Project Sonic 1: Two-Eight

oh geez, I always somehow forget to post what I release at SonicRetro here too =$ (Also wasn't sure if the Q&A was infact the best place to post this, by all means staff, move if you feel it's necessary.)

 

Heh-heh. You have 256 posts! =P


Haha, this is interesting! I can see this opening the pathway for many new ideas of level editing!


But ask me this: Why is there 2 LZ3 projects? Just curious. =P

 

I'M MOVING THIS STRAIGHT TO THE TRASH!

 

Haha, oh boy, man how could I have not spotted that!

I'll answer you it insted of asking, basically in LZ act 3 there's a switch, when pressing that switch a chunk ID in layout ram is changed, this makes a slide/wall change or open up, and when going through the wall, the wall is retored, but because of the nature of Sonic 2's layout data being too big, it had to be read from rom insted of ram as it wouldn't fit in it's original space, and as you well know, altering the rom's values is prohibited. So there are two layouts, one with the wall intacted as a slide (the normal LZ 3), and one with the wall removed and replaced with an opened space (the LZ 3 (WALL)), which are read individually depending on whether the button/switch is pressed or not.

 

Nice one Markey Jester thanking you!!!

 

Doing it now, bare with me...


(Will edit this post when information is ready)


EDIT:


Ok found what's wrong, when porting the Rev effects, it ports not only the BG deformation but the draw code from the Rev version, and of course, this overwrites my modification of the 128x128 engine.


If you've ported the Rev effects to the Two-Eight engine, then you must follow these further steps to enable it to work correctly:

Code:

----------------------------------------------------

goto sub_6886:



change



		lea	($FFFFA440).w,a4



to



		movea.l	($FFFFA404).w,a4&#59; MJ: Load address of layout BG



----------------------------------------------------

goto LoadTilesAsYouMove:



change



		lea	($FFFFA440).w,a4



to



		movea.l	($FFFFA404).w,a4&#59; MJ: Load address of layout BG



and change



		lea	($FFFFA400).w,a4



to



		movea.l	($FFFFA400).w,a4&#59; MJ: Load address of layout



----------------------------------------------------

goto sub_70AC:  (Was sub_6B32: in normal S1)



change



		btst	#4,(a0)



to



		btst	#3,(a0)		&#59; MJ: checking bit 3 not 4 (Flip)



and change



		btst	#3,(a0)



to



		btst	#2,(a0)		&#59; MJ: checking bit 2 not 3 (Mirror)



----------------------------------------------------

goto loc_70E8: (Was loc_6B6E: in normal S1)



change



		btst	#3,(a0)



to



		btst	#2,(a0) 	&#59; MJ: checking bit 2 not 3 (Mirror)







----------------------------------------------------

goto loc_712C: (Was sub_6BD6: in normal S1)



remove



		lsr.w	#1,d3



change



		andi.w	#$380,d3



to



		andi.w	#$780,d3	&#59; MJ: get within 780 (Not 380) (E00 pixels (not 700)) in multiples of 80





and change



		lsr.w	#5,d0



to



		lsr.w	#4,d0		&#59; MJ: divide by 10 (Not 20)



under this command



		andi.w	#$7F,d0; ''



insert this



		lsl.w	#$01,d3		&#59; MJ: multiply by 2 (So it skips the BG)



remove these two



		beq.s	locret_7172

		subq.b	#1,d3



change



		andi.w	#$7F,d3; ''



to



		andi.w	#$FF,d3		&#59; MJ: keep within FF



under this command



		ror.w	#7,d3



insert this



		ror.w	#2,d3		&#59; MJ: ..plus an extra 2 (so it's within 80 bytes, not 200)



remove



		add.w	d4,d4



change these two



		andi.w	#$1E0,d4

		andi.w	#$1E,d5



to this



		andi.w	#$070,d4	&#59; MJ: keep Y pos within 80 pixels

		andi.w	#$0E,d5		&#59; MJ: keep X pos within 10



----------------------------------------------------

goto LoadTilesFromStart:



change



		lea	($FFFFA400).w,a4



to



		movea.l	($FFFFA400).w,a4&#59; MJ: Load address of layout



and change



		lea	($FFFFA440).w,a4



to



		movea.l	($FFFFA404).w,a4&#59; MJ: Load address of layout BG

You don't have to have the "; MJ:" comments in there, but it is suggested that you do, so you can at least remember where the changes were to be made, for the record I will provide a disassembly here of the Two-Eight engine with the rev effects, thanks for the bug report, much appreciated.