Creating a rotating light

DaveLee · July 20, 2010

Hey everyone! I've been experimenting with creating a rotating emergency light (similar to those seen in STALKER). My initial plan was to create a spinning light case and put a point light inside of that. It worked, but there were a few shadow artifacts that I could never completelu get rid of due to how close the point light and spinning model were.

My next idea was to remove the animation from the model, and attach two spot lights to it via LUA scripts like this:

>o<

...and then I would rotate the entire model+lights setup via LUA.

The problem is, I'm not a programmer by any means. B) I was able to get one spotlight attached to the model, but I'm at a loss about how to rotate it.

Does anyone have any suggestions?

Here's my code so far (the light is facing down the wrong axis atm):

require("scripts/class")

local class=CreateClass(...)

beginframe1  =  0
endframe1    = 81

class.sound_ambient=LoadSound('abstract::ambient_lighthum.ogg')

function class:InitDialog(grid)
self.super:InitDialog(grid)
group=grid:FindGroup( "Appearance" )
group:AddProperty("castshadows",PROPERTY_CHOICE,"Disabled,Dynamic,Static,Dynamic + Static,Dynamic + Static + Buffered","Cast shadows")	
group=grid:AddGroup("Light")
group:AddProperty("shadowresolution",PROPERTY_CHOICE,"256,512,1024,2048","Shadow resolution")
group:AddProperty("linearoffset",PROPERTY_FLOAT,"0,1,2","Linear offset")
group:AddProperty("Range",PROPERTY_FLOAT,"1,100,0")
group:AddProperty("coneangles",PROPERTY_VEC2,"0,180","Cone angles")
group:Expand(1)
end

function class:CreateObject(model)
local object=self.super:CreateObject(model)
object.light=CreateSpotLight(10,model)	
object.light:SetShadowMode(1+2+4)
object.light:SetRotationf( 1,1,1, 1 )

function object:SetKey(key,value)
	if key=="shadowresolution" then
		if value=="0" then
			self.light:SetShadowmapSize(256)
		elseif value=="1" then
			self.light:SetShadowmapSize(512)
		elseif value=="2" then
			self.light:SetShadowmapSize(1024)
		elseif value=="3" then
			self.light:SetShadowmapSize(2048)
		end
	elseif key=="castshadows" then
		local mode=tonumber(value)
		if mode==0 then
			self.light:SetShadowMode(0)
		elseif mode==1 then
			self.light:SetShadowMode(1)
		elseif mode==2 then
			self.light:SetShadowMode(2)
		elseif mode==3 then
			self.light:SetShadowMode(3)
		elseif mode==4
			then self.light:SetShadowMode(7)
		end
	elseif key=="coneangles" then
		local angles=StringToVec2(value)
		self.light:SetConeAngles( angles.x, angles.y )
	elseif key=="range" then
		self.light:SetRange(value)
	elseif key=="castshadows" then
	--	local mode=tonumber(value)--+4
	--	self.model:SetShadowMode(mode,1)
	elseif key=="multoffset" then
		self.light:SetShadowOffset(self.light:GetShadowOffset(0,0),value,0)
	elseif key=="linearoffset" then
		self.light:SetShadowOffset(value,self.light:GetShadowOffset(1,0),0)
	else
		return self.super:SetKey(key,value)
	end
	return 1
end

function object:GetKey(key,value)
	if key=="linearoffset" then
		return self.light:GetShadowOffset(0,0)
	elseif key=="castshadows" then
		local mode=self.light:GetShadowMode()
		if mode==0 then
			return 0
		elseif mode==1 then
			return 1
		elseif mode==2 then
			return 3
		elseif mode==3 then
			return 3
		elseif mode==7 then
			return 4
		end
	elseif key=="multoffset" then
		return self.light:GetShadowOffset(1,0)
	elseif key=="coneangles" then
		return self.light.innerconeangle..","..self.light.outerconeangle
	elseif key=="shadowresolution" then
		resolution=self.light:GetShadowmapSize()
		if resolution==256 then
			return 0
		elseif resolution==512 then
			return 1
		elseif resolution==1024 then
			return 2	
		elseif resolution==2048 then
			return 3
		else
			return -1
		end
	elseif key=="range" then
		return self.light:GetRange()
	else
		return self.super:GetKey(key,value)
	end
	return value
end

end

cocopino · July 20, 2010

Hi,

haven't tried your code but I'm guessing you're parenting to the whole model when instead you only need a small part of it rotating.

You can create a pivot (invisible entity) by using something like

lampPivot = CreatePivot()

then attach lights to it by

light = createSpotLight(10,lampPivot)

now you can

turnEntity(lampPivot,vec3(0,1,0))

on every update

AggrorJorn · July 20, 2010

Just put this rotating light between the other lights, set a rotation value and press apply. It also has a rotation icon.

See the download section: http://leadwerks.com/werkspace/index.php?/files/file/159-rotating-light/

Rotating light.zip

AggrorJorn · July 25, 2010

The rotation has a default value but it just doesn't rotate immediately. You have to go to its lua menu and press apply. Then it will start rotating.

I've added a new zip. Can you test it out?

flachdrache · July 25, 2010

great,

thx for sharing.

FYI - need to change for le 2.31


require("scripts/class")

local class=CreateClass(...)

function class:InitDialog(grid)
self.super:InitDialog(grid)
group=grid:FindGroup( "Appearance" )
group:AddProperty("castshadows",PROPERTY_CHOICE,"Disabled,Dynamic,Static,Dynamic + Static,Dynamic + Static + Buffered","Cast shadows")	

group=grid:AddGroup("Light")
group:AddProperty("shadowresolution",PROPERTY_CHOICE,"256,512,1024,2048","Shadow resolution")
group:AddProperty("linearoffset",PROPERTY_FLOAT,"0,1,2","Linear offset")
group:AddProperty("Range",PROPERTY_FLOAT,"1,100,0")
group:AddProperty("coneangles",PROPERTY_VEC2,"0,180","Cone angles")

group=grid:AddGroup("Rotation")
group:AddProperty("rotationspeed",PROPERTY_VEC3,"Rotation Speed")
group:Expand(1)
end

function class:CreateObject(model)
local object = self.super:CreateObject(model)

local lampPivot = CreatePivot()
--MoveEntity(lampPivot, EntityPosition(object.model))

EntityParent(lampPivot, object.model, 0)

object.light=CreateSpotLight(5, lampPivot)	
object.light:SetShadowMode(1+2+4)
object.model:SetKey("rotationspeed","0.0,1.0,0.0")

function object:SetKey(key,value)
	if key=="shadowresolution" then
		if value=="0" then
			self.light:SetShadowmapSize(256)
		elseif value=="1" then
			self.light:SetShadowmapSize(512)
		elseif value=="2" then
			self.light:SetShadowmapSize(1024)
		elseif value=="3" then
			self.light:SetShadowmapSize(2048)
		end
	elseif key=="castshadows" then
		local mode=tonumber(value)
		if mode==0 then
			self.light:SetShadowMode(0)
		elseif mode==1 then
			self.light:SetShadowMode(1)
		elseif mode==2 then
			self.light:SetShadowMode(2)
		elseif mode==3 then
			self.light:SetShadowMode(3)
		elseif mode==4
			then self.light:SetShadowMode(7)
		end
	elseif key=="coneangles" then
		local angles=StringToVec2(value)
		self.light:SetConeAngles( angles.x, angles.y )
	elseif key=="range" then
		self.light:SetRange(value)
	elseif key=="castshadows" then
	--	local mode=tonumber(value)--+4
	--	self.model:SetShadowMode(mode,1)
	elseif key=="multoffset" then
		self.light:SetShadowOffset(self.light:GetShadowOffset(0,0),value,0)
	elseif key=="linearoffset" then
		self.light:SetShadowOffset(value,self.light:GetShadowOffset(1,0),0)
	elseif key=="rotationspeed" then
                       self.rotationspeed = StringToVec3(value)
	else
		return self.super:SetKey(key,value)
	end
	return 1
end

function object:GetKey(key,value)
	if key=="linearoffset" then
		return self.light:GetShadowOffset(0,0)
	elseif key=="castshadows" then
		local mode=self.light:GetShadowMode()
		if mode==0 then
			return 0
		elseif mode==1 then
			return 1
		elseif mode==2 then
			return 3
		elseif mode==3 then
			return 3
		elseif mode==7 then
			return 4
		end
	elseif key=="multoffset" then
		return self.light:GetShadowOffset(1,0)
	elseif key=="coneangles" then
		return self.light.innerconeangle..","..self.light.outerconeangle
	elseif key=="shadowresolution" then
		resolution=self.light:GetShadowmapSize()
		if resolution==256 then
			return 0
		elseif resolution==512 then
			return 1
		elseif resolution==1024 then
			return 2	
		elseif resolution==2048 then
			return 3
		else
			return -1
		end
	elseif key=="range" then
		return self.light:GetRange()
	else
		return self.super:GetKey(key,value)
	end
	return value
end

function object:Update() -- Le 2.32 uses Draw() ?!
               lampPivot:Turn(self.rotationspeed,0)
       end

end

AggrorJorn · July 25, 2010

Good point flachdrache

cocopino · July 25, 2010

Since it's a light, you'll probably need update() instead of draw() because draw() will only rotate the light when the light itself is being rendered. This will mean that it's not casting shadows and such when off screen.

(I haven't tested this though)

gordonramp · July 25, 2010

I've added a new zip. Can you test it out?

This works when I run it after setting the speed property to 1.0 then 'apply' but the angle must be out because only 60% of the arc gets lit.

AggrorJorn · July 25, 2010

Since it's a light, you'll probably need update() instead of draw() because draw() will only rotate the light when the light itself is being rendered. This will mean that it's not casting shadows and such when off screen.

(I haven't tested this though)

Yes I thought about that too. I tried that out but it doesn't seem to be doing anything different. The light and shadow gets rendered with both Update as well as Draw, even when the light entity is ofscreen.

This works when I run it after setting the speed property to 1.0 then 'apply' but the angle must be out because only 60% of the arc gets lit.

Yes, it bothers me that the rotation only starts after pressing 'apply'. When you load from a save where the light was turning, then the light is still rotating correctly.

But what do you mean with 'the angle must be out'?

sometimes icons are completely black, do you guys have this problem to? Here is a movie

http://visualknights.com/rotating%20light/lights.mp4

gordonramp · July 25, 2010

But what do you mean with 'the angle must be out'?

I placed the light above a flat terrain and as it rotated the light was only visible for 60% of the rotate.

AggrorJorn · July 25, 2010

I can not repeat this in my editor. Which version are you using at the moment? Have you placed the light a little higher in the air?

I also made a separate topic for the 'default value issue'.

gordonramp · July 26, 2010

Fixed it.. I rotated the light by 90 degrees in the 'General' area of the Properties. It now displays on the terrain in a full rotation. Not sure what I would use this for but it's nice to have it anyway. Thanks for writing it.

AggrorJorn · July 26, 2010

Glad that it is fixed. In the meanwhile Rick and Macklebee helped me out with the apply button issue.

The rotating light now starts directly rotating when you drag it in to the scene.

See the download section: http://leadwerks.com/werkspace/index.php?/files/file/159-rotating-light/

DaveLee · July 27, 2010

This actually worked great! But, I was having issues with my rotating light model, so it may not make it into the final project. Great work though, thanks!

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Creating a rotating light

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