How to improve the fade in and fade out progressions in Sonic 1 and 2

MarkeyJester · Dec 18, 2011

The palette fading routines in Sonic 1 and Sonic 2 (and possibly to a degree Sonic 3 & Knuckles) known as "Pal_FadeTo" and "Pal_FadeFrom", aren't 100% true to their name. Here is a screenshot of Sonic 1's title screen 6 frames during fade in:

From a logical point of view, this is incorrect fading, what happens here is it fades the blue parts in first, then fades the green parts in, and then finally fades the red parts in, the same goes for fading out, red first, then green, finally blue.

Strictly speaking for a the nearest possible perfect fade, all colours need to be fading in and out simultaneously (At the correct timing of course), so for example the colour 06E4 should fade in the pattern of:

0020 0040 0060 0080 02A0 04C2 06E4

And fade out in the pattern of:

04C2 02A0 0080 0060 0040 0020 0000

To correct for Sonic 1, you'll need to go to the routine "Pal_FadeTo" and replace everything from there down to "; End of function Pal_DecColor" with this:

(Unfortunately this is going to look more messy than it is until IPB can get the fucking tab spaces fixed properly)

Pal_FadeTo:
move.w #$3F,($FFFFF626).w

Pal_FadeTo2:

moveq #0,d0

lea ($FFFFFB00).w,a0

move.b ($FFFFF626).w,d0

adda.w d0,a0

moveq #0,d1

move.b ($FFFFF627).w,d0

Pal_ToBlack:

move.w d1,(a0)+

dbf d0,Pal_ToBlack ; fill pallet with $000 (black)

moveq #$0E,d4 ; MJ: prepare maximum colour check

moveq #$00,d6 ; MJ: clear d6

loc_1DCE:

bsr.w RunPLC_RAM

move.b #$12,($FFFFF62A).w

bsr.w DelayProgram

bchg #$00,d6 ; MJ: change delay counter

beq loc_1DCE ; MJ: if null, delay a frame

bsr.s Pal_FadeIn

subq.b #$02,d4 ; MJ: decrease colour check

bne loc_1DCE ; MJ: if it has not reached null, branch

move.b #$12,($FFFFF62A).w ; MJ: wait for V-blank again (so colours transfer)

bra DelayProgram ; MJ: ''

; End of function Pal_FadeTo

; ---------------------------------------------------------------------------

; Pallet fade-in subroutine

; ---------------------------------------------------------------------------

; ||||||||||||||| S U B R O U T I N E |||||||||||||||||||||||||||||||||||||||

Pal_FadeIn: ; XREF: Pal_FadeTo

moveq #0,d0

lea ($FFFFFB00).w,a0

lea ($FFFFFB80).w,a1

move.b ($FFFFF626).w,d0

adda.w d0,a0

adda.w d0,a1

move.b ($FFFFF627).w,d0

loc_1DFA:

bsr.s Pal_AddColor

dbf d0,loc_1DFA

cmpi.b #1,($FFFFFE10).w

bne.s locret_1E24

moveq #0,d0

lea ($FFFFFA80).w,a0

lea ($FFFFFA00).w,a1

move.b ($FFFFF626).w,d0

adda.w d0,a0

adda.w d0,a1

move.b ($FFFFF627).w,d0

loc_1E1E:

bsr.s Pal_AddColor

dbf d0,loc_1E1E

locret_1E24:

rts

; End of function Pal_FadeIn

; ||||||||||||||| S U B R O U T I N E |||||||||||||||||||||||||||||||||||||||

Pal_AddColor: ; XREF: Pal_FadeIn

move.b (a1),d5 ; MJ: load blue

move.w (a1)+,d1 ; MJ: load green and red

move.b d1,d2 ; MJ: load red

lsr.b #$04,d1 ; MJ: get only green

andi.b #$0E,d2 ; MJ: get only red

move.w (a0),d3 ; MJ: load current colour in buffer

cmp.b d5,d4 ; MJ: is it time for blue to fade?

bhi FCI_NoBlue ; MJ: if not, branch

addi.w #$0200,d3 ; MJ: increase blue

FCI_NoBlue:

cmp.b d1,d4 ; MJ: is it time for green to fade?

bhi FCI_NoGreen ; MJ: if not, branch

addi.b #$20,d3 ; MJ: increase green

FCI_NoGreen:

cmp.b d2,d4 ; MJ: is it time for red to fade?

bhi FCI_NoRed ; MJ: if not, branch

addq.b #$02,d3 ; MJ: increase red

FCI_NoRed:

move.w d3,(a0)+ ; MJ: save colour

rts ; MJ: return

; End of function Pal_AddColor

; ||||||||||||||| S U B R O U T I N E |||||||||||||||||||||||||||||||||||||||

Pal_FadeFrom:

move.w #$3F,($FFFFF626).w

moveq #$07,d4 ; MJ: set repeat times

moveq #$00,d6 ; MJ: clear d6

loc_1E5C:

bsr.w RunPLC_RAM

move.b #$12,($FFFFF62A).w

bsr.w DelayProgram

bchg #$00,d6 ; MJ: change delay counter

beq loc_1E5C ; MJ: if null, delay a frame

bsr.s Pal_FadeOut

dbf d4,loc_1E5C

rts

; End of function Pal_FadeFrom

; ---------------------------------------------------------------------------

; Pallet fade-out subroutine

; ---------------------------------------------------------------------------

; ||||||||||||||| S U B R O U T I N E |||||||||||||||||||||||||||||||||||||||

Pal_FadeOut: ; XREF: Pal_FadeFrom

moveq #0,d0

lea ($FFFFFB00).w,a0

move.b ($FFFFF626).w,d0

adda.w d0,a0

move.b ($FFFFF627).w,d0

loc_1E82:

bsr.s Pal_DecColor

dbf d0,loc_1E82

moveq #0,d0

lea ($FFFFFA80).w,a0

move.b ($FFFFF626).w,d0

adda.w d0,a0

move.b ($FFFFF627).w,d0

loc_1E98:

bsr.s Pal_DecColor

dbf d0,loc_1E98

rts

; End of function Pal_FadeOut

; ||||||||||||||| S U B R O U T I N E |||||||||||||||||||||||||||||||||||||||

Pal_DecColor: ; XREF: Pal_FadeOut

move.w (a0),d5 ; MJ: load colour

move.w d5,d1 ; MJ: copy to d1

move.b d1,d2 ; MJ: load green and red

move.b d1,d3 ; MJ: load red

andi.w #$0E00,d1 ; MJ: get only blue

beq FCO_NoBlue ; MJ: if blue is finished, branch

subi.w #$0200,d5 ; MJ: decrease blue

FCO_NoBlue:

andi.b #$E0,d2 ; MJ: get only green

beq FCO_NoGreen ; MJ: if green is finished, branch

subi.b #$20,d5 ; MJ: decrease green

FCO_NoGreen:

andi.b #$0E,d3 ; MJ: get only red

beq FCO_NoRed ; MJ: if red is finished, branch

subq.b #$02,d5 ; MJ: decrease red

FCO_NoRed:

move.w d5,(a0)+ ; MJ: save new colour

rts ; MJ: return

; End of function Pal_DecColor

This will result in proper fading:

The same for Sonic 2:

Pal_FadeTo:
move.w #$3F,($FFFFF626).w

moveq #0,d0

lea (Normal_palette).w,a0

move.b ($FFFFF626).w,d0

adda.w d0,a0

moveq #0,d1

move.b ($FFFFF627).w,d0

; loc_23DE:

Pal_ToBlack:

move.w d1,(a0)+

dbf d0,Pal_ToBlack ; fill palette with $000 (black)

moveq #$0E,d4 ; MJ: prepare maximum colour check

moveq #$00,d6 ; MJ: clear d6

- bsr.w RunPLC_RAM

move.b #$12,(Delay_Time).w

bsr.w DelayProgram

bchg #$00,d6 ; MJ: change delay counter

beq - ; MJ: if null, delay a frame

bsr.s Pal_FadeIn

subq.b #$02,d4 ; MJ: decrease colour check

bne - ; MJ: if it has not reached null, branch

move.b #$12,(Delay_Time).w ; MJ: wait for V-blank again (so colours transfer)

bra DelayProgram ; MJ: ''

; End of function Pal_FadeTo

; ---------------------------------------------------------------------------

; Palette fade-in subroutine

; ---------------------------------------------------------------------------

; ||||||||||||||| S U B R O U T I N E |||||||||||||||||||||||||||||||||||||||

; sub_23FE:

Pal_FadeIn:

moveq #0,d0

lea (Normal_palette).w,a0

lea (Second_palette).w,a1

move.b ($FFFFF626).w,d0

adda.w d0,a0

adda.w d0,a1

move.b ($FFFFF627).w,d0

- bsr.s Pal_AddColor

dbf d0,-

tst.b (Water_flag).w

beq.s return_243C

moveq #0,d0

lea (Underwater_palette).w,a0

lea (Underwater_palette_2).w,a1

move.b ($FFFFF626).w,d0

adda.w d0,a0

adda.w d0,a1

move.b ($FFFFF627).w,d0

- bsr.s Pal_AddColor

dbf d0,-

return_243C:

rts

; End of function Pal_FadeIn

; ||||||||||||||| S U B R O U T I N E |||||||||||||||||||||||||||||||||||||||

; sub_243E:

Pal_AddColor:

move.b (a1),d5 ; MJ: load blue

move.w (a1)+,d1 ; MJ: load green and red

move.b d1,d2 ; MJ: load red

lsr.b #$04,d1 ; MJ: get only green

andi.b #$0E,d2 ; MJ: get only red

move.w (a0),d3 ; MJ: load current colour in buffer

cmp.b d5,d4 ; MJ: is it time for blue to fade?

bhi FCI_NoBlue ; MJ: if not, branch

addi.w #$0200,d3 ; MJ: increase blue

FCI_NoBlue:

cmp.b d1,d4 ; MJ: is it time for green to fade?

bhi FCI_NoGreen ; MJ: if not, branch

addi.b #$20,d3 ; MJ: increase green

FCI_NoGreen:

cmp.b d2,d4 ; MJ: is it time for red to fade?

bhi FCI_NoRed ; MJ: if not, branch

addq.b #$02,d3 ; MJ: increase red

FCI_NoRed:

move.w d3,(a0)+ ; MJ: save colour

rts ; MJ: return

; End of function Pal_AddColor

; ||||||||||||||| S U B R O U T I N E |||||||||||||||||||||||||||||||||||||||

; sub_246A:

Pal_FadeFrom:

move.w #$3F,($FFFFF626).w

moveq #$07,d4 ; MJ: set repeat times

moveq #$00,d6 ; MJ: clear d6

- bsr.w RunPLC_RAM

move.b #$12,(Delay_Time).w

bsr.w DelayProgram

bchg #$00,d6 ; MJ: change delay counter

beq - ; MJ: if null, delay a frame

bsr.s Pal_FadeOut

dbf d4,-

rts

; End of function Pal_FadeFrom

; ---------------------------------------------------------------------------

; Palette fade-out subroutine

; ---------------------------------------------------------------------------

; ||||||||||||||| S U B R O U T I N E |||||||||||||||||||||||||||||||||||||||

; sub_248A:

Pal_FadeOut:

moveq #0,d0

lea (Normal_palette).w,a0

move.b ($FFFFF626).w,d0

adda.w d0,a0

move.b ($FFFFF627).w,d0

- bsr.s Pal_DecColor

dbf d0,-

moveq #0,d0

lea (Underwater_palette).w,a0

move.b ($FFFFF626).w,d0

adda.w d0,a0

move.b ($FFFFF627).w,d0

- bsr.s Pal_DecColor

dbf d0,-

rts

; End of function Pal_FadeOut

; ||||||||||||||| S U B R O U T I N E |||||||||||||||||||||||||||||||||||||||

; sub_24B8:

Pal_DecColor:

move.w (a0),d5 ; MJ: load colour

move.w d5,d1 ; MJ: copy to d1

move.b d1,d2 ; MJ: load green and red

move.b d1,d3 ; MJ: load red

andi.w #$0E00,d1 ; MJ: get only blue

beq FCO_NoBlue ; MJ: if blue is finished, branch

subi.w #$0200,d5 ; MJ: decrease blue

FCO_NoBlue:

andi.b #$E0,d2 ; MJ: get only green

beq FCO_NoGreen ; MJ: if green is finished, branch

subi.b #$20,d5 ; MJ: decrease green

FCO_NoGreen:

andi.b #$0E,d3 ; MJ: get only red

beq FCO_NoRed ; MJ: if red is finished, branch

subq.b #$02,d5 ; MJ: decrease red

FCO_NoRed:

move.w d5,(a0)+ ; MJ: save new colour

rts ; MJ: return

; End of function Pal_DecColor

Sonic 2 has a specialised object to deal with title screen fading, so a correction is needed there too, At:

loc_13302:
addq.b #2,routine(a0)

moveq #0,d0

move.b subtype(a0),d0

lea (PaletteChangerDataIndex).l,a1

adda.w (a1,d0.w),a1

move.l (a1)+,objoff_3A(a0)

movea.l (a1)+,a2

move.b (a1)+,d0

move.w d0,objoff_34(a0)

lea (Second_palette).w,a3

adda.w d0,a3

move.b (a1)+,d0

move.w d0,objoff_36(a0)

Place this instruction directly at the end:

move.b #$0E,objoff_33(a0) ; MJ: set fade counter

At:

NewRoutine:
subq.b #1,objoff_30(a0)

bpl.s return_1337A

move.b objoff_31(a0),objoff_30(a0)

subq.b #1,objoff_32(a0)

bmi.w DeleteObject

Place these instructions directly underneath (Just above "movea.l objoff_3A(a0),a2"):

moveq #$00,d4 ; MJ: clear d4

move.b objoff_33(a0),d4 ; MJ: load fade counter

subq.b #$02,objoff_33(a0) ; MJ: decrease fade counter

And finally:

off_1338C: C9PalInfo Pal_AddColor, Pal_1342C, $60, $F,2,$15

Replace the $15 on the end with $07, this will correct the palette fading in and out for Sonic 2:

Left old, right new, here are some roms with the code in action:

Sonic 1 Fade

Sonic 2 Fade

Psycho RFG · Dec 17, 2011

Nice! Good work MarkeyJester. Now the palettes fit perfecly when using fades. The white starting as blue was too weird sometimes. Thanks for this fix.

redhotsonic · Dec 18, 2011

loc_1332E:
move.w (a2)+,(a3)+

dbf d0,loc_1332E

move.b (a1)+,d0

move.b d0,objoff_30(a0)

move.b d0,objoff_31(a0)

move.b (a1)+,objoff_32(a0)

rts

; ===========================================================================

; unused/dead code ; a0=object

subq.b #1,objoff_30(a0)

bpl.s return_1337A

move.b objoff_31(a0),objoff_30(a0)

subq.b #1,objoff_32(a0)

bmi.w DeleteObject

movea.l objoff_3A(a0),a2

movea.l a0,a3

move.w objoff_36(a0),d0

move.w objoff_34(a0),d1

lea (Normal_palette).w,a0

adda.w d1,a0

lea (Second_palette).w,a1

adda.w d1,a1

So that code isn't really dead then? =P Also, I applied your new fading technique and it's nice and it works from going from one level to another, but the title menu has gone wrong now, any reason?

EDIT: Although, when the stars twinkle just before the art work loads, if you press start, it all loads up instantly and then it's viewable. If I don't press start and let the artwork fade in, I get the above result.

Selbi · Dec 18, 2011

Man, we should really get these ASM tags to work again. But until that is done, it'd be a better idea to use [code] tags, so it'd be great if you could edit your post again (as annoying as it may seem).

As for the actual content, this is one of these "Never noticed it before you mentioned it" kind of things. This comes from the fact that I always found the fade transition fine as it was, but taking a closer look really shows me that I was wrong. This looks cleaner and more accurate, the way it should've always been.

However, it did give me a weird feeling. I noticed that I've seen this before. So, is it just me or did you use this feature in your own projects for years now, but never had time to actually make a guide for it? Because when I downloaded the Sonic 1 example, I immediately thought "Yep, this is done by MarkeyJester".

MarkeyJester · Dec 18, 2011

As a matter of fact, no, it isn't, it was just overlooked by a table that was disassembled when it shouldn't have been:

Code:

	move.w	loc_132FE(pc,d0.w),d1

	jmp	loc_132FE(pc,d1.w)

; ===========================================================================



loc_132FE:

	ori.b	#$46,d4

That ori.b #$46,d4 is infact two words of pointer data being 0004 and 0046, these are the routines address minus the table start address:

Code:

	move.w	loc_132FE(pc,d0.w),d1

	jmp	loc_132FE(pc,d1.w)

; ===========================================================================



loc_132FE:

	dc.w	loc_13302-loc_132FE

	dc.w	NewRoutine-loc_132FE



loc_13302:

Where "NewRoutine" points to that "unused" routine you've noted. As for what's gone wrong on your end, it's beyond me, if you don't have this code then it simply won't run correctly:

Code:

; ===========================================================================

; ----------------------------------------------------------------------------

; Object C9 - "Palette changing handler" from title screen

; ----------------------------------------------------------------------------

; Sprite_132F0:

ObjC9:

	moveq	#0,d0

	move.b	routine(a0),d0

	move.w	loc_132FE(pc,d0.w),d1

	jmp	loc_132FE(pc,d1.w)

; ===========================================================================



loc_132FE:

	dc.w	loc_13302-loc_132FE

	dc.w	NewRoutine-loc_132FE



loc_13302:

	addq.b	#2,routine(a0)

	moveq	#0,d0

	move.b	subtype(a0),d0

	lea	(PaletteChangerDataIndex).l,a1

	adda.w	(a1,d0.w),a1

	move.l	(a1)+,objoff_3A(a0)

	movea.l	(a1)+,a2

	move.b	(a1)+,d0

	move.w	d0,objoff_34(a0)

	lea	(Second_palette).w,a3

	adda.w	d0,a3

	move.b	(a1)+,d0

	move.w	d0,objoff_36(a0)

		move.b	#$0E,objoff_33(a0)			; MJ: set fade counter



loc_1332E:

	move.w	(a2)+,(a3)+

	dbf	d0,loc_1332E

	move.b	(a1)+,d0

	move.b	d0,objoff_30(a0)

	move.b	d0,objoff_31(a0)

	move.b	(a1)+,objoff_32(a0)

	rts

; ===========================================================================

	; unused/dead code ; a0=object



NewRoutine:

	subq.b	#1,objoff_30(a0)

	bpl.s	return_1337A

	move.b	objoff_31(a0),objoff_30(a0)

	subq.b	#1,objoff_32(a0)

	bmi.w	DeleteObject

		moveq	#$00,d4					; MJ: clear d4

		move.b	objoff_33(a0),d4			; MJ: load fade counter

		subq.b	#$02,objoff_33(a0)			; MJ: decrease fade counter

	movea.l	objoff_3A(a0),a2				; load routine to run

	movea.l	a0,a3						; store current object

	move.w	objoff_36(a0),d0				; load length

	move.w	objoff_34(a0),d1				; load loadtooffset

	lea	(Normal_palette).w,a0

	adda.w	d1,a0

	lea	(Second_palette).w,a1

	adda.w	d1,a1



-	jsr	(a2)	; dynamic call! to Pal_AddColor, loc_1344C, or loc_1348A, assuming the PaletteChangerData pointers haven't been changed

	dbf	d0,-

	movea.l	a3,a0



return_1337A:

	rts

	

; ===========================================================================

; off_1337C:

PaletteChangerDataIndex:

	dc.w off_1338C - PaletteChangerDataIndex; 0

	dc.w off_13398 - PaletteChangerDataIndex; 1

	dc.w off_133A4 - PaletteChangerDataIndex; 2

	dc.w off_133B0 - PaletteChangerDataIndex; 3

	dc.w off_133BC - PaletteChangerDataIndex; 4

	dc.w off_133C8 - PaletteChangerDataIndex; 5

	dc.w off_133D4 - PaletteChangerDataIndex; 6

	dc.w off_133E0 - PaletteChangerDataIndex; 7



C9PalInfo macro codeptr,dataptr,loadtoOffset,length,fadeinTime,fadeinAmount

	dc.l codeptr, dataptr

	dc.b loadtoOffset, length, fadeinTime, fadeinAmount

	endm



off_1338C:	C9PalInfo Pal_AddColor, Pal_1342C, $60, $F,2,$07 ; MJ: 15 to 7

off_13398:	C9PalInfo	loc_1344C, Pal_1340C, $40, $F,4,7

off_133A4:	C9PalInfo	loc_1344C,  Pal_AD1E,   0, $F,8,7

off_133B0:	C9PalInfo	loc_1348A,  Pal_AD1E,   0, $F,8,7

off_133BC:	C9PalInfo	loc_1344C,  Pal_AC7E,   0,$1F,4,7

off_133C8:	C9PalInfo	loc_1344C,  Pal_ACDE, $40,$1F,4,7

off_133D4:	C9PalInfo	loc_1344C,  Pal_AD3E,   0, $F,4,7

off_133E0:	C9PalInfo	loc_1344C,  Pal_AC9E,   0,$1F,4,7



Pal_133EC:	BINCLUDE "art/palettes/Title Sonic.bin"

Pal_1340C:	BINCLUDE "art/palettes/Title Background.bin"

Pal_1342C:	BINCLUDE "art/palettes/Title Emblem.bin"



; ===========================================================================

I haven't actually applied it to any hacks before, but I did note about it a few years ago, but that was in a private channel, so chances are you've never seen any hack associated with me to do with palette fading

OrdosAlpha · Dec 18, 2011

For two decades the fading in and fading out routines have irritated me. Now I can finally correct it.

SpirituInsanum · Dec 18, 2011

Nice work, and very well commented as usual

Well, I tested it, and don't like it much. It's technically perfect, but it looks kind of depressing to me for some reason. It probably isn't colourful enough.

I modified a few bits here and there to turn it into a secondary fading routine though, I'll probably use it in a few cases (death or pale/greyish levels for example).

I think I'll experiment a little with it, for example increasing the blue for one frame, then the blue and the green, and finally all colours. I'll report if the results are... worth reporting xD

redhotsonic · Dec 18, 2011

MarkeyJester said: ↑
Code:
	move.w	loc_132FE(pc,d0.w),d1

	jmp	loc_132FE(pc,d1.w)

; ===========================================================================



loc_132FE:

	dc.w	loc_13302-loc_132FE

	dc.w	NewRoutine-loc_132FE



loc_13302:
Click to expand...
This was the probem. As you can see when I quoted to you that dead (yet undead) code, there was no label pointing to it and right above it is an 'rts', so it was truley being "unused". Adding the new code you quoted above and then adding the "NewRouine" label next to the "dead" code, it now works perfectly. Cheers, mate =)

SpirituInsanum · Dec 19, 2011

I experimented a little with this, as said above, and have this version where the blue loads 1 frame before the green, and the green one frame before the red.

Screenshot (not from the original s1, but little was modified)

This is only for the first part, and you may have to remove the "Neutral_" from the labels. It goes from "Pal_ToBlack" to "; End of function Pal_AddColor"

Pal_Neutral_ToBlack:

move.w d1,(a0)+

dbf d0,Pal_Neutral_ToBlack ; fill pallet with $000 (black)

moveq #$12,d4 ; MJ: prepare maximum colour check ($E) ; SI: maximum is not enough, MOOOAAAR

moveq #$00,d6 ; MJ: clear d6

@loop:

bsr.w RunPLC_RAM

move.b #$12,($FFFFF62A).w

bsr.w DelayProgram

bchg #$00,d6 ; MJ: change delay counter

beq @loop ; MJ: if null, delay a frame

bsr.s Pal_Neutral_FadeIn

subq.b #$02,d4 ; MJ: decrease colour check

cmpi.b #4,d4

bne @loop ; MJ: if it has not reached null, branch

@loop2:

move.b #$12,($FFFFF62A).w ; MJ: wait for V-blank again (so colours transfer)

bsr.w DelayProgram ; MJ: ''

bchg #$00,d6 ; MJ: change delay counter

beq @loop2 ; MJ: if null, delay a frame

bsr Pal_Neutral_FadeInGR ; SI: add more green and red

@loop3:

move.b #$12,($FFFFF62A).w ; MJ: wait for V-blank again (so colours transfer)

bsr.w DelayProgram ; MJ: ''

bchg #$00,d6 ; MJ: change delay counter

beq @loop3 ; MJ: if null, delay a frame

bsr Pal_Neutral_FadeInR ; SI: add more red

move.b #$12,($FFFFF62A).w ; MJ: wait for V-blank again (so colours transfer)

bra DelayProgram ; MJ: ''

Pal_Neutral_FadeIn: ; XREF: Pal_Neutral_FadeTo

moveq #0,d0

lea ($FFFFFB00).w,a0

lea ($FFFFFB80).w,a1

move.b ($FFFFF626).w,d0

adda.w d0,a0

adda.w d0,a1

move.b ($FFFFF627).w,d0

@loop:

bsr.s Pal_Neutral_AddColor

dbf d0,@loop

cmpi.b #1,($FFFFFE10).w

bne.s @skip

moveq #0,d0

lea ($FFFFFA80).w,a0

lea ($FFFFFA00).w,a1

move.b ($FFFFF626).w,d0

adda.w d0,a0

adda.w d0,a1

move.b ($FFFFF627).w,d0

@loop2:

bsr.s Pal_Neutral_AddColor

dbf d0,@loop2

@skip:

rts

; End of function Pal_Neutral_FadeIn

; ||||||||||||||| S U B R O U T I N E |||||||||||||||||||||||||||||||||||||||

Pal_Neutral_AddColor: ; XREF: Pal_Neutral_FadeIn

move.b (a1),d5 ; MJ: load blue

move.w (a1)+,d1 ; MJ: load green and red

move.b d1,d2 ; MJ: load red

lsr.b #$04,d1 ; MJ: get only green

andi.b #$0E,d2 ; MJ: get only red

move.w (a0),d3 ; MJ: load current colour in buffer

addi.b #4,d5 ; SI: this is blue magic

cmp.b d5,d4 ; MJ: is it time for blue to fade?

bhi @FCI_NoBlue ; MJ: if not, branch

addi.w #$0200,d3 ; MJ: increase blue

@FCI_NoBlue:

addi.b #2,d1 ; SI: this is green magic

cmp.b d1,d4 ; MJ: is it time for green to fade?

bhi @FCI_NoGreen ; MJ: if not, branch

addi.b #$20,d3 ; MJ: increase green

@FCI_NoGreen:

cmp.b d2,d4 ; MJ: is it time for red to fade?

bhi @FCI_NoRed ; MJ: if not, branch

addq.b #$02,d3 ; MJ: increase red

@FCI_NoRed:

move.w d3,(a0)+ ; MJ: save colour

rts ; MJ: return

Pal_Neutral_FadeInGR: ; XREF: Pal_Neutral_FadeTo

moveq #0,d0

lea ($FFFFFB00).w,a0

lea ($FFFFFB80).w,a1

move.b ($FFFFF626).w,d0

adda.w d0,a0

adda.w d0,a1

move.b ($FFFFF627).w,d0

@loop:

bsr.s Pal_Neutral_AddColorGR

dbf d0,@loop

cmpi.b #1,($FFFFFE10).w

bne.s @skip

moveq #0,d0

lea ($FFFFFA80).w,a0

lea ($FFFFFA00).w,a1

move.b ($FFFFF626).w,d0

adda.w d0,a0

adda.w d0,a1

move.b ($FFFFF627).w,d0

@loop2:

bsr.s Pal_Neutral_AddColorGR

dbf d0,@loop2

@skip:

rts

Pal_Neutral_AddColorGR: ; XREF: Pal_Neutral_FadeIn

move.w (a1)+,d1 ; MJ: load green and red

move.b d1,d2 ; MJ: load red

lsr.b #$04,d1 ; MJ: get only green

andi.b #$0E,d2 ; MJ: get only red

move.w (a0),d3 ; MJ: load current colour in buffer

addi.b #2,d1 ; SI: don't ask, it works

cmp.b d1,d4 ; MJ: is it time for green to fade?

bhi @FCI_NoGreen ; MJ: if not, branch

addi.b #$20,d3 ; MJ: increase green

@FCI_NoGreen:

cmp.b d2,d4 ; MJ: is it time for red to fade?

bhi @FCI_NoRed ; MJ: if not, branch

addq.b #$02,d3 ; MJ: increase red

@FCI_NoRed:

move.w d3,(a0)+ ; MJ: save colour

rts ; MJ: return

Pal_Neutral_FadeInR: ; XREF: Pal_Neutral_FadeTo

moveq #0,d0

lea ($FFFFFB00).w,a0

lea ($FFFFFB80).w,a1

move.b ($FFFFF626).w,d0

adda.w d0,a0

adda.w d0,a1

move.b ($FFFFF627).w,d0

@loop:

bsr.s Pal_Neutral_AddColorR

dbf d0,@loop

cmpi.b #1,($FFFFFE10).w

bne.s @skip

moveq #0,d0

lea ($FFFFFA80).w,a0

lea ($FFFFFA00).w,a1

move.b ($FFFFF626).w,d0

adda.w d0,a0

adda.w d0,a1

move.b ($FFFFF627).w,d0

@loop2:

bsr.s Pal_Neutral_AddColorR

dbf d0,@loop2

@skip:

rts

Pal_Neutral_AddColorR: ; XREF: Pal_Neutral_FadeIn

move.w (a1)+,d1 ; MJ: load green and red

move.b d1,d2 ; MJ: load red

andi.b #$0E,d2 ; MJ: get only red

move.w (a0),d3 ; MJ: load current colour in buffer

addi.b #2,d2 ; SI: no questions please.

cmp.b d2,d4 ; MJ: is it time for red to fade?

bhi @FCI_NoRed ; MJ: if not, branch

addq.b #$02,d3 ; MJ: increase red

@FCI_NoRed:

move.w d3,(a0)+ ; MJ: save colour

rts ; MJ: return

The changes are a little dirty, but it works. I did it for experimental purpose, there are probably better ways to do it.

redhotsonic · Dec 28, 2011

A bug has appeared in the Sonic 2 Fade-in routine, although this only seems to happen on the Title screen.

(Don't worry, the selection menu is gone because I took it out myself)

When the title screen is in the middle of fading in, if you press start to go straight to the point, the palette goes wrong (or doesn't seem to finish loading). I tried the ROM you supplied us, MJ, and the bug exists in that too, so I know it's not any of my work interfering.

(The ROM you supplied in your first post)

Any solutions?

MarkeyJester · Dec 28, 2011

Gah, there is always something now isn't there, go to:

loc_135D6:
move.l (a1)+,(a2)+

dbf d6,loc_135D6

tst.b objoff_30(a0)

bne.s return_135E8

moveq #$19+$80,d0 ; title music

bsr.w JmpTo4_PlayMusic

And insert the instruction:

sf.b (Object_RAM+($100+$32)).w ; set fade counter to 00 (finish)

Just after the dbf instruction, this will set the palette fading object's fade counter to 0 and set the object to delete itself.

redhotsonic · Dec 28, 2011

MarkeyJester said: ↑

Gah, there is always something now isn't there...
Click to expand...

I'm sorry =(

It's fixed, cheers =P

Irixion · Dec 30, 2011

This sir, is the best thing on the planet. I love you. I really do. This has bugged me for I don't even know, and to see a fix, it makes me squirm with excitement.

Irixion · Jan 3, 2012

Sorry for the double post--but this works for the SVN disassembly as well, few changes though:

DelayProgram: is WaitForVint:

Delay_Time: is Vint_routine:

loc_13302: is ObjC9_Init:

NewRoutine: is ObjC9_Main:

The rest is the same. Make sure you do the very last step as it can bork things up if you forget! Thanks again Markey!

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How to improve the fade in and fade out progressions in Sonic 1 and 2

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How to improve the fade in and fade out progressions in Sonic 1 and 2

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