[4.5.x] Speed up music

[kevin81]

Hello everyone! I've written a small snippet you can use to speed up a song while it's playing. You could, for example, use it on a timer, for when the player is running out of time (you know, like in that turtle-kicking plumber game). The tempo gets reset to the original speed (by NESMaker/GGsound design) when the game loads a new song.

; This constant defines how much the tempo increases.
; A bigger value equals a bigger increase in tempo.
; Change this value to your liking.
MUSIC_SPEED_INCREMENT = #$B0

; Check if the high byte needs decreasing.
; A lower stream_tempo_ value indicates a higher speed,
; so these variables could be considered to be "length"
; rather than "tempo".
    LDA stream_tempo_lo
    SEC
    SBC #MUSIC_SPEED_INCREMENT
    BCS +changeLowByte

; Check if speed can be increased further.
; If not, skip changing the tempo altogether.
    STA temp
    LDA stream_tempo_hi
    CMP #$01
    BEQ +doNotChange

; Decrease the high byte values.
    DEC stream_tempo_hi
    DEC stream_tempo_hi+1
    DEC stream_tempo_hi+2
    DEC stream_tempo_hi+3    

; Decrease DPCM channel low byte only if DPCM is enabled
    ifdef FEATURE_DPCM
        DEC stream_tempo_hi+4
    endif

; Change the low byte values.
    LDA temp
+changeLowByte:
    STA stream_tempo_lo
    STA stream_tempo_lo+1
    STA stream_tempo_lo+2
    STA stream_tempo_lo+3

; Change DPCM channel low byte only if DPCM is enabled
    ifdef FEATURE_DPCM
        STA stream_tempo_lo+4
    endif

; we're done here
+doNotChange:

I have tested this code as an input script and that worked. Also it accounts for DPCM sample usage, although I didn't actually test this with the DPCM channel enabled. Please feel free to let me know what you think! If it works - or doesn't work - as intended, I'd love to hear that too.

 

[5kids2feed]

Whaaaat!? This is awesome! Could’ve used this ages ago. Thank you

 

[Bucket Mouse]

Does it go anyplace special, like a specific script or bank, or can it be used anywhere?

 

[kevin81]

Does it go anyplace special, like a specific script or bank, or can it be used anywhere?

The script only modifies a couple values in RAM, so it should work from any bank at any location. I've only tested it as an input script though, which sits in the static ($1F) bank. As long as you make sure the script gets executed only once (instead for instance at a tile collision, which gets run every frame or so, which will keep increasing the music speed to max value in no-time), you'll be good.

 

[dale_coop]

A similar topic:

Macro for changing current song speed

This is pretty straight forward. Whatever value you use for the argument is the equivalent of the speed setting in Famitracker. If anyone else is secretly messing with the DPCM channel, you need to add one more line. Also you may notice that this implies that you could set the speed of each...

www.nesmakers.com

 

[timefor]

I integrated this into a simple timer script, but with the repeating nature of a timer loop, any thoughts on a simple way to make sure the tempo increase runs only once? If I use the code as is, the speed increases until the max immediately. This code loops many times right at the "30" second mark.

;; Do Handle Game Timer Maze Module from NESmakers Forum (DALE COOP, 5kids2feed, ARCTIC BLIZZARD) ;;

;; What this script does is the Game Timer counts down.        ;;
;; When timer reaches zero your game will reset by default. ;;

;;; Game Timer Ticks ;;;

    LDA gameTimerTicks
    CLC
    ADC #$04             ;; this represents the speed myTimer will tick ;;
    STA gameTimerTicks
    BCC +normalwhatever

;; myTimer OFF when Screen Flag below is ACTIVE ;;

    LDA ScreenFlags00
    AND #%01000000 ;; if "hide hud" is set.
    BNE +normalwhatever ;; skip all the code related to myTimer

    SubtractValue #$02, myTimer, #$1, #$00
    UpdateHudElement #$06

+normalwhatever

;;; Game Timer 1's, & 10's place, & 100's place,  ;;;

    LDA gameTimerLo
    ADC #$09        ;; this represents the 1's place in the timer.
    STA gameTimerLo
    LDA gameTimerHi
    ADC #$09        ;; this represents the 10's place in the timer.
    STA gameTimerHi
    LDA gameTimerHigher
    ADC #$09        ;; this represents the 100's place in the timer.
    STA gameTimerHigher


;;; checking the value of the Game Timer ;;;

    LDA myTimer_100
    BNE +notEnded
    
    LDA myTimer_10
    CMP #$03 ;check if 10's place = 3
    BNE +notEnded ;skip if not
        LDA myTimer
        CMP #$00 ;check if 1's place = 0
        BNE +notEnded ;skip if not
            
            ;Play sound if myTime equals 30
            PlaySound #sfx_timeout
            
            ; This constant defines how much the tempo increases.
            ; A bigger value equals a bigger increase in tempo.
            ; Change this value to your liking.
            MUSIC_SPEED_INCREMENT = #$B0

            ; Check if the high byte needs decreasing.
            ; A lower stream_tempo_ value indicates a higher speed,
            ; so these variables could be considered to be "length"
            ; rather than "tempo".
                LDA stream_tempo_lo
                SEC
                SBC #MUSIC_SPEED_INCREMENT
                BCS +changeLowByte

            ; Check if speed can be increased further.
            ; If not, skip changing the tempo altogether.
                STA temp
                LDA stream_tempo_hi
                CMP #$01
                BEQ +doNotChange

            ; Decrease the high byte values.
                DEC stream_tempo_hi
                DEC stream_tempo_hi+1
                DEC stream_tempo_hi+2
                DEC stream_tempo_hi+3   

            ; Decrease DPCM channel low byte only if DPCM is enabled
                ifdef FEATURE_DPCM
                    DEC stream_tempo_hi+4
                endif

            ; Change the low byte values.
                LDA temp
            +changeLowByte:
                STA stream_tempo_lo
                STA stream_tempo_lo+1
                STA stream_tempo_lo+2
                STA stream_tempo_lo+3

            ; Change DPCM channel low byte only if DPCM is enabled
                ifdef FEATURE_DPCM
                    STA stream_tempo_lo+4
                endif

            ; we're done here
            +doNotChange:   
    
    LDA myTimer_10
    BNE +notEnded
    LDA myTimer
    BNE +notEnded

;; when Game Timer reaches 00.

    JMP RESET        ;; TESTING to RESET GAME ;;

+notEnded:

 

[kevin81]

I integrated this into a simple timer script, but with the repeating nature of a timer loop, any thoughts on a simple way to make sure the tempo increase runs only once? If I use the code as is, the speed increases until the max immediately. This code loops many times right at the "30" second mark.

The easiest way I can think of right now is using a helper variable, and add that as an extra check in the timer script.

The general idea is this:

1) Add a variable to your zero page settings, called isSpedUp, with an initial value of 0

2) In your post screen load script, reset this variable to zero:

    LDA #0
    STA isSpedUp

3) When the timer hits thirty, check if isSpedUp is zero:

    LDA isSpedUp
    BEQ +
        JMP +doNotChange
    +

4) If isSpedUp is zero, set it to one:

    LDA #1
    STA isSpedUp

and execute the speed-up script.

Ideally you would use a screenFlag instead of a variable, since you'll only need a single bit instead of a whole byte. But as long as you've got an extra zero page variable to spare, this method will work as well.

 

[kevin81]

A similar topic:

Macro for changing current song speed

This is pretty straight forward. Whatever value you use for the argument is the equivalent of the speed setting in Famitracker. If anyone else is secretly messing with the DPCM channel, you need to add one more line. Also you may notice that this implies that you could set the speed of each...

www.nesmakers.com

Whelp, I guess I overlooked that post before adding this topic... Sorry for the duplicate!

 

[dale_coop]

Whelp, I guess I overlooked that post before adding this topic... Sorry for the duplicate!

Do'nt be sorry. Your script is different. It's nice to have different approaches.
I just added the link because it's related (if people are interested/curious to check).