Raycasting in Shadowmap

Help and Feedback Scripting Support
#1

I am trying to make my shooter game compatible with ShadowMap lighting. However I ran into few performance problems.

Before I start, I wanna clarify that I don’t have a top tier PC and this was done in a map with around 4k parts, with ShadowMap lighting, of course. I believe that if my PC aren’t even able to handle this, neither some my players will.
Also everything works fine with no frame drops/spikes in Voxel lighting.

Whenever I’m calling Clone or Instance.new, there will be a sight frame spike which can be viewed in the Micro Profiler. For an example, I clone a bullet shell from ReplicatedStorage or create a bullet hole part and clone an Effect on it or cloning a bullet part with a trail attached on it, there will be a frame spike.

https://gyazo.com/4b52fd13bf69aff7c9407e219fd1744a

Here are some code examples that caused such behavior, I think they are just some really generic instance.new/clone stuff.

	local FlingShell = bullet:Clone() -- lag spike already, no matter parenting or not
	PhysicsService:SetPartCollisionGroup(FlingShell, "Players")
	FlingShell.CFrame = tool.BoltEject.CFrame
	FlingShell.Orientation = Vec3new(math.random(0,180),math.random(0,180),math.random(0,180))
	FlingShell.Velocity = tool.BoltEject.CFrame.LookVector * 10
	FlingShell.Parent = workspace
	FlingShell.Anchored = false
	delay(5,function()
		FlingShell:Destroy()
		FlingShell = nil
	end)

function CreateBulletHolePart(hit, pos, norm)
	
	local BulletHolePart = Instance.new("Part")
	BulletHolePart.FormFactor = Enum.FormFactor.Custom
	BulletHolePart.Name = "BulletHole"
	BulletHolePart.Size = Vec3new(0.3,0.3,0.05)
	BulletHolePart.Anchored = true
	BulletHolePart.Transparency = 1
	BulletHolePart.CFrame = CFnew(pos, pos + norm)
	BulletHolePart.CanCollide = false
						
	local BulletHoleDecal = Instance.new("Decal")
	BulletHoleDecal.Face = "Front"
	BulletHoleDecal.Texture = "http://www.roblox.com/asset/?id=4813872065"
																	
	local HitEffect = rs.HitEffect:Clone()
	HitEffect.Enabled = true
	HitEffect.Parent = BulletHolePart
	
	local HitEffect2 = rs.SmokeEffect:Clone()
	HitEffect2.Enabled = true
	HitEffect2.Parent = BulletHolePart
												
	debris:AddItem(HitEffect, 0.15)
...

I’m not sure is RayCasting the reason behind but I do raycasting per step, which means 60 times per second until a part hit is detected. It is a really short ray and I set the bullet part’s CFrame which is anchored, and CanCollide false. When the part was initially created, there will be a spike (which is the problem mentioned above), I was using FindPartOnRayWithIgnoreList with a table with ignored parts (maybe a thousand so) and I changed to FindPartOnRay with no ignore parts for testing purpose, nothing much changed.

I’m wondering how does other games can perform it so perfectly without a single lag spike? Take Arsenal as an example, they used ShadowMap but I have literally no problems on it. They also have bullet trails, raycasting per step, and particles like I do, and I believe the map size is also similar,

Any suggested approaches to fix this?..

1 Like
#2

If your game was working fine before enabling shadowmap, try disabling the CastShadow property on the bullets. I imagine trying to create an accurate shadow for multiple fast moving objects is causing unnecessary strain.

#3

I’d recommend trying PartCache rather than creating new parts. It helps a lot with performance.

But @MayorGnarwhal’s solution could be especially helpful in this case aswell.

#4

Everything has Cast Shadow off already, CanCollide false, and Anchored true, no collisions / physics were calculated.

I’ll try PartCache if it’s possible.

#5

I dont think its the cloning because my laptop is not that great and I made a simple gun that runs pretty smooth. I split up my rays using heartbeat though and I use the delta time to make them travel at a set speed, and then i use a Body velocity to make the bullets move

#6

Are you trying it in a map with around 3k parts? Also in Max Graphics in main game instead of studio.
Yes, we have the similar approach except I use CFraming. When the bullet part is initially created, there’s a lag spike.

#7

well 3k parts is alot, I dont think other arsenal maps have so much from the looks of it. Could you send a link so i can see the game, and no i dont use max graphics, if your pc is not very good why are using max?

#8

Sadly Roblox is down right now lol, can’t do anything. I’ll send it to you when it’s back up.

#9

and it says that partcache is only for instance.new and not for cloning.