require("audio")

capsaudio = capsaudio or Audio()
local time = 0

local function getpitch(offset)
    return 440 * 2 ^ ((offset - 48) / 12)
end

local function saw(offset)
    return (time * getpitch(offset))%1
end

local function pwm(offset, w)
    w = w or 0.5

    return (time * getpitch(offset))%1 > w and 1 or 0
end

local function sin(offset)
    return math.sin(time * math.pi * 2 * getpitch(offset))
end

local v
local function tri(offset)
    v = (time * getpitch(offset))%1

    return v > 0.5 and (-v + 1) or v
end

local function waveform()
    return tri(62)
end

local volume = 1
local value
local source = here
local orientation = Vector(0,0,0)

local distance = 300
local doppler = 1

local function calcsource(eye, rgt, src, dist, fwd, vel)
    dist = dist or distance

    local vol = math.Clamp(-((eye - src):Length() / dist) + 1, 0, 1)
    local dot = rgt:Dot((src - eye):Normalize())

    orientation.x = vol

    orientation.y = math.Clamp(dot, 0, 1) + 0.5
    orientation.z = math.Clamp(-dot, 0, 1) + 0.5

    return vol ~= 0
end

function capsaudio.process(buffer)
    volume = GetConVarNumber("volume")

    if not calcsource(LocalPlayer():EyePos(), LocalPlayer():EyeAngles():Right(), source, 300, LocalPlayer():GetAimVector(), LocalPlayer():GetVelocity()) then return end

    for i = 0, #buffer / 2 - 1 do
        value = waveform() * (volume * orientation.x)

        buffer[i * 2 + 1] = value * orientation.y
        buffer[i * 2 + 2] = value * orientation.z
        time = time + ((1 / capsaudio.rate) * doppler)
    end
end

capsaudio:start()