import { tangent } from "flo-bezier3";
import { cross, toUnitVector } from "flo-vector2d";
import { CpNode } from "../cp-node.js";
import { getMatCurveToNext } from "./get-mat-curve-to-next.js";


/**
 * 
 * @param cpNode1 
 * @param cpNode2 
 * @returns 
 */
function getInitialDegAngleBetweenMatCurves(
        cpNode1: CpNode,
        cpNode2: CpNode) {

    const tan1 = toUnitVector(tangent(
        getMatCurveToNext(cpNode1), 
        0
    ));
    const tan2 = toUnitVector(tangent(
        getMatCurveToNext(cpNode2), 
        0
    ));

    const cross_ = cross(tan1, tan2);
    const angle = Math.abs(Math.asin( cross_ ) * (180/Math.PI));

    return angle;
}


export { getInitialDegAngleBetweenMatCurves }