7 replies to this topic

[RetroX]

I'm trying to replace the oval in Sonic 1 Title Cards. I import it in SonMapEd and remake the mappings but I build and get this:


Is there anything wrong I'm doing or they it just can't be changed?

Edited by RetroX, 04 July 2012 - 06:37 PM.

[Irixion]

You sure that the mappings are in the right format?

[RetroX]

Yeah, I use SonMapEd to edit them, I haven't had any problems except with this.

[Mike B Berry]

Do you know where the mappings are located? If tyou change the art shape without changing the mappings, you'll load garbage.

[RetroX]

Yes, they're in the sonic1.asm file. I moved them to a separate file and saved the mappings in SonMapEd. It loads fine in there, but it won't load in the game.

[Mike B Berry]

Change the compression rate, did you save the file in Nemisis format, or uncompressed?

[MarkeyJester]

• The problem is not with the mappings and its format.
• The problem is not with the art and its compression.
• The problem is VRAM space.

I recognise the pattern on that square block anywhere, it is the pattern of plane map data. In Sonic games, they set the VDP Plane A space to VRAM address C000 - CFFF, the title card art gets decompressed to VRAM address B000 - BFFF, Sonic Team JUST managed the squeeze all of the letters, act numbers, and oval art, into that space and that is 80 tiles they got in.

I know for a fact that you have put in more art, you've put in more tiles (probably for more letters or for more art for that square sprite there), and that's where the problem lies, it is now over 80 tiles (bigger than 1000 bytes), the art will be decompressed to B000 right up to BFFF, and will continue over into C000 and beyond. The art is now in VRAM, but then, the draw code does what it is suppose to do; draw the map data to Plane A at VRAM address C000 - CFFF, this will overwrite the art that went into C000 and beyond, your square's art was obviously in that space, and thus has been overwritten by map data (as you can clearly see).

What you will need to do, is either:

• Reduce the number of tiles to 80 maximum.
• Set the title card art to decompress in another location, but one that isn't occupied, or isn't occupied "yet" and that you write the original art back when the title card is finished.
• Set the title card to move out the screen before the level is drawn and fades in.

B is probably the most difficult, A being the most common, and C being an interesting idea, but not preferred.

[RetroX]

• The problem is not with the mappings and its format.
• The problem is not with the art and its compression.
• The problem is VRAM space.

I recognise the pattern on that square block anywhere, it is the pattern of plane map data. In Sonic games, they set the VDP Plane A space to VRAM address C000 - CFFF, the title card art gets decompressed to VRAM address B000 - BFFF, Sonic Team JUST managed the squeeze all of the letters, act numbers, and oval art, into that space and that is 80 tiles they got in.

I know for a fact that you have put in more art, you've put in more tiles (probably for more letters or for more art for that square sprite there), and that's where the problem lies, it is now over 80 tiles (bigger than 1000 bytes), the art will be decompressed to B000 right up to BFFF, and will continue over into C000 and beyond. The art is now in VRAM, but then, the draw code does what it is suppose to do; draw the map data to Plane A at VRAM address C000 - CFFF, this will overwrite the art that went into C000 and beyond, your square's art was obviously in that space, and thus has been overwritten by map data (as you can clearly see).

What you will need to do, is either:

• Reduce the number of tiles to 80 maximum.
• Set the title card art to decompress in another location, but one that isn't occupied, or isn't occupied "yet" and that you write the original art back when the title card is finished.
• Set the title card to move out the screen before the level is drawn and fades in.

B is probably the most difficult, A being the most common, and C being an interesting idea, but not preferred.

Tried Option A and it worked! Thanks!