Enabling and disabling the Spike Behavior in the Title Screen

Enabling and disabling the Spike Behavior in the Title Screen


Sofia Mirror: http://www.sonicringnetwork.co.uk/sofia/show.php?p=10


EDIT: Since this is more copy and paste, I decided to move this to Source Code Exchange. The guide itself is for about 90% still the same.


=====Starts here=====


This is big problem: The Spike Behavior! Many people remove it from their hack, because it's really anoying.


But some people are still using it (I don't know why). So, I decided to create a code, on how to enable and disable it, without creating multiple versions of a hack.


Want it? Simply do this:


1: Open up your sonic1.asm and go to "loc_3230:". You should see this:



loc_3230:
tst.w ($FFFFF614).w


beq.w Demo


andi.b #$80,($FFFFF605).w ; check if Start is pressed


beq.w loc_317C ; if not, branch



2: Replace it with this:



loc_3230:
tst.w ($FFFFF614).w ; is there time left before the demo starts?


beq.w Demo ; if not, run demo


andi.b #$80,($FFFFF605).w ; has Start been pressed?


beq.w StartCheck ; if not, branch


cmpi.b #$40,($FFFFF605) ; has A been pressed?


bne.s StartCheck ; if not, branch


tst.b ($FFFFFFE0).w ; is level select enabled?


bne.w Title_ChkLevSel ; if yes, branch


tst.b ($FFFFFFFD).w ; was the Spike Behavior already enabled?


bne.s Disable_SB ; if yes, branch


move.b #1,($FFFFFFFD).w ; enable the Spike Behavior


move.b #$A6,d0 ; set spike death sound


jsr PlaySound_Special ; play spike death sound


bra.s StartCheck ; jskip Disable_SB


Disable_SB:


subi.b #1,($FFFFFFFD).w ; disable the spike behavior again


move.b #$C7,d0 ; set chain sound


bsr.w PlaySound_Special ; play chain sound


StartCheck:


andi.b #$80,($FFFFF605).w ; check if Start is pressed


beq.w loc_317C ; if not, branch



This code will check, if A is pressed and if yes, play a Spike Death sound and enable the Spike Behavior. If you press it again, you will hear another sound (the MZ Chain sound) and the Behavior is disabled again.


There is also a check for the Level Select, because you enable the behavior with A, and you'll need A for the Level Select. If you press A+Start, you will enable the Spike bug with the Level Select! So I made this. Also, if you want to use B or C instead of A, than replace in the third line the #$40 with:

You can delete the Level Select check if you are changing the button after that.


Note: If you added new characters (with the Tutorial on Sonic Retro), then replace every "Title_ChkLevSel" with "Title_CheckForB".


3: Now go to "Obj36_Hurt:". If you already disabled the Spike Behavior with the Tutorial on SR, you should see this:



Obj36_Hurt: ; XREF: Obj36_SideWays; Obj36_Upright
tst.b ($FFFFFE2D).w ; is Sonic invincible?


bne.s Obj36_Display ; if yes, branch


tst.w ($FFFFD030).w ; +++ is Sonic invulnerable?


bne.s Obj36_Display ; +++ if yes, branch


move.l a0,-(sp)


movea.l a0,a2


.


.


.



Otherwise, this:



Obj36_Hurt: ; XREF: Obj36_SideWays; Obj36_Upright
tst.b ($FFFFFE2D).w ; is Sonic invincible?


bne.s Obj36_Display ; if yes, branch


move.l a0,-(sp)


movea.l a0,a2


.


.


.



4: Replace everthing to "move.l a0,-(sp)" with this:



Obj36_Hurt: ; XREF: Obj36_SideWays; Obj36_Upright
tst.b ($FFFFFE2D).w ; is Sonic invincible?


bne.s Obj36_Display ; if yes, branch


tst.b ($FFFFFFFD).w ; was the Spike Behavior enabled?


bne.s Obj36_Hurt_Rest ; if yes, branch


tst.w ($FFFFD030).w ; +++ is Sonic invulnerable? (Spike Behavior check)


bne.s Obj36_Display ; +++ if yes, branch


Obj36_Hurt_Rest:



This will check, if the Spike Behavior is enabled. If yes, branch to "Obj36_Hurt_Rest:" (the other code). If not disable Spike Behavior.


Note: Spike Behavior is now disabled by default. If you want to enable it by default, then change:



beq.s Obj36_Hurt_Rest ; if yes, branch



To:



bne.s Obj36_Hurt_Rest ; if not, branch



Also you should switch the sounds.


5: That's it! Save and Build your ROM. In the Title Screen press A. You should here the Spike death sound. Start the game and search for some spike's to die! And? You are dead! Play it again, this time without pressing A. Search for the Spikes again and now? Not dead! And now, start it again and press A 2x. You should here a chain sound and you will not die again. Understand?


However, I hope you can do something with this!


Credits:


Me (Selbi) for everything (coding, guide)


FraGag for the Tutorial on SR, how to fix the Spike Behavior


The Add new characters tutorial at Sonic Retro, because this guide is based on it.


Version:


v1.1 (Found a huge bug and fixed it. Code updated a bit.)

 

Thank you Selbi, that was helpful.

 

Pretty cool your tutorials. Thanks again, but I prefer to remove it definately. =P Once more, thanks.

 

Update: The guide is now in the Sourcecode Exchange forum, because this was actually just a copy/paste guide with my code.

 

IS there a way to add in an Options menu to Sonic 1 like in Sonic 1 MegaMix where you can choose to enable or disable the spike bug?

 

Yes, Magic


Though it seems it's not as simple as flicking a lightswitch, or changing a lightbulb, or bumping a year old topic =P