@woosh/meep-engine/src/core/geom/2d/aabb/aabb2_intersects_ray.js

Pure JavaScript game engine. Fully featured and production ready.

import { fabsf } from "../../../math/fabsf.js";

/**
 *
 * @param {number} x0
 * @param {number} y0
 * @param {number} x1
 * @param {number} y1
 * @param {number} origin_x
 * @param {number} origin_y
 * @param {number} direction_x
 * @param {number} direction_y
 * @return {boolean} true if hit found and false otherwise
 */
export function aabb2_intersects_ray(
    x0, y0,
    x1, y1,
    origin_x, origin_y,
    direction_x, direction_y
) {
    // Z Projection
    const extents_x = (x1 - x0) * 0.5;

    const center_x = x0 + extents_x;

    const diff_x = origin_x - center_x;

    if (diff_x * direction_x >= 0.0 && fabsf(diff_x) > extents_x) {
        return false;
    }

    // Y projection
    const extents_y = (y1 - y0) * 0.5;

    const center_y = y0 + extents_y;

    const diff_y = origin_y - center_y;

    if (diff_y * direction_y >= 0.0 && fabsf(diff_y) > extents_y) {
        return false;
    }

    const abs_direction_y = fabsf(direction_y);

    const abs_direction_x = fabsf(direction_x);

    const f2 = fabsf(direction_x * diff_y - direction_y * diff_x);

    return f2 <= extents_x * abs_direction_y + extents_y * abs_direction_x;
}