gLargeParticles = 4
gSmallParticles = 2
gSmokeParticles = 24
gParticleColor = {0.3, 0.25, 0.2}
gSmokeColor = {0.7, 0.65, 0.6}
local dustintesity = 0.45
local dusttimer = 0


function rnd(mi, ma)
	return math.random(1000)/1000*(ma-mi) + mi
end


function rndVec(t)
	return Vec(rnd(-t, t), rnd(-t, t), rnd(-t, t))
end
 
 
function getParticlePos(rMin, rMax, life)
	local camPos = GetCameraTransform().pos
	local p = rndVec(1)
	p[2] = 0
	local d = rnd(rMin, rMax)
	p = VecScale(VecNormalize(p), d)
	p = VecAdd(p, camPos)
	p = VecSub(p, VecScale(GetWindVelocity(p), life * 0.5))
	p[2] = 20;
	local hit, dist = QueryRaycast(p, Vec(0,-1,0), 20)
	if not hit then dist = 20 end
	p[2] = math.max(p[2] - dist, 1)
	p[2] = p[2] + rnd(0, 0.5)
	return p, d
end


function update(dt)
	dusttimer = dusttimer + dt
	
	if dusttimer > dustintesity then
		dusttimer = 0
		
		ParticleReset()
		ParticleType("plain")
		ParticleRadius(0.8)
		ParticleColor(gParticleColor[1], gParticleColor[2], gParticleColor[3])
		ParticleAlpha(1, 1, "constant", 0.5, 0.5)
		ParticleCollide(0)
		ParticleTile(8)
		for i = 1, gLargeParticles do
			local life = 1.0
			local p, d = getParticlePos(8, 12, life);
			local vel = GetWindVelocity(p);
			SpawnParticle(p, vel, life)
		end
		
		ParticleReset()
		ParticleType("plain")
		ParticleRadius(0.02)
		ParticleGravity(-5)
		ParticleColor(gParticleColor[1], gParticleColor[2], gParticleColor[3])
		ParticleAlpha(1, 1, "constant", 0.5, 0.5)
		ParticleCollide(1)
		ParticleTile(4)
		for i = 1, gSmallParticles do
			local life = 1.0
			local p, d = getParticlePos(6, 10, life);
			local vel = GetWindVelocity(p);
			SpawnParticle(p, vel, life)
		end

		ParticleReset()
		ParticleType("plain")
		ParticleGravity(-5)
		ParticleColor(gSmokeColor[1], gSmokeColor[2], gSmokeColor[3])
		ParticleAlpha(0.1, 0.1, "constant", 0.5, 0.5)
		ParticleCollide(1)
		ParticleTile(0)
		for i = 1, gSmokeParticles do
			local life = 1.0
			local p, d = getParticlePos(2, 8, life);
			local vel = GetWindVelocity(p);
			ParticleRadius(d/10)
			SpawnParticle(p, vel, life)
		end
	end
end