lighttroupe/luz

class ActorEffectKScope2 < ActorEffect
    title                "KScope2"
    description "Kaleidescope effect."

    categories :transform, :child_producer

    setting 'folds', :float, :range => 1.0..100.0, :default => 1.0..2.0

    def render
        return yield if folds == 0.0

        fold_count = folds.floor
        folds_doubled = fold_count * 2

        remainder = folds % 1.0
        angle_for_remainder = remainder * (1.0 / (fold_count + 1)) 
        angle_per_step = ((1.0 - angle_for_remainder) / folds_doubled)

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

        child_count = folds_doubled
        child_count += 1 if (remainder > 0.0)

        with_roll(-(angle_for_remainder) - (angle_per_step / 2.0)) {
            for i in (0...folds_doubled)
                # The rotation here affects the clip planes and the actor
                with_roll(-angle_per_step * i + (angle_for_remainder / 2.0)) {
                    # 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 => total_children
                            end
                        }
                    }
                }
            end
        }
    end
end