Bouncing/reflecting projectiles using Raycasting

[ceyhunveysel (moonflow)]

Hello! I am making a Touhou style bullet hell game where you avoid projectiles thrown at you by Rigs of some friends as a little project. I am currently working on trying to make projectiles reflect off of walls; this is all going well so far but on some walls of the arena the reflection doesn’t work. This is the formula I’m using:

(Projectile.CFrame.lookVector - (2 * Projectile.CFrame.lookVector:Dot(raycastresult.Normal) * raycastresult.Normal))

The raycast is casted correctly (I know because I’ve visualized the raycast) but this only bounces the projectile properly if being reflected off of one of four walls, like this:

Here is the full code I use for collision: (This code is ran whenever the projectile hits a wall)

local begin = Projectile.Position - Projectile.CFrame.lookVector * 25 -- To start the raycast a few studs before the projectile, to make sure the raycast isn't in the wall
local final = Projectile.CFrame.lookVector*50 -- 50 studs of distance
local raycastresult = workspace:Raycast(begin, final, params)
local r = visualizeRaycast(begin, final)
if not raycastresult then print(":("); r.Color = Color3.new(1, 0, 0); return end -- If the raycast didn't hit anything, paint the visualized raycast part red to show that it failed (can be ignored)
local newnorm = (Projectile.CFrame.lookVector - (2 * Projectile.CFrame.lookVector:Dot(raycastresult.Normal) * raycastresult.Normal)) -- Calculate the reflected normal
local reflect = newnorm
Projectile.Orientation = reflect
Projectile:SetAttribute("reflect", Projectile:GetAttribute("reflect") - 1) -- Decrement the amount of reflections left on the projectile by 1
table.insert(bypass, Projectile)
task.delay(0.2, function()
	table.remove(bypass, table.find(bypass, Projectile))
end)

Why would the behavior in the video be happening?

[hya123456h (KingBob)]

replace the original Projectile.CFrame.lookVector with the unit direction of the first ray then keep updating it. The best way to do this would be a function which you can iterate over by passing in a direction

[ceyhunveysel (moonflow)]

Can you elaborate on what you mean by “unit direction of the first ray”? Sorry I’m kind of new to raycasting
Also, the reason I thought I didn’t need a function to iterate is because I have another script that handles the movement part of the projectile using the projectile’s lookVector, would this not work?

[BubasGaming]

@ceyhunveysel

Projectile.Orientation = reflect

why are you putting a LookVector into Orientation?
Whouldn’t it be:

Projectile.CFrame = CFrame.lookAt(Projectile.Position, reflect)

[ceyhunveysel (moonflow)]

Whoops. Makes sense. I’ll be closing this post now

[hya123456h (KingBob)]

A unit is just a normalized version of it so clamped between -1 and 1. And I can’t see the rest of your code so I don’t know how you have done it but for me iterating is easier as you can add in certain parameters and stop the bullet at certain points