-- LUA Script - precede every function and global member wit	h lowercase name of script + '_main'
local fp_rocket_assigned = {}
local fp_rocket_timer    = {}

local sin    = math.sin
local cos    = math.cos

function fp_rocket_ammo_init(e)
	CollisionOff(e)
	Hide(e)
	SetEntityHealth(e, 10000)
end

function FP_RocketFire(e, ax, ay, az)
	fp_rocket_assigned[e] = {fired = true, 
							 smoke = false, 
							 xA = ax, yA = ay, zA = az} 
									 
	fp_rocket_timer[e] = 0
end

local function Rotate3D (x, y, z, xrot, yrot, zrot) 

	function RotatePoint2D (x, y, Ang)  -- Ang in radians
		local Sa, Ca = sin(Ang), cos(Ang)
		return x*Ca - y*Sa, x*Sa + y*Ca
	end
 
	local NX, NY, NZ = x, y, z

	-- X
	NZ, NY = RotatePoint2D (NZ, NY, -xrot)
	
	-- Y
	NX, NZ = RotatePoint2D (NX, NZ, -yrot)
	
	-- Z
	NY, NX = RotatePoint2D (NY, NX, -zrot)

	return NX, NY, NZ
end

function fp_rocket_ammo_main(e)
	local timer = fp_rocket_timer[e]
	
	if timer == nil then
		fp_rocket_timer[e] = 0
		return
	end
	
	if g_Time > timer and FP_AddRocket ~= nil then
		if fp_rocket_assigned[e] == nil then
			if FP_AddRocket(e) then 
				fp_rocket_assigned[e] = {fired = false}
				timer = math.huge
			end
		end

		fp_rocket_timer[e] = g_Time + 3000
	end
	
	local hr = fp_rocket_assigned[e]
	
	if hr == nil then return end
	
	if hr.fired then

		-- change the vector to match 'forward' for the model, i.e. pointing up is 0,0,1 left would be 1,0,0 etc
		local vX, vY, vZ = Rotate3D (0, 0, 1, hr.xA, hr.yA, hr.zA)
		local Ent = g_Entity[e]
		
		local nX = Ent.x + vX * 50
		local nY = Ent.y + vY * 50
		local nZ = Ent.z + vZ * 50
		
		-- check collision with terrain or an object
		if nY < GetTerrainHeight(nX, nZ) or 
		   IntersectAll(Ent.x, Ent.y, Ent.z, nX, nY, nZ, Ent.obj) ~= 0 then
		   
			SetEntityHealth(e, 0)
			hr.fired = false
			StopParticleEmitter(e)
		else
			if not hr.smoke then
				StartParticleEmitter(e)
			end
			-- move rocket		
			CollisionOff(e)
			SetPosition(e, nX, nY, nZ)
			CollisionOn(e)
		end
	end
end