def particle_spawner
        pic_index = 21
        spawn_interval = 20

        on_screen_particle = []
        rand_pos_x = []; target_pos_x = []; current_pos_x = []
        rand_pos_y = []; target_pos_y = []; current_pos_y = []
        rand_scale = []; target_scale = []; current_scale = []
        rand_angle = []; target_angle = []; current_angle = []
        rand_speed = []
        lifetime = []
        index = pic_index

        spawn_loop = 40

        #update function
        loop do
            #--------------------------------------------------------------
            # Check if you should spawn particle
            #--------------------------------------------------------------
            p (on_screen_particle)
            if (spawn_loop >= spawn_interval)
                if (on_screen_particle.empty?)
                    index = pic_index
                else
                    for i in pic_index..pic_index+10
                        if (!on_screen_particle.include?(i))
                            #msgbox(on_screen_particle)
                            #msgbox("particale #" + i.to_s + " is not in the array!")
                            #msgbox("so, spawn a particle with #" + i.to_s)
                            index = i
                            break
                        end
                    end
                end
                #msgbox(index)
                on_screen_particle.insert(0, index)
                #msgbox(on_screen_particle)
                #--------------------------------------------------------------
                # Spawning a new particle
                #--------------------------------------------------------------
                rand_pos_x.insert(0, rand(484) + 30); target_pos_x.insert(0, rand_pos_x[0] + 10 + rand(20))
                rand_pos_y.insert(0, rand(356) + 30); target_pos_y.insert(0, rand_pos_y[0] - 100 - rand(20))
                rand_scale.insert(0, 100 + rand(100)); target_scale.insert(0, rand_scale[0] + rand(30))
                rand_angle.insert(0, -30 + rand(60)); target_angle.insert(0, rand_angle[0] - 30 + rand(60))
                rand_speed.insert(0, 40 + rand(80))
                lifetime.insert(0, 0)

                screen.pictures[on_screen_particle[0]].show(
                    "Screenfx/Heart_Particle" , 1,
                    rand_pos_x[0],
                    rand_pos_y[0],
                    rand_scale[0],
                    rand_scale[0],
                    100, 1)
                current_pos_x.insert(0, rand_pos_x)
                current_pos_y.insert(0, rand_pos_y)
                current_scale.insert(0, rand_scale)
                current_angle.insert(0, rand_angle)

                screen.pictures[on_screen_particle[0]].start_tone_change(
                    Tone.new(0,255,0,255), 1)

                rotate_pic(on_screen_particle[0],rand_angle[0],1,1)
                spawn_loop = 0
            else
                spawn_loop += 1
            end
            #--------------------------------------------------------------
            # If no particle exist in canvas, next
            #--------------------------------------------------------------
            if (on_screen_particle.count < 1)
                wait(1)
                next
            end
            #--------------------------------------------------------------
            # updating the position of particles
            #--------------------------------------------------------------
            for i in 0..on_screen_particle.count-1
                #msgbox(rand_pos_y[i].to_s + target_pos_y[i].to_s + )
                current_pos_x[i] = lerp( rand_pos_x[i], target_pos_x[i], lifetime[i]*100/rand_speed[i])
                current_pos_y[i] = lerp( rand_pos_y[i], target_pos_y[i], lifetime[i]*100/rand_speed[i])
                current_scale[i] = lerp( rand_scale[i], target_scale[i], lifetime[i]*100/rand_speed[i])
                current_angle[i] = lerp( rand_angle[i], target_angle[i], lifetime[i]*100/rand_speed[i])

                screen.pictures[on_screen_particle[i]].move(
                    1,
                    current_pos_x[i],
                    current_pos_y[i],
                    current_scale[i],
                    current_scale[i],
                    100,0,1
                    )

                rotate_pic(on_screen_particle[i],current_angle[i],1,1)
                lifetime[i] += 1

                if(lifetime[i] >= rand_speed[i])
                    erase_pic(on_screen_particle[i])
                        #msgbox("deleting particle #"+ on_screen_particle[i].to_s )
                    on_screen_particle.delete_at(i)

                    rand_pos_x.delete_at(i); target_pos_x.delete_at(i); current_pos_x.delete_at(i)
                    rand_pos_y.delete_at(i); target_pos_y.delete_at(i); current_pos_y.delete_at(i)
                    rand_scale.delete_at(i); target_scale.delete_at(i); current_scale.delete_at(i)
                    rand_angle.delete_at(i); target_angle.delete_at(i); current_angle.delete_at(i)
                    rand_speed.delete_at(i)
                    lifetime.delete_at(i)
                       # msgbox(on_screen_particle.count)
                end
            end

        wait(1)
        end
    end


    def lerp(origin, destination, time)
        return (origin * (100-time) + destination * time)/100
    end