lighttroupe/luz

#
# SamplePlayer calls provided proc once per name=value sample when passed-in time passes the sample time (like sheet music).
#
class SamplePlayer
    Sample = Struct.new(:time, :name, :value)

    def initialize(samples, time_offset=0.0)
        @samples, @time_offset = samples, time_offset
        @last_time = 0.0
        @next_index = 0
    end

    def on_sample(&proc)
        @proc = proc
    end

    def move_to_time(time)
        time += @time_offset

        if @last_time
            if time < @last_time
                # reset to 0 then go forward to time
                @last_time = 0.0
                @next_index = 0
                move_forward_to_time(time) if time > 0.0
            elsif time > @last_time
                # move forward to time
                move_forward_to_time(time)
            end
        else
            # move forward to time
            move_forward_to_time(time) if time > 0.0
        end
    end

private

    def move_forward_to_time(time)
        while (sample=@samples[@next_index]) and (time >= sample.time)
            @proc.call(sample.name, sample.value)
            @next_index += 1
        end
        @last_time = time
    end
end