@rbxts/fast-cast

FastCastRedux by Eti the Spirit, packaged for roblox-ts.

The Luau source is shipped verbatim (no transpilation), with hand-written TypeScript declarations on top — so runtime behavior is identical to the original module.

Installation

From a local checkout:

npm install /path/to/fast-cast

Or publish/install from a registry as @rbxts/fast-cast.

Usage

import { Workspace } from "@rbxts/services";
import FastCast from "@rbxts/fast-cast";

// One caster per gun. NEVER create a caster per bullet.
const caster = new FastCast();

const params = new RaycastParams();
params.FilterType = Enum.RaycastFilterType.Exclude;

const behavior = FastCast.newBehavior();
behavior.RaycastParams = params;
behavior.Acceleration = new Vector3(0, -Workspace.Gravity, 0);
behavior.MaxDistance = 1000;

caster.LengthChanged.Connect((cast, lastPoint, rayDir, displacement, segmentVelocity, bullet) => {
	// Move your cosmetic bullet here.
	if (bullet) {
		bullet.CFrame = new CFrame(lastPoint.add(rayDir.mul(displacement)), lastPoint.add(rayDir.mul(displacement + 1)));
	}
});

caster.RayHit.Connect((cast, result, segmentVelocity, bullet) => {
	print(`Hit ${result.Instance.GetFullName()}`);
});

// Fire: origin, direction, speed (or a velocity Vector3), behavior
caster.Fire(origin, direction, 500, behavior);

Notes

• FastCast.DebugLogging and FastCast.VisualizeCasts are static toggles for debugging.
• behavior.CosmeticBulletProvider must be a real PartCache instance (e.g. from @rbxts/partcache) — FastCast validates it at runtime via its metatable.
• The CanPierceFunction must never yield.