local W,H = 1024, 1024
local tex =  Texture(1024, 1024, ETF_A8R8G8B8)

ffi.cdef("typedef struct { uint8_t r, g, b, a; } rgba_pixel;")
local length = W*H
local img = ffi.new("rgba_pixel[?]", length)
for i = 0, length-1 do
    img[i].r = math.random(255)
    img[i].g = math.random(255)
    img[i].b = math.random(255)
    img[i].a = math.random(255)
end

tex:SetData(img)

local rect = Rect(0, 0, W, H)


hook.Add("PostDrawMenu", "draw_texture_noise", function()
    rect.x, rect.y = mouse.GetPos()

    graphics.Set2DFlags()
    graphics.DrawTexture(tex, rect, nil, nil, true)
end)