Restore the GHZ Ball from Sonic 1 Prototype

In new dumped prototype Hidden Palace streamed, we finally got to see the ball in action. However I heard people like me had some errors porting it in and now ill show you guys how to restore it perfectly in the final! This tutorial is for github only.

1: Importing the code
Everyone knows that the Ball id is "19" (not to get confused with 48 "Swinging Ball Boss"), so we will be porting the code into Obj19! So heres the code in raw form:

Code:

ObjRollingBall:
        moveq    #0,d0
        move.b    $24(a0),d0
        move.w    off_5C8E(pc,d0.w),d1
        jmp    off_5C8E(pc,d1.w)
; ---------------------------------------------------------------------------

off_5C8E:    dc.w loc_5C98-off_5C8E, loc_5D2C-off_5C8E, loc_5D86-off_5C8E, loc_5E4A-off_5C8E, loc_5CEE-off_5C8E
; ---------------------------------------------------------------------------

loc_5C98:
        move.b    #$18,$16(a0)
        move.b    #$C,$17(a0)
        bsr.w    ObjectFall
        jsr    ObjectHitFloor
        tst.w    d1
        bpl.s    locret_5CEC
        add.w    d1,$C(a0)
        move.w    #0,$12(a0)
        move.b    #8,$24(a0)
        move.l    #MapRollingBall,4(a0)
        move.w    #$43AA,2(a0)
        move.b    #4,1(a0)
        move.b    #3,$19(a0)
        move.b    #$18,$18(a0)
        move.b    #1,$1F(a0)
        bsr.w    sub_5DC8

locret_5CEC:
        rts
; ---------------------------------------------------------------------------

loc_5CEE:
        move.w    #$23,d1
        move.w    #$18,d2
        move.w    #$18,d3
        move.w    8(a0),d4
        bsr.w    sub_A2BC
        btst    #5,$22(a0)
        bne.s    loc_5D14
        move.w    (ObjectsList+8).w,d0
        sub.w    8(a0),d0
        bcs.s    loc_5D20

loc_5D14:
        move.b    #2,$24(a0)
        move.w    #$80,$14(a0)

loc_5D20:
        bsr.w    sub_5DC8
        bsr.w    ObjectDisplay
        bra.w    loc_5E2A
; ---------------------------------------------------------------------------

loc_5D2C:
        btst    #1,$22(a0)
        bne.w    loc_5D86
        bsr.w    sub_5DC8
        bsr.w    sub_5E50
        bsr.w    ObjectMove
        move.w    #$23,d1
        move.w    #$18,d2
        move.w    #$18,d3
        move.w    8(a0),d4
        bsr.w    sub_A2BC
        jsr    ObjSonic_AnglePosition
        cmpi.w    #$20,8(a0)
        bcc.s    loc_5D70
        move.w    #$20,8(a0)
        move.w    #$400,$14(a0)

loc_5D70:
        btst    #1,$22(a0)
        beq.s    loc_5D7E
        move.w    #$FC00,$12(a0)

loc_5D7E:
        bsr.w    ObjectDisplay
        bra.w    loc_5E2A
; ---------------------------------------------------------------------------

loc_5D86:
        bsr.w    sub_5DC8
        bsr.w    ObjectMove
        move.w    #$23,d1
        move.w    #$18,d2
        move.w    #$18,d3
        move.w    8(a0),d4
        bsr.w    sub_A2BC
        jsr    ObjSonic_Floor
        btst    #1,$22(a0)
        beq.s    loc_5DBE
        move.w    $12(a0),d0
        addi.w    #$28,d0
        move.w    d0,$12(a0)
        bra.s    loc_5DC0
; ---------------------------------------------------------------------------

loc_5DBE:
        nop

loc_5DC0:
        bsr.w    ObjectDisplay
        bra.w    loc_5E2A
; ---------------------------------------------------------------------------

sub_5DC8:
        tst.b    $1A(a0)
        beq.s    loc_5DD6
        move.b    #0,$1A(a0)
        rts
; ---------------------------------------------------------------------------

loc_5DD6:
        move.b    $14(a0),d0
        beq.s    loc_5E02
        bmi.s    loc_5E0A
        subq.b    #1,$1E(a0)
        bpl.s    loc_5E02
        neg.b    d0
        addq.b    #8,d0
        bcs.s    loc_5DEC
        moveq    #0,d0

loc_5DEC:
        move.b    d0,$1E(a0)
        move.b    $1F(a0),d0
        addq.b    #1,d0
        cmpi.b    #4,d0
        bne.s    loc_5DFE
        moveq    #1,d0

loc_5DFE:
        move.b    d0,$1F(a0)

loc_5E02:
        move.b    $1F(a0),$1A(a0)
        rts
; ---------------------------------------------------------------------------

loc_5E0A:
        subq.b    #1,$1E(a0)
        bpl.s    loc_5E02
        addq.b    #8,d0
        bcs.s    loc_5E16
        moveq    #0,d0

loc_5E16:
        move.b    d0,$1E(a0)
        move.b    $1F(a0),d0
        subq.b    #1,d0
        bne.s    loc_5E24
        moveq    #3,d0

loc_5E24:
        move.b    d0,$1F(a0)
        bra.s    loc_5E02
; ---------------------------------------------------------------------------

loc_5E2A:
        move.w    8(a0),d0
        andi.w    #$FF80,d0
        move.w    (CameraX).w,d1
        subi.w    #$80,d1
        andi.w    #$FF80,d1
        sub.w    d1,d0
        cmpi.w    #$280,d0
        bhi.w    ObjectDelete
        rts
; ---------------------------------------------------------------------------

loc_5E4A:
        bsr.w    ObjectDelete
        rts
; ---------------------------------------------------------------------------

sub_5E50:
        move.b    $26(a0),d0
        bsr.w    GetSine
        move.w    d0,d2
        muls.w    #$38,d2
        asr.l    #8,d2
        add.w    d2,$14(a0)
        muls.w    $14(a0),d1
        asr.l    #8,d1
        move.w    d1,$10(a0)
        muls.w    $14(a0),d0
        asr.l    #8,d0
        move.w    d0,$12(a0)
        rts
; ---------------------------------------------------------------------------
        include "levels/GHZ/RollingBall/Sprite.map"
        even
; ---------------------------------------------------------------------------

Replace this:

Code:

ObjRollingBall:

With this:

Code:

Obj19:

2: Valid Code
This doesn't mean build up your rom, when building it will show up errors. That is because the code seen in Obj19 doesn't have any existing code! Lets fix that.

This is out first problem, the mapping code. The maps doesnt exist and so does the GFX, so all we have to do is replace this:

Code:

        move.l    #MapRollingBall,4(a0)

        move.w    #$43AA,2(a0)

With this:

Code:

        move.l    #Map_GBall,obMap(a0)
        move.w    #$43AA,obGfx(a0)

Our second problem is sub_A2BC. It doesn't exist either! sub_A2BC is a more earlier version of SpeedToPos. So replace any instances of sub_A2BC to SpeedToPos. This also goes with the GetSine code, replace all GetSine with the newer version (CalcSine). This is for every code (Obj_SonicAnglePosition,ObjectDelete,ObjectDisplay,Obj_SonicFloor). Do not add ObjectDelete, as it will remove the Ball in the process of it moving!

Our third problem is the ObjectMove code, it also doesn't exist! ObjectMove is basically BossMove. but again, an earlier version. Get the BossMove code from sonic.asm and put it in 19.asm (obj19). Then replace "BossMove:" with "ObjectMove:"

The last problem is ObjectFloorDistance. Replace that with ObjFloorDist.

3. Solid Ball

All we have to do is add the SolidObject code. you need to put this under all "bsr.w SpeedToPos". Here is the code:

Code:

move.w   #$20,d1
move.w   #$1B,d2
move.w   #$18,d3
bsr.w       SolidObject

Also, delete any instances of ObjectList!

4. Build

Build it an it should be done. Enjoy your new Rolling Ball!

 

thank you for this!

 

No problem! However, if it says theres errors in sub SolidObject about the "bsr.w MvSonicOnPlatform", change bsr.w to jsr instead.

Edit: set it to jsr not jmp

 

Don't do this, that's not the right instruction for any distance branching and returning.

Do jsr instead, jmp is for bra instructions.

 

Thank you GottaGoFast. Now i can build my own Sonic 1 Beta Remake.

 

Thank you so much for this tutorial! I hope to see more working GHZ Prototype Balls in new hacks! ;P