function interpolate( _a, _b, _t )
    return _a + (_b - _a) * _t
end

function inverseInterpolate( _a, _b, _value )
    return (_value - _a) / (_b - _a)
end

function convertBones( _iluPath, _uvRatio )

    includeReference(_iluPath)
    
    local bounds = ITF_GFX_UV_ATLAS[1]
    local xMin = bounds.uv0.x
    local xMax = bounds.uv1.x
    local yMin = bounds.uv0.y
    local yMax = bounds.uv1.y

    local bones = {}
    
	for i=2, #ITF_GFX_UV_ATLAS do
        local uvData = ITF_GFX_UV_ATLAS[i]
        local bone =
        {
            SpriteBone =
            {
                name = uvData.flag,
                
                -- normalize X on [0, 1] and Y [-1, 1]
                p0 = vector2dNew(inverseInterpolate(xMin, xMax, uvData.uv0.x), 1 - 2 * inverseInterpolate(yMin, yMax, uvData.uv0.y)),
                p1 = vector2dNew(inverseInterpolate(xMin, xMax, uvData.uv1.x), 1 - 2 * inverseInterpolate(yMin, yMax, uvData.uv1.y)),
                
                uv0 = vector2dNew(uvData.uv0.x, 1 - uvData.uv0.y / _uvRatio),
                uv1 = vector2dNew(uvData.uv1.x, 1 - uvData.uv1.y / _uvRatio),
            },
        }
        bone.TestSpriteBone = bone.SpriteBone
        appendTable(bones, {bone})
	end
    
    return bones
end

function convertMetaData( _iluPath, _uvRatio )
    local meta =
    {
        SpriteMetaData =
        {
            sprite = ITF_GFX_UV_ATLAS[1],
            bones = convertBones(_iluPath, _uvRatio),
        },
    }
    meta.TestSpriteMetaData = SpriteMetaData
    return meta
end