NightExcessive

--snow_data = nil

snow_data = snow_data or {}


if table.Count(snow_data) == 0 then

    local max = 16000
    local grid_size = 512
    local range = max/grid_size

    local pos

    for x = -range, range do
        x = x * grid_size
        for y = -range, range do
            y = y * grid_size
            for z = -range, range do
                z = z * grid_size

                pos = Vector(x,y,z)
                local up = util.QuickTrace(pos, vector_up*max*2)
                local conents = util.PointContents( pos )

                if (up.HitTexture == "TOOLS/TOOLSSKYBOX" or up.HitTexture == "**empty**") and (conents == CONTENTS_EMPTY or conents == CONTENTS_TESTFOGVOLUME)  then
                    table.insert(snow_data, pos)
                end
            end
        end
    end

end

local function FastLength(point)
    return point.x*point.x+point.y*point.y+point.z*point.z
end

local draw_these = {}

local emitter = ParticleEmitter(EyePos(), false)

hook.Add("Think", "snow", function()
    for _, point in pairs(draw_these) do
        if math.random() < 0.95 then continue end
        local particle = emitter:Add("particle/snow", point)
        if (particle) then
            particle:SetVelocity(VectorRand()*70*Vector(1,1,0))
            particle:SetAngles(Angle(math.random(360), math.random(360), math.random(360)))
            particle:SetLifeTime(0)
            particle:SetDieTime(10)
            particle:SetStartAlpha(255)
            particle:SetEndAlpha(0)
            particle:SetStartSize(0)
            particle:SetEndSize(5)
            particle:SetGravity(Vector(0,0,math.Rand(-30, -200)))
            particle:SetCollide(true)
        end
    end
end)

local iterations = 10000
local lastkey
timer.Create("hide_points", 1, 0, function()
    local c = #snow_data
    print(c, lastkey, iterations)
    for i=1,iterations do
        local key = (lastkey or 0)+i
        if key > c then key = key-c end
        local point = snow_data[key]
        if FastLength(point - LocalPlayer():EyePos()) < 4000000 then
            draw_these[key] = point
        else
            draw_these[key] = nil
        end
        if i >= iterations then lastkey = key break end
    end
end)

do return end

--[[ hook.Remove("HUDPaint",1)

local mat = Material("sprites/sent_ball")

hook.Add("PostDrawOpaqueRenderables", 1, function()

    render.SetMaterial(mat)
    for key, point in pairs(draw_these) do
        render.DrawSprite(point, 50, 50, color_white)
    end

end)]]