[4.5.9] Holding B to Run

dale_coop · Feb 15, 2024

A small tutorial to show how to implement the Holding B to Run in your projects.

The principle is simple, we'll modify the Physics to modify the speed when B is pressed.

INSTRUCTIONS

Modify your Handle Physics script (you can find it in the "Project Settings > Script Settigns" under "SubRoutines").
Find those exact lines in the script (around line 110 or 270 or 280 depending of the module used):

Code:

        LDY Object_type,x
        LDA ObjectMaxSpeed,y
        ASL
        ASL
        ASL
        ASL
        ;AND #%00001111
        STA myMaxSpeed
        LDA ObjectMaxSpeed,y
        LSR
        LSR
        LSR
        LSR
        STA myMaxSpeed+1

And replace those lines with:

Code:

        LDY Object_type,x
        LDA ObjectMaxSpeed,y
        STA tempA
        ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
        ;; if holding B
        CPX player1_object
        BNE +skip   ;; if not the player object, we skip
            LDA gamepad
            AND #%00000010  ;; B button
            BEQ +skip
                LDA tempA
                ASL     ;; double the speed
                STA tempA
        +skip:
        ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
        LDA tempA
        ASL
        ASL
        ASL
        ASL
        ;AND #%00001111
        STA myMaxSpeed
        LDA tempA
        LSR
        LSR
        LSR
        LSR
        STA myMaxSpeed+1

Voilà, that's it.

NightMusic · Feb 15, 2024

dale_coop said:
A small tutorial to show how to implement the Holding B to Run in your projects.

View attachment 7869

The principle is simple, we'll modify the Physics to modify the speed when B is pressed.

INSTRUCTIONS

Modify your Handle Physics script (you can find it in the "Project Settings > Script Settigns" under "SubRoutines").
Find those exact lines in the script (around line 110 or 270 or 280 depending of the module used):

Code:

LDY Object_type,x LDA ObjectMaxSpeed,y ASL ASL ASL ASL ;AND #%00001111 STA myMaxSpeed LDA ObjectMaxSpeed,y LSR LSR LSR LSR STA myMaxSpeed+1

And replace those lines with:

Code:

LDY Object_type,x LDA ObjectMaxSpeed,y STA tempA ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; if holding B CPX player1_object BNE +skip ;; if not the player object, we skip LDA gamepad AND #%00000010 ;; B button BEQ +skip LDA tempA ASL ;; double the speed STA tempA +skip: ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; LDA tempA ASL ASL ASL ASL ;AND #%00001111 STA myMaxSpeed LDA tempA LSR LSR LSR LSR STA myMaxSpeed+1

Voilà, that's it.

This is awesome! Run Agent Cooper Run! (get that next cup of midnight black coffee!)

thank you

dale_coop · Feb 15, 2024

NightMusic said:
This is awesome! Run Agent Cooper Run! (get that next cup of midnight black coffee!) thank you

Oh yes! I should make a small arcade/maze game about agent Cooper running after his coffee!

5kids2feed · Feb 16, 2024

dale_coop said:
Oh yes! I should make a small arcade/maze game about agent Cooper running after his coffee!

That or Agent Cooper running to everybody’s projects trying to help fix their buggy code!

TheRetroBro · Feb 28, 2024

dale_coop said:
A small tutorial to show how to implement the Holding B to Run in your projects.

View attachment 7869

The principle is simple, we'll modify the Physics to modify the speed when B is pressed.

INSTRUCTIONS

Modify your Handle Physics script (you can find it in the "Project Settings > Script Settigns" under "SubRoutines").
Find those exact lines in the script (around line 110 or 270 or 280 depending of the module used):

Code:

LDY Object_type,x LDA ObjectMaxSpeed,y ASL ASL ASL ASL ;AND #%00001111 STA myMaxSpeed LDA ObjectMaxSpeed,y LSR LSR LSR LSR STA myMaxSpeed+1

And replace those lines with:

Code:

LDY Object_type,x LDA ObjectMaxSpeed,y STA tempA ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; if holding B CPX player1_object BNE +skip ;; if not the player object, we skip LDA gamepad AND #%00000010 ;; B button BEQ +skip LDA tempA ASL ;; double the speed STA tempA +skip: ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; LDA tempA ASL ASL ASL ASL ;AND #%00001111 STA myMaxSpeed LDA tempA LSR LSR LSR LSR STA myMaxSpeed+1

Voilà, that's it.

will this work in platformer if Im using b to shoot?

dale_coop · Feb 28, 2024

it should work too (like when Mario shoot a fireball before starting to run

)
(....Unless your 'B shoot' stops the player's movements)

TheRetroBro · Feb 28, 2024

dale_coop said:
it should work too (like when Mario shoot a fireball before starting to run )
(....Unless your 'B shoot' stops the player's movements)

Nope I can jump move etc when shooting so shouldnt be a problem : )

TheRetroBro · Feb 28, 2024

dale_coop said:
it should work too (like when Mario shoot a fireball before starting to run )
(....Unless your 'B shoot' stops the player's movements)

So I implemented this and it works . My only questions is can I change the increase speed to say 20% instead of 50? 50 is just way too fast!

dale_coop · Mar 1, 2024

If you want to use a more precise speed run, you could replace the

Code:

LDA tempA
ASL     ;; double the speed
STA tempA

With:

Code:

LDA tempA
CLC
ADC #16 ;; you can use any value here from 00 to 255 to adjust the running speed
STA tempA

Luxnolucas · Mar 9, 2024

It works perfectly! Is it possible to create a tile based on the same principle?

dale_coop · Mar 11, 2024

Would be doable (using a variable to set/check), but a little more complicated.

Luxnolucas · Mar 11, 2024

Yep, i try to use this

Code:

pha
  CPX player1_object
  LDA Object_h_speed_hi,x
  SEC
  SBC #$02   ; Ralentissement
  STA Object_h_speed_hi,x
 
  LDA Object_v_speed_hi,x
  SEC
  SBC #$00   ; Ralentissement
  STA Object_v_speed_hi,x
pla

But it's not really smooth... And ultimately, managing the scrolling speed with keys is more suitable than with tiles.
thanks

Lord_Klump_Of_Kongo_Bongo · Jun 19, 2024

Hey Dale it's me that annoying guy again! just curious your script currently doubles the speed... is there a way to make the speed 1.5 times the normal amount?
because doubling the speed seems too fast for what I'm trying to do

SciNEStist · Jun 19, 2024

the part where it has

Code:

LDA tempA
ASL     ;; double the speed
STA tempA

can be replaced with anything you want.
Just keep in mind that "myMaxSpeed" is the lo amount (sub pixels), and "myMaxSpeed+1" is the hi amount (pixels) and from a quick look, its stored as "HHHHLLLL" So you want to save your variable accordingly

zeldafreakneo · Aug 18, 2024

dale_coop said:
If you want to use a more precise speed run, you could replace the

Code:

LDA tempA ASL ;; double the speed STA tempA

With:

Code:

LDA tempA CLC ADC #16 ;; you can use any value here from 00 to 255 to adjust the running speed STA tempA

How could you use this to subtract speed?

dale_coop · Aug 19, 2024

zeldafreakneo said:
How could you use this to subtract speed?

to subtract:

Code:

LDA tempA
SEC
SBC #16 ;; you can use any value here from 00 to 255 to adjust the running speed
STA tempA

zeldafreakneo · Aug 19, 2024

dale_coop said:
to subtract:

Code:

LDA tempA SEC SBC #16 ;; you can use any value here from 00 to 255 to adjust the running speed STA tempA

Just to be clear the "#16" is the value you change to adjust running speed?

smilehero65 · Aug 19, 2024

zeldafreakneo said:
Just to be clear the "#16" is the value you change to adjust running speed?

yep

General Panzer · Oct 11, 2024

So I used this a little differently. I wanted the bats in Frontiers to charge the player. I added a check against the bats action step instead of the players button. The bat starts at 1/3 speed, dives, and then when he changes to the action step that I want him to charge in the speed boost takes over

So if you are designing a monster that needs a speed boost for an attack this might be your solution!

LDY Object_type,x
LDA ObjectMaxSpeed,y
STA tempA
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; if holding B
LDA Object_type,x
CMP #33
BEQ +Bats
JMP +skip
+Bats
TXA
STA temp ;; assumes the object we want to move is in x.
GetActionStep temp ;; get current action state
CMP #02 ;compare to 6
BNE +skip
LDA tempA
ASL
ASL
ASL ;; double the speed
STA tempA
+skip:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
LDA tempA
ASL
ASL
ASL
ASL
;AND #%00001111
STA myMaxSpeed
LDA tempA
LSR
LSR
LSR
LSR
STA myMaxSpeed+1
;;; now high max speed byte is the actual high byte of speed
;;; low max speed byte is the low byte of speed

dale_coop · Oct 13, 2024

9Panzer said:
So I used this a little differently. I wanted the bats in Frontiers to charge the player. I added a check against the bats action step instead of the players button. The bat starts at 1/3 speed, dives, and then when he changes to the action step that I want him to charge in the speed boost takes over

So if you are designing a monster that needs a speed boost for an attack this might be your solution!

Amazing idea !

[4.5.9] Holding B to Run

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