Visualizer = {
    AudioChannel = nil,
    Data = {},
    SmoothData = {},
    BlurMat = Material("blur3.png", "smooth noclamp"),
    MovingMat = Material("blurbackground.png", "smooth noclamp"),
    NoteMat = Material("musicnote.png", "smooth noclamp"),
    Intensity = 50,
}



local function DrawCircle( x, y, radius, seg )
	local cir = {}

	table.insert( cir, { x = x, y = y, u = 0.5, v = 0.5 } )
	for i = 0, seg do
		local a = math.rad( ( i / seg ) * -360 )
		table.insert( cir, { x = x + math.sin( a ) * radius, y = y + math.cos( a ) * radius, u = math.sin( a ) / 2 + 0.5, v = math.cos( a ) / 2 + 0.5 } )
	end

	local a = math.rad( 0 ) -- This is needed for non absolute segment counts
	table.insert( cir, { x = x + math.sin( a ) * radius, y = y + math.cos( a ) * radius, u = math.sin( a ) / 2 + 0.5, v = math.cos( a ) / 2 + 0.5 } )

	surface.DrawPoly( cir )
end
local i = 1
function DrawBackgroundD(mat, clr, x, y, w, h, limitW, limitH)

    render.ClearStencil();
    render.SetStencilEnable( true );
    render.SetStencilCompareFunction( STENCIL_ALWAYS );
    render.SetStencilPassOperation( STENCIL_REPLACE );
    render.SetStencilFailOperation( STENCIL_KEEP );
    render.SetStencilZFailOperation( STENCIL_KEEP );
    render.SetStencilWriteMask( 255 );
    render.SetStencilTestMask( 255 );
    render.SetStencilReferenceValue( 1 );

	surface.SetDrawColor( clr )
	surface.DrawRect( x, y, limitW, limitH )

    render.SetStencilCompareFunction( STENCIL_EQUAL );

    -- clear the inside of our mask so we have a nice clean slate to draw in.
    render.ClearBuffersObeyStencil( 0, 0, 0, 0, true );
    surface.SetDrawColor( clr )
    surface.SetMaterial( Visualizer.BlurMat	)
	local texW = 3840
	local texH = 2400
	local limitW2, limitH2 = limitW, limitH
	surface.DrawTexturedRect( x, y, w, h )
	surface.SetMaterial( Visualizer.MovingMat )
	surface.DrawTexturedRect( x - Visualizer.Intensity or 50/2, y - Visualizer.Intensity/2 or 50/2, w, h )
    render.SetStencilEnable( false );
end


function Visualizer.PlayURL(url, flags, callback)
    sound.PlayURL(url, flags, function(channel, err, errtxt)
        if IsValid(channel) then
			for i = 1, 1024 do
				Visualizer.SmoothData[i] = 0
			end
            callback(channel, err, errtxt)
            Visualizer.AudioChannel = channel
        else
            return
        end
    end)
end

function Visualizer.PlayFile(path, flags, callback)
    sound.PlayFile(path, flags, function(channel, err, errtxt)
        if IsValid(channel) then
            callback(channel, err, errtxt)
            Visualizer.AudioChannel = channel
        else
            return
        end
    end)
end

local blur = Material("pp/blurscreen")
local function DrawCircleBlur(x, y, radius, seg, amount)
    surface.SetDrawColor(20, 20, 20, 200)
    draw.NoTexture()
	DrawCircle(x, y, radius, seg)
end

hook.Add( "PostDrawOpaqueRenderables", "example", function()
 local pos = Vector(-11100, -1550, -8050)
 local angle = Angle(0, 90, 90)
	cam.Start3D2D( pos, angle, 1 )
		DrawBackgroundD( Visualizer.BlurMat, Color(255, 255, 255, 255), 0, 0, 1280/6 + Visualizer.Intensity, 720/6 + Visualizer.Intensity, 1280/6, 720/6)
		if IsValid(Visualizer.AudioChannel) and Visualizer.AudioChannel:GetState() == 1 then
			Visualizer.Data = { }
			Visualizer.AudioChannel:FFT(Visualizer.Data, FFT_2048)
			for i = 1, 1024 do
				Visualizer.SmoothData[i] = Lerp(5 * FrameTime(), Visualizer.SmoothData[i], Visualizer.Data[i])
			end
			Visualizer.Intensity = Visualizer.SmoothData[5] * 1000
			surface.SetDrawColor( 0, 0, 0, 200 )
			DrawCircleBlur(1280/6/2, 720/6/2, math.Clamp(Visualizer.Intensity or 50, 50, 100), 30 )
			surface.SetDrawColor( 255, 255, 255, 255 )
			surface.SetMaterial(Visualizer.NoteMat)
			DrawCircle(1280/6/2, 720/6/2, math.Clamp(Visualizer.Intensity - 15 or 35, 35, 85) , 30)
		end
	cam.End3D2D()
end )