lighttroupe/luz

class ActorOffscreenCanvas < Actor
    title                "Canvas"
    description "A canvas upon which the Actor Render or Actor Pen plugins can draw."

    setting 'pages', :integer, :range => 1..1000, :default => 1..6
    setting 'forward', :event
    setting 'backward', :event
    #setting 'previous_color', :color, :default => [1.0, 1.0, 1.0, 0.2]

    hint 'The drawn image is persistent, unless erased by effects.'

    FBO_USING_OPTIONS = {:clear => false}

    def render
        current_fbo.with_image { unit_square }
    end

    # 'using' is called by the actor_effects that draw on us
    def using
        current_fbo.using(FBO_USING_OPTIONS) {
            yield
        }
    end

private

    def current_fbo
        fbos[page_index]
    end

    def page_index
        (forward.count - backward.count) % pages
    end

    def fbos
        @fbos ||= Hash.new { |hash, key| hash[key] = create_fbo }
    end

    def create_fbo
        GLFrameBufferObject.new(:height => 1024, :width => 1024)
    end
end