lighttroupe/luz

class ActorEffectKScope < ActorEffect
    title                "KScope"
    description "Kaleidescope effect."

    categories :transform, :child_producer

    setting 'folds', :integer, :range => 0..100, :default => 1..2

    def render
        folds_doubled = folds * 2
        return yield if folds_doubled == 0

        # Rotate left half of one slice
        start_radians = RADIANS_UP - ((RADIANS_PER_CIRCLE / folds_doubled) / 2.0)
        end_radians = start_radians + (RADIANS_PER_CIRCLE / folds_doubled)

        for i in (0...folds_doubled)
            # The rotation here affects the clip planes and the actor
            with_roll(i * -(1.0 / folds_doubled)) {
                # Create the two clip planes (a V-shape)
                with_clip_plane([-Math.sin(start_radians), -Math.cos(start_radians), 0.0, 0.0]) {
                    with_clip_plane([Math.sin(end_radians), Math.cos(end_radians), 0.0, 0.0]) {
                        # Flip every other slice left-right so the edges mesh perfectly
                        if i.odd?
                            with_scale(-1, 1) { yield :child_index => i, :total_children => folds_doubled }
                        else
                            yield :child_index => i, :total_children => folds_doubled
                        end
                    }
                }
            }
        end
    end
end