lighttroupe/luz

require 'parent_user_object'

class Curve < ParentUserObject
    title 'Curve'

    attr_reader :vector, :approximation

    attr_accessor :gui_render_list

    def new_renderer
        GuiCurveRenderer.new(self)
    end

    def to_yaml_properties
        super + ['@vector', '@approximation']
    end

    def effects
        []        # never has any
    end

    def after_load
        set_default_instance_variables(:title => 'New Curve', :vector => (0...9).to_a.collect {|x| x / 8.0 }, :approximation => [0.0, 1.0])
        super
    end

    def vector=(rhs)
        @vector, @last_x_unclamped = rhs, nil        # NOTE: Clears cached value
    end

    def approximation=(rhs)
        @approximation, @last_x_unclamped = rhs, nil        # NOTE: Clears cached value
    end

    def value(x_unclamped)
        return @last_value if x_unclamped == @last_x_unclamped        # Simple cache

        x = x_unclamped.clamp(0.0, 1.0)

        step_size = (1.0 / (@approximation.size - 1))

        ia = (x * (@approximation.size - 1)).floor.to_i
        ib = (ia + 1) % (@approximation.size)

        percent_between = (x - (ia * step_size)) / step_size

        @last_x_unclamped, @last_value = x_unclamped, percent_between.scale(@approximation[ia], @approximation[ib])
        @last_value
    end

    #
    # Helpers that describe the nature of the curve (used for coloring it and building lists of only eg. increasing/up curves)
    #
    def up?
        (@vector.first == 0.0) && (@vector.last == 1.0)
    end

    def down?
        (@vector.first == 1.0) && (@vector.last == 0.0)
    end

    def middle?
        (@vector.first == 0.5) && (@vector.last == 0.5)
    end

    def looping?
        @vector.first == @vector.last
    end

    def linear?
        up? && (@approximation.size == 2)
    end
end