Function isIntersecting

src/engineMath.js:230–262

Returns true if a line segment is intersecting an axis aligned box * @param {Vector2} start - Start of raycast * @param {Vector2} end - End of raycast * @param {Vector2} pos - Center of box * @param {Vector2} size - Size of box * @return {boolean} - True if intersecting * @memb

(start, end, pos, size)

 *  @return {boolean}      - True if intersecting
 *  @memberof Math */
function isIntersecting(start, end, pos, size)
{
    // Liang-Barsky algorithm
    const boxMin = pos.subtract(size.scale(.5));
    const boxMax = boxMin.add(size);
    const delta = end.subtract(start);
    const a = start.subtract(boxMin);
    const b = start.subtract(boxMax);
    const p = [-delta.x, delta.x, -delta.y, delta.y];
    const q = [a.x, -b.x, a.y, -b.y];
    let tMin = 0, tMax = 1;
    for (let i = 4; i--;)
    {
        if (p[i])
        {
            const t = q[i] / p[i];
            if (p[i] < 0)
            {
                if (t > tMax) return false;
                tMin = max(t, tMin);
            }
            else
            {
                if (t < tMin) return false;
                tMax = min(t, tMax);
            }
        }
        else if (q[i] < 0)
            return false;
    }

    return true;
}

/** Returns an oscillating wave between 0 and amplitude with frequency of 1 Hz by default
 *  @param {number} [frequency] - Frequency of the wave in Hz