pocket-physics/esm/overlap-aabb-aabb.js

Verlet physics extracted from pocket-ces demos

import { set, v2 } from "./v2";
/**
 * Create a result object to use for overlap tests.
 */
export const createAABBOverlapResult = () => {
    return { resolve: v2(), hitPos: v2(), normal: v2() };
};
/**
 * Compute the "collision manifold" for two AABB, storing the result in `result`.
 * Note: The `normal` is always perpendicular to an AABB edge, which may produce
 * some slighly weird-looking collisions. `collisionResponseAABB()` will compute
 * a normal using the midpoints, which looks more natural.
 */
export const overlapAABBAABB = (center1X, center1Y, width1, height1, center2X, center2Y, width2, height2, result) => {
    const dx = center2X - center1X;
    const px = width2 / 2 + width1 / 2 - Math.abs(dx);
    const dy = center2Y - center1Y;
    const py = height2 / 2 + height1 / 2 - Math.abs(dy);
    if (px <= 0)
        return null;
    if (py <= 0)
        return null;
    set(result.resolve, 0, 0);
    set(result.hitPos, 0, 0);
    set(result.normal, 0, 0);
    if (px < py) {
        const sx = dx < 0 ? -1 : 1;
        result.resolve.x = px * sx;
        result.normal.x = sx;
        // Really not sure about these values.
        result.hitPos.x = center1X + (width1 / 2) * sx;
        result.hitPos.y = center2Y;
    }
    else {
        const sy = dy < 0 ? -1 : 1;
        result.resolve.y = py * sy;
        result.normal.y = sy;
        // Really not sure about these values.
        result.hitPos.x = center2X;
        result.hitPos.y = center1Y + (height1 / 2) * sy;
    }
    return result;
};