to reduce ambiguity of the semantics behind the collision checks.
 *
 * @example Collision.is(rect).collidingWith(circle); // boolean
 * @example Collision.is(circle).surroundedBy(rect); // boolean
 */
class CollisionSubject {
    shape;
    constructor(shape) {
        this.shape = shape;
    }
    collidingWith(shape) {
        const shape1 = this.shape;
        const shape2 = shape;
        if (shape1 instanceof Rect && shape2 instanceof Rect) {
            return this.isRectCollidingWithRect(shape1, shape2);
        }
        if (shape1 instanceof Rect && shape2 instanceof Circle) {
            return this.isRectCollidingWithCircle(shape1, shape2);
        }
        if (shape1 instanceof Circle && shape2 instanceof Rect) {
            return this.isRectCollidingWithCircle(shape2, shape1);
        }
        if (shape1 instanceof Circle && shape2 instanceof Circle) {
            return this.isCircleCollidingWithCircle(shape1, shape2);
        }
        throw new Error(`unsupported collision between ${shape1.constructor.name} and ${shape2.constructor.name}`);
    }
    surrounding(shape) {
        const shape1 = this.shape;
        const shape2 = shape;
        if (shape1 instanceof Rect && shape2 instanceof Rect) {
            return this.isRectSurroundingRect(shape1, shape2);
        }
        if (shape1 instanceof Rect && shape2 instanceof Circle) {
            return this.isRectSurroundingCircle(shape1, shape2);
        }
        if (shape1 instanceof Circle && shape2 instanceof Rect) {
            return this.isCircleSurroundingRect(shape1, shape2);
        }
        if (shape1 instanceof Circle && shape2 instanceof Circle) {
            return this.isCircleSurroundingCircle(shape1, shape2);
        }
        throw new Error(`unsupported collision between ${shape1.constructor.name} and ${shape2.constructor.name}`);
    }
    isRectCollidingWithRect(rect1, rect2) {
        return !(rect2.x > rect1.x + rect1.w ||
            rect2.x + rect2.w < rect1.x ||
            rect2.y > rect1.y + rect1.h ||
            rect2.y + rect2.h < rect1.y);
    }
    isCircleCollidingWithCircle(circle1, circle2) {
        return circle1.center().distance(circle2.center()) <= circle1.r + circle2.r;
    }
    isRectCollidingWithCircle(rect, circle) {
        if (rect.contains(circle.center())) {
            return true;
        }
        if (circle.contains(rect.center())) {
            return true;
        }
        const x = Math.max(rect.x, Math.min(circle.x, rect.x + rect.w));
        const y = Math.max(rect.y, Math.min(circle.y, rect.y + rect.h));
        const dx = circle.x - x;
        const dy = circle.y - y;
        return dx * dx + dy * dy <= circle.r * circle.r;
    }
    isRectSurroundingRect(rect1, rect2) {
        return (rect1.x > rect2.x &&
            rect1.y > rect2.y &&
            rect1.x + rect1.w < rect2.x + rect2.w &&
            rect1.y + rect1.h < rect2.y + rect2.h);
    }
    isCircleSurroundingCircle(circle1, circle2) {
        const distance = circle1.center().distance(circle2.center());
        return distance + circle1.r < circle2.r;
    }
    isRectSurroundingCircle(rect, circle) {
        const circleCenter = circle.center();
        const rectCenter = rect.center();
        const distanceX = Math.abs(circleCenter.x - rectCenter.x);
        const distanceY = Math.abs(circleCenter.y - rectCenter.y);
        const halfRectWidth = rect.w / 2;
        const halfRectHeight = rect.h / 2;
        if (distanceX > halfRectWidth || distanceY > halfRectHeight) {
            return false;
        }
        if (distanceX <= halfRectWidth - circle.r && distanceY <= halfRectHeight - circle.r) {
            return true;
        }
        const cornerDistanceSq = (distanceX - halfRectWidth) ** 2 + (distanceY - halfRectHeight) ** 2;
        return cornerDistanceSq <= circle.r ** 2;
    }
    isCircleSurroundingRect(circle, rect) {
        const circleCenter = circle.center();
        const rectCenter = rect.center();
        const distanceX = Math.abs(circleCenter.x - rectCenter.x);
        const distanceY = Math.abs(circleCenter.y - rectCenter.y);
        const halfRectWidth = rect.w / 2;
        const halfRectHeight = rect.h / 2;
        if (distanceX > halfRectWidth + circle.r || distanceY > halfRectHeight + circle.r) {
            return false;
        }
        if (distanceX <= halfRectWidth || distanceY <= halfRectHeight) {
            return true;
        }
        const cornerDistanceSq = (distanceX - halfRectWidth) ** 2 + (distanceY - halfRectHeight) ** 2;
        return cornerDistanceSq <= circle.r ** 2;
    }
}