require "math"

function table.shallow_copy(t)
    local t2 = {}
    for k,v in pairs(t) do
        t2[k] = v
    end
    return t2
end

function thisorthat(c, a, b)
    if c then return a else return b end
end

function pingpong(at, over)
    local c = (over - 1) * 2
    if math.fmod(at, c) >= over then
        return c - math.fmod(at, c)
    else
        return math.fmod(at, c)
    end
end

function linease(c, t, d, b)
    return c * t / d + b
end

function sinease(c, t, d, b)
    return -c*math.cos(t/d*(math.pi/2)) + c + b
end