Interpolate for NyuFX

interpolate.lua

-- Almost Ctr+C Ctrl+V of
-- https://bitbucket.org/alquimista/crayon/
-- Author: Alquimista <alquimistaotaku@gmail.com>

-- Equation
-- http://codeplea.com/simple-interpolation
-- http://algorithmist.wordpress.com/

-- Add this module to the includes in NyuFX [http://youka.xobor.de/]



interpolate = {}

-- How to use?
-------------------------------------------------------------------------------
-- Interpolate2(<0-1>, <nomber,asscolor,assalpha>, 
--              <number,asscolor,assalpha>, [<function>])
-- Interpolate2(0.5, &HFFFFFF&, &H000000&)
-------------------------------------------------------------------------------


-- Like a class in python
function interpolate.new ()
    local self = {}

    function self:linear (t, vmin, vmax)
        return t * (vmax - vmin) + vmin
    end

    function self:cosine (t, vmin, vmax)
        t = 0.5 - (math.cos(math.pi * t) / 2)
        return self:linear(t, vmin, vmax)
    end

    function self:smooth_step (t, vmin, vmax)
        t = (t ^ 2) * (3 - (2 * t))
        return self:linear(t, vmin, vmax)
    end

    function self:acceleration (t, vmin, vmax)
        t = t ^ 2
        return self:linear(t, vmin, vmax)
    end

    function self:deceleration (t, vmin, vmax)
        t = 1 - (1 - t) ^ 2
        return self:linear(t, vmin, vmax)
    end
    return self
end


function Interpolate2(t, vmin, vmax, func)
   -- Default argument(interpolate function)
    if not func then
        func = 'linear'
    end

    -- I am repeating much code to lack of knowledge of lua
    local i = interpolate.new ()
    if func == 'linear' then
        -- Nummber
        if type(vmin) == "number" and type(vmax) == "number" then
            return i:linear(t, vmin, vmax)
        end
        local r1, g1, b1 = ASS_to_RGB(vmin)
        local r2, g2, b2 = ASS_to_RGB(vmax)
        -- Color RGB &HBBGGRR&
        if b1 and b2 then
            local r, g, b
            r = i:linear(t, r1, r2)
            g = i:linear(t, g1, g2)
            b = i:linear(t, b1, b2)
            return RGB_to_ASS(r, g, b)
        end
         -- Color ALPHA &HAA&
        local a1 = ASS_to_A(vmin)
        local a2 = ASS_to_A(vmax)
        if a1 and a2 then
            local a = i:linear(t, a1, a2)
            return A_to_ASS(a)
        end
    elseif func == 'cosine'then
        if type(vmin) == "number" and type(vmax) == "number" then
            return i:cosine(t, vmin, vmax)
        end
        local r1, g1, b1 = ASS_to_RGB(vmin)
        local r2, g2, b2 = ASS_to_RGB(vmax)
        if b1 and b2 then
            local r, g, b
            r = i:cosine(t, r1, r2)
            g = i:cosine(t, g1, g2)
            b = i:cosine(t, b1, b2)
            return RGB_to_ASS(r, g, b)
        end
        local a1 = ASS_to_A(vmin)
        local a2 = ASS_to_A(vmax)
        if a1 and a2 then
            local a = i:cosine(t, a1, a2)
            return A_to_ASS(a)
        end
    elseif func == 'smooth_step' then
        if type(vmin) == "number" and type(vmax) == "number" then
            return i:smooth_step(t, vmin, vmax)
        end
        local r1, g1, b1 = ASS_to_RGB(vmin)
        local r2, g2, b2 = ASS_to_RGB(vmax)
        if b1 and b2 then
            local r, g, b
            r = i:smooth_step(t, r1, r2)
            g = i:smooth_step(t, g1, g2)
            b = i:smooth_step(t, b1, b2)
            return RGB_to_ASS(r, g, b)
        end
        local a1 = ASS_to_A(vmin)
        local a2 = ASS_to_A(vmax)
        if a1 and a2 then
            local a = i:smooth_step(t, a1, a2)
            return A_to_ASS(a)
        end
    elseif func == 'acceleration' then
        if type(vmin) == "number" and type(vmax) == "number" then
            return i:acceleration(t, vmin, vmax)
        end
        local r1, g1, b1 = ASS_to_RGB(vmin)
        local r2, g2, b2 = ASS_to_RGB(vmax)
        if b1 and b2 then
            local r, g, b
            r = i:acceleration(t, r1, r2)
            g = i:acceleration(t, g1, g2)
            b = i:acceleration(t, b1, b2)
            return RGB_to_ASS(r, g, b)
        end
        local a1 = ASS_to_A(vmin)
        local a2 = ASS_to_A(vmax)
        if a1 and a2 then
            local a = i:acceleration(t, a1, a2)
            return A_to_ASS(a)
        end
    elseif func == 'deceleration' then
        if type(vmin) == "number" and type(vmax) == "number" then
            return i:deceleration(t, vmin, vmax)
        end
        local r1, g1, b1 = ASS_to_RGB(vmin)
        local r2, g2, b2 = ASS_to_RGB(vmax)
        if b1 and b2 then
            local r, g, b
            r = i:deceleration(t, r1, r2)
            g = i:deceleration(t, g1, g2)
            b = i:deceleration(t, b1, b2)
            return RGB_to_ASS(r, g, b)
        end
        local a1 = ASS_to_A(vmin)
        local a2 = ASS_to_A(vmax)
        if a1 and a2 then
            local a = i:deceleration(t, a1, a2)
            return A_to_ASS(a)
        end
    end
end