pocket-physics/cjs/rewind-to-collision-point.js

Verlet physics extracted from pocket-ces demos

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.rewindToCollisionPoint = void 0;
const v2_1 = require("./v2");
const segment_intersection_1 = require("./segment-intersection");
const tunnelPoint = (0, v2_1.v2)();
const offset = (0, v2_1.v2)();
const v = (0, v2_1.v2)();
const direction = (0, v2_1.v2)();
const radiusSegment = (0, v2_1.v2)();
const cposIncludingRadius = (0, v2_1.v2)();
function rewindToCollisionPoint(point3, radius3, point1, point2) {
    // detect if a collision has occurred but would have been missed due to
    // point3 moving beyond the edge in one time step.
    // TODO: this should accept some sort of manifold or collision contact object,
    // not randum args (radius, etc). Without a manifold it's imposible to know 
    // if the point "tunneled" due to a collision or the result of _resolving_
    // a collision!
    // Compute where the cpos would be if the segment actually included the
    // radius.
    // Without this, we would rewind to the point3 center, and the direction
    // of two points colliding with each other exactly is undefined.
    (0, v2_1.sub)(v, point3.cpos, point3.ppos);
    (0, v2_1.normalize)(direction, v);
    (0, v2_1.scale)(radiusSegment, direction, radius3);
    (0, v2_1.add)(cposIncludingRadius, radiusSegment, point3.cpos);
    const hasTunneled = (0, segment_intersection_1.segmentIntersection)(cposIncludingRadius, point3.ppos, point1, point2, tunnelPoint);
    if (!hasTunneled)
        return false;
    // Translate point3 to tunnelPoint, including the radius of the point.
    (0, v2_1.sub)(offset, cposIncludingRadius, tunnelPoint);
    (0, v2_1.sub)(point3.cpos, point3.cpos, offset);
    (0, v2_1.sub)(point3.ppos, point3.ppos, offset);
    return true;
}
exports.rewindToCollisionPoint = rewindToCollisionPoint;
function debuggerIfNaN(point) {
    if (isNaN(point.x) || isNaN(point.y)) {
        debugger;
    }
}