constraint-solver-js/build/rot-constraint.js

2D rigid body constraint solver written in typescript.

import { relativeToGlobalPos } from "./cord-sys-utils.js";
import { substractVectors } from "./vector-utils.js";
export class RotConstraint {
    /**
     * Rotational constraint constructor
     * @param bodyA constraint's body A
     * @param anchorA position (relative to body A coordinate system) where
     * it is constrained.
     * @param bodyB constraint's body B
     * @param anchorB position (relative to body B coordinate system) where
     * it is constrained.
     */
    constructor(bodyA, anchorA, bodyB, anchorB) {
        if (bodyA.id === bodyB.id) {
            throw new Error(`A body cannot be constraint to itself. Body id: ${bodyA.id}`);
        }
        this.bodyA = bodyA;
        this.anchorA = anchorA;
        this.bodyB = bodyB;
        this.anchorB = anchorB;
    }
    f(xa, ya, thetaA, xb, yb, thetaB) {
        const cmA = { x: xa, y: ya };
        const cmB = { x: xb, y: yb };
        const anchAglobal = relativeToGlobalPos(this.anchorA, cmA, thetaA);
        const anchBglobal = relativeToGlobalPos(this.anchorB, cmB, thetaB);
        const resultVec = substractVectors(anchAglobal, anchBglobal);
        return [resultVec.x, resultVec.y];
    }
}