Flying strawberries

A flying berry in 400m of Celeste Classic

Flying strawberries, also called winged berries, are a collectible that first appeared in Celeste Classic. They are similar to non-flying strawberries, but they have wings and fly upward once the player dashes.

Original Code

fly_fruit={

    tile=28,

    if_not_fruit=true,

    init=function(this)

        this.start=this.y

        this.fly=false

        this.step=0.5

        this.solids=false

        this.sfx_delay=8

    end,

    update=function(this)

        --fly away

        if this.fly then

         if this.sfx_delay>0 then

          this.sfx_delay-=1

          if this.sfx_delay<=0 then

           sfx_timer=20

           sfx(14)

          end

         end

            this.spd.y=appr(this.spd.y,-3.5,0.25)

            if this.y<-16 then

                destroy_object(this)

            end

        -- wait

        else

            if has_dashed then

                this.fly=true

            end

            this.step+=0.05

            this.spd.y=sin(this.step)*0.5

        end

        -- collect

        local hit=this.collide(player,0,0)

        if hit~=nil then

         hit.djump=max_djump

            sfx_timer=20

            sfx(13)

            got_fruit[1+level_index()] = true

            init_object(lifeup,this.x,this.y)

            destroy_object(this)

        end

    end,

    draw=function(this)

        local off=0

        if not this.fly then

            local dir=sin(this.step)

            if dir<0 then

                off=1+max(0,sign(this.y-this.start))

            end

        else

            off=(off+0.25)%3

        end

        spr(45+off,this.x-6,this.y-2,1,1,true,false)

        spr(this.spr,this.x,this.y)

        spr(45+off,this.x+6,this.y-2)

    end

}

Glitches

When flying berries flap up and down, they don't follow a perfect cycle due to rounding errors and problems with pico-8's implementation of sin(). Over a very long time, these errors can accumulate and make the berry drift slowly upward. Since the berry's y position is an integer, it will underflow to a positive (lower) y position if the berry drifts any higher than y=-32768. While flying berries also drift slightly in emuulated versions of the game, the drift is much slower, and eventually stops happening altogether; as a result, this is usually considered a PICO-8 only glitch.

This slow drift takes a very long time; it takes 9 years for the berry to underflow. If you can't dash to make it rise back quickly, it takes another 9 years for the flying berry to drift back up into the main map. This glitch is used mainly in minimalist challenge runs, like getting the berry in 700m without jumping. It is also the primary technique in longleste, a challenge to make the longest beatable level.