rayPlane

function rayPlane(origin: ArrayLike<number>, direction: ArrayLike<number>, point: ArrayLike<number>, normal: ArrayLike<number>): number

import { rayPlane } from '@driftengine/core';

Parameters

In depth

The plane is a point and a normal rather than four coefficients, because every caller here has a point — a gizmo's origin, a target's position — and would otherwise compute d to have it undone one line later.

A ray within 1e-6 of parallel is a miss and not a hit at infinity. The alternative returns a number that is finite, enormous and wrong, and what a caller does with it is teleport whatever it was dragging. Callers that grab against a plane depend on this refusal; see gizmo.ts.

The normal does not have to be unit length, but direction and normal must be in the same space, and a plane behind the ray reports -1 the way every other miss does.